基于伪阻抗体波形聚类的贝壳灰岩储层预测方法

Coquina reservoir prediction method of seismic pseudo-impedance waveform clustering

碳酸盐岩储层在全球油气分布中占有重要地位,其储量约占全世界油气总储量的50%。贝壳灰岩是一种重要的碳酸盐岩储层,其特点是非均质性较强,且与围岩的常规岩石物理特征差异不明显。因此基于岩石物理特征的有利储层分布预测存在一定难度。在分析贝壳灰岩储层岩石物理及地震相特征基础上,明确贝壳灰岩及其围岩阻抗及地震相差异;并针对性采用预测反褶积与相对阻抗反演的联合方法,计算伪阻抗体凸显贝壳灰岩内部反射特征,进而采用波形聚类方法对贝壳灰岩进行预测。最后结合研究区沉积微相和古地理分析论述预测结果的合理性,同时预测结果被实钻井证实,说明了采用的基于伪阻抗体波形聚类方法是可靠有效的。

Carbonