Drilling and workover best practices

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BEST PRACTICES AND MINIMUM REQUIREMENTS FOR DRILLING AND COMPLETION ACTIVITIES

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: !

" # $

% Issued by P. Magarini C. Lanzetta A. Galletta

28-04-2000 28-04-2000 28-04-2000

REVISIONS PREP'D CHK'D APPR'D

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INTRODUCTION

PURPOSE OF THE DOCUMENT

The purpose of the Best Practices and Minimum Requirements is to guide technicians and engineers, involved in Eni-Agip’s Drilling & Completion worldwide activities, through the Manuals & Procedures and the Technical Specifications 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.

The Best Practices and Minimum Requirements (also defined by the acronym BP&MR) is the main reference document for the Audits on the Drilling & Completion activities that the Corporate will be carrying out in the Districts and Affiliates.

IMPLEMENTATION

The “Best Practices and Minimum Requirements” document addresses all well area activities, from the initial feasibility study through completion and workover operations. The topics have been divided in three main sections:

1) PLANNING (

PL

)

It includes the fundamental actions preceding the well operations, such as feasibility study, authorisations, operational planning, construction of the location, etc.

2) OPERATIONS (

OP

)

It address the operations carried out in the well area, such as drilling, well testing, completion, workover, equipment inspection and waste treatment.

3) REPORTING & FEEDBACK (

RF

)

This section describes all the reports, forms and documents to be filled in and sent to the Corporate Drilling & Completion Standards Department in Eni-Agip Division Headquarters. This should be done either periodically or at the end of each operation. This will provide a record of the well and where to find all relevant information necessary for studies, analysis and evaluations of the operations. This will enable improvement and optimisation of further activities.

For every BP&MR specified, the source (manual, procedure, technical specification) has been listed, to help finding the entire and associated subjects, if required.

Where the reference column is blank, this means that there are no reference documents available or they are currently under preparation.

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UPDATING, AMENDMENT, CONTROL & DEROGATION

The BP&MR 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 BP&MR 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 BP&MR, when the updating of the document will be advisable.

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INDEX

ABBREVIATIONS

SECTION 1 PLANNING (PL)

PRELIMINARY (PL.01)

GEOLOGICAL AND DRILLING WELL PROGRAMME (PL.02)

COMPLETION DESIGN (PL.03)

SECTION 2 OPERATIONS (OP)

MOVING AND POSITIONING (OP.01)

DRILLING OPERATIONS (OP.02)

COMPLETION AND WORKOVER OPERATIONS (OP.03)

MATERIALS AND TRANSPORTATION (OP.04)

WASTE TREATMENT AND DISPOSAL (OP.05)

SECTION 3 REPORTING & FEEDBACK (RF)

REPORTING AND FEEDBACK FORMS (RF.01)

FINAL DRILLING REPORT (RF.02)

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ABBREVIATIONS

The following tables contain the abbreviations used in the document: AC/DC Alternate Current, Direct Current NB Near Bit Stabiliser AHTS Anchor Handling Towing Supply NDT Non Destructive Test API American Petroleum Institute NMDC Non Magnetic Drill Collar

BG Background gas NSG North Seeking Gyro

BHA Bottom Hole Assembly NTU Nephelometric Turbidinity Unit BHP Bottom Hole Pressure OBM Oil Base Mud

BHT Bottom hole temperature OD Outside Diameter

BJ Blast Joint OEDP Open End Drill Pipe

BMT Blue Methylene Test OH Open Hole

BOP Blow Out Preventer OHGP Open Hole Gravel Packing BPD Barrel Per Day OIM Offshore Installation Manager BPM Barrels Per Minute OMW Original Mud weight

BPV Back Pressure Valve ORP Origin Reference Point BSW Base Sediment & Water OWC Oil Water Contact BUR Build Up Rate P&A Plugged & Abandoned BWOC By Weight Of Cement P/U Pick-Up

BWOW By Weight Of Water PBR Polished Bore Receptacle

C/L Control Line PCG Pipe Connection Gas

CBL Cement Bond Log PDC Polycristalline Diamond Cutter CCD Centre to Centre Distance PDM Positive Displacement Motor CCL Casing Collar Locator PGB Permanent Guide Base CDP Common Depth Point PI Productivity Index CET Cement Evaluation Tool PKR Packer

CGR Condensate Gas Ratio PLT Production Logging Tool

CMT Cement POB Personnel On Board

CP Conductor Pipe POOH Pull Out Of Hole

CR Cement Retainer PPB Pounds per Barrel

CRA Corrosion Resistant Alloy PPG Pounds per Gallon

CSG Casing ppm Part Per Million

CT Coiled Tubing PTR Piano Tavola Rotary

CW Current Well PV Plastic Viscosity

DC Drill Collar PVT Pressure Volume Temperature

DE Diatomaceous Earth Q Pump Rate

DHM Down Hole Motor Q/A Q/C Quality Assurance, Quality Control DHSV Down Hole Safety Valve R/D Rig Down

DIF Drill in Fluid R/U Rig Up

DLS Dog Leg Severity RBP Retrievable Bridge Plug

DLS Dog Leg Severity RCP Reverse Circulating Position (GP) DM /

D&CM

Drilling & Completion Manager RFT Repeat Formation Test DOB Diesel Oil Bentonite RIH Run In Hole

DOBC Diesel Oil Bentonite Cement RJ Ring Joint

DOR Drop Off Rate RKB Rotary Kelly Bushing

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DPHOT Drill Pipe Hang off Tool ROP Rate Of Penetration

DRLG Drilling ROU Radios Of Uncertainty

DST Drill Stem Test ROV Remote Operated Vehicle

DV DV Collar RPM Revolutions Per Minute

E/L Electric Line RPSP Reduced Pump Strokes Pressure ECD Equivalent Circulation Density RT Rotary Table

ECP External Casing Packer S (HDT) High Resolution Dipmeter EMS Electronic Multi Shot S/N Serial Number

EMW Equivalent Mud Weight S/O Slack-off

EOC End Of Curvature S/S Short String

EP External Pressure S/V Supply Vassal

ESD Electric Shut-Down System SAFE Slapper Activated Firing Equipment ESP Electrical Submersible Pump SBA Safe Breathing Area

ETA Expected Arrival Time SBHP Static Bottom Hole Pressure ETU Endless Tubing Unit SBHT Static Bottom Hole Temperature FBHP Flowing Bottom Hole Pressure SCBA Self Contained Breathing

Apparatus

FBHT Flowing Bottom Hole Temperature SCC Stress Corrosion Cracking FC Flow Coupling SCSO Single Completion Seal Flange FINS Ferranti International Navigation

System

SCSSV Surface Controlled Subsurface Safety Valve

FPI/BO Free Point Indicator / Back Off SCUBA Self Contained Underwater Breathing Apparatus FTHP Flowing Tubing Head Pressure SD Separation Distance FTHT Flowing Tubing Head Temperature SDE Senior Drilling Engineer GCT Guidance Continuous Tool SF Safety Factor

GLR Gas Liquid Ratio SG Specific Gravity

GLS Guidelineless Landing Structure SICP Shut-in Casing Pressure GMS Gyro Multi Shot SIDPP Shut-in Drill Pipe Pressure GOC Gas Oil Contact SIMOP Simultaneous Operations

GOR Gas Oil Ratio SN Seating Nipple

GP Gravel Pack SPM Stroke per Minute

GPM Gallon (US) per Minute SPV Supervisor GPS Global Positioning System SR Separation Ratio

GR Gamma Ray SRG Surface Readout Gyro

GRA Guidelineless Re-entry Assembly SSC Sulphide Stress Cracking GSS Gyro Single Shot SSD Sliding Sleeve Door Valve HAZOP Hazard and Operability SSLV Sub Surface Lubricator Valve HDT High Resolution Dipmeter SSR Sub surface Release Plugs HHP Hydraulic Horsepower SSSV Sub Surface Safety Valve

HO Hole Opener SSTT Sub Surface Test Tree

HP/HT High Pressure - High Temperature SSTV Subsea Television HSI Horsepower per Square Inches ST Steering Tool HW/HW

