In order to finely characterize the reservoir geological characteristics of Pinghu Formation in Pingbei area of Pinghu tectonic belt in Xihu Sag, the high-resolution oil-based mud electric imaging technology has been utilized on the study of lithology and lithofacies identification, sedimentary environment research, provenance direction analysis and tectonic evaluation for the first time. The results show that the reservoir lithology of Pinghu Formation is dominated by fine sandstone and siltstone. It is determined that four categories of sandstone lithofacies and four types of mudstone lithofacies are mainly developed in Pinghu Formation.
Based on lithology, lithofacies and regional geological characteristics, it was determined that Pinghu Formation is mainly composed of tidal flat and delta front deposit. Due to the development of cross bedding, it has been determined that the provenance direction of Pinghu Formation during the depositional period was mainly southeast in the early stage and turned to southwest in the later stage. In Pinghu Formation, there are two fracture types: open fracture and closed fracture. The orientation of induced fracture and borehole caving is determined by high-resolution imaging. And the fine description of fracture and current stress field direction are realized. The research results provide a strong geological basis for pay zone optimization and well location design on Pinghu Formation in Pingbei area of Pinghu tectonic belt in the future.
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