The present document is CONFIDENTIAL and it is property of AGIP It shall not be shown to third parties nor shall it be used for reasons different from those owing to which it was given
TITLE
COMPLETION PROCEDURES MANUAL
DISTRIBUTION LIST
Eni - Agip Division Italian Districts Eni - Agip Division Affiliated Companies
Eni - Agip Division Headquarter Drilling & Completion Units STAP Archive
Eni - Agip Division Headquarter Subsurface Geology Units Eni - Agip Division Headquarter Reservoir Units
Eni - Agip Division Headquarter Coordination Units for Italian Activities Eni - Agip Division Headquarter Coordination Units for Foreign Activities
NOTE: The present document is available in Eni Agip Intranet (http://wwwarpo.in.agip.it) and a CD-Rom version can also be distributed (requests will be addressed to STAP Dept. in Eni - Agip Division Headquarter)
Date of issue:
„ ƒ ‚ •
€ Issued by M. Bassanini C. Lanzetta A. Galletta
28/06/99 28/06/99 28/06/99
REVISIONS PREP'D CHK'D APPR'D
INDEX
1.
INTRODUCTION
9
1.1. PURPOSE OF THE MANUAL 9
1.2. IMPLEMENTATION 9
1.3. UPDATING, AMENDMENT, CONTROL & DEROGATION 9
2.
RESPONSIBILITIES
10
2.1. DRILLING COMPLETION AND WORKOVER MANAGER 10
2.2. WELL OPERATIONS SUPERINTENDENT 11
2.3. COMPLETION AND WORKOVER ENGINEER 11
2.4. FLUIDS SPECIALIST 12
2.5. OFFSHORE INSTALLATION MANAGER (OIM) 13
2.6. WELL OPERATIONS SUPERVISOR 13
2.7. PRODUCTION SUPERVISOR 14
3.
DOCUMENTATION
15
3.1. PRELIMINARY INFORMATION 15
3.2. WELLSITE REPORTS 15
3.3. FEED BACK REPORTS 15
3.4. OTHER REPORTS 16
3.5. PERMIT PROCEDURES 16
3.5.1. Guidance For Permits 16
3.6. WELL HANDOVER PROCEDURES 17
3.6.1. Well Handover Certificate 17
3.6.2. Well Intervention Handover Certificate 18
4.
HOLE PREPARATIONS
23
4.1. PRELIMINARY CHECKS 23
4.2. WELL CLEAN UP PROCEDURES 23
4.3. BOP STACK CONFIGURATION AND TESTING 24
4.5. OIL BASED MUD DISPLACEMENT 24
4.5.1. Displacement Objectives 24
4.5.2. Logistical Considerations 25
4.5.3. Drilling Fluid Preparation 25
4.5.4. Surface Equipment Preparation 26
4.5.5. Well Clean Up Pill Sequence 26
4.5.6. Pill Functions 27
4.5.7. Pit Requirements 27
4.5.8. Pumping Sequence 27
4.6. DISPLACEMENT OF WATER BASED MUDS 28
4.6.1. Drilling Fluid Preparation 28
4.6.2. Surface Equipment Preparation 28
4.6.3. Well Clean Up Pill Sequence 28
4.6.4. Pill Functions 29
4.6.5. Pit Requirements 29
4.6.6. Pumping Sequence 29
4.7. COMPLETION AND WORKOVER FLUIDS 29
4.7.1. Brines Transportation 29
4.7.2. Completion And Workover Fluid Quality 30
4.8. FILTRATION SYSTEMS 30
4.8.1. Fluid Cleanliness 30
4.9. LOST CIRCULATION 31
4.9.1. Viscous Pills 31
4.9.2. Sized Salt Pills 31
4.9.3. Calcium Carbonate Pills 32
4.10. CASING GAUGE CONTROL 33
5.
PERFORATING PROCEDURES
34
5.1. GENERAL 34
5.2. METHODS OF PERFORATING 35
5.3. GENERAL SAFETY PROCEDURES 35
5.4. WIRELINE CONVEYED PERFORATING 37
5.4.1. Casing Guns Run In Overbalance 37
5.4.2. Perforating Procedures For Through Tubing Conveyed Guns 38
5.5. SAFE SYSTEM 39
5.5.1. SAFE System Description (Slapper Activated Firing Explosives) 40
5.6. TCP PROCEDURES 40
5.6.1. Well Preparation for TCP Operations 41
5.6.2. Ancillary TCP Equipment 41
5.6.3. Firing Systems for TCP Operations 43
5.6.4. General TCP Safety Precautions and Running Procedures 44
5.6.5. Firing Procedure for Tubing Installed Pressure Activated Head 45
5.6.6. Firing Procedure for Wireline Installed Pressure Activated Head 45
5.6.7. Firing Procedure for Mechanical Impact Activated Head 45
5.6.8. Firing Procedure for Electrically Activated TCP Guns 46
5.6.9. Procedure For TCP Anchor Running 47
5.7. MISFIRE PROCEDURES 51
5.7.1. Mechanical Firing Head 51
5.7.2. Hydraulic Firing Head 52
5.7.3. Fixed Hydraulic Firing Head 53
5.7.4. Retrievable Hydraulic Firing Head 53
5.8. COILED TUBING PERFORATING 53
6.
GRAVEL PACKING PROCEDURES
54
6.1. GRAVEL PLACEMENT OBJECTIVES 54
6.2. SCREEN SIZE 54
6.3. GRAVEL CALCULATIONS 55
6.3.1. Sand Volume Required 55
6.3.2. Carrier Fluid Volume 56
6.4. COMMON GRAVEL PACK PROCEDURES 56
6.5. OPEN HOLE GRAVEL PACK PROCEDURE 57
6.6. CASED HOLE GRAVEL PACK PROCEDURE 59
7.
PACKER INSTALLATION
64
7.1. HOLE PREPARATION 64
7.2. WIRELINE PACKER SETTING PROCEDURE 64
7.2.1. Running Procedure 65
7.3. TUBING INSTALLED PACKER SETTING PROCEDURE 66
7.3.1. Workstring Running Procedure 66
7.3.2. Completion String Running Procedure 67
8.
COMPLETION INSTALLATION
68
8.1. CARBON STEEL AND PLASTIC COATED TUBING 68
8.2. CHROME TUBULARS 68
8.2.1. Transportation 68
8.2.2. Transport From The Mill 69
8.2.3. Road Transport 69
8.2.4. Marine Transport 69
8.2.5. Handling At The Wellsite 69
8.2.6. Thread Compounds 71
8.2.7. Running Chrome Tubulars 72
8.2.8. Retrieving Chrome Tubulars 73
8.3. EQUIPMENT PRE-INSTALLATION PROCEDURES 74
8.3.1. Material Requisition Lists 74
8.3.2. Completion Sub Assemblies 74
8.3.3. Tubing Hanger 75
8.3.4. Landing Joint 75
8.3.5. Control Line 75
8.3.6. Xmas Tree 75
8.4. COMPLETION ASSEMBLIES 76
8.4.1. Workshop Make-up and Test Procedures 76
8.4.2. Sub-Surface Safety Valves 76
8.4.3. Wireline Nipple Assemblies 77
8.4.4. Side Pocket Mandrels 77
8.5. COMPLETION RUNNING PROCEDURES 78
8.5.1. General 78
8.5.2. Running Procedure 79
8.5.3. TRSCSSV Installation Procedure 80
8.5.4. WRSCSSV Installation Procedure 81
8.6. XMAS TREE INSTALLATION 82
8.6.1. Installation Procedures 82
8.7. POST COMPLETION TEST PROCEDURES 83
8.7.1. SCSSV Test Procedure 83
8.7.2. Xmas Tree Valve Test Procedure 83
9.
