Detailed individual well programmes will be issued for all wells to be tested, which includes development, appraisal and exploration wells.
Each programme will include contents, the exact details of which will be well specific dependent upon the well status and expected well parameters. The following is the contents of a typical test programme.
a) Test Objectives.
b) General well data and perforating details.
c) Summary of test programme.
d) Guidelines for liner lap test and space-out calculations.
e) Sequence of operations for running downhole tools and surface equipment rig up.
f) Flowing procedures for each test conducted.
Also included will be the following, possibly as appendices:
• Hole cleaning and displacement to brine procedure.
• Stimulation programme (if applicable, e.g. coil tubing rig up).
• Sampling requirements.
Detailed string diagrams and equipment layout diagrams will be included, as well as all relevant pressure testing procedures and equipment ratings.
11.1. GENERAL
a) The testing string shall normally be made up of tubing. The use of drill pipe is only allowed in limited fluid entry test (DST).
b) All equipment and material used in production tests shall be H2S service.
c) Governmental bodies charged with the control of drilling activity and/or other state agencies shall be notified, if required, on test execution with advanced notice.
d) Before starting and upon completion of flaring operations, company shall give notice to competent authorities.
e) Prior to the start of casing perforating, visitors and non essential personnel shall leave the rig and rig personnel shall be limited to the minimum.
f) Prior to start well testing operations a meeting shall be held by wellsite Company Drilling and Completion Supervisor and Drilling Contractor Toolpusher to make all personnel involved are acquainted with detailed operating program (procedures and rules).
11.2. TUBING HANDLING
a) Tubing must always have the pin and box protectors in place while being handled.
b) Tubing should always be handled with either certified nylon or cable slings or with single joint elevators when picking up or running out the tubing from the Vee door.
Never Use Hook Ends
c) Avoid rough handling of the tubing which may damage the joint.
d) Never allow the tubing to be dropped when loading and or moving.
e) Never bundle tubing in greater quantities than ten.
f) Tubing joints will be supplied in singles with protectors fitted and should be laid down on deck in even layers, no more than 10 levels high.
g) After removing the protectors, the connections should be thoroughly cleaned and inspected after drifting. One of the following Agip approved methods of cleaning should be used:
• Use of non-metallic brush and a recommended solvent.
• Steam clean using a high pressure jet of steam and solvent.
• A rotary bristle brush jetted water and cleaning solvent.
h) The pins and boxes should be visually inspected for any damage by a qualified Tubing Inspector.
i) Reject and damaged joints should be painted red and documented and then returned to the onshore base for remedial work if necessary.
j) The tubing should then be drifted/measured, and each joint numbered in the middle of the joint with white paint and strapped and tally recorded (drift the pipe box to pin at all times).
k) After the threads have been cleaned and inspected it is important they be protected from corrosion. Never leave the threads for longer than two hours without corrosion protection.
l) If the connections are cleaned more than two hours but less than 12hrs prior to the joint being run, then a light oil should be used to prevent corrosion. If it is to be longer than 12hrs then a light film of dope and protectors should be reapplied.
11.3. RUNNING AND PULLING
a) Any protective coating which has been applied to the tubing for storage should be cleaned off before the tubing is run for a DST. This can probably be done most conveniently during the procedures for casing cleaning and displacement to brine.
With the tubing string in the hole, proprietary cleaning fluids can be circulated to remove the coating material.
b) Ensure all accessories/tools are on the rig floor and are in prime condition ready to run the tubing, i.e. pup joints, crossovers, stabbing guides, single joint elevators, modified pipe dope, dog collar, slip type elevators.
c) Ensure the safety clamp (dog collar) is correctly sized ready for the 41/2” tubing (the dog collar should be used above the rotary table slips until the first 20 joints or until the Company Production Test Supervisor thinks enough weight is available to properly set slips.
d) Slip type elevators to be used at all times. Check the elevator setting plate for proper operation. This will ensure the elevators set on the body of the pipe, not on the upset or connection area.
e) Check the alignment of the rotary table and the elevators.
f) During make-up, the tubing must be allowed to spin freely, which may necessitate slacking off on the blocks until the weight is off the elevators.
g) Use power tongs and integral hydraulic back-up for all make-up and break-outs at recommended optimum torque valves. The use of a torque/turn analysis system, such as Weatherford’s ‘Jam’ system, is recommended.
h) The power tong lead line should be attached to a back-up post and should be labelled. Ideally the angle with the tong arm should be 90o.
i) When pulling the tubing, always use a wiper rubber.
j) Always install the pin protector fully before standing the tubing in the derrick.
k) Never use a sledge hammer on connections to assist the break-out.
l) Ensure tubing set back in the derrick is properly supported with a belly band to prevent undue bending.
m) Always use the manufacturers recommendations for running, pulling or make-up.
n) Check that the calibration of the torque machine is valid.
o) A tubing inspector or the Company Production Test Supervisor must be on the rig floor witnessing the make-up of all the joints that make-up the test string.
p) If there is insufficient space in the derrick to store both drillpipe (51/2”, 31/2”) and tubing, then lay down drill pipe in preference.
