Abstract

The discovery of deep basement reservoir in Bohai Bay, China is of great importance to vitalize oil and gas production of this long-developed field. However, the future development is full of challenges introduced by:

1. Extremely high formation temperature

2. Very abrasive formation

3. Highly deviated and extended well trajectories

4. Highly heterogeneous fractured reservoir

To address them, considering from tool reliability, logging accuracy and risk management, advanced logging-while-drilling (LWD) services including high-definition electrical imager, multipole acoustic measurements, density and neutron are provided as the feasible solution. However, to understand the formation effectiveness within a very complex lithology and further manage the risk of chemical source requires one more cutting-edge technology. In 2022, a high-definition, high accuracy, 2-dimension LWD nuclear magnetic resonance (NMR) service was introduced to the field and gained a remarkable success. Despite the very tough operation condition to any NMR, the high-quality service provided high-definition pore structure to identify production promising intervals in metamorphic rock, differentiated borehole damage from production zones through factor analysis (FA), integrated with high-definition image to evaluate pore effectiveness and find main contributing intervals.

Eventually, the new technology was acknowledged to be a safer and effective solution in studied project and deployed to replace conventional density and neutron logging in the second well.

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