Citation: | HUANG Jianliang, YANG Huaizhong, LI Haibin, GUO Yun, SHI Ruiqi. KEY TECHNOLOGY FOR EXPLORATION OF COMPLEX PRESALT TRAPS IN THE DEEP WATERS OF GABON BASIN, WEST AFRICA[J]. Marine Geology Frontiers, 2020, 36(12): 56-64. doi: 10.16028/j.1009-2722.2019.200 |
In recent years, global deepwater oil and gas exploration, as demonstrated by West Africa and the Gulf of Mexico, has become increasingly active. Verification of structures is always the key problem in salt basin exploration. Therefore, it really is a great need to develop a set of technology for trap identification to support the exploration of oil and gas under salt cap in the deep water of Gabon Basin. Based on the studies of the mechanisms of salt rock deformation and its impacts on seismic imaging, a set of key technology is proposed in this paper. It includes: ①Establishment of interpretation models for structures based on the mechanism of salt rock deformation; ②Introducing the technique for pre-salt seismic horizon interpretation based on the fine recognition of dirty salt bodies; ③Integration of gravity, magnetic and seismic data for multiscale comprehensive interpretation of pre-salt faults; ④Adoption of the method for distinguishing false images from the real based on wave equation forward modeling. Using the method, a series of pre-salt traps are effectively identified in the research area, and drilling proves that the M trap is a large pre-salt gas field. It is concluded that the technical system proposed can help solve the problem of the verification of pre-salt structures, which can be used as a reference for similar oil fields in West Africa and other regions.
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Geological profile of Gabon Basin[16]
3D seismic data of the study area in Gabon Basin
Seismic profile across well M in study area
The seismic profile of tensional triangular diapir in study area
Intersection chart of logging velocity and GR of main lithology in Ezanga Formation of well N-1
The characteristics of dirty salt bodies in Ezanga Formation
Schematic diagram of multi-layer linkage interpretation of pre-salt horizons in study area
Thought for interpretation of pre-salt fault system in study area
Isodepth slice of seismic attributes at a depth of 7 200 m in study area
The phenomenon of false structure imaging in practical seismic data