Abstract

A blowout occured in 1984 during drilling operations on the BC platform of the Bekapai Field, located in the offshore area of the Mahakam permit, East Kalimantan. When the platform collapsed, the 30" conductor pipes were bent to 90 degrees and several of them were fractured. A few days after the incident, no uncontrolled hydrocarbon sources were observed. However, in 1991, substantial hydrocarbon leaks reoccured.

The long drifting hydrocarbon traces (gas condensate mixed with light oil) visible at the surface were at first thoroughly monitored by the offshore field operators to ensure that the coastal area was not affected. Subsea surveys identified gas escaping primarily from two wells both of which were believed to have high production potential. Following a careful feasibility study with a detailed engineering phase, the decision was then taken to conduct subsea operations to cap the leaking wells in early 1993.

Several original techniques were used for this capping. Subsea works were conducted by divers in saturated mode. Conductor pipes were cut. Mechanical connectors, subsea manifolds, flexible jumpers and flexible lines were installed allowing diversion of the escaping flow to the existing production facilities of the BEKAPAI field via an existing, unused subsea line. Twenty two days and fifty dives were necessary to ensure the success of the offshore operations.