(20) TUBING AND WELLHEAD INTEGRITY PRESSURE TEST
When a hole in the tubing, HIT, is suspected, then confirm the HIT with a pressure test. If no fluid is produced to the surface, then the test is performed by shutting down the well and pumping clean treated water into the tubing. The tubing is usually pressured up to 500 psi(g) and the pressure is held for a time period. If a hole is present, then the tubing pressure will quickly leak off. A collar leak can take much longer time to leak off. If fluid is produced to surface, then the typical procedure is to use the sucker rod pump to increase surface pressure by pumping against a closed valve.
If a sudden drop in production occurs, then a recommended practice is to pressure test the tubing, casing check valve, and tubing back pressure valve. High speed tubing pressure data acquired in conjunction with a dynamometer test provides the operator with enhanced troubleshooting capability.