Integrated Formation Evaluation to Peek and Unlock Hydrocarbon Potential in High Gamma Ray-High Resistivity of Argillaceous Thin-Bed Laminated Sandstone in The Ngrayong - Tawun Formation East Java Basin

Abstract

Most of the old oil fields that producing from clasticreservoirs in the Cepu Block area have been exhausted and depleted with high water production (Water Cut > 90%) because these have been producing since the Dutch era. Most of the good quality oil reservoirs in clastic formations in the Cepu Block area have been found and produced. This makes a hard challenge to find new hydrocarbon potential in clastic reservoirs in this area.

Integrated formation evaluation from Mud Log, Advanced Wireline Log (Triple Combo Log, Borehole Image Log, Nuclear Magnetic Resonance Log, and Formation Tester) and Side Wall Core Analysis (Routine Core, Petrography, Scanning Electron Microscopy, and X-Ray Diffraction Analysis) data has been evaluated to find the upside potential of oil reservoir in the Ngrayong and Tawun Formation East Java Basin in the AK Field. Based on the evaluation results, it was found the potential oil in the tight reservoir of Argillaceous Thin-Bed Laminated Sandstone with a distinctive characteristic of High Gamma Ray – High Resistivity. With this discovery, the Integrated Formation Evaluation in the AK Field has unlocked the hidden hydrocarbon potential in the clastic reservoirs of the Ngrayong and Tawun Formation in the Cepu Block area, East Java Basin. This has proven and opened new potential of tight oil sand (Unconventional Reservoir) in the Clastic reservoirs in the Cepu Block area, East Java Basin.

Doing further exploration on another area of East Java Basin and find out an effective production technology scheme for this tight Argillaceous Thin-Bed Laminated Sandstone reservoir become some challenges and could be the future interesting study topics, so that this potential could be found even greater and can be produced economically.