GAS LIFT INSTALLATION
85
9.1. MANDREL INSTALLATION 85
9.1.1. SPM Installation Procedure 85
9.1.2. Gas Lift Valve Installation Procedure 87
9.2. UNLOADING PROCEDURE 88
9.3. TROUBLESHOOTING 88
10. DOWNHOLE PUMP INSTALLATION
89
10.1. ELECTRICAL SUBMERSIBLE PUMPS 89
10.1.1. Handling 89 10.1.2. Installation 89 10.1.3. Pulling Procedure 93 10.1.4. Troubleshooting 93 10.2. ROD PUMPS 96 10.2.1. Completion Installation 96
10.2.2. Tubing String Installation 96
10.2.3. Rod Installation 98
10.3. HYDRAULIC PUMPS 98
10.3.1. Jet Pump 99
10.3.2. Turbine Pump 101
11. SUBSEA COMPLETIONS
102
11.1. SUBSEA EQUIPMENT PRE-DEPLOYMENT TESTING 103
11.1.1. Guidewire Establishment Tool 103
11.1.2. Guidewire Latchess 103
11.1.3. Diverless Guideposts 103
11.1.4. Casing Hanger Elevation Test Tool 104
11.1.5. Tubing Hanger System 104
11.1.6. Tubing Hanger Running/Orientation Tools 106
11.1.7. Tubing Hanger Verification Tool 109
11.1.8. Tubing Hanger Isolation Plugs 110
11.1.9. Subsea Tree And Workover Equipment 110
11.1.10. Install the LRP/TRT onto the XT 115
11.1.11. Production Riser 117
11.1.12. Surface Xmas Tree 118
11.2. DEPLOYMENT PROCEDURES 118
11.2.1. Running The Completion And Tubing Hanger 118
11.2.2. Pull The Drilling BOPs 120
11.3. WORKOVER AND PRODUCTION CONTROLS SYSTEM PRE-DEPLOYMENT TESTING 120
11.3.1. Workover Controls Equipment 120
11.3.2. Production Controls Equipment 120
11.3.3. WOCS Pre-Deployment Testing 121
11.3.4. Production Controls Pre-Deployment Testing 124
11.3.5. Function Test using SEM B 128
11.3.6. Pressure Test Tree Valves 131
11.4. RUNNING THE SUBSEA XMAS TREE 136
11.4.1. Unplugging The Well 136
11.4.2. Perforating And Well clean-Up 137
11.5. PULLING THE LRP 137
11.5.1. Disconnect The LRP And Tree Running Tool 137
11.6. DEPLOYMENT OF THE TREE CAP 138
11.7. DEPLOYMENT AFTER COMMISSIONING ACTIVITIES 138
12. WELL UNLOADING
139
12.1. UNLOADING BY CIRCULATION 139
12.2. UNLOADING BY BULLHEADING 141
12.3. UNLOADING BY COILED TUBING 141
13. COILED TUBING OPERATIONS
142
13.1.1. PREPARATION 142
13.2. SAFETY CONSIDERATIONS 142
13.2.1. Tubing 143
13.2.2. Risers and BOPs 143
13.2.3. H2S Considerations 144
13.4. RIG UP PROCEDURES 145
13.4.1. Equipment Preparation and Siting 145
13.4.2. Coiled Tubing Rig-Up 145
13.4.3. Pressure Testing 146 13.4.4. Treating Lines 148 13.4.5. Injector Frame 148 13.4.6. Rigging Down 148 13.5. RUNNING PROCEDURES 149 13.6. OPERATING PROCEDURES 150 13.6.1. Gas Lifting 150 13.6.2. Well Treatment 151 13.6.3. Sand Cleanout 153
14. NITROGEN PROCEDURES
155
14.1. PREPARATION 155 14.2. SAFETY CONSIDERATIONS 155 14.3. NITROGEN HANDLING 156 14.3.1. Safety Equipment 15614.3.2. Safety Data Sheets 157
14.3.3. Pressurised Lines 157
14.4. RIG-UP PROCEDURES 157
14.4.1. Equipment Preparation and Siting 157
14.4.2. Equipment Rig-up 157
14.4.3. Pressure Testing 158
14.4.4. Treating Lines 158
14.4.5. Rigging Down 158
14.5. NITROGEN TREATMENT PROCEDURES 159
14.5.1. Pressures 159
14.5.2. Pump Rates 159
14.5.3. Coiled Tubing Gas Lift 159
14.5.4. Nitrogen Cushion - Tubing Conveyed Perforation 160
14.5.5. Nitrified Treatment 161
14.6. NITROGEN TECHNICAL INFORMATION 161
14.7. EMERGENCY PROCEDURES (During Nitrogen Operations) 162
14.7.1. Production Shutdown 162
14.7.2. General Platform Alarm 162
14.7.3. Prepare to Abandon Platform 162
14.7.4. Liquid Nitrogen Spill 163
14.7.5. Injury to Personnel 163
15. STIMULATION PROCEDURES
164
15.1. INTRODUCTION 164 15.2. SAFETY CONSIDERATIONS 164 15.2.1. Chemical Handling 165 15.2.2. Pressure 166 15.3. PERMIT REQUIREMENTS 167 15.4. RIG-UP PROCEDURES 16715.4.1. Equipment Preparation and Siting 167
15.4.3. Pressure Testing 168 15.4.4. Treating Lines 169 15.4.5. Rigging Down 169 15.5. TREATMENT PROCEDURES 169 15.5.1. Matrix Acidising 170 15.5.2. Fracture Acidising 170 15.5.3. Acid Wash 170 15.5.4. Scale Dissolver 170 15.5.5. Bullhead 171 15.5.6. Coiled Tubing 171
15.5.7. Asphaltene and Wax/Dissolvers 171
15.6. STIMULATION TECHNICAL INFORMATION 171
15.6.1. Factors Affecting Acid Reaction 172
15.6.2. Acid Properties 174
15.7. ACID ADDITIVES 175
APPENDIX A - REPORT FORMS
177
A.1. Initial Activity Report (ARPO 01) 177
A.2. Daily Report (ARPO 02) 178
A.3. Cementing Job Report (ARPO 04B) 179
A.4. Waste Report (ARPO 6) 180
A.5. Perforating Report (ARPO 07) 181
A.6. Gravel Pack Report (ARPO 08) 182
A.7. Matrix Stimulation Report (ARPO 09) 183
A.8. Well Problem Report (ARPO 13) 184
A.9. Malfunction & Failure Report(FB-1) 185
A.10. Contractor Evaluation (FB-2) 186
APPENDIX B - ABBREVIATIONS
187
1.
INTRODUCTION
1.1. PURPOSE OF THE MANUAL
The purpose of the Completions Procedures Manual is to guide technicians and engineers, involved in Eni-Agip’s Drilling & Completion worldwide activities, through the Procedures and the Technical Specifications for general completion operations which are part of the Corporate Standards.
Such Corporate Standards define the requirements, methodologies and rules that enable to operate uniformly and in compliance with the Corporate Company Principles. This, however, still enables each individual Affiliated Company the capability to operate according to local laws or particular environmental situations.
The final aim is to improve performance and efficiency in terms of safety, quality and costs, while providing all personnel involved in Drilling & Completion activities with common guidelines in all areas worldwide where Eni-Agip operates.
It is intended to guide users towards using procedures which have been found to provide the most efficient and cost effective operations.
1.2. IMPLEMENTATION
The policies included in this manual apply to all Eni-Agip Division and Affiliates operations. All supervisory and technical personnel engaged in Eni-Agip’s completion and workover operations are expected to make themselves familiar with these and comply with the policies and procedures specified and contained in this manual.
