The Use of Tubing Tester Valve to Optimize Completion Cost and Time

Abstract

The job of pressure testing the tubing while running in a well was left up to running a standing valve to a nipple profile with a slick line unit. This involved multiple runs to set, test, and pull the standing valves, and with the advent of horizontal well's completion, the completion cost increases as more slick line trips are made. However, in high angle/horizontal wells, the slick-line associated hole problem has become a major challenge because of the inability of the gravity-assisted, slick line run to convey a standing valve to angles greater than 65°. This slick line limitation and associated challenges has resulted to major operators to find a more efficient method to pressure test the completion string. Various operators have done different things; including pressure testing the annulus of the string/casing to verify the tubing integrity to avoid slick line associated hole problems. In the quest to solve this problem and adding to body of knowledge, Addax petroleum team of engineers introduced a tubing tester valve as part of the completion string and used it to test the pressure integrity of the completion string connections while running in hole. In carrying out a tubing pressure test, the pumping sub with surface lines was rigged up directly on the tubing from the cement pumping unit, and pressure tested. The pressure testing exercise of this string took approximately 40 minutes. Also, to note that the tubing tester valve is a full-opening tester valve that allows completion string to self-fill while running in hole. The completion string could be pressure-tested as many times as required as it is run in the hole. The tester valve has reduced the rig non-productive time and risks associated with slick line deployments. The tester valve consists of a curved flapper valve and spring, a shear ring and locking dogs that allow the curved flapper to be fully closed during a pressure test; while the valve can be fully over ridden with a higher hydraulic pressure, which then opens a large-internal diameter through valve bore, permitting the internal diameter of the string to an unobstructed production rates and future well intervention access. The production string pressure test has been successfully carried out in sixty horizontal wells to date. The cost evaluation analysis performed between the slick line standing valve and the tubing tester valve tests for some of the wells shows cost savings as much as $240,000 per well on the jack up rig.