Maximizing Reserves Addition via Seismic-Driven Net Sand Estimation for a Clastic Gas Reservoir: A Case Study

Field X is a sizeable gas field that was first discovered in 1975 (X1) which proved the presence of gas-bearing reservoirs within the H, I, J and K intervals. In 1992, exploration well X2 was drilled approximately 7 km away followed by an appraisal well (X3) in 2010 located in between the two exploration wells ( Figure 1 ). In 2018, the first development campaign (FDP 1) was executed through installation of a 12-slot wellhead platform and drilling of three gas producers targeting the massive K sands and one producer targeting the deeper I reservoirs.

Utilizing data from the new well penetrations, a review of seismic interpretation, attributes analysis and 2D volumetrics were conducted to substantiate the volume in-place and identify the best well-placement targets as part of the FDP for Campaign 2 (FDP 2). Between Nov 2023 to April 2024, Campaign 2 was successfully executed through drilling of another four gas producers. This paper focuses on the fit-for-purpose method in net-sand estimation of the thinner, shallower I & J sands (relative to K) established during FDP vs actual results from the drilling campaign.