11.4. PACKER AND TEST STRING RUNNING PROCEDURE
Before running the test string all the earlier procedures should have been carried out to prepare the well, tubing and tools for the test. The procedure for running the test string will vary depending upon the equipment used.
The main difference in running the string is due to the type of packer being used and whether it is from a floater or a Jack-up rig. Example test string running procedures are given below for running strings with both types of packers from a semi-submersible drilling unit. For a Jack-up, the SSTT would be replaced by the sub-surface safety valve.
The specific running procedures will always be detailed in the well specific test programme.
11.5. RUNNING THE TEST STRING WITH A RETRIEVABLE PACKER 1) Run a junk basket on wireline to below the packer setting depth.
2) Before running the test string, hold a brief safety meeting on the drill floor and re-emphasise the precautions that should be taken during operations.
3) Ensure a Kelly Cock is situated on the drill floor for emergency use.
4) The downhole gauges should be programmed and installed into the gauge carrier(s) in advance.
5) Make up and run the TCP gun assembly.
6) Install the packer assembly as per the string diagram.
7) Continue making up the string using a back-up tong to ensure that the packer is not turned to the right.
8) Pick up the test tools in reverse running order and make them up to the correct torque.
Care should be taken that no connections are backed out and that the packer is not turned to the right.
9) Run the tools into the well and make up the crossover and first joint(s) of intervening drill collars.
10) Ensure the BOP blind rams are open before the test tools reach them.
11) Continue running the minor string as per the string diagram, until all the collars and slip joints have been made up. Note the string weight.
12) When the first tubing joint of the major string has been run, pressure test the minor string.
13) Run the tubing.
14) When the test string has been run half way into the well, the tubing should again be pressure tested (optional).
15) If there is a liner hanger above the packer setting depth, run the tailpipe and packer through the liner hanger slowly.
16) When all major string has been run, it is recommended that the string should again be pressure tested.
17) Pick up the SSTT assembly and make up to the tubing and function test.
18) Continue running the landing string, strapping the SSTT hoses to the tubing.
19) Install the lubricator valve.
20) Continue running the landing string and the space-out pup joints, strapping all hoses to the pipe.
21) Install the surface test tree and 50ft bails or CTU lifting frame.
22) Run a GR/CCL log to verify the packer setting depth. (Refer to appropriate section according to gun type).
23) Set the packer and set down weight until the fluted hanger lands out in the wellhead.
24) Set the packer and set down weight until the fluted hanger lands out in the wellhead.
25) Run a GR/CCL log to verify the packer setting depth. (Refer to appropriate section according to gun type).
26) Carry out the hook-up and final pressure testing.
27) The well is now ready to be perforated and tested.
11.6. RUNNING A TEST STRING WITH A PERMANENT PACKER 1) Run a junk basket to below the packer setting depth 2) A safety meeting should first be held on the drill floor.
3) If the TCP guns are being run below the packer, make up the TCP gun assembly.
4) Install the packer and packer tailpipe assembly as per the programme. The packer should be spaced out so that it is at least 5ft away from a casing collar.
5) Run the packer/TCP assembly on drillpipe with a radioactive marker sub, one stand above the setting tool.
6) Open the blind rams before the test tools reach them.
7) Rig up and run a GR/CCL and correlation gun setting depth.
8) Rig down the wireline. Adjust the setting depth as required.
9) Set and pressure test the packer. Pull the work string.
10) Ensure a Kelly Cock is situated on the drill floor for emergency use.
11) The downhole gauges should be programmed and installed into the gauge carrier(s) in advance.
12) If the TCP guns are to be run on the string, make up the gun assembly.
13) Install the space out tubing and then the seal assembly.
14) Continue and pick up the DST tools in reverse running order and make them up to the correct torque. Care should be taken that no connections are backed out.
15) Continue running the minor string as per the string diagram, until all the collars and slip joints have been made up. Record the string weight.
16) When the first tubing joint of the major string has been run pressure test the minor string.
17) Run the tubing.
18) When the test string has been run half way into the well, the tubing should again be pressure tested (optional).
19) If there is a liner hanger above the packer setting depth, run the end of the string slowly through the liner hanger.
20) When approaching the permanent packer, pick up by one tubing joint to check the up weight and slack back down to check the down weight.
21) Run in slowly and tag the packer. Mark the pipe and calculate the spacing out.
22) It is recommended that the string be pressure tested.
23) Pull slowly out of the packer and pull back the pipe to install the SSTT.
24) Space out and pick up the SSTT assembly, install onto the tubing and function test.
25) Continue running the landing string, strapping the SSTT hoses to the tubing.
26) Install the lubricator valve.
27) Continue running the landing string, strapping all hoses to the pipe.
28) With the seal assembly still out of the packer, install the surface test tree attached to the final joint. Rig up the 50ft bails or CTU lifting frame.
29) Carry out the hook-up pressure test.
30) Slowly lower the seal assembly into the packer and land the SSTT hanger.
31) Conduct the final string pressure tests.
32) The well is now ready to be perforated and tested.