9 5/8” Casing Point Determination Using ZoneTrak Near Bit Resistivity Technology of SBG-22 Drilling Well, Subang Field, North West Java BasinTM

Abstract

SBG-22 drilling well is located in West Pegaden District, Subang Regency, West Java Province, or about 110 km from DKI Jakarta City. Geologically, the SBG-22 well is part of the Subang Structure and part of Subang Field area. The target of the SBG-22 well is to penetrate the reservoir closure of the Parigi Formation, which is characterized by reef limestone lithology. The Parigi reservoir thickness (net pay) is around 14 meters, and expected to fulfill the gas target of 6 mmscfd and 145 bcpd. The method used for determining the depth of 9 5/8” casing point is using ZoneTrak Near Bit Resistivity technology. Principle measurement of this technology is using apparent resistivity, WBM drilling mud, and resistivity contrast (lithological change) in front of the tool. Objectives obtained from the use of this technology are to prevent potential loss zones in the Parigi Formation when using mud
weight of 1.6 SG (12 ¼ trajectory), to stop drilling in determining casing point 9 5/8” right at the top of Parigi Formation, and to prevent early 9 5/8” casing point above the top of Parigi Formation which causes remaining Cisubuh claystone interval above the Parigi Formation. The claystone interval has potential to break out and stuck the bit string, when using mud weight of 1.02 – 1.05 during drilling on 8 1/2” trajectory.