PETROPHYSICAL ANALYSES AND PHI-K TRENDS OF MAHAKAM DELTA, A REVIEW FOR NEW PETROPHYSICAL CUT-OFF DEFINITION USING INTEGRATED STATIC AND DYNAMIC APPROACHES: CASE STUDY IN HANDIL FIELD

摘要

Pertamina Hulu Mahakam (PHM) has been using petrophysical cut-off based on PHIE and Vshale values. Following those cut-off, there are 3 grades of reservoirs quality: Very good (A-Sands), Good (B-Sands), and Poor quality (C-Sands). However, it is necessary to calibrate the existing petrophysical cutoff with additional static and dynamic data obtained after decades of production. Petrophysical review in the Internal-Median Axis of Mahakam Delta (Handil, Tambora, Tunu, Peciko, and Bekapai fields) that refer to burial compaction trend, microscopic textures, and clay mineralogy, showed approximately similar results. It indicates that those fields have similar petrophysical parameters and hence can be integrated as complement to each other in the static data domain. Moreover, there are 3 different PHI-k trends (i.e. Shallow, Intermediate, Deep zone) representing burial compaction which are used then as new cutoff zonation. Labeling PHI-k data with sedimentary core descriptions has provided new static PHIE cut-off on C-Sand quality. Furthermore, applying Vshale cutoff together with PHIE cut-off showed no added value. The cut-off can be put either on PHIE or Vshale with subsea depth as they are redundant. In practice, it is better to put PHIE since Vshale is very sensitive to depth. They can be used together as cutoff, but Vshale is chosen sufficiently high just to remove unreasonable PHIE due to bad holes. Dynamic cut-off was carried out on this study by using pressure, mobility, PVT data, and perforation results to define the dynamic PHIE cut-off. Different PHIE static and dynamic cut-off confirmed the existing grades of reservoirs quality. Applying new static cut-off in Handil field has resulted in more consistent net sand thickness respected to log responses. This paper will further detail its impact on Hydrocarbon Pore Meter in each zone.