Abstract

Discovery and delineation wells which proved the Udang Field did not yield sufficient data to indicate the complexity of the reservoir. Development drilling showed the Udang pay section to be a series of interbedded shales and sands having individual gas caps and water/oil contacts. The initial plan, to complete the wells by perforating a 40-foot section and installing a screen with slurry pack, was quickly changed in favour of multizone single selective completions.

This paper describes the various types of completions and equipment used, and the success achieved by utilizing single selective completions to control excessive gas and water production.

The field commenced production in January 1979. Since then to the present, about 100 trips have been made with wireline tools to open or close sliding sleeves with only one failure. In 3 wells the same sliding sleeve was successfully actuated six times. This has been achieved even though some wells have 65 degree inclinations and most all wells produce measurable amounts of sand. It is concluded that these type completions have substantially increased present and projected oil recovery from the Udang Field.