1.3. UPDATING, AMENDMENT, CONTROL & DEROGATION
This is a ‘live’ controlled document and, as such, it will only be amended and improved by the Corporate Company, in accordance with the development of Eni-Agip Division and Affiliates operational experience. Accordingly, it will be the responsibility of everyone concerned in the use and application of this manual to review the policies and related procedures on an ongoing basis.
Locally dictated derogations from the manual shall be approved solely in writing by the Manager of the local Drilling and Completion Department (D&C Dept.) after the District/Affiliate Manager and the Corporate Drilling & Completion Standards Department in Eni-Agip Division Head Office have been advised in writing.
The Corporate Drilling & Completion Standards Department will consider such approved derogations for future amendments and improvements of the manual, when the updating of the document will be advisable.
2.
RESPONSIBILITIES
The following job descriptions outline the individual responsibilities and duties of specific key personnel involved in Eni-Agip Completion operations. These are generalised summary of the individual responsibilities and duties which are specific to completion operations and as such augment, but do not supersede their current employer’s approved job descriptions. 2.1. DRILLING COMPLETION AND WORKOVER MANAGER
The Drilling/Completions and Workover Manager reports directly to the District Manager and supervises the Well Operations Superintendent, Completions and Workover Superintendent, Drilling Engineering/Completions and Workover Engineering.
His duties include the following:
• Ensuring the definition of scope of work and requisitioning of drilling and completion/workover contracts are correctly processed by the contracts department and approved first by the District Manager, in order to comply with time schedule, quality and technical conditions as defined in the programme.
• Ensuring the pre-qualification and technical tender evaluation phases comply with company policies and procedures and to provide the Contracts department with all technical details necessary for a thorough commercial evaluation.
• Approving the completions programmes, ensuring they fully meet the prognosis target, pursuing the best results in terms of safety, time schedule and cost effectiveness.
• Managing day-to-day completions operations, co-ordinating the activities of contractors and units/positions involved, in order to guarantee that operations meet the company policies and standards.
• Controlling operational costs and provides the technical approval for invoice payment. Verifies the consistency of the expenditure with AFEs and with the administration validity of the contracts.
• Liaising, timely and effectively, with the regulatory bodies in order to obtain consent for well related operations.
• Instituting, monitoring and reviewing completions safety policies within the Safety Management System, in order to maximise effectiveness and safety of the operations.
2.2. WELL OPERATIONS SUPERINTENDENT
The Well Operations Superintendent reports to the Drilling, Completion and Workover Manager and supervises rig site supervisors.
His duties include the following:
• Ensuring operational progress follows the approved well programme and provides technical advice to the rig site on a daily basis, as required.
• Ensuring the correct scheduling of completion materials and services, provides a timely supply to the rigs while optimising the cost of transport, materials and manpower within established programmes and budgets.
• Administering service contracts, providing the technical control of contractor performance giving the first authorisation to the payment of invoices and ensuring the control of current total expenditure on each contract.
• Ensuring that operations comply with current legislation and company standards.
• Preparing scopes of work and technical specification for services to be tendered and review those for services and equipment.
• Providing technical advice during pre-qualification and tender evaluation phases, in order to ensure that the selection of contractors and suppliers fully meet technical targets and company standards.
• Providing timely and accurate requisitions for all services and materials relevant to well operations.
• Ensuring, in liaison with AQS, the correct interface of the Contractor’s procedures are to Eni-Agip’s policies and procedures.
• Ensuring simultaneous completion and production procedures are reviewed. 2.3. COMPLETION AND WORKOVER ENGINEER
Reports to the Drilling, Completion and Workover Manager. His duties include the following:
• Preparing and reviewing technical specifications and scopes of work for equipment to be tendered and services for completion, workover, wireline and well testing operations.
• Co-operating with the Well Operations Superintendent for providing advice during pre-qualification and tender evaluation phases, in order to ensure that the selection of contractors and suppliers fully meet technical targets and company standards.
• Supplying well cost estimates for future operations budgets and current operations AFEs, ensuring the reliability of the data provided.
• Contributing, in liaison with the Petroleum Engineer and with the Reservoir Engineers, to the planning of development projects, providing technical input to the project teams, in order to optimise cost and effectiveness of the project.
• Monitoring, in liaison with the Petroleum Engineer and with the Reservoir Engineers, the performance of wells and reservoirs, in order to provide technical expertise and advice for identifying and initiating enhancements to well potential.
• Appraising new completion, workover, wireline and well testing technology and products to determine their application to Eni-Agip’s completion operations, in order to improve time cost performance and safety conditions.
• Preparing and reviewing completion, workover, wireline and well testing programmes and final reports and to ensure the production of adequate feedback about the operations as per the Safety Management System corporate requirements.
• Reviewing daily the operations versus the programme, providing a thorough investigation of operational times.
• Providing engineering assistance to the Well Operations Superintendent in the follow up of operations.
• Providing reports and analysis on the operated and non-operated activities for presentation, meetings and reporting to the management and to ensure the operational feedback reporting system is consistent with Eni-Agip and corporate requirements.
• Assisting his supervisor in contacts with partners and regulatory bodies providing the necessary documentation and reports.
• Providing the monthly updates on the variance between actual and estimated expenditures for each job centre for each class of cost, also to liaise with the Completion/Workover Superintendent, in order to update the expenditure on each contract.
• Ensuring the production and review of the Completions Procedure Manual in order to comply with company policies and the current legislation.
2.4. FLUIDS SPECIALIST
Reports to the Drilling, Completions and Workover Manager for routine operational matters. His duties include the following:
• Preparing technical specifications for tenders.
• Advising on pre-qualifications and tender evaluations exercises.
• Preparing programmes ensuring the compliance with regulatory requirements.
• Ensuring the compilation of final fluids reports and the feedback documents relevant to the activities under his scope of work.
• Maintaining up to date knowledge of the technical and regulatory evolution’s for the activities under his scope of work.
• Liaising with logistics department for ensuring the provision of services, transportation and materials to well site.
2.5. OFFSHORE INSTALLATION MANAGER (OIM) If applicable, his duties include the following:
• Reporting directly to Asset Operations Manager.
• Co-ordinating and supervising all operations on the installation. The senior representatives for each discipline are responsible for the activities of their own discipline and must keep the OIM informed on their own respective operations. The Production Supervisor will keep the OIM informed on the status of production operations.
• Authorise all work permits in accordance with the Permit to Work System, and will ensure countersignature by the Well Operations Supervisor, or other Discipline Heads.
• For completion operations, he will delegate responsibility to the Well Operations Supervisor or another Company Representative (e.g. Production Supervisor) as dictated by asset ownership or control at the time of the ongoing operations.
• Is responsible for the actions to be followed under the various installation operating modes. The OIM will require advice from the Well Operations/Production Supervisor or other Discipline Heads, e.g. Maintenance Supervisor, etc.
2.6. WELL OPERATIONS SUPERVISOR
Represents Eni-Agip’s interests on the installation with respect to the Drilling Contractor and Service Companies.
The Senior Well Operations Supervisor is directly responsible for the drilling and completion equipment and all operations conducted during the drilling completion and workover phase. His duties include the following:
• Ensuring all Company policies relating to drilling and completing operations and emergency situations are adhered to at all times for the safety of personnel, rig equipment, well stability and control.
• Directing the Drilling Contractor and Service Company representatives in the operations to be performed and supervises the conduct of the operations.
• Ensuring all operations, detailed in the Drilling and Completion Programme, are performed efficiently and safely using the procedures detailed in the programme and/or Completion Procedures Manual.
• Responsibility for the Hot Permit System when ‘hot work’ is being conducted in the drilling module.
