Integrated Logging While Drilling and Wireline Borehole Seismic for Safe Exploration Drilling in the Andaman Sea, Deepwater Indonesia

A vertical exploration well, Timpan-1, was drilled in the offshore Andaman Field, deepwater Indonesia, using a unique integration of logging while drilling (LWD) and wireline borehole seismic/vertical seismic profiling (VSP) to reduce risk and increase safety while exploring the carbonate reservoir. The seismic while drilling (SWD) technology was used on the 12 ¼-in. hole section for geostopping decisions to set the 9 5/8-in. casing at the correct depth immediately above the carbonate reservoir. Once the casing reached the bottom and the drilling operation continued to well total depth (TD) on the 8 ½-in. hole section, wireline VSP was acquired to obtain the velocity profile and VSP image. The depth prediction was determined using the lookahead method, where the closer the seismic sensor, the more accurate the depth prediction. The final integrated data of both 1D images of the corridor stack from SWD and wireline VSP was displayed side by side, with overlapping levels. This aim is to have the data for the whole section and fully utilize both acquisition data. In conclusion, SWD technology is used for geostopping purposes, and wireline VSP provided the best conveyance option to help manage the depth uncertainty for the final hole section and other advanced applications of ZVSP, such as attenuation (Q) estimation. Integrating the borehole seismic acquisitions technology is the correct strategy to mitigate significant depth and velocity uncertainty risks. Thus, SWD and wireline VSP can provide a better understanding of the velocity profile and seismic interpretation of nearby Timpan-1 well.