鄂尔多斯盆地中部下古生界白云岩含气性地震检测  

Seismic Detection for Gas-Bearing Lower Palaeozoic Dolomite,the Middle of the Ordos Basin

作　　者：赵玉华[1,2] 李坤白 张杰[1,2] 蒲仁海[3,4] 张盟勃[1,2] 陈晓晶[3,4] 

机构地区：[1]中国石油长庆油田分公司低渗透油气田勘探开发国家工程实验室,西安710018 [2]中国石油长庆油田分公司勘探开发研究院,西安710018 [3]西北大学大陆动力学国家重点实验室,西安710069 [4]西北大学地质学系,西安710069

出　　处：《地质科技情报》2015年第3期191-197,共7页Geological Science and Technology Information

基　　金：国家自然科学重点基金项目(41390451);长庆油田企业项目"叠前含气性检测方法试验"(2012-158)

摘　　要：利用AVO、叠前弹性参数反演和高频地震能量衰减等方法检测砂岩是否含气得到了较为广泛的应用,但是这些方法是否适用于层状白云岩储层含气性检测并不清楚。针对鄂尔多斯盆地马五5白云岩的岩性和含气性变化,采用岩石物理分析、AVO类型分析、叠前反演、叠后能量衰减等多种地震方法进行了试验研究。研究表明,岩石物理参数交会图不能严格区分含气白云岩、不含气的含灰白云岩和含泥白云岩,但白云岩气层与灰岩和砂泥岩的参数差异较明显。通过截距-梯度交会图与正演模型相结合可以判断研究区白云岩属于第Ⅰ类和第Ⅳ类AVO异常,但因影响因素过多,因此不能完全依靠AVO类型进行含气性判别。在各种叠前弹性参数反演中,纵横波速度比反演以及泊松比反演可以较好地反映白云岩含气层厚度、分布与尖灭。分频能量衰减分析表明,含气段比不含气段的最高能量对应的频率会降低大约5Hz。叠前弹性参数反演和分频能量衰减检测白云岩是否含气具有一定的效果和一致性。Detecting whether the sandstone gas bearing by the method of AVO,pre-stack elastic parameter inversion and high frequency seismic energy attenuation has been widely used, but whether these methods are suitable to the dolomite gas detection is not clear. In view of the Ordos Basin Mawu5 dolomite＇s litholo- gy and gas-bearing/s change, this article uses the seismic methods such as rock physics analysis,AVO type analysis,pre-stack inversion and post-stack energy attenuation to test the effectiveness of the methods for dolomite reservoirs. The results indicate the rock physics parameters crossplot cannot distinguish the gas dolomite, gas-free ealcitic dolomite and argillaceous dolomite. There is an obvious difference between dry limestone and siliclastical rocks however. Through the combination of the P-G crossplot and forward mod- el, dolomite in the research area is class I and IV AVO anomalies. Nevertheless, some uncertainties of AVO types exists which limits the judge of bearing gas or not. In variable of pre-stack elastic parameters inversion,vp/v, inversion and Poisson ration inversion can reveal the gas zone of dolomite reservoirs. Spec- tral decomposition energy attenuation analysis shows that the highest energyts frequency of gas-bearing intervals is 5 Hz lower than the no gas-bearing intervals. The detection of gas-bearing dolomite with Pre-stack parameters in- version and spectral decomDosition energy attenuation has proved viable and consistency.

关 键 词：鄂尔多斯盆地 马家沟组 白云岩 AVO叠前反演 分频能量衰减 

分 类 号：P618.13[天文地球—矿床学]