Publications

Shallow gas is a geohazard usually avoided in drilling activities due to the risk of blow outs. More, recently shallow gas has been viewed as a new unconventional gas reserves resources that can be explored and exploited. The purpose of this research is to map the distribution of shallow biogenic gas in and around Namamu field, calculate the volumetrics of shallow gas potential, and determine the shallow gas prospect zones. The challenges are that the shallow gas petroleum system is different from the prospect area in general. Limited data availability, particularly the absence of well log data makes gas area identification and volumetric calculations, essential to determine the prospect of shallow gas reserves difficult. The assumptions are the shallow biogenic gas in study area has similar reservoir quality with S-01 well, and that the geochemistry data in C-23 well is representative for shallow biogenic gas in Namamu field in general. The shallow gas prospect zone is determined by analysis of seismic attribute maximum - minimum and Amplitude Variation with Offset (AVO) which is used to calculated the thickness of sandstone to give total volumetrics of shallow gas and distance from the platform. There are 4 shallow gas potential areas between depths 1433-1533 ft containing as much as 81.1 MMSCF. Also there are 7 shallow gas potential areas between depths 1309-1379 ft containing as much as 79.9 MMSCF. Keywords: Shallow biogenic gas, Asri Basin, Seismic Attributes, Maximum and Minimum Amplitude, AVO, Gas Volumetric.