DP

Hewi Wate Drill Pipe STD Stand

IADC International Drilling Contractor STG Short trip gas

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ICGP Inside Casing Gravel Packing STHT Static Tubing Head Temperature

ID Inside Diameter STT Surface Test Tree

IFR Imposta Fabbricazione Ridotta SX Sacks

IP Internal Pressure TBG Tubing

IPR Inflow Performance Relationship TCP Tubing Conveyed Perforations JAM Joint Make-up Torque Analyser TD Total Depth

KMW Kill mud weight TDB Total Drilling Control

KOP Kick Off Point TDS Top Drive System

L/D Lay-Down TFA Total Flow Area

L/S Long String TG Trip Gas

LAT Lowest Astronomical Tide TGB Temporary Guide Base

LC 50 Lethal Concentration 50% THA Tubing Head Adapter (bonnet) LCDT Last Crystal to Dissolve °C TOC Top of Cement

LCM Lost Circulation Materials TOL Top of Liner

LCP Lower Circulation Position (GP) TRSV Tubing Retrievable Safety Valve LEL Lower Explosive Limit TTBP Through Tubing Bridge Plug LMRP Low Marine Riser Package TVD True Vertical Depth

LN Landing Nipple TW Target Well

LOT Leak Off Test UAR Uncertainty Area Ratio LQC Log Quality Control UCP Upper Circulating Position LTA Lost Time Accident UEL Upper Explosion Level LTT Lower Tell Table (GP) UGF Universal Guide Frame LWD Log While Drilling UHF Ultra High Frequency

M/D Martin Decker UR Under Reamer

M/U Make-Up UTM Universal Transverse of Mercator

MAASP Max Allowable Annular Surface Pressure

VBR Variable Bore Rams (BOP)

MD Measured Depth VDL Variable Density Log

MLH Mudline Hanger VHF Very High Frequency

MLS Mudline Suspension VSP Velocity Seismic Profile MMS Magnetic Multi Shot W/L Wire Line

MODU Mobile Offshore Drilling Unit WBM Water Base Mud

MOP Margin of Overpull WC Water Cut

MPI Magnetic Particle Inspection WHP Well Head Pressure

MSCL Modular Single Completion Land WHSIP Well Head Shut-in Pressure

MSL Mean Sea Level WL Water Loss

MSS Magnetic Single Shot WO Workover

MUT Make Up Torque WOB Weight On Bit

MW Mud Weight WOC Wait On Cement

MWD Measurement While Drilling WOW Wait On Weather

N/D Nipple-Down WP Working Pressure

N/U Nipple-Up XO Cross Over

NACE National Association of Corrosion Engineers

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SECTION 1

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INDEX

PL1.

PRELIMINARY

7

PL. 1.1. FEASIBILITY STUDY 7

1. NEW WELL 7

2. WELL RE-ENTRY 7

PL. 1.2. DRILLING & COMPLETION DEPARTMENT ACTIVITIES 8

1. DEPARTMENT RESPONSIBILITIES 8

PL. 1.3. RIG SELECTION 10

1. TECHNICAL SPECIFICATIONS CONTENTS 10

PL. 1.4. AUTHORISATIONS AND PERMITS 12

1. GENERAL 12

PL. 1.5. TECHNICAL DOCUMENTATION 13

1. RIG SITE 13

2. DRILLING & COMPLETION DEPARTMENT 13

PL. 1.6. MAIN CONTRACTORS 14

1. DRILLING CONTRACTOR 14

2. MUD LOGGING 18

3. MUD SERVICE, CHEMICAL SUPPLY, CENTRIFUGES RENTAL 20

4. CEMENTING SERVICE 22

PL. 1.7. ESTIMATED COSTS 25

1. BUDGET 25

2. COSTS 25

PL2.

GEOLOGICAL AND DRILLING WELL PROGRAMME

26

PL. 2.1. GEOLOGICAL AND DRILLING WELL PROGRAMME STRUCTURE 27

1. NUMBER OF THE SECTIONS 27

2. PRINT MODEL 27

PL. 2.2. GENERAL INFORMATION (SECTION 1) 28

1. GENERAL 28

2. GENERAL WELL DATA 28

3. GENERAL RECOMMENDATIONS 29

4. GENERAL CHARACTERISTICS OF THE RIG, BOP STACK AND SAFETY

EQUIPMENT 29

5. LIST OF THE MAIN CONTRACTORS 29

6. CONTACTS IN CASE OF EMERGENCY 30

7. REFERENCE MANUALS 30

8. MEASUREMENT UNITS 30

9. SIGNATURE 30

PL. 2.3. LAYOUT OF THE DRILLING PROGRAMME (SECTION 4) 33

1. BASIC REQUIREMENTS 33

PL. 2.4. OPERATIVE SEQUENCE (SECTION 4) 35

1. PRELIMINARY INFORMATIONS 35

2. CONDUCTOR PIPE PHASE 35

3. SURFACE PHASE 36

4. INTERMEDIATE PHASES 36

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7. TYPE OF COMPLETION 37

8. WELL ABANDONMENT 38

PL. 2.5. SOFTWARE (SECTION 4) 39

1. STANDARDS 39

2. ALTERNATIVES 39

PL. 2.6. PRESSURE GRADIENTS PROGNOSIS (SECTION 4) 40

1. PRELIMINARY DATA COLLECTION 40

2. DEFINITIONS 41

3. PRESSURE GRADIENTS PREDICTION & EVALUATION 43

PL. 2.7. SHALLOW GAS 48

1. PRELIMINARY SHALLOW GAS INVESTIGATION 48

2. SHALLOW-GAS DRILLING GUIDELINES 48

3. DIVERTER 50

PL. 2.8. CASING SETTING DEPTH 51

1. DETERMINE PROPER SETTING DEPTH FOR EACH CASING TYPE 51

2. GENERAL GUIDELINES ON CASING SETTING DEPTHS 51

3. SAFETY REQUIREMENTS 52

PL. 2.9. DIRECTIONAL WELL PLANNING 53

1. PRELIMINARY DIRECTIONAL PLAN INFORMATION 53

2. DEFINITIONS 54

3. SURVEY CALCULATIONS 55

4. SURVEY TOOL SELECTION 56

5. FREQUENCY AND TYPE OF SURVEYS 59

6. ANTI-COLLISION 59

7. BHA ANALYSIS 63

8. REPORTING 64

PL. 2.10. CASING DESIGN 70

1. CASING SETTING DEPTH AND FUNCTIONS OF CASING STRINGS 70

2. CASING AND HOLE SIZES 70

3. CASING DESIGN CRITERIA AND DESIGN FACTORS 70

4. DECREASING IN THE CASING PERFORMANCE PROPERTIES 72

5. DRILLING PROGRAMME CONTENTS 76

PL. 2.11. DRILLING FLUIDS PROGRAMME 80

1. GENERAL 80

2. PRELIMINARY INFORMATION 80

3. GENERAL PARAMETERS FOR A MUD SYSTEM 80

4. SURFACE EQUIPMENT FOR TREATING & HANDLING MUD 81

5. CONTINGENCY PLANS FOR POTENTIAL HOLE PROBLEMS 82

6. SAFETY REQUIREMENTS 82

PL. 2.12. HYDRAULIC PROGRAMME 83

1. SOFT WARE 83

2. FLOW REGIME DEFINITION 83

3. FRICTION PRESSURE LOSSES CALCULATION 83

4. BIT NOZZLES SELECTION 84

5. DRILLING PROGRAMME CONTENTS 84

PL. 2.13. WELLHEAD 86

1. GENERAL SERVICE CONDITION (NO SOUR SERVICE) ONSHORE,

OFFSHORE JACK-UP & FIXED PLATFORMS WELLHEAD SYSTEM 86

2. MATERIAL 86

3. UNITISED WELLHEAD (COMPACT) 87

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5. MATERIAL REQUIREMENTS 88

6. PRESSURE TESTS 89

7. DRILLING PROGRAMME CONTENTS 89

8. UNCONVENTIONAL WELLHEAD SYSTEM 89

9. SUBSEA WELLHEAD SYSTEM 89

PL. 2.14. WELL CONTROL 91

1. BOP SELECTION CRITERIA 91

2. EQUIPMENT REQUIREMENTS 91

3. BOP & CASING TESTS 92

4. TESTS FREQUENCY 95

5. DURATION OF TESTS 96

6. WELL CONTROL DRILLS 96

7. PRIMARY WELL CONTROL 97

8. SECONDARY WELL CONTROL 98

PL. 2.15. CEMENT PROGRAMME 99 1. PRELIMINARY INFORMATION 99 2. SLURRY DESIGN 99 3. SPACER DESIGN 100 4. HYDRAULIC CALCULATIONS 101 5. PLACEMENT TECHNIQUES 101

