Publications

This paper details the integration of advanced formation evaluation procedures and interpretation of image logs with novel and innovative formation testing methods used to plan and optimise drill stem tests (DST) conducted across multiple reservoirs in an offshore well drilled by SAKA Energi. Drilled North-East of Java in the Pangkah Block, the main objective of this appraisal well was to accurately assess productivity of the three main reservoirs discovered by the exploration well in this block. Deployed on wireline, formation evaluation and electrical borehole image logs were acquired in the open hole section of the well. Nuclear magnetic resonance (NMR) and image logs were processed simultaneously in near real time to facilitate the planning of the subsequent formation pressure testing and fluid sampling programme. Using the recently introduced advanced formation testing technology, reservoir deliverability was accurately established, in addition to characterising fluids and obtaining reservoir fluid samples. Interpreted results were integrated and consequently used to optimise the well testing programme across the intercepted heterogeneous and low permeability limestone reservoirs. In addition to determining porosities, free fluid volumes and the range of permeabilities, DST zones were confidently defined using the free water levels ascertained by constructed vertical pressure profiles. As a result, DST measurements matched the permeability and productivity estimations across the individual pay zones. The integrated approach of formation evaluation, textural analysis and permeability and productivity measurements enabled the evaluation of the complex limestone reservoirs discovered in this field, which included secondary porosities and interconnected vugs. These results were ultimately verified and confirmed by the well tests conducted across each reservoir.