In recent years an increasing number of exploration wells in the North Sea have targeted deep, high pressure, gas condensate prospects. BP Exploration has recently successfully drilled and tested an abnormally pressured Jurassic reservoir with a formation pressure of approximately 15,900 psi and a temperature of 375°F.
Well 22/28b-2 was spudded in October 1988, but following the Ocean Odyssey incident the well was suspended after setting 9-5/8" casing. The well was re-entered in May 1990 using the semi-submersible rig Sedco/BP 711 and drilled to a TD of 5477 mBRT. The reservoir interval was successfully tested from the semi-submersible rig and a maximum shut-in wellhead pressure of 12,300 psi was recorded.
This paper outlines the testing philosophy adopted and discusses the planning, procedures and equipment requirements. It also indicates how the test design was modified in light of changes in the well condition discovered on re-entry.