6. DOWN HOLE EQUIPMENT SELECTION 101

7. SURFACE EQUIPMENT SELECTION 102

8. OPERATING PROGRAMME 102

PL. 2.16. DRILL STRING DESIGN 104

1. DESIGN PARAMETERS 104

PL. 2.17. BIT SELECTION & DRILLING PARAMETERS 108

1. FACTORS AFFECTING BIT SELECTION 108

PL. 2.18. EXPECTED DRILLING PROBLEMS & RECOMMENDATIONS 110

1. DRILLING DIFFICULTIES 110 2. SUGGESTIONS 110 3. GENERALITIES 110 4. LOSSES CIRCULATION 110 5. DIFFERENTIAL STICKING 111 6. CAVING HOLE 112 7. HOLE RESTRICTION 113 8. HOLE IRREGULARITIES 113

9. HYDROGEN SULPHIDE GUIDELINES 114

PL. 2.19. WELL ABANDONING 118

1. GENERAL GUIDELINES 118

2. TEMPORARY ABANDONMENT 118

3. PERMANENT ABANDONMENT - PLUGGING 120

PL3.

COMPLETION DESIGN

124

PL. 3.1. FUNDAMENTAL 124 1. CONCEPTUAL DESIGN 124 2. COMPLETION OBJECTIVES 124 3. FUNCTIONS OF A COMPLETION 125 4. RESEVOIR CONSIDERATIONS 125 5. RESERVOIR/PRODUCTION FORECAST 126

PL. 3.2. RESERVOIR FLUIDS CHARACTERISTICS 130

1. GENERAL 130

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4. GAS CONDENSATE CHARACTERISTICS 131

5. SAMPLING 132

PL. 3.3. RESERVOIR ROCK CHARACTERISTICS 133

1. GENERAL 133

2. AREA OF INTEREST 133

3. MAIN CHARACTERISTICS 133

4. CORE ANALYSIS 134

PL. 3.4. EFFECTS OF RESERVOIR CHARACTERISTICS 135

1. GENERAL 135

2. DESIGN PARAMETERS 135

3. COMPLETION DESIGN THROUGH FIELD LIFE 135

4. NEAR WELLBORE RESTRICTIONS 135

5. STRATEGY TO MINIMISE THE SKIN EFFECTS 137

6. WELL INFLOW PERFORMANCE 138

PL. 3.5. TUBING PERFORMANCE 141 1. GENERAL 141 2. TEMPERATURE GRADIENT 142 3. PVT DATA CALCULATION 142 4. PVT PARAMETERS TO BE MATCHED 143 5. VALIDATION 144 6. LIMITS 145

7. OPTIMUM TBG SIZE THROUGH FIELD LIFE 145

PL. 3.6. STRESS ANALYSIS 146 1. GENERAL 146 2. PARAMETERS 146 3. CALCULATION METHOD 148 4. SAFETY FACTOR 149 5. OPERATIONAL CASES 149 6. TBG - PACKER INTERACTIONS 150

7. TUBING MECHANICAL PROPERTIES 151

PL. 3.7. MATERIAL SELECTION 152

1. CORROSION GENERAL 152

2. CORROSION CONTROL MEASURES 156

3. MATERIAL SELECTION 157

4. CORROSION MONITORING 160

5. ELASTOMER SELECTION 161

6. ELASTOMER PRACTICAL GUIDELINES 161

PL. 3.8. LIFTING DESIGN 163

1. DEFINITION 163

2. BASIC METHODS OF ARTIFICIAL LIFT 163

3. SELECTIONCRITERIA 163

4. ROD PUMPING 166

5. GAS LIFTING 167

6. ELECTRICAL SUBMERSIBLE PUMPING 168

7. JET PUMPING 169

PL. 3.9. COMPLETION AND PACKER FLUIDS 170

1. DEFINITIONS 170

2. COMPLETION FLUID DUTY 171

3. PACKER FLUID 171

4. BRINE PROPERTIES 171

5. FORMATION INTERACTIONS 172

6. BRINE FILTRATION 173

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8. OIL BASE MUD 174

PL. 3.10. PACKERS 175

1. DEFINITIONS 175

2. SINGLE COMPLETION PACKER 175

3. SINGLE SELECTIVE COMPLETION PACKER 180

4. DUAL COMPLETION PACKER 183

5. DUAL SELECTIVE COMPLETION PACKER 184

PL. 3.11. TUBING JOINT 185

1. GENERAL 185

2. JOINT SELECTION 185

PL. 3.12. TUBING SAFETY VALVE 187

1. GENERAL NOTES 187

2. SEALING SYSTEM 189

3. APPLICATION 191

4. SELECTION CRITERIA 191

PL. 3.13. ANNULUS SAFETY VALVE 192

1. GENERAL NOTES 192

2. VALVE TYPES 192

3. APPLICATION 192

4. SELECTION CRITERIA 192

PL. 3.14. LANDING NIPPLES AND SLIDING VALVE 194

1. TUBING HANGER NIPPLE 194

2. INTERMEDIATE DOWN HOLE EQUIPMENT 194

3. TAIL PIPE 194 4. NIPPLES SELECTION 194 5. GENERAL 194 6. WORKING PRESSURE 195 PL. 3.15. CHRISTMAS TREE 196 1. GENERAL GUIDELINES 196 2. PRESSURE RATING 196 3. CONFIGURATION 196 4. ACTUATORS 197 5. MATERIALS 198 6. SEALS 198 7. TUBING HANGER 200

8. TUBING HEAD ADAPTER SEAL FLANGE 200

PL. 3.16. WORKOVER AND COMPLETION PROGRAMME 201

1. GENERAL 201

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PL1. PRELIMINARY

PL. 1.1. FEASIBILITY STUDY

1. NEW WELL Reference

1.1. The Drilling & Completion Department (D&C Dept.) obtain input data from the Exploration or Reservoir departments, relevant to:

• Location co-ordinates. • Targets specifications.

• Reference to offset well information. • Potential production.

1.2. The D&C Dept. evaluate all input data in order to be able to: • Determine if any natural or artificial impediments may exist. • Verify the environmental impact.

• Select the type of rig (Land, Jack Up or Floater).

• Determine the range of pore pressures, which may be encountered.

• Define the type of drilling fluid.

• Fix preliminary casing points and if necessary, also produce the casing design.

• Establish a preliminary directional well plan in order to evaluate collision risks.

• Plan the configuration of the well completion.

• Carry out an operations optimisation analysis (pre-drilling, early production, simultaneous production, etc.).

• Estimate expected time of operations. • Estimate expected costs.

2. WELL RE-ENTRY Reference

2.1. Other additional information will be obtained, such as:

• Purpose of re-entry (reinstate production, workover, abandoning, etc.).

• Well history and status. • Wellhead sketch.

2.2. In addition to the normal evaluations, some additional issues must be taken into consideration:

• Re-establishment of the location (onshore wells).

• The ability to approach existing platforms, cluster or single wells (offshore).

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PL. 1.2. DRILLING & COMPLETION DEPARTMENT ACTIVITIES

1. DEPARTMENT RESPONSIBILITIES Reference

1.1. The D&C Dept. is activated by the Exploration Department (exploratory wells) or Project Manager (development wells).

1.2. The D&C Dept. obtain the following from the District Geological Department:

1.2.1. The ‘Geological Programme’ to include: • Geological Framework • Seismic Interpretation • Source Rocks • Sealing Rocks • Lithostratigraphic Profile • Reference Wells

• Annexes and/or Figures

P-1-M-6100 16.4.2 P-1-N-6001-E 7.2

1.2.2. The ‘Operational Geological Programme’ to include: • Surface Logging

• Samplings • Cuttings

• Bottom Hole Cores • Side Wall Cores • Fluids Sampling • Logging While Drilling • Wireline Logging • Seismic Survey • Wireline Testing • Testing

• Studies And Drawings • Reference Wells

• Annexes and/or Figures

P-1-M-6100 16.4.3 P-12-N-6001-E 7.3

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1.3. The D&C Dept. inform the other departments in accordance with their functions:

• Authorisations & permits • Budget cost centre opening • Location preparation

• Contracts acquisition

• Means of transport selection • Material supplies.

1.4. The D&C Dept. issue technical specification for the Drilling Rig.

1.5. The D&C Dept. activate its Engineering Section to prepare and distribute the Drilling Programme.

P-1-M-6100 16 P-1-N-6001-E 7.4

Reference List:

‘Drilling Design Manual’ STAP-P-1-M-6100

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PL. 1.3. RIG SELECTION

1. TECHNICAL SPECIFICATIONS CONTENTS Reference

1.1. General data:

• Well name or activity name • Foreseen date for starting activity • Activity time • Well number • Job number • Eni-Agip District • Location • RKB/sea level

• Distance from nearest house • Soundproofing required. 1.2. Type of well: • Exploration wells • Development wells • Single wells • Cluster wells

• Number of wells per cluster • Vertical wells

• Deviated wells.

1.3. Well characteristics for rig evaluation: • Rig capacity with 5” DP:

• Hole diameter • Hole depth

• Casing/liner diameter • Casing/liner setting depth • Casing/liner weight in air. 1.4. Type of mud predicted:

• If oil based mud predicted, adequate mixing system. • Max predicted mud density.

• H2S predicted.

P-1-M-6140 6.4 P-1-M-6100 5.8

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1.5. Wellhead for each type of well: • Base flange

• Type of flange for casing spool • Type of flange for casing spool • Type of flange for tubing spool • Type of flange for tubing spool.

P-1-M-6140 15

Reference List:

‘Drilling Procedures Manual’ STAP-P-1-M-6140

‘Drilling Design Manual’ STAP-P-1-M-6100

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PL. 1.4. AUTHORISATIONS AND PERMITS

1. GENERAL Reference

1.1. Authorisations, approvals and documentation necessary to operate in the various Countries are usually substantially different and depend upon local laws and rules.

Each District / Affiliate have to issue a complete list, specifying the type of documents and the competent authority.

1.2. Rig site:

All the authorisations and permits relative to the current activity shall be available for inspection by any authorised personnel.

1.3. Well Area Department:

All the authorisations and permits relative to the current activity shall be available for inspection by any authorised personnel.

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PL. 1.5. TECHNICAL DOCUMENTATION

1. RIG SITE Reference

1.1. Below is a list of the technical manuals and documentation that shall be available on the rig site during any well operations:

1.1.1. 1. Drilling And Completion Activities: • Drilling Data Handbook - IFP

• Formulaire du Producteur - IFP. • Composite Catalogue - WORLD OIL

• Drilling Design Manual - STAP-P-1-M-6100. • Drilling Procedures Manual - STAP-P-1-M-6140 • Well Control Policy - STAP-P-1-M-6150

• Directional Control and Surveying Procedures - STAP-P-1-M-6100

• Drilling Fluids Handbook - STAP-P-1-M-6160 • Well Test Procedures Manual - STAP-P-1-M-7130 • Completion Design Manual - STAP-P-1-M-7100 • Completion Procedures Manual - STAP-P-1-M-7120 • Specific Technical and Operating Manual for each tool. 1.1.2. 2. Workover And Wireline Activities:

• Formulaire du Producteur - IFP • Composite Catalogue - WORLD OIL • Well Control Policy - STAP-P-1-M-6150

• Completion Design Manual - STAP-P-1-M-7100 • Completion Procedures Manual - STAP-P-1-M-7120 • Wireline Procedures Manual - STAP-P-1-M-7110. • Specific technical and operating manual for each tool.

2. DRILLING & COMPLETION DEPARTMENT Reference

2.1. The D&C Dept. of the District/Affiliate must have available and updated all the technical manuals and documentation to be sent to rig site.

2.2. The D&C Dept. have to take care of the updating status of all the Corporate Eni-Agip manuals sending request to the Drilling & Completion Standards Department or competent Units in Eni-Agip Headquarters.

2.3. All technical reports regarding the current activity received from the rig shall be filed in and then will constitute the ‘Official Well File’ in which all the relevant information, related to the well to be used for further well planning, can be found (see section RF ‘Reporting & Feedback’).

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PL. 1.6. MAIN CONTRACTORS

1. DRILLING CONTRACTOR Reference

1.1. Rig inspections:

1.1.1. The rig must be inspected by the Company before the operating daily rate commences.

1.1.2. Any unconformity must be reported and rectified as soon as possible. Any unconformity should be periodically reported to the Company base Office.

1.2. Certification

1.2.1. The following certification shall be available on the rig site: • Cranes

• Lifting equipment (blocks, brakes, links, etc..) inspection • Handling equipment (pipe wrench, elevators, etc.) inspection • Wire and cables

• Air winches (over 200kg pulling force) • Tubular inspection

• BOP inspection 1.3. Registers

1.3.1. The following registers shall be available at the rig site: • Diesel

• Wire and cables • Oils consumed • Accident at work • Personnel on site • Emergency drills

• BOP and choke manifold tests.

1.3.2. The ‘Service Order’ system must be made aware to all personnel involved in operations.

1.4. Manuals

1.4.1. The following manuals shall be available on rig site: • Safety manual

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1.5. Procedures

1.5.1. Emergency procedures for major scenarios such as: • Fire/explosion

• Toxic material release • Man overboard • Well control • Medical emergency • Stability control • Helicopter crash • Rig evacuation

Must be documented and readily accessible at the rig site.

The Emergency Procedures must be readily accessible and made aware to all supervisory personnel on the rig location.

Appendix ‘E’ Drilling Contract ‘Drilling and Workover safety requirements to be complied with by the Contractor’

1.6. Personnel Requirements

1.6.1. All Contractor Personnel at the work site must be fully trained and currently qualified for their job function in accordance with the following minimum standards:

•••• Well control and Blow-out Prevention

The rig manager, toolpusher, driller, assistant driller, and subsea engineer (offshore rig), must posses a current certificate in well control and blow out prevention (biannual) issued by an industry training institute recognised by the Company.

Fire fighting

All supervisory personnel should receive training in Basic Fire Fighting. In addition, those personnel assigned as members of a fire team on offshore rigs should receive formal fire team training.

•••• Survival at sea

All personnel working on an offshore rig must receive survival at sea training given by an industry training institution recognised by the Company.

First aid

All supervisory personnel must possess a valid First Aid Certificate.

•••• Hydrogen sulphide

When drilling operations are to take place in an area where H2S is present or potentially a hazard, all rig personnel must undergo training in the use of breathing apparatus and escape sets.

Appendix ‘E’ Drilling Contract ‘Drilling and Workover safety requirements to be complied with by the Contractor’

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1.6.2. Regularly scheduled safety meetings are required and every person has to attend a safety meeting at least once per hitch (work cycle). Each meeting must be documented, and the minutes must include a list of the attendees, topics covered, and any safety concerns raised and the follow-up action to be taken. The minutes of each meeting have to be passed to the Company Representative.

Appendix ‘E’ Drilling Contract ‘Drilling and Workover safety requirements to be complied with by Contractor”

1.6.3. Health certificates for all the personnel shall be available. 1.7. Personnel qualification

1.7.1. The Contractor’s organisation chart must be available on rig site. 1.7.2. The Contractor will certify that all personnel on duty are qualified for

their job in accordance with the following minimum standards: •••• Derrickman

One year as floorman and shall have attended courses on drilling activities and drilling mud.

