考虑断层岩成岩程度的张性断层侧向封闭性定量评价

Based on the fault sealing mechanism, shale content and diagenetic grade of fault rock are the foremost geological factors impacting fault lateral seal ability. Though the quantitative research of fault rock shale content has been mature, the fault rock diagenesis degree study has always been a formidable difficulty in the evaluation of fault sealing which is still in the stage of exploration and not be considered in the quantitative evaluation of fault lateral sealing ability. On the basis of the predecessors' research and the understanding that the diagenesis degree on some point of fault is identical with the one of surrounding rock strata whose depth between the breaking point and the most shallow strata broken by fault, via the combination of the field outcrop observation, core test, geological analysis and mathematical method, this topic focuses on researching how to properly restore the fault rock diagenesis pressure and compaction time this two geological parameters which decides the fault rock diagenetic degree. The geological model of quantitative evaluation of fault rock diagenetic degree is established with the combination of the reservoir exploration and development data of typical fault-trap in Nanpu Sag. Setting up quantitative evaluation method of fault sealing which considering fault rock diagenetic degree has a scientific significance to perfect the theory of fault sealing and reduce the fault-trap hydrocarbon drilling risk.

基于断层侧向封闭油气机理，断层岩的泥质含量及成岩程度是影响断层侧向封闭油气能力最关键的地质因素。断层岩泥质含量的定量研究已经非常成熟，而断层岩成岩程度的研究一直是断层封闭性评价中难以逾越的难题，尚处于探索阶段，且并未考虑进断层侧向封闭性定量评价中。本课题在前人研究基础上，通过野外露头观测、岩心测试、地质分析与数学方法相结合，基于断裂任一断点处断层岩的成岩程度应与埋深介于该断点和断裂所断移最浅地层之间的某一深度围岩地层的成岩程度相同这一认识，重点研究如何准确恢复断层岩成岩压力和承压时间这2个决定断层岩成岩程度的地质参数，建立断层岩成岩程度定量评价的地质模型，结合南堡凹陷典型断层型油藏勘探开发数据资料，实现建立考虑断层岩成岩程度的断层封闭性定量评价方法的目标，对于完善断层封闭油气理论和降低断层圈闭油气钻探风险性具有一定的科学意义。

以往开展断层封闭油气能力的研究更多的是关注如何更加准确的计算出断层岩的泥质含量，而忽视了断层岩成岩程度对于断层封闭油气能力的影响。本课题在前人研究基础上，通过野外露头观测、岩心测试、地质分析与数学方法相结合，分析影响断层岩程度的地质因素，建立了考虑断层岩成岩压力与承压时间的断层岩成岩程度的定量评价地质模型，结合围岩地层岩石排替压力的预测，最终形成了考虑断层岩成岩程度的断层封闭能力定量评价方法，并选取南堡凹陷1号构造典型断层进行精细解剖，利用实际油藏数据验证了所建立方法的可行性和准确性。课题研究成果对于完善断层封闭油气理论和降低断层圈闭油气钻探风险性具有一定的科学意义。