WELL TESTING OPERATIONS BEST PRACTICES

11/8/04

PRE-TEST

1) Order test string (Usually 3-1/2” PH-6) to be on location several days prior to start of test. Tubing should be hydroblasted and inspected. (This can take 3 or 4 days to complete).

2) Have drill collars inspected and connections redressed if necessary prior to DST. Drill collars must be free of scale.

3) If heavy brines are to be used (> 86 PCF), consider having frac tanks on location to store brine and prevent contamination of the mud system.

4) Notify service companies early of possible test. Engineer should provide Pre-test data a minimum of two weeks prior to test.

5) Consider well testing requirements when pressure testing casing and liners.

TEST

1) Scale has been the cause of numerous failures in the past year especially when locking out TST/TFTV valves. Minimize the problems from scale by:

  1. Making sure tubing received from Shedgum has been hydroblasted and externally wirebrushed immediately prior to delivery.
  2. Use drill collars that have been cleaned and are free of scale.
  3. If possible, make trip with tubing prior to running test tools.
  4. Prior to locking open TST/TFTV valves, reverse circulate one tubing capacity. Minimize the time from shutting down pumps to applying pressure to lock open valve.
  5. Rattle tubing with rubber hammer when running out of derrick.
  6. If tubing is to be racked in derrick after test, pump heavy slug and chase with water prior to POH. Pour a bucket of diesel and/or corrosion inhibitor into pipe every 20 stands or so to help prevent scale buildup. Clean and dope box and pin connections and install protectors.
  7. Tubing that has been in derrick for more than a couple of weeks can develop scale. Tripping prior to running test tools is recommended.

2) Detailed written “Game Plan” should be completed and distributed prior to start of testing operations by the responsible drilling foreman.

3) Hold pre-job meeting with all relevant personnel.

4) Specify running procedures for test assembly and tubing. (Make up torque, doping procedures, running speed, stabbing guides, etc.)

5) Rattle tubing with rubber hammer as picked up.

6) First pressure test (After picking up test assembly and 1 jt tubing) is critical. Monitor until confident that there are no leaks.

7) Minimize the number of times the DST packer is set/unset during a test as well as the number of times downhole DST tools are functioned. More usage normally equates to failures. Optimally, set/unset packer one time during DST.

8) Circulation rates during displacements should be controlled as per service company recommendation. Usually 2-3 BPM.

9) Install chart recorder on annulus to monitor functioning of tools. Log should be kept on drill floor recording casing pressure every 30 minutes and tool functioning.

10) Packer limitations should be fully understood. Packer failure has been the major cause of test failure over the past year.

POST TEST:

1) Any problems incurred during test should be discussed with service company involved.

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