•••• Assistant Driller

Two years as derrickman and shall have attended courses on drilling activities and have an adequate basic knowledge of all rig components. He shall attend theoretical and practical Blowout prevention courses every two years and obtain a Well Control Certificate.

•••• Driller

Two years as assistant driller and shall have attended courses on drilling activities and have an adequate basic knowledge of all rig components. He shall attend theoretical and practical Blowout prevention courses every two years and obtain a Well Control Certificate.

•••• Tourpusher

Four years as a driller and shall have undertaken courses and examinations for a toolpusher at a recognised educational Institute. He shall attend theoretical and practical Blow-out prevention courses every two years and obtain a Well Control Certificate.

•••• Toolpusher

One year as tourpusher or four years as driller; as per tourpusher requirements and also have some years of education in scientific or technical subjects. He shall attend theoretical and practical Blowout prevention courses every two years and obtain a Well Control Certificate.

Appendix ‘A’ - section ‘B’ ‘Personnel to be provided by Contractor’

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Rig Manager

Five years as a toolpusher or, if coming from years of education in a scientific or technical field, a minimum of one years training after a toolpusher course. He shall attend theoretical and practical Blowout prevention course every two years and obtain the Well Control Certificate.

Captain or Barge Master

One year as barge engineer; he shall have attended courses in ballast control buoyancy and stability. He shall hold years of education in a scientific or technical subject.

•••• Subsea Engineer

He shall have a through knowledge of, and extensive experience in, the operation and maintenance of BOP, BOP control and subsea equipment. He shall have attended appropriate specialised courses on under water equipment. He shall attend theoretical and practical Blowout prevention course every two years and obtain the Well Control Certificate.

He shall also have some years of education in a scientific or electric/electronic field.

1.7.3. Prior to start with operations, the ‘Curriculum Vitae’ of the Contractors rig personnel shall be sent to the Company Base.

1.8. Accident reporting

1.8.1. An accident reporting procedure, consistent with local rules, must be instituted. The Contractor must report all incidents occurring to Contractor’s or ancillary contractor’s personnel, to the Company on the day that the incident occurs.

The Contractor must provide the Company with a written report of the investigation into each such incident within seven days of the occurrence.

Appendix ‘E’ Drilling Contract ‘Drilling and Workover safety requirements’

1.8.2. On the first work day of each month, the Contractor must provide the Company with a monthly safety report which includes:

• Number of personnel (rig site and support staff) assigned. • Numbers of man-hours worked (rig site and support staff). • Number of fatalities.

• Number of lost time accidents (LTA).

• Number of days away from work resulting from LTA. • Number of no-lost time accidents.

• Number of near misses.

Appendix ‘E Drilling Contract‘ Drilling and Workover safety requirements’

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1.9. Permit To Work system

1.9.1. A ‘Permit to work procedure’ for operations such as hot work, concurrent operations, confined space entry and handling of radioactive materials must be in place.

Appendix ‘E’ Drilling Contract.

1.9.2. The permit system must have a space for the entry of hazard(s) identified and the precautions to be implemented.

The ‘Permit to Work Procedures’ must apply to all personnel on the rig site including the subcontractor’s and third party personnel.

2. MUD LOGGING Reference

2.1. Surface logging service

2.1.1. All paper recording shall be collected and filed day by day. A-1-SS-1722 3-b 2.1.2. Every sensor shall be independent from any other sensor already

existing on the rig.

A-1-SS-1722 3-d

2.1.3. Each measurement system shall be equipped with automatically operating visual and acoustic alarm.

A-1-SS-1722 3-e

2.1.4. Standard parameters shall be displayed and recorded in a double data base (function depth and time) with a clear indication of scale and recorded data.

A-1-SS-1722 3-i

2.1.5. All geological and engineering data shall be loaded on software furnished by the Company. The aim of this activity is the collection, QC and entry of well data into the Corporate DB

A-1-SS-1722 3-i

2.1.6. The contractor shall give engineering assistance. A-1-SS-1722 3-o 2.1.7. Contractor shall inform Company representative about any change of

well conditions, especially for pit level, pressure and mud return from the well.

A-1-SS-1722 3-p

2.2. Operative service

2.2.1. The operating service, carry out on 24 hours basis, shall be request when the Company needs geological surveillance and drilling service with a control of all parameters and recorded data.

A-1-SS-1722 3.1

2.2.2. A team of 4 (four) surface logger; 2 (two) of them can be junior; it is intended that a surface logger junior can be employed only if on the rig there is in service a surface logger senior

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2.3. Reduced service

2.3.1. The company could require a ‘Restricted Service’ that shall have, at least, the following configuration:

• 1 (one) surface logger senior

• Surface Logging unit and relevant equipment • Gas detector

• Degasser

• Standpipe pressure • Pump stroke • Hook load • Mud pit level • Hook movements.

A-1-SS-1722 3.2

2.3.2. Stored data shall be available in ASCII format if requested A-1-SS-1722 3-g 2.4. Mud logging unit

2.4.1. The unit, installed above a skid and in compliance with local laws, shall be equipped with a no break generating set able to supply electric power for at least for 15 minutes; Contractor shall specify the maximum length, breadth, height and maximum weight.

A-1-SS-1722 4.1-b

2.4.2. All equipment must be intrinsically safe and explosion proof. A-1-SS-1722 4.1-c 2.4.3. Recommended spare parts and a complete set of spare sensors shall

be always available in the Unit for a prompt intervention by on site Contractor personnel, in case of a possible malfunction besides, in case of major malfunctioning, the Contractor shall provide for the immediate replacement of the faulty equipment

A-1-SS-1722 4.1-f

2.4.4. Mud logging unit shall be pressurised. 2.5. Personnel

2.5.1. A Senior Surface Logger is required to have a minimum of three years experience working on surface logging service company

A-1-SS-1722 2.1

2.5.2. A Junior Surface Logger is required to have a minimum of one year experience working on surface logging service company.

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2.5.3. Senior Surface Logger and Junior Surface Logger:

• ‘Well control course’ issued by Company IWCF approved.

• ‘Survival course’ (for offshore activity) issued by Company approved.

A-1-SS-1722 2.1

2.5.4. Personnel qualification cards shall be duly and accurately filled in (Annex 9.3), and full details on courses attended, and certificates shall be provided.

A-1-SS-1722 2.3

2.6. Radioactive sources

2.6.1. In absence of local lows or regulations the following criteria could be a Worldwide guideline:

1. Certification to able the use of radioactive sources released from competent authority

2. Particulars of the deputy “Qualified Expert” or his representative 3. Radioactive safety detailed report drawn up by Qualified expert 4. Procedure to adopt in case of tools failure

5. Particulars of the “Qualified Doctor” for the Medical Surveillance 6. Statement that the radioactive source operative activity will be

performed by suitable personnel with medical examination performed in the last 6 months

7. Classification of personnel in terms of radioactive exposure. 8. Declaration stating that land transports are carried out using

vehicles owned by Contractor

Policy for to perform operations by radioactive sources

3. MUD SERVICE, CHEMICAL SUPPLY, CENTRIFUGES RENTAL Reference

3.1. Personnel

3.1.1. Senior Fluid Engineer is required to have a minimum of 5 (five) years field experience as Fluid Engineer.

A-1-SS-1719 4.1

3.1.1.1. He shall be in possession of the following certificates: • ‘Mud engineer course’

• ‘Completion fluid course’

• ‘Survival course’ (for offshore activity) issued by approved Company

• ‘Basic well control course’ IWCF or IADC Wellcap approved

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3.1.2. Fluid Engineer is required to have a minimum of one years field experience as Fluid Engineer.

A-1-SS-1719 4.2

3.1.2.1. He shall be in possession of the following certificates: • ‘Mud engineer course’

• ‘Completion fluid course’

• ‘Survival course’ (for offshore activity) issued by approved Company

• ‘Basic well control course’ IWCF or IADC Wellcap approved

A-1-SS-1719 4.2

3.1.3. Technical Supervisor is required to have a minimum of eight years field experience as Fluid Engineer.

A-1-SS-1719 4.3

3.1.4. Laboratory technician is required to have at minimum three years experience in laboratory test as per API RP 13I “Standard Procedure for Laboratory Testing Drilling Fluid” and as per API RP 13J ‘Testing Heavy Brines’

A-1-SS-1719 4.4

3.1.5. During the activity, the Contractor shall supply the following documentation:

• Fluid program (if requested) • Daily mud report.

