伊拉克A油田地震异常体识别与成因分析

Seismic Reflection Anomaly Identification and Origin Analysis of A Oilfield in Iraq

刘俊海 徐明华 王自明 韩翀 王海峰

LIU Junhai XU Minghua WANG Ziming HAN Cong WANG Haifeng

中国石油天然气集团有限公司川庆钻探工程有限公司地质勘探开发研究院, 四川 成都 610051

Geological Exploration and Development Research Institute of Chuanqing Drilling Engineering Co. Ltd., CNPC, Chengdu, Sichuan 610051, China

A油田地震资料上广泛存在地震反射异常，其表现为地震同相轴局部的下凹、错断，目前对地震异常体识别及成因机制未开展深入研究，没有取得明确的认识，影响了研究区油气勘探进程。利用相干、方差、似然等多种地震属性进行了地震异常体识别。结果表明，地震异常体横向延伸距离很短，纵向延伸距离变化较大，从几十米到上千米不等，其在平面上为近似圆形，多数没有明显的分布规律，少数为线状或雁列状分布。根据目的层构造演化过程、地应力及岩芯资料对地震异常体成因进行了综合分析。结果表明，地震反射异常体是溶蚀作用和挤压作用的综合结果。早期目的层发生了溶蚀作用，但溶蚀作用强度在平面上和垂向上分布不均匀，由于后期挤压作用较弱，只在局部脆弱的地方发生了断裂。部分异常体是目的层主要纵向油气运移通道，破坏了下部层系圈闭的完整性。

In Oilfield A there are many seismic reflection anomalies which is concave or broken seismic event. At present, there is a lack of in-depth research and clear understanding of identification and origin of seismic anomalies, which has affected the oil and gas exploration process. Coherence, variance and likelihood seismic attributes are used to identify seismic reflection anomaly. The results indicate seismic anomaly extends shortly laterally but extends from dozens of meters to a kilometer vertically, and they are of subcircular shape in plan view, most of which are irregular distribution and few of which is linear or echelon distribution. A comprehensive analysis of the origin of seismic anomaly is made based on structural evolution, stress and core data of target formation. The results indicate that seismic reflection anomalies are the combined result of dissolution and compression. Dissolution develops in target formation but development intensity is uneven horizontally and vertically. Because late compression is weak, fault is generated in fragile area of target formation. Some seismic anomalies are the vertical path of oil migration and some seismic anomalies destroy trap of lower formation.

10.11885/j.issn.1674-5086.2018.09.10.03