Abstract

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Title:: Evaluation Method and Application of Fault Lateral Sealing Ability in Quiescent Undiagenetic Period

Author(s):: FU Guang; GE Si; School of Earth Sciences, Northeast Petroleum University, Daqing 163318, Heilongjiang, China

Keywords:: fault lateral sealing ability; quiescent period; undiagenetic; displacement pressure; filler; Dongying Formation; Nanpu sag

Abstract:: In order to study the distribution law of petroleum in the fault zone of petroliferous basin, the fault lateral sealing mechanism and influencing factors in quiescent undiagenetic period were discussed; by comparing the time at which the fault rock starts compaction and diagenesis with the time at which the fault stops the above activities, it was determined whether or not the fault filler was compacted and diagenetic; then comparing the displacement pressures of fault filler and reservoir rocks located, a set of evaluation method of fault lateral sealing ability in quiescent undiagenetic period was established, and it was applied on the assessment of lateral sealing ability of f₁ fault in Ed₁, Ed₂ and Ed₃ of No.5 tectonic region, Nanpu sag, Bohai Bay Basin. The results show that the displacement pressure of f₁ fault in Ed₁, Ed₂ and Ed₃ are 0.70, 0.73, 0.74 MPa, respectively, and the corresponding displacement pressures of reservoir rock located are 0.19, 0.15, 0.10 MPa, respectively; the formers are larger than the latters, so the fault can be sealed in lateral and is beneficial for the accumulation and preservation of petroleum, which is consistent with the distribution of petroleum discovered in Ed₁, Ed₂ and Ed₃ of No.5 tectonic region, Nanpu sag (there is not petroleum in Ed₂, because there is not trap), indicating that this method is feasible for evaluating the fault lateral sealing ability in quiescent undiagenetic period.