Operational Aspects of Extended High-Pressure Well Tests from a Floater

Abstract

Summary During Summer 1985, an extended high-pressure gas-condensate well test was conducted from a semisubmersible drilling unit in Block 29/5a. This paper is a case history discussing the planning and implementation of the production-test operation. The Well 29/5a-3 production test is believed to have been the most extensive high-pressure test conducted in the U.K. North Sea from a floating drilling unit. In the past, because of equipment and/or environmental constraints, high-pressure testing has been limited to short flow and buildup periods. Also, the majority of "expected" high-pressure tests conducted with 15,000-psi [103-MPa] equipment either have rapidly depleted (high-pressure, low-volume zone) or have been terminated prematurely because of mechanical problems. In contrast, the Well 29/5a-3 production test experienced no major equipment failures. In addition, surface pressure readout gauges were successfully installed under extreme pressure and temperature conditions. Proper operational planning and equipment selection proved vital in implementing the production test and achieving the main objectives.