Application and Extension of Fine Fault Recognition Technology in Surrounding Area of Penglai 19-3 Oilfield, Bohai Bay Basin, Eastern China

Abstract

At present, the main exploration target in Bohai oilfield is still structural traps, with the increase of exploration degree, large-scale traps have become less and less, so the fine fault interpretation is an important guarantee for searching new structural traps, and improving the success rate of exploration. Penglai A structure located in the east of Penglai 19-3 Oilfield, Which was a complicated fault block trap formed by controlling large boundary faults and strike-slip faults. The position of structural area is at the confluence of the Tancheng-Lujiang fault and Zhangjiakou-Penglai fault, where faults are very developed with varied lateral trends, stress properties and structural orders.We couldn’t deploy appraisal wells in the too lower part of the trap, most of the trap area was invalid.

In view of this problem, a comparative analysis was carried out based on the conventional methods of faults identification, and finally, a high-precision coherency cube and fault likelihood attribute technique based on construction oriented filtering technique were used to fine identification faults. The strike-slip faults in the lower part of Penglai A-3 structure are recognized by using high precision coherence cube, and then found and implement Penglai A-2 structure；a new subtle strike-slip fault located on the west side of PLA-2-2 well is discovered based on the fault likelihood attribute technique，the successful drilling of PLA-2-6 well deploying at its lower levels upgraded 6.48 million tons of proven oil reserves.

Furthermore, Penglai A-4 structure was discovered in the western lower part of Penglai A-2 structure by this method, and the trap area was increased by 9km², which laid out a good foundation for the further exploration. The combination of high precision coherence cube with fault likelihood technique can identify faults at different scales, which is the key to fine interpretation. With the development of fine fault recognition technique, a number of new structural traps will be discovered in Bohai oilfield.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018