高含水油田断层精细解释的地质任务与方法

油田开发及生产需求分析表明,在高含水油田开展地震资料断层解释包括以下主要地质任务:落实井孔内断点纵向位置,改善地质分层质量;孤立断点代表的小断层解释;合理组合井资料对比、解释的断点;井间小断层识别与解释;重新认识大断层;断层体系建模,辅助井位与井轨迹设计;认证开发调整井位,辅助开发调整方案设计;分析油水井注采关系,预测剩余油富集区。利用常规断层解释方法解释小断层时,由于岩性、构造等因素的变化也可造成地震反射同相轴的连续性、光滑程度和振幅强弱的变化(疑似断层现象),致使小断层解释存在多解性,为此,文中提出了"井中断点引导、地质分层数据控制"的井控断层解释方法。在大庆油田的应用效果表明:井控断层解释方法能够对约3m断距的断层进行有效解释;在薄互层储层中的断距约为3m的井间小断层,能够对油水井注采关系起到重要的分割作用,因此在高含水老油田开展小断层解释十分必要。

Geological task and fine fault interpretation in high water cut oilfield

According to the development and production requirements of a high water cut oilfield,the following main geology objects are put forward for fine fault interpretation:① Define the exact vertical location of breaking point on well and geological formations;② Interpret minor faults represented by single breaking points;③ Correlate these interpreted breaking points with well data;④ Identify and interpret inter-well minor faults;⑤ Redefine large faults;⑥ Build fault system model to assist well location and path designs;⑦ Reconsider proposed well locations to help development program design;⑧ Analyze relationship between water injection and oil production,and predict favorable remaining oil area.The changes of lithology,structure and other geologic factors cause discontinuous events and weak amplitude.So minor fault interpretation may lead ambiguity.For this purpose,this paper presents a well-controlled fault interpretation using breaking point as guide and geologic horizon data as control.Applications in Daqing Oilfield indicate that this method can identify minor fault with displacement of 3m.Such minor faults in the thin bed reservoir play an important partition role in injection/production wells.Therefore,this approach is essential for minor fault interpretation in high water cut oilfields.