• End phase mud report. • Final well mud report.

A-1-SS-1719 6

3.2. Mud chemicals identification

3.2.1. For each product , contractor shall furnish the following informations: • Commercial name

• Chemical name and composition • Products classification

• Product application and recommended concentration • Type of packing (sacks, drums etc.)

• Material safety data sheet.

A-1-SS-1719 5.5

3.2.2. Contractor shall also inform of any possible danger in using the products offered (HSE information).

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3.3. Equipment

3.3.1. Contractor shall have the availability, when needed a specific technical support, of a laboratory able to perform tests according with API RP 13B-1, 13B-2 (Standard Procedure for Field Testing Drilling Fluids) and with API RP13I-2 (Standard Procedure for Laboratory Testing Drilling Fluids).

A-1-SS-1719 5.3

3.3.2. The main performance request is: • ‘G’ factor up to 3.000

• must be able to work on 5 microns size solids • high speed

• must be able to treat up to 18m3/h • RPM up to 3.300

3.3.3. On request, Contractor must be able to provide centrifuges with independent generator.

A-1-SS-1719 5.4.1

3.3.4. Nothing shall relieve the contractor of the responsibility for performing such analysis, tests, inspections and other activities that he considers necessary to ensure that the product, and workmanship are satisfactory for the service intended, or as may be required by common usage or good practice.

A-1-SS-1719 3

4. CEMENTING SERVICE Reference

4.1. Engineering

4.1.1. The contractor shall provide an adeguate service for engineering support which shall include the following duties:

A-1-SS-1729 5.1

4.1.2. • Drawing up of cement slurry programmes

• Supplying all the laboratory equipment necessary for testing slurries, spacers and API tests on chemical products including quality control on cement,

• Computer monitoring for cementing operations, real time acquisition of data (delivery, pressure, density) for the possible of a subsequent processing of the data recorded,

• Drawing up of reports concerning the works carried out and relevant evaluation.

• Drawing up a final well report.

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4.2. Personnel

4.2.1. The Contractor shall supply professional curricula for all personnel he intends to use, indicating background, training and work experience.

A-1-SS-1729 5.2

4.2.2. All personnel involved in offshore operations shall hold a survival at sea certificate issued by a Company-approved Organisation or Institute.

A-1-SS-1729 5.2

4.2.3. An operator is required to have a adeguate skill acquired through an appropriate training course and with at least five years of field experience

A-1-SS-1729 5.2.1

4.2.4. Helper is required to have an adequate skill acquired through an appropriate training course.

A-1-SS-1729 5.2.2

4.2.5. Contractor will guarantee availability of a technical supervisor from a base close to the area of operation.

A-1-SS-1729 5.2.3

4.2.6. Contractor shall provide a laboratory technician to perform the required tests on cement, cement additives and cement slurry.

A-1-SS-1729 5.2.4

4.3. Equipment

4.3.1. The design of equipment and units shall ensure safety operations. A-1-SS-1729 5.3 4.3.2. Cement Pumping Unit must be provided with:

• Twin triplex pumping units for pumping the cement slurry.

• The pumping unit working pressure shall be 10,000 psi and 500 HHP.

• The engines will be equipped with spark arresting air filters and air inlet shut-off valve

• The unit shall include two displacement tanks of 1,500/1,600litres capacity each.

• The tanks will be provided with appropriate level gauges calibrated in liters.

• Cement pump pressure gauge 15,000 psi fitted with a pre-select pump cut out system.

A-1-SS-1729 5.3.1

4.3.3. Recirculation Mixing System shall grant mixing of the cement slurry and its recirculation before it is pumped into the well.

It will include a 1,300-1,500ft basin divided into two parts, each supplied with a mixer.

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4.4. Batch Mixer shall grant the ‘surface’ mixing of determined quantities of cement slurry, spacers and/or other fluids. It will consist of tanks of capacity ranging from 3 to 30m3, each one self sufficient, provided with agitators, centrifugal pump and gauge to measure the pumped quantities.

A-1-SS-1729 5.3.3

4.5. Documentation

4.5.1. Contractor will prepare and submit for approval, before the execution of each service, a detailed ‘Operations Program’.

A-1-SS-1729 6.2

4.5.2. After the execution of the service, Contractor shall provide to Company Operations a ‘Job Report’

A-1-SS-1729 6.3

4.5.3. At the end of the operations, Contractor shall prepare the final report which shall include all the ‘Job Report’, ‘Operation Program’ and final considerations and suggestions, reason for the deviation from the program

A-1-SS-1729 6.4

Reference List:

‘Standard Specifications for Drilling and Completion Fluid Services’ STAP-A-1-SS-1719 ‘Technical Specifications for Surface Logging’ STAP-A-1-SS-1722 ‘Cementing and Pumping Service for Drilling Completion

and Workover Activity’ STAP-A-1-SS-1729

‘Drilling Contract ‘Drilling and Workover safety requirements. Appendix ‘E’’

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PL. 1.7. ESTIMATED COSTS

1. BUDGET Reference

1.1. The Well Area Department, requested by the ‘Project’ or ‘Exploration Manager’, will make cost estimation of the planned well (based on the best information available at the time), this will be inserted into the yearly budget.

2. COSTS Reference

2.1. Before starting the activity, the Well Area Department, requested by the ‘Project’ or ‘Exploration Manager’, will make a cost estimation of the forthcoming well. It will be split by class of cost, based on the progress chart included in the drilling (or completion, or workover) program, on the selected rig rates and on the other acquired contracts.

2.2. The Estimated Cost shall include:

• Materials (casings, wellhead, mud, etc.) • Services (contractors)

• Standard costs (supply vessels, helicopters, transports, etc.) • Logs (from District Geological Department)

• Supervision and operative base costs.

2.3. ‘Project’ or ‘Exploration Manager’, after receiving the Estimated Cost, will check the conformity with the original budget (at this point a budget revision may be made) and will start the procedure for the Job centre opening.

2.4. After Job Centre opening the Estimated Costs can be input in S3C (if available)

2.5. Draw-up a Progress Cost Chart (depth versus cost) and follow up the actual daily costs comparing the same with the previously estimated costs, in order to evaluate the activity performance.

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PL2. GEOLOGICAL AND DRILLING WELL PROGRAMME

The purpose of this document is to provide general guidelines in order to correctly plan a well and prepare a proper Geological and Drilling Well Programme.

It gives the ‘best practices’ covering all aspects in planning a well, in an orderly sequence of steps that must be followed when a Geological and Drilling Well Programme is being prepared.

The Geological and Drilling Well Programme defines the objectives/targets of the well, reports the basic engineering data, specifies equipment and procedures necessary to drill safely a well, provides a realistic forecast of its final cost.

The last column in the document indicates the available reference documents covering the particular topic.

The list of reference documents and available computer programmes are reported at the end of each section.

Continuous references to operating document sections are necessary for further investigation by the user.

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PL. 2.1. GEOLOGICAL AND DRILLING WELL PROGRAMME STRUCTURE

1. NUMBER OF THE SECTIONS Reference

1.1. The ‘Geological and Drilling Well Programme’, from now on defined as ‘G&DWP’, comprises of four sections:

• GENERAL INFORMATION (Section 1)

• GEOLOGICAL PROGRAMME (Section 2) • OPERATION GEOLOGY PROGRAMME (Section 3)

• DRILLING PROGRAMME (Section 4)

P-1-M-6100 16 P-2-N-6001E (introduction)

1.2. The G&DWP will be drawn in accordance with local regulations, and ENI Agip District or affiliate internal rules, taking into account:

1. IGUs Operation Geology Procedures (Specific Agip Rules Nr. 1.4.15.3-8; Procedure Di Geologia Operativa Vers. 0.0 07/94 GESO)

2. FGUs Subsurface & Operation Geology Procedures.

3. STAP-P-1-M-6060 (Best Practices and Minimum Requirements for Drilling & Completion Activities) and all the documents concerning the planning and execution of the well, cited in the same BP&MR.

4. Operative Procedure for drafting the Well Drilling Programme, STAP-P-1-N-6001E

5. Procedures for well seismic acquisition

6. Procedure for the location of offshore and onshore wells 7. Local law and legislative decrees

8. Well Name Designation

9. Rules for Management and Control of Technical Documents 10. Standardisation of documents

P-1-M-6100 16 P-2-N-6001E (introduction)

2. PRINT MODEL Reference

2.1. Whenever Microsoft Office products are available in the Eni Agip districts or Affiliates, for preparing each section of the ‘G&DWP’’, it is recommended to use the model built in “WORD 6”, titled ‘WLPR_ING.dot’

P-1-M-6100 16 P-2-N-6001E 1

2.2. The four sections composing the G&DWP’, are identified by the name of the well.

P-1-M-6100 16 P-2-N-6001E 3 2.3. In order to make the Well Drilling Programme easily manageable’

either in E-Mail or with shared network disks, the graphic representations must be in an electronic format

P-1-M-6100 16 P-2-N-6001E 5

Reference List:

‘Drilling Design Manual’ STAP-P-1-M-6100

‘Operative Procedure for Preparing the Geological and Drilling

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PL. 2.2. GENERAL INFORMATION (SECTION 1)

1. GENERAL Reference

1.1. This section will be written in close co-operation by the Drilling & Completion and Subsurface Geology Departments of the Affiliate.

P-1-M-6100 16 P-2-N-6001E 7.1

1.2. All depths, both for offshore and on-shore wells must be referred to the Rotary Table.

P-1-M-6100 16 P-2-N-6002E 7.1

1.3. Section 1 comprises the chapters numbered and titled as follows: 1.1. GENERAL WELL DATA

1.2. WELL TARGET

1.3. GENERAL RECOMMENDATIONS

1.4. GENERAL CHARACTERISTICS OF THE RIG, BOP STACK AND SAFETY EQUIPMENT

1.5. LIST OF THE MAIN CONTRACTORS 1.6. CONTACTS IN CASE OF EMERGENCY 1.7. REFERENCE MANUALS

1.8. MEASUREMENT UNITS

P-1-M-6100 16 P-2-N-6001E 7.1

2. GENERAL WELL DATA Reference

2.1. The ENI Agip District or Affiliate’s Drilling & Completion Department will give the Well Profile, the Time Vs Depth Diagram, and the Location Layout.

P-1-M-6100 16 P-2-N-6001E 7.1.1

2.2. Identificative Well Data

2.2.1. • Affiliate or District in charge • Name and acronym of the well • Initial classification (LAHEE) • Expected Final depth

• Permission/concession • Operator

• Older of the Permit/ Lease (shares specified as %) • Municipal Authority (on-shore wells)

• Province (on-shore wells)

• Harbour-master office (off-shore wells) • Zone (off-shore wells)

• Distance Rig/coast (off-shore wells) • Distance Rig/operative base

• Altitude (on-shore wells) • Sea Depth (off-shore wells)

P-1-M-6100 16 P-2-N-6001E 7.1.1

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2.3. Well Profile

2.3.1. The Well Profile contains a Table showing, against the depth (total vertical depth), at least the following data:

• Pore pressure gradient • Formation fracture gradient • Overburden gradient • Mud weight

• MAASP

• Max differential pressure • Drilling balance pressure • Casings setting depth • Static temperature gradient

2.3.2. Diagram showing all above information, including expected lithology.

3. GENERAL RECOMMENDATIONS Reference

3.1. Will be written in close co-operation between the Drilling & Completion and Subsurface Geology Departments.

P-1-M-6100 16 P-2-N-6001E 7.1.3

3.1.1. LWD operation joint Considerations: • The more suitable tools.

• Their positioning in the BHA. • The drilling parameters to be used.

• The stabilisers are correctly positioned in the BHA, according to LWD tools.

• The maximum admissible flow through the LWD tools must not be exceeded, otherwise substantial erosion damage will occur inside the tool.

• Limiting the solid content in the mud in order not to exceed the LWD tools limitations.

P-1-M-6140 13.1.2

3.1.2. To highlight the possible operative problems envisaged P-2-N-6001E 7.1.3 4. GENERAL CHARACTERISTICS OF THE RIG, BOP STACK AND

SAFETY EQUIPMENT

Reference

4.1. Contains the information of Tables PL.02.02-1 and PL.02.02-2 P-2-N-6001E 7.1.4.1 P-2-N-6001E 7.1.4.2

5. LIST OF THE MAIN CONTRACTORS Reference

5.1. Will be written by the Affiliate’s Drilling & Completion Department in co-operation with the Subsurface Geology Department.

P-1-M-6100 16 P-2-N-6001E 7.1.5

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6. CONTACTS IN CASE OF EMERGENCY Reference

6.1. Will be written by the ENI Agip District or Affiliate’s Drilling & Completion Department and shows:

1. The ‘flow chart’ of emergency contacts

2. The telephone numbers of the people in charge of the emergency.

P-1-M-6100 16 P-2-N-6001E 7.1.6

7. REFERENCE MANUALS Reference

7.1. Will be written by the ENI Agip District or Affiliate’s Drilling & Completion Department. It consists of a list of basic manuals to be referred for planning and implementation phases of the well.

P-1-M-6100 16 P-2-N-6001E 7.1.7

8. MEASUREMENT UNITS Reference

8.1. Will be written in strict co-operation between the ENI Agip District or Affiliate’s Drilling & Completion and Subsurface Geology Departments. It will contain a list of the units of measurement of the main parameters used in the Geological Operation and Drilling sections.

P-1-M-6100 16 P-2-N-6001E 7.1.8

9. SIGNATURE Reference

9.1. The names and signatures of the technicians and managers involved in the preparation and control of the section will always be specified.

P-1-M-6100 16 P-2-N-6001E 7.1.9

Reference List:

‘Drilling Design Manual’ STAP-P-1-M-6100

‘Drilling Procedures Manual’ STAP-P-1-M-6140

‘Operative Procedure for Preparing the Geological and Drilling

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ITEM DESCRIPTION Contractor

Rig name Rig type

Rotary table elevation on ground level Only on-shore rigs Rotary table elevation on sea level Only off-shore rigs Number of places available Only off-shore rigs Power installed

Drawwork Type

Rig potential with 5” DP’s

Max. operative water depth Only off-shore rigs Clear height rotary beams/ground level Only on-shore rigs Top Drive System type

Swivel assembly working pressure If without Top Drive System Dynamic hook load

Set back capacity

Deck load Only for semisub rigs

Total load Only for semisub rigs

Rotary table diameter Rotary table capacity

Stand pipe working pressure Mud Pumps number and type Available liner size

Total mud capacity

Shaleshaker number and type

Drinking water storing capacity Only for off-shore rigs Industrial water storing capacity

Gasoil storing capacity Barite storing capacity Bentonite storing capacity Cement storing capacity

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ITEM DESCRIPTION Diverter type

Diverter size

Diverter working pressure BOP stack type

BOP size

BOP working pressure

Choke Manifold size and working pressure Kill Lines size and working pressure Choke Lines size and working pressure BOP Control Panel type

BOP Control Panel location Inside BOP type

Inside BOP location

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PL. 2.3. LAYOUT OF THE DRILLING PROGRAMME (SECTION 4)

1. BASIC REQUIREMENTS Reference

1.1. The Drilling Program must accomplish with basic requirement setforth in the Geological Program in terms of total depth, targets and reservoir specified needs.

