Recent Hydrocarbon Discovery in Pre-Carbonate Clastic Reservoir: Unlocking Deeper Potential in Sarawak Offshore!

Abstract

A recent Oil and Gas discovery in an exploratory well in the Balingian Province could be the prelude to a new era of hydrocarbon exploration in deeper stratigraphy (Cycle-I) of the Sarawak offshore. In spite of various hydrocarbon discoveries made previously, only few wells flowed naturally from Cycle-I due to low permeability. Hence, natural oil flow during a DST from the well is a first of its kind in the block and nearby area. With limited data, few well penetrations and poor seismic data quality, Cycle-I exploration remains challenging and less understood. Hence the success is more of a "challenge" to "cherish" story. An extensive regional study, including preparation of time/depth structure maps, regional isopach maps, well penetration charts, play fairway maps and post drill analyses (PDA) of available wells was carried out for the prospect de-risking. Poor seismic data (mainly due to lower frequency in deeper section and shallow gas clouds overlying the objective at the well location) and the uncertainty of reservoir quality (low permeability) observed in the block become the major challenges in finding the best spot to test hydrocarbon prospectivity of Cycle-I. Despite of being low permeability, the reservoir of Cycle-I sand flowed around 400-500 bopd. This flow rate is significant as this is the first recorded data that the Cycle-I reservoir has been production tested in the block and nearby area. Usage of a robust workflow, state-of-art software and cutting edge technology contributed to the success in this well. Apart from various technical studies carried out during the project, the decisive factor behind the success of the well is the "explorer mindset" of the team and full support from the management. The discovery has wider implications for the hydrocarbon exploration of the deeper stratigraphy in this mature basin.