地震岩石物理在渤海PL油田流体检测中的应用

Application of seismic rock physics for fluid detection in Bohai PL oilfield

地震岩石物理通过研究岩石岩性特征、流体特征和岩石弹性参数之间的关系,快速解释储层流体变化所引起的地震响应变化,是利用地震资料进行流体检测的物理基础.渤海PL油田位于渤海东部海域,油田区新近系测井资料受地层疏松的影响,横波质量不准确,流体检测基础资料难以保证.并且根据钻井揭示,油田区储层含油或含水在地震资料上都可表现为强能量反射特征,由于对储层地震响应机理的不明确,缺乏有针对性的流体检测方法,导致以往的流体检测结果不理想.本次研究利用岩石物理建模技术,对目标曲线进行优化和校正.在岩石物理建模基础上,通过对典型砂体进行流体替换和孔隙度替换,从岩石骨架和流体两方面开展地震响应机理研究.并通过构建区域岩石物理量版,划分该区目标储层的分布范围,实现了对目标储层AVO响应特征的定量研究.研究成果为该油田流体检测方法的改进和有效应用提供了重要指导,也为渤海相近油田开展流体检测研究提供了很好的借鉴.

Seismic rock physics is the physical basis for the fluid detection by studying the relationship between rock characteristics,fluid characteristics and rock elastic parameters, and quickly explaining the changes in seismic response caused by reservoir fluid changes. The Bohai PL oil field is located in the eastern part of the Bohai Sea. The logging data of the Neogene in the oilfield are affected by the loosening of the strata,the quality of the shear wave curve is not accurate,and the basic data of the fluid detection is difficult to be guaranteed. According to the drilling,it is revealed that oil-bearing or water-bearing reservoirs in the oilfield can be characterized by strong energy seismic reflection. Due to the unclear mechanism of reservoir seismic response and the lack of targeted fluid detection methods,the previous fluid detection results are not ideal. In this study,the rock physics modeling technique is used to optimize and calibrate the target curve. On the basis of rock physical modeling,we study the seismic response mechanism from fluid and rock matrix by the fluid replacement and porosity replacement of typical sand body. The distribution range of the target reservoir is divided by constructing the regional rock physics template, and the quantitative analysis of AVO response characteristics of the target reservoir is realized. The research results provide an important guidance for the improvement and effective application of the fluid detection method in the oilfield,and also provide a good reference for the research of fluid detection in Bohai oilfield.