P-1-M-6100 16 P-1-N-6001E 6

1.2. Particularly, paragraphs 4.2.1 (Forecast on pressure and temperature gradients) and 4.2.2 (Drilling problems) will be made in co-operation between Drilling & Completion and Geology District/Afiiliate Departments

P-1-M-6100 16 P-1-M-6100 16.4.4

1.3. All depths, both for offshore and on-shore wells must be referred to the rotary table. If the rotary table elevation is not yet available, it will be assumed based on past experiences with similar drilling rig types

P-1-M-6100 16 P-1-N-6001E 6

1.4. Section 4 will comprise the sub-sections numbered and titled as follows:

List of contents:

4.1 OPERATIVE SEQUENCE 4.1.1. Preliminaries

4.1.2. Conductor pipe phase 4.1.3. Surface hole phase 4.1.4. Intermediate phases 4.1.5. Final phase 4.1.6. Testing 4.1.7. Completion 4.1.8. Well abandoning 4.3 WELL PLANNING

4.2.1. Pressure and temperature gradients forecast 4.2.2. Drilling problems

4.2.3. Casing setting depths 4.2.4. Casing design 4.2.5. Mud programme 4.2.6. Cementing programme 4.2.7. BOP 4.2.8. Wellhead 4.2.9. Hydraulic programme 4.2.10. B.H.A. and stabilisation 4.2.11. Bits and Drilling Parameters

4.2.12. Well trajectory (directional drilling plan) Annexes and/or figures

P-1-M-6100 16 P-1-N-6001E 6.1

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1.5. The Drilling Programme index and numbering of sections must be laid down as shown above; whenever a topic is not applicable to the actual programme, the relevant sections/paragraphs shall be marked with ‘not applicable’.

P-1-M-6100 16 P-1-N-6001E 6.1

Reference List:

‘Drilling Design Manual’ STAP-P-1-M-6100

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PL. 2.4. OPERATIVE SEQUENCE (SECTION 4)

1. PRELIMINARY INFORMATIONS Reference

1.1. It will detail operations to be undertaken before the spud-in. P-1-M-6100 16

2. CONDUCTOR PIPE PHASE Reference

2.1. The following information must be provided: 1. Driven conductor pipe:

• Type of Pile Hammer • Diameter of the CP • Weight of the CP • Steel grade of the CP • Connection Type • Expected driving depth

• Refusal point (1,000 strokes/m)

• Remarks/off-set driving data if available 2. Drilled conductor pipe:

• Diameter of the bit

• Drilling procedures for hole cleaning • Final phase depth

• Diameter of the CP • Weight of the CP • Steel grade of the CP • Connection type • Cementing procedures • Remarks

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3. SURFACE PHASE Reference

3.1. The following minimum information must be included:

• Description of difficulties and reference to a specific paragraph for further details

• Description of shallow gas, anticollision procedures (if applicable)

• Hole size and other requirements (hole opened-underreamed) • Measured shoe depth and, (if applicable) vertical depth at the

end of the phase

• Diameter, steel grade and weight of the casing

• Brief description of operations (drilling, casing run, cementing) • Mud type and density and their adjustment for the entire phase

length

• Survey and directional drilling requirements, if any • Well head test pressure value

• Diverter/BOP stack installation • Remarks

P-1-N-6001E 6.2.3

4. INTERMEDIATE PHASES Reference

4.1. The following minimum information must be included:

• Description of difficulties and reference to a specific paragraph for further details

• Reference to anticollision procedures (if applicable)

• Hole size and other requirements (hole opened-underreamed) • Measured depth and, (if applicable) vertical depth at shoe depth • Eventual coring requirements and logging programme

• Diameter, steel grade and weight of the casing or liner • Estimated fracture gradient below the previous casing shoe • Requirements for FIT. or LOT. (if applicable)

• Brief description of operations (drilling, casing run, cementing) • Mud type and density and their adjustment for the entire phase

length

• Survey and directional drilling requirements, if any • Hanging casing in well head (with or without overpull) • Value of the liner head seal test pressure (if applicable) • Casing and well head test pressure value

• BOP stack test • Remarks

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5. FINAL PHASE Reference

5.1. The following information is included:

• Description of difficulties and reference to a specific paragraph for further details

• Reference to anticollision procedures (if applicable)

• Hole size and other requirements tied with drilling operations in target/reservoir (e.g. target details, eventual use of non damaging fluids, depth of multiple targets, etc.)

• Vertical and measured total depth

• Brief description of operations (drilling, casing run, cementing) • Eventual requirements for coring and/or testing operations • Logging programme

• Diameter, steel grade and weight of the casing or liner • Estimated fracture gradient below the previous casing shoe • Requirements for FIT or LOT (if applicable)

• Mud type and density and their adjustment for the entire phase length

• Survey and directional drilling requirements, if any

• Hanging casing in well head (if applicable, with or without overpull)

• Hanging of liner and liner head seal test pressure (if applicable) • Casing and well head test pressure values

• BOP stack test • Remarks

P-1-N-6001E 6.2.5

6. TESTING Reference

6.1. On the basis of information available during the planning phase this paragraph should describe operations related to the well testing.

P-1-N-6001E 6.2.6

7. TYPE OF COMPLETION Reference

7.1. On the basis of information available during the planning phase, this paragraph should describe the sequence of operations and main information on the type of the foreseen completion.

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8. WELL ABANDONMENT Reference

8.1. On the basis of information available during the planning phase sets out a programme for well abandoning, describing the operations to perform for the abandonment (temporary or permanent) of the well, including the following minimum information:

• Open hole abandonment procedures

• Tested intervals perforations squeeze-off procedures • Temporary abandonment of opened producing intervals • Setting of bridge plugs - cement retainers

• Sequence and height of cement plugs and their eventual testing • In-hole fluids characteristics

• Eventual temporary completion/killing string composition • Eventual casing cutting and recovery specifications • Well head/mud line temporay abandonment/recovery • Surface restoration, if any.

P-1-N-6001E 6.2.8

Reference List:

‘Drilling Design Manual’ STAP-P-1-M-6100

(46)

PL. 2.5. SOFTWARE (SECTION 4)

1. STANDARDS Reference

As concerns:

• Analysis of pressure and temperature gradients • The casing point,

• Choke margin and differential pressure, • Casing design,

• Hydraulic programme,

• The design and control of directional drilling.

Reference should be made to the use of calculation models and formats of the IWIS system if available.

P-1-N-6001E 6.3

2. ALTERNATIVES Reference

2.1. COMPASS for the design of directional drilling and anticollision analysis for wells.

P-1-N-6001E 6.3

2.2. Concerning the evaluation of stresses induced: • In the drilling string,

• In casing and liners

Estimates can be derived from Maurer Engineering Inc.’s Torque & Drag -Casing Wear software.

P-1-N-6001E 6.3

2.2.1. These evaluations must be run for all the deviated/deep wells and duly checked for calibration while drilling.

P-1-N-6001E 6.3

Reference List:

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PL. 2.6. PRESSURE GRADIENTS PROGNOSIS (SECTION 4)

1. PRELIMINARY DATA COLLECTION Reference

1.1. Geological data 1.1.1. Structure map. 1.1.2. Lithological column. 1.2. Seismic data

1.2.1. Seismic data can be used to estimate the formation pressure and give an indication of any pore pressure abnormalities. In all cases, it must be considered an approximate solution.

P-1-M-6130 3.6

1.2.2. Offshore seismic data1 can be used to determine the possible presence of shallow gas.

P-1-M-6130 3.6

1.2.3. Seismic data are usually given as vertical average velocity (RMS-velocity, m/s), Vs ‘two way travel time’ (10-3 sec), for a single CDP2(Common Depth Point).

P-1-M-6130 3.6

1.3. Offset/reference well data 1.3.1. Drilling records - Drilling reports:

The drilling parameters, the recording and interpretation of which only give a qualitative evaluation of overpressure (i.e., its possible presence and the location of its top), include the following:

• Drilling rate • Torque • Overpull

• Caving and hole tightening • Pump pressure and flow rate • Level in mud pits

• Amount of cuttings at shale-shaker • Mud pH and resistivity

• Resistivity of shales collected at shale-shaker • Amount of gas present (gas shows)

• Mud temperature

• Montmorillonite percentage.

ARPO-02/A

P-1-M-6130 4.1

1 In this case, a high resolution seismic is performed, which usually investigates formations down to 500 meters depth below the seabed.

2 When the relative position of the shot points and geophone locations are known, is possible to identify a series of seismic traces that are reflected from approximately the same position on reflecting bed, this position is known as common depth point (CDP).

Figure

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