• Requisitioning the equipment and materials required to complete the operations. He will requisition the materials when appropriate and liaise with the Completion and Workover Superintendent to ensure arrival at the rig-site in ample time to allow inspection and preparation prior to use.
• Ensuring all tools are suitable for purpose, inspected and dressed prior to running in the well.
• Introducing changes to the Drilling and Completion Programme but only in an emergency or when operating conditions do not allow for communication with the Drilling and completion Workover Department.
• Ensuring all reports required, are accurate in content and are submitted as required. Reporting requirements are outlined in section 3.
• Liaising with the OIM, Company Production Supervisor, and other operational Heads on a daily basis to discuss operational considerations and the possible impact on the other operations.
• Supervising and directs well control operations in accordance with the Eni-Agip Well Control Manual.
• Liaising with the OIM to give advice on what actions to take, if any of the Platform Operating Modes are associated with the drilling operation, or arise from operations in the drilling module.
• On completion of the programme, i.e. Xmas tree is secured with all operations completed, officially handing over the well to the Production Department (Production Supervisor). Both parties must sign the relevant well handover document.
• Co-ordinating all completion activities including wireline and/or coil tubing/nitrogen, acid stimulation, perforating as well as all preliminary pressure testing of equipment.
• Ensuring the safe and correct installation of all tubulars and completion sub-assembly components, i.e. in the correct order and proper depth as per the completion programme.
2.7. PRODUCTION SUPERVISOR
Reports to the Company Production Superintendent (Office). His duties include the following:
• Representing Eni-Agip’s interests on the platform with respect to production, and when dealing with service companies involved with operations during the production phase.
• Ensuring that, during heavy lift operations such as handling Xmas trees etc., neighbouring wells are closed-in to minimise risk to wellheads, flowlines, production equipment, the platform and personnel.
• Informing the Well Operations Supervisor, OIM and other Discipline Heads on the status of the production operations and the possible impact on other operations in general.
• Prior to a workover being carried out, handing the well over to Drilling/Completion (Well Operations Supervisor) stating the exact condition of the well. Both parties must sign the handover document.
3.
DOCUMENTATION
This section outlines the documentation necessary for conducting efficient completion operations and reporting of these operations.
3.1. PRELIMINARY INFORMATION
Before performing any well operations the following documentation and information must be available:
A detailed programme including:
• Name of Field
• Name of Well
• Well Code
• Well Co-ordinates (wellhead and bottom hole)
• Cost Centre Number
• RKB Elevation
• Completion String Schematic (completion components ID, length, tubing size/weight, depths, etc.)
• Intervals to be perforated
• Specifications of Completion Equipment. 3.2. WELLSITE REPORTS
To schedule future operational programmes, all operations must be properly documented and kept on file to maintain the history of operations performed on any well.
The operations performed during rig operations (completion string gauging, packer setting, etc.) will be reported in the Daily Well Report. This and other service reports for gravel packing, stimulation and other well operations are shown in Appendix A.
It is responsibility of the Well Operations Supervisor to compile and forward the reports (indicated below) to the Well Operations Superintendent. The Superintendent will then check and approve the reports before distribution and filing.
3.3. FEED BACK REPORTS
The following reports are compiled at the end of the operations: a) FB-01 Report on Equipment Damage and Malfunctions b) FB-02 Service Company Evaluation Report
3.4. OTHER REPORTS
The Eni-Agip Representative must sign the Service Reports of the Service Companies which must include the following information :
• Name of Well
• Name of Field
• Order Number
• Date
• Personnel and equipment used
• Description of the operations conducted
• Starting and completion dates for service company charges. 3.5. PERMIT PROCEDURES
No work can be performed without a valid permit to work. All requirements as laid out in the Company Permit to Work Procedures must be adhered to at all times. Although the operation of a permit system is the responsibility of the installation manager, safe operating practice is compulsory and the responsibility of all personnel involved in completion operations.
The Permit to Work System is drawn up in accordance with standard Oil Industry practices in order to improve offshore safety during all phases of operations. All personnel involved in completion operations should clearly understand the particular installation Permit to Work System, and be aware that the issuing of a permit in itself cannot guarantee that any job is safe.
As each installation will have its own distinct PTW system according to the type of installation, location and country, it is not possible to describe a generic system in this manual.
3.5.1. Guidance For Permits
Examples of activities which require permits to work (hot and cold) must listed in Permit to Work Procedures. Those activities not normally requiring a work permit must also be listed. It should be stressed however, that some of these activities will be brought within the Permit to Work System from time to time as circumstances dictate. It remains the responsibility of the Area Authority to ensure that the correct permits and certificates are in force during all phases of operations. The responsibilities of those individuals involved in the administration of the Permit to Work System should be clearly defined in the Permit to Work Procedures.
3.6. WELL HANDOVER PROCEDURES
Operations performed on a well will be the responsibility of a designated ‘Area Authority’. The Well Operations Supervisor will be the responsible person for drilling, completion, workover, wireline, coiled tubing, and stimulation operations. The Production Supervisor will be the responsible person for production operations.
The Production Supervisor will be the competent person during Xmas tree repairs or change-outs even when these works are performed by maintenance personnel with the assistance of a vendor service engineer.
The action of transferring the responsibility for a well between area authority will be documented and recorded on the ‘Well Handover Certificate’ or ‘Well Intervention Handover Certificate’. All preparatory work and the status of the well when handed over will be described in the appropriate Handover Certificate. A typical example of a Handover Certificate (Eni-Agip) with the information to be recorded is shown in figure 3.a and figure 3.b.
The completed Handover Certificate must be signed by the responsible persons handing over and receiving the well. It must be placed in the appropriate well file. Copies are to be faxed to the Well Operations Superintendent when a new well is handed over.
There are two types of Well Handover Certificates:
• Well Handover Certificate
• Well Intervention Handover Certificate. 3.6.1. Well Handover Certificate
The well Handover Certificate is to be used for all new wells and wells worked over (Drilling, Completion through to Production).
New Wells
Following the successful drilling and completion of a new well, the Operations department will complete a Well Handover Certificate. Prior to handover of the well to Production, the well status should be outlined as below:
• Xmas tree installed and fully pressure tested
• Swab cap installed and pressure tested
• SCSSV installed and fully tested
• All wireline plugs removed
• All obstructions removed, the wellhead and Xmas tree areas are clean and tidy
• Written procedure for the venting of annular pressure, if necessary.
Once the Production Supervisor is satisfied that the status of the well is satisfactory, he will sign the handover certificate in acceptance of the well. Examples of Well Handover Certificates are shown in figure 3.a and figure 3.b.
Workover Wells
Workover is defined in this instance as any well operation which involves the change-out of any completion component from the wireline re-entry guide to the Xmas tree.
Following the successful completion of a well which has been worked over, Well Operations department will complete a Well Handover Certificate. Prior to handover of the well to Production the well status should be outlined as below:
• Xmas tree installed and fully pressure tested
• Swab cap installed and pressure tested
• SCSSV installed and fully tested
• All wireline plugs removed
• All obstructions removed, the wellhead and Xmas tree areas are clean and tidy
• Written procedure for the venting of annular pressure, if necessary
Once the Production Supervisor is satisfied that the status of the well is satisfactory, he will sign the handover certificate in acceptance of the well.
3.6.2. Well Intervention Handover Certificate
The Well Intervention Handover Certificate is to be used for all interventions such as:
• Mechanical wireline operations
• Electric wireline operations
• Coiled tubing operations
• Snubbing operations (except where these constitute a ‘Workover’)
• Well stimulation operations.
Prior to handover of the well by Production to Well Services the Production Supervisor will complete a Well Intervention Handover Certificate and ensure the following procedures are completed:
1) All chemical injection lines on the flowline will be bled down and isolated.
2) The test and production, or injection, header isolating valves will be closed, and the flowline bled down to the closed drains and isolated when no liquid or gas is observed at the sample point. Blind flanges should be installed on the flowline termination. 3) The SCSSV control lines will be bled off ready to be disconnected. All lines from the
wellhead to the remote control panel will also be bled down.
4) If the tree is to be removed all instrumentation and control lines will be removed from the well.
5) All obstructions (e.g. scaffolding) all instrumentation and control lines will be removed. Once the Well Operations Supervisor is satisfied that the status of the well is satisfactory he will sign the Well Intervention Handover Certificate in acceptance of the well.
Following an intervention operation the Well Operations Supervisor will complete a Well Handover Certificate. Prior to handover of the well to Production, the well status should be outlined as below:
• Xmas tree installed and fully pressure tested.
• Swab cap installed and pressure tested.
• SCSSV installed and fully tested.
• All wireline plugs removed.
• All obstructions removed, the wellhead and Xmas tree areas are clean and tidy
• Written procedure for the venting of annular pressure, if necessary.
Once the Production Supervisor is satisfied that the status of the well is satisfactory, he will sign the Well Intervention Handover Certificate in acceptance of the well. An example of a Well Intervention Handover Certificate is shown in figure 3.c.
WELL HANDOVER CERTIFICATE
Well No: Date:
WELL DETAILS
Well Type: Producer/Injector/Gas Lift/__________________ PERFORATION DETAILS
ft MD/TVD ft MD/TVD
ft MD/TVD ft MD/TVD
ft MD/TVD ft MD/TVD
ft MD/TVD ft MD/TVD
Last Hold Up Depth: ft MD/TVD Date: Details of Junk:
Bridge Plug(s) ft MD/TVD TUBING DETAILS
Tubing
Size TubingGrade Condition or InjectingProducing TubingFluid Shut in WellheadPressure Date last on line
SAFETY VALVE DETAILS String Valve Open or
Closed Type Date LastTested Remarks
TUBING PLUG DETAILS String Plug
Type Depth TestedDate PressureTest Remarks
XMAS TREE DETAILS
Type: Pressure Rating:
psi
Tested to: Date Tested:
S/N of Block
Valve S/N Status Valve S/N Status
Swab Valve Manual Master
Hydraulic Master Hydraulic Wing
Manual Wing
(prod) Manual Wing(kill)
ANNULUS DETAILS
Annulus Pressure Fluid Status
e.g. Shut-in, Open, Venting, Seized Valves, etc.
Flowline Status: ADJACENT WELLS
Well No SCSSV Plugs Xmas
Tree Flowline
Status Tested Date Status Tested Date Depth Status Status
All Production/Operations equipment removed from area ? Y/N Remarks:
Changes From Programme Status:
Authorised By: Production/Operations Accepted By: Production/Operations
WELL INTERVENTION HANDOVER CERTIFICATE
Well No: Date:
Well Details : Producer/Injector : Single/Dual String : Permit Order No:
Description of Operation
BARRIERS REQUIRED BARRIERS REMOVED (SITE TIDY) SAFETY VALVE DETAILS
Handover Handback
String Status** Remarks** String Status** Remarks**
XMAS TREE DETAILS
Handover Handback
Valve Status
** Valve Status** Valve Status** Valve Status**
Prod Side Ann Side Prod Side Ann Side
Flow Wing Man Wing Flow Wing Man Wing
Choke Choke
Swab Valve Man Master Swab Valve Man Master
Hyd. Master Hyd Master Hyd. Master Hyd Master
Man. Master Man. Master
**OPEN/CLOSED, HYDRAULICS ISOLATED/DE-ISOLATED
ANNULUS DETAILS
Handover Handback
Annulus Pressure Fluid Status Annulus Pressure Fluid Status
Above P-Off Above P-Off
DOWNHOLE TUBING DETAILS
(e.g.: equipment set in nipple/component failures/fish in hole etc.)
Handover Handback
String Detail Depth Remarks String Detail Depth Remarks
Authorised By : Production/Well Services Authorised By : Production/Well Services Accepted By : Production/Well Services Accepted By : Production/Well Services
Time/Date : Time/Date :
4.
HOLE PREPARATIONS
The procedures in this section described the preparation of the hole and surface facilities for completion operations.
4.1. PRELIMINARY CHECKS
Sometime prior to completions operations, the following equipment should be checked to confirm availability and to specification for the forthcoming operations:
a) Workstring of the appropriate grade and size in sufficient length, taking into consideration if a tapered string is to be used.
b) BOPs are equipped with the correct size-pipe/variable (single or dual) rams to cover all the range of tubulars to be run in the hole.
c) Wear bushing for the tubing hanger spool, equipped with the running/pulling tool.
d) BOP test tool with the appropriate running and pulling tools and a sufficient quantity of seals.
e) All relevant handling tools for the workstring including elevators and slips verifying they are in good working condition.
f) Safety valves have been tested and are available already made up with the crossovers to the workstring and Weco connections to suit the kill line connection.
g) The rig has been equipped with the safety and emergency systems as per the contract and that they are fully operational.
h) Rig pumps are equipped with the appropriate liner sizes and that they have been tested.
i) Mud logging or monitoring system is installed and operational. 4.2. WELL CLEAN UP PROCEDURES
After the production casing, or liner, has been cemented in place, a bit and scraper assembly will be run. The purpose of this trip is to clean out any excess cement within the casing, and particularly to remove any cement that may be on the casing wall at the packer setting depth.
A suitably sized bit, or junk mill, and tandem scraper assembly will be run to clean out the casing or liner of any excess cement, and to scrape the intended perforated interval(s). The packer setting depth will also be scraped during this operation to ensure it will have a good setting area. Precise details of packer setting depths, perforation intervals and maximum clean out depth will be given in the well operations/drilling programme.
Note: The casing and liner string may be pressure tested at this point, and an inflow test on liner laps and shoe tracks performed.
For detailed procedures on how to perform inflow and pressure tests refer to the Drilling Procedures Manual.
If a liner lap is a found to be leaking it may be necessary to run a tie back packer into the top of the liner lap, otherwise it will be necessary to perform a remedial cement squeeze. The decision on which method to adopt will depend on the location and nature of the leak.
4.3. BOP STACK CONFIGURATION AND TESTING
a) The BOP stack configuration including ram sizes should be in accordance with the Well Programme.
b) All components must be fully certified and will be tested with water in accordance to company policy or local regulations, whichever is the most stringent. testing on a new completion will be accomplished by using either the test tool or the tubing hanger with the tubing hanger plug installed.
c) Duration of pressure tests will be 10min with a maximum allowable pressure drop of 100psi unless local legislation dictates otherwise.
d) If it is necessary to use a cup tester for testing the BOP stack, the test pressure must not exceed the safe working pressure of the casing.
e) The test schedule will be according to local regulations but will be at least every 14 days. If operational constraints prevent a scheduled pressure test, a dispensation will be requested and issued by the authorities and held on file. f) The function and pressure tests will be recorded on a chart recorder and the
charts held in file.
g) In workover operations prior to pulling the tubing, the BOP stack will be tested against plugs set in the tubing hanger.
h) Function test at the same time as the BOP stack the surface control panel, accumulator package and remote control panel. if using a subsea BOP stack, check from both blue and yellow pods.
4.4. WELL CONTROL
Well control procedures will be in accordance with the Company Well Control Policy Manual, a copy of which must be kept available on the rig.
4.5. OIL BASED MUD DISPLACEMENT
Prior to displacing the well to the completion brine, it will be necessary to displace the drilling mud from the well. In order to ensure that circulation time, rig time and filtration time are kept to an absolute minimum, it is essential that the well clean up is as efficient (and economical) as possible in removing the mud, solids and any other associated debris in the well.
4.5.1. Displacement Objectives
• Displace oil based mud out of the well with a minimal interface between the oil based mud and the clean up chemicals.
• Keep the brine interface to an absolute minimum.
• Minimise filtration time and cost.
• Change the wetability of all downhole surfaces from oil wet to water wet.
• Prevent the discharge of oil based mud, contaminated water and/or contaminated brine to the environment.
• Minimise the requirement for back-loading oily water for disposal.
• Remove pipe scale, solids, mud solids and other contaminants from the wellbore.
4.5.2. Logistical Considerations
In advance of the displacement, the logistics of the operation from start to finish should be addressed. The areas which should be addressed include (but are not limited to) the following:
a) Vessel(s) for back-loading mud and taking on the clean up chemicals, brine and kill pill material.
b) The quantities of clean up chemicals, brine and kill pill material required including any contingency material that may be required.
c) Pit space requirements for mud and brine and the permits required for cleaning the appropriate pits and lines.
d) The equipment required to install and operate the filtration equipment. e) Personnel requirements and available accommodation.
4.5.3. Drilling Fluid Preparation
1) Pick up the workstring with scrapers placed in it to ensure that the liner or casing packer setting depths are thoroughly scraped during the trip. Once on bottom, bottoms up should be circulated to remove any additional debris.
2) Circulate and condition the oil based mud with oil mud thinner or oil wetting agent in order that the yield point and gel strengths are reduced but not to a point where the fluid loses the ability to keep barite/drilled solids in suspension. Typically, the yield point should be reduced to 12 lbs/100 ft2 and the 10min gel to <15 lbs/100 ft2. The actual quantity of material required to do this must be determined by pilot testing performed by the mud engineer to determine the most cost effective treatment.
3) Throughout the drilling fluid conditioning process, the flow rate used should be the maximum practical rate. At a very minimum, the circulation rate should be just within the turbulent flow regime.
4) Whilst conditioning the mud, the drill string should be reciprocated and rotated. The combined effect of the scrapers being run in the hole, the high flow rate and the reciprocation/rotation will help to remove/disperse large quantities of mud solids and general debris. The reciprocation stroke should be +/-30ft and the rotation speed should be +/-15rpm.
5) Near the end of the conditioning operation, temporarily shut down the pumps and stroke each set of pipe rams to clear any debris from the ram cavities except any pipe rams which are smaller than the workstring. Continue circulation to remove the debris. 6) During this operation, as much of the surface volume of mud should be removed from
the pits to accommodate the completion fluid and the well clean up chemicals. Once the mud has been back-loaded, surface preparation can be carried out.
4.5.4. Surface Equipment Preparation
As much of the surface volume of mud should be sent back to the base leaving only one tank into which the mud returned from the displacement can be dumped:
1) Wash and scrub all of the pits and storage tanks designated for the completion fluid with steam cleaners. Once the top and sides are scrubbed, the bottom of each tank should be swept to the suction line and the contents sent to a contaminated fluid storage pit.
2) All pits, sandtraps, gumbo traps, flowlines, ditches and in particular areas where the accumulation of solids can be overlooked such as underneath lines and grates, above and behind angle irons, in the corners and crevices of beams should all be thoroughly cleaned.
3) Once everything has thoroughly been cleaned, fill one pit with fresh water and add the recommended volume of surfactant/flocculant. Agitate the pit to keep the product dispersed.
4) Circulate the surfactant/flocculant pill at the maximum possible flow rate (for +/-20mins) throughout the entire surface system including all pits, pumps, lines or other areas that the completion fluid may contact.
5) Provided the water is not contaminated it can be dumped. If the water is contaminated, it should be diverted to a pit designated for contaminated fluid.
6) As before, the pits should all be swept clean and dry.
7) Once all of the above has been done, dump valve seats should be inspected and replaced wherever necessary and then guided into place to ensure they seal properly before filling with brine.
8) Once sealed, all dump valves should be locked shut. 4.5.5. Well Clean Up Pill Sequence
The following is the normal sequence for pumping the various fluids and pills. a) Weighted hard surface detergent pill
b) Viscous hard surface detergent pill c) Drill water or seawater
d) Solvent pill
e) Drill water or seawater. f) Surfactant/flocculant pill
g) Viscous hard surface detergent pill
h) Drill water or seawater (water should be pumped until returns are below 60 NTU, usually 1-2 circulations).
i) Viscous pill.
4.5.6. Pill Functions
a) The weighted detergent pill is pumped directly behind oil based mud to initiate oil and filter cake removal.
b) The solvent pill has a solvating action on oil based mud residue and filter cake residue. This is the main pill for actually removing the mud residue. It should not be mixed with any water or base oil to cut it back as this reduces the efficiency of the pill.
c) The surfactant/flocculant pill is used as a chemical flocculating agent to dislodge any residue loosened by the solvent. A large pill is required to ensure adequate contact time to remove all solids.
d) The viscous detergent pill is a detergent pill used to convert the surfaces into a water wet state.
4.5.7. Pit Requirements
Pits/storage tanks will be required for the following: a) Mud pit for the detergent pill
b) Mud pit for the surfactant/flocculant pill c) The solvent pill in the cement unit d) Drill water or seawater
e) The viscous pill in the pill tank f) Completion brine.
4.5.8. Pumping Sequence
The pumping sequence and direction should be in accordance with the well programme. The Mud Engineer should confirm the depths, volumes and rates provide the correct contact times for the various pills.
Seawater should be pumped until returns are clear (1-2 circulations) after which time the seawater can be displaced out with a viscous pill by the completion brine.
4.6. DISPLACEMENT OF WATER BASED MUDS
The displacement of a water based to a clear fluid is an easier procedure requiring fewer steps. This is due mainly to both fluids being compatible and all surfaces already water wet. As with the clean up of oil based mud, it is essential that the well clean up is as efficient (and economical) as possible.
As before the logistical aspect of the displacement from start to finish should be addressed. The areas to be addressed include:
1) Transportation for taking well clean up chemicals, brine and filtration equipment/ consumables to the rig.
2) Personnel requirements. 3) Surface equipment cleaning. 4.6.1. Drilling Fluid Preparation
1) The mud properties should be reduced to the levels specified for oil based mud, namely YP of 12 lbs/100 ft2 and 10min gel <15 lbs/100 ft2. The most cost effective method of treatment is by adding water to the system. However, this should only be done under the direction of the Mud Engineer and only after pilot testing.
2) As per section 4.5.3. 3) As per section 4.5.3.
4) The surface volume of water based mud can be dumped overboard (providing the constituents allow) as can the mud returns from the displacement.
4.6.2. Surface Equipment Preparation Same as section 4.5.4.
4.6.3. Well Clean Up Pill Sequence
The following is the normal sequence for pumping the various fluids and pills. a) Drill water/caustic pill.
b) Surfactant/flocculant pill.
c) Viscous detergent pill (un-weighted).
d) Water, pump until returns are below 60 NTU (usually 1-2 circulations). e) Viscous pill, using the completion brine as the base fluid.
4.6.4. Pill Functions
a) Drill water/caustic soda pill is used as a preflush to strip away and denature the heavy, concentrated water based mud filter cake and solids.
b) Surfactant/flocculant pill is used as a chemical flocculating agent to remove the residues dislodges by the drill water/caustic soda pill. A large pill is required to ensure an adequate contact time to remove all solids.
c) Detergent pill is a polishing pill to ensure all downhole surfaces are thoroughly cleaned prior to pumping the seawater.
4.6.5. Pit Requirements
a) Mud pit for the Caustic Soda Pill. b) Mud pit for the surfactant/flocculant pill. c) Pill tank for the detergent pill.
d) Drill water or seawater as required. e) Pill tank for the viscous pill.
f) Completion Brine. 4.6.6. Pumping Sequence
The pumping sequence and direction should be in accordance with the well programme. The Mud Engineer should confirm the depths, volumes and rates provide the correct contact times for the various pills.
4.7. COMPLETION AND WORKOVER FLUIDS 4.7.1. Brines Transportation
Prior to loading any brine at the suppliers facility the vessel tanks and manifolds will be inspected for cleanliness and dryness.
Note: Boat manifolds may contain residual materials that could contaminate the brine. Therefore all manifolds, pumps, etc. that will be involved in brine delivery will be thoroughly flushed and dried.
Brine will not be loaded onto a vessel or truck until the Company’s responsible person is satisfied that the brine will arrive at the rig site with the same clarity, density, and solids content as originally loaded.
Samples of the brine will be taken during the loading operation from the loading tanks and the vessel's receiving tanks or truck. The volume, density and clarity of the fluid after loading must be identical to the fluid from the suppliers tanks.
Prior to transferring the brine to the installation from the tanks all hoses, connections, dump valves, etc. will be checked for leaks.
The volume and density of the brine will be monitored as it is transferred from the vessel. Any discrepancies in density and volume will be recorded.
4.7.2. Completion And Workover Fluid Quality
The quality of the fluid used during a completion and workover operation cannot be over-emphasised as the productivity is governed not only by the damage caused by visible contaminants such as solids but also the damage caused by invisible contaminants such as calcium ions, sulphate ions and dissolved iron. It is, therefore, essential that all of these and other similar contaminants are controlled to as low a level as feasible and, wherever possible, completely removed (Refer to the Drilling Fluids Manual).
Other contaminants such as iron and sulphates can be controlled on surface by chemical treatment but can be avoided altogether by ensuring that the quality of the fluid supplied is correct, the quality of all the sacked and drummed material meets the required specification and the rig is thoroughly cleaned before taking on the completion brine.
During well completion and workover operations, all steps must be taken to ensure that, if any fluid is in contact with the formation, it is both clean and filtered. A fluid in any other condition will, for the reasons stated above, result in some degree of formation impairment. 4.8. FILTRATION SYSTEMS
The prime filtration system is the Diatomaceous Earth filter press with a bag filter system for use as a downstream guard filter. Sometimes, on standby is a low pressure, Cartridge Filter unit.
Both the DE and the cartridge units are capable of filtering down to 2 microns.
The DE is preferable as the prime equipment as it is more suited to high solids loading which can be removed using various different grades of DE to form a porous, permeable filter cake on a filter cloth. The nature of the DE is such that it must be added using a ‘safe handling system’ to ensure that there is a totally dust free environment thereby eliminating any hazard to the operator or any other personnel in the vicinity. On no account should loose DE be used.
4.8.1. Fluid Cleanliness
Before filtering, all the tanks should be thoroughly cleaned out and any mud residues washed out (as per the pit cleaning procedure described earlier in section 4.5.4).
a) A pit of brine will not be filtered by circulation on itself. b) Brine will be filtered from the dirty pits to a clean empty tank.
c) All filtered brine will be checked to ensure that it meets the required level of cleanliness. Normal specifications are:
• By laser particle counter: < 250ppm total undissolved solids
• By turbidity meter: < 20NTU
4.9. LOST CIRCULATION
The use of lost circulation materials may be necessary if the well has suffers any serious fluid losses as can be experienced such as on open hole, gravel pack or wells which are perforated prior to running the completion, etc.
The types of LCM pills preferred for the various uses from slow seepage to high losses in particular situations are fully described in the Drilling Fluids Manual along with the formulations and placement procedures.
Prior to using an LCM pill, consideration will be given to reducing the hydrostatic head by reducing the brine weight (with drill water) and so reduce the level of losses. This will only be attempted if the reduction in weight does not compromise the safety of the well.
Obviously the LCM pills used in completion operations should be selected in order minimise potential damage to producing formations. Some of the most common LCM pills used in completion operations are described below.
4.9.1. Viscous Pills
These can be built, either, using drill water, completion brine or a higher weight brine as a base and adding a predispersed liquid viscosifier to increase the funnel viscosity according to the well programme. The addition of a predispersed liquid viscosifier is preferable as it will yield rapidly without forming ‘fish eyes’ which may cause a problem when it comes time for the removal of the pill downhole.
There are both advantages and disadvantages is using high viscosity pills for controlling fluid loss. These are as follows:
1) Advantages
• They contain no particulate material to impair the formation.
• They can be built quickly and easily.
• They can be removed by thermal degradation, acid, chemical breakers or by flowing the well.
2) Disadvantages
• They are limited normally to temperatures <280 F.
• They are only effective in low permeability formations where seepage losses are low to moderate (<1.5 - 2bbl/min).
4.9.2. Sized Salt Pills
The actual composition of the sized salt pill will be determined primarily by the porosity, permeability and temperature of the formation to be bridged.
Sized salt pills must be formulated in a saturated brine base to prevent solution of the bridging material.
A typical formulation for a sized salt pill in a 10ppg sodium chloride brine is as follows: Volume per bbl - Vol. as required
Formulation Saturated Brine 0.94bbl Bridgesal Plus 500lbs
Notes:
1) The above formulation will give a final weight of 10.5ppg assuming that a 10ppg NaCl brine is used as the base.
2) If a higher density is required, the formulation will require modification by the addition of FL-7 Plus and Watersal A. The specific formulation will be determined by the Fluids Engineer on the rig. However, typical formulations are as follows (see table below). 3) Mixing order of products should be listed.
4) A small amount of defoamer is required (0.2gal/bbl) to minimise foaming. Density 11 ppg Density 12 ppg Density 12.5 ppg Composition* Saturated Brine (bbl) Bridesal Plus (lbs/bbl) FL-7 Plus (lbs/bbl) Watersal A (lbs/bbl) 0.88 40 2 57 0.75 30 4 164 0.69 30 4 210 Properties Plastic Viscosity (cp) Yield Point (lbs/100 sq.ft)
10 sec Gel Strength (lbs/100 sq.ft) 10 min Gel Strength (lbs/100 sq.ft) pH 30 35 8 10 7.4 62 61 10 13 7.1 77 67 11 14 7.2 4.9.3. Calcium Carbonate Pills
Calcium carbonate can be used as a drilling fluid and for LCM pills to control fluid losses. In completion operations it is now the most commonly used fluid for controlling fluid losses within Eni-Agip’ operations.
The composition of a calcium carbonate LCM pill is dependent upon the formation porosity, permeability and temperature. A range of particle sizes is available which may be mixed to provide the ideal mixture for the formation pore size. The calcium carbonate uses a viscous pill as a carrier (Refer to section 4.9.1 above).
Typical of a calcium carbonate fluid is Baker Hughes Inteq’s reservoir drill-in fluid system called ‘Perflow’ that is designed to lower overall well completion costs while improving long-term production rates.
Used as a drill-in fluid, Perflowmaintains the properties of a drilling fluid while protecting the well's pay zone against damage. Itprovides lubricity, inhibition, solids suspension, cuttings removal, and wellbore stability. In its protective role, the fluid bridges on pore openings exposed to the wellbore, remains intact during completion and workover operations, and is easily removed with production.
The system's performance has made it effective in a number of wellsite applications. These applications include use as a drill-in fluid, coring fluid, fluid loss pill, underreaming fluid, TSO (Tip Screen Out) prepad fluid, and as a kill fluid.
The system's simplified cleanup reduces rig time during completion and workover operations. While other fluids require costly processes for removal, removal is simply accomplished by flowing the well.
The system utilises very pure calcium carbonate with a broad particle size distribution to effectively bridge the pore openings of the formation. The bridging agent and polymer chemistry form a thin filter cake to protect the pay zone from damage caused by fluid invasion. The filter cake is effectively removed by low break-out pressures, leaving no significant residual material to inhibit the well's production.
Before using a calcium carbonate pill, any potential damaging effects from the calcium carbonate needs to be assessed as any particles trapped in pore spaces can only be removed by an HCl acid treatment.
4.10. CASING GAUGE CONTROL
Prior to running any completion equipment, it is necessary to ensure the hole is within gauge to allow passage of tools such as packers and TCP guns.
Checking the hole gauge is carried out by electric line services by running a gauge ring of a size according to the casing drift size. It is normal practice to run the gauge ring in conjunction with a junk basket after the well clean out procedure. The junk basket is run to catch junk which has not been circulated out of the hole during the well clean out operation (typically rubber, pieces of cement, etc.).
Any tight spots should be logged and reported. Ultimately the casing may require further scraping. It is extremely important that the casing is drifted as the sticking of completion equipment can incur high costs in retrieval, loss or damage to equipment and may even cause a side-track.
5.
PERFORATING PROCEDURES
5.1. GENERAL
Two methods are currently used to perforate wells: wireline conveyed guns and tubing conveyed guns (Refer to the Completion Design Manual). In the drive to obtain maximum perforating efficiency, tubing conveyed perforating is the preferred method for most completion operations as the zones to be tested can be perforated underbalanced in one run with a large size charges, if possible. However, under some circumstances wireline conveyed guns may still be preferred. The procedures for both methods are described in the following sections.
The type of explosive to be used will depend mainly on the bottom hole temperature and the length of time the guns are likely to be on bottom before firing. Refer again to the perforating section in the Completions Design Manual and to suppliers technical specification sheets.
The BOPs and the rig manifolds should have undergone a recent full programme of pressure testing.
At the safety meeting, the perforating operation should be discussed in fine detail. Apart from outlining the sequence of operations and contingency plans, all present should be clearly aware of the extent to which their own area of responsibilities may affect, and be affected by, the special requirements of a perforating operation.
The perforating engineer should have a diagram of the well, clearly indicating the interval(s) to be perforated, the fluids present, the pressures/temperatures expected and the depths, diameters and angles of any changes in the well geometry. There must be no doubt about the method of referencing the top shot and the settings of the tools (e.g. shear pin settings, timer delays, etc.). These must be discussed with the Completions Supervisor and fully understood.
No crane lifts should be made over loaded perforating guns or over the logging cable. Only essential personnel will be permitted in the vicinity of loaded guns, especially at the loading area, catwalk, drill floor and spider deck. All personnel, except the perforating engineer, should be clear of these areas while the guns are being armed.
Diving activities are not permitted during the perforating operation. Electrical Activation
In addition, whenever the gun firing sequence is initiated by electrically operated detonators, the following will apply:
• Weather forecasts (two independent sources) must confirm there will be no likelihood of electrical storms for the duration of the perforating operation.
• Offshore, the perforating engineer should remain on the drill floor at all times when TCP guns are in the hole still above ground level.
• The perforating engineer must verify there are no stray voltages (greater than 0.25 V) between the rig and the casing or riser.
• Radio silence must be in force before connecting the firing head and until the guns are 100m below ground level, unless the Schlumberger SAFE firing system or similar is used (Refer to section 2)).
• The firing head detonator must not be installed until the Completion Supervisor confirms to the Perforating Engineer that the rig is on radio silence.
• On recovery of the guns, regardless of any indications that the guns have fired, radio silence must be reinstated prior to the guns being retrieved above 100 metres below the sea bed. This period will end only after the detonator sub-system has been removed and the perforating engineer has confirmed to the Completion Supervisor that the guns have been made safe.
• No electric/MIG welding is permitted during the perforating operation.
• Cathodic protection should be shut down and isolated during the period of radio silence.
• No diving is to be allowed during perforating.
• No crane lifts should be made over the wire during perforating, if applicable.
• No boats should be alongside during perforating.
• No helicopter landings should be allowed during radio silence.
• All non-essential personnel should be excluded from the areas affected, including the gun loading area, the catwalk, the drill floor and the moonpool, around the riser below the drill floor.
5.2. METHODS OF PERFORATING
The perforating procedure is dependent upon the type of gun system used for the application in the completion process. The six main methods are:
• Wireline-conveyed carrier guns inside casing - perforating overbalance
• Wireline-conveyed through tubing guns - perforating underbalance
• TCP run on a temporary well test string - perforating underbalance
• TCP guns run on the permanent completion string - perforating underbalance
• TCP guns run on a perforating anchor - perforating underbalance
• TCP guns run on coiled tubing - perforating underbalance
Common to all perforating operations, a safety meeting should be held before the operation commences. This is important because perforating will impose restrictions on other rig operations, such as radio silence, diving and use of the cranes. These procedures are to be used as a guideline. They should be used only in conjunction with other company procedures for these operations.
5.3. GENERAL SAFETY PROCEDURES
The following comments are applicable to both TCP and wireline conveyed methods. Additional comments are given in section specific to wireline conveyed perforating.
a) All perforating operations, since they involve the handling and use of explosives and possibly radioactive materials, require special safety procedures to be strictly observed at all times.
b) Perforating operations should be carried out strictly according to the safety policies of Eni-Agip and the perforating Contractor. In the event of any inconsistency between policies, the most conservative policy will apply.
a) Operations involving the use of explosives shall only be performed by Contractor’s specialised personnel responsible for perforation and similar operations. The number of persons involved shall be as low as possible.
b) Only perforating Contractor’s personnel are allowed to remain in the hazardous area (gangway, rig floor etc.) during arming of guns. The number of personnel should be limited when the guns are within 500ft of surface when tripping in and out of the hole.
c) Any operation involving the use of explosives is not allowed in the presence of thunder, lighting and thick fog, as these are sources of electric potential.
d) Explosives shall be kept on site for the shortest possible time, any remaining at the end of the operation shall be removed from the installation.
e) Explosives shall be stored on site in proper containers, within a confined area on the rig. Detonators shall be stored in separate boxes, in the same area as explosives.
f) Warning signs must be placed around the hazardous area where explosives are used.
g) All radio transmitters, radio beacons included, within a radius of 500ft from the well, shall be turned off, (since they may detonate blasting caps), starting from gun arming until perforating guns are 500ft below the sea bottom (similarly, when pulling guns out of hole and guns above 500 ft). All portable transmitters (both Eni-Agip’s and Contractors) shall be placed inside the Eni-Agip office and turned off to avoid accidental transmission. Avoid critical periods of perforating coinciding with arrival and take-off of helicopters.
h) Cranes and welding machines shall be put out of service starting from gun arming till gun pulling out and unloading.
i) District Office shall be advised by the Well Operations Supervisor on the estimated time of radio silence two hours before starting operations. The Radio Operator shall communicate actual timing.
j) Casing perforating can be performed during daylight or at night. However, the first series of shots must be carried out in daylight hours. Before perforating casing, the acceptable cement job quality shall be ascertained by means of CBL/VDL and/or by squeeze jobs.
k) Explosives are to be transported unarmed and clearly labelled to the site in secure and protective containers. Extreme care must be applied during loading and off-loading.
l) At the rig it is the responsibility of the Installation Manager to ensure that these precautions are taken.