???????????????2??????????AVO????

AVO分析方法是利用地震反射波振幅与炮检距的关系来识别岩性、检测油气的一种地震技术。它充分利用地震采集中的多种信息，进行资料处理与分析，对于岩性勘探有很好的帮助。鄂尔多斯盆地上古生界下二叠统山西组含气砂岩主要属湖相三角洲平原分流河道沉积，是一种具低孔低渗和高阻抗特征的岩性气藏。在岩性处理解释上，很难区分含气砂岩和致密砂岩。引入AVO处理分析方法，利用不同岩性泊松比差异所形成的AVO特征响应，可以有效区分地震高阻抗层的岩性及含气性，部分避免了地震岩性解释上的陷阱。在长庆气田榆林区山西组山2段高阻抗砂岩气藏的勘探开发中，应用高保真的CDP集资料进行AVO处理分析，提高了天然气钻井的成功率，取得了较好的应用效果。

AVO Analysis of the Shan-2 Member Sandstone Gas Reservoir in Yulin Region of Changqing Gas Field

??AVO analysis method is a seismic technique by use of the relation of the amplitude of seismic reflection wave with offset to distinguish lithology and to detect oil and gas.It is greatly conducible to the lithological exploration,because the data can be processed and analyzed by fully applying many kinds of information obtained from seismic acquisition.The gas-bearing sandstone in the Shanxi Formation of the Lower Permian of the Upper Paleozoic in E'erduosi Basin are mainly the lacustrine facies,delta plain,distributary river course depositions,being a lithological gas reservoir with the properties as low porosity,low permeability and high impedance.It is very difficult to differentiate the gas-bearing sandstones from tight sandstones in lithological processing and interpretation,therefore the AVO processing and analyzing method introduced may effectively detect the lithology and gas potential of the seismic high impedance formation by use of the AVO characteristic response caused by the Poissons ratio difference between different lithological properties,so as to raise the accuracy in seismic lithological interpretation to a certain extent.Through applying the high-fidelity CDP gather data to make the AVO processing and analyzing,the drilling success ratio was raised and a better practical effectiveness was achieved in the exploration and development of the Shan-2 member sandstone gas reservoir with high impedance in Yulin region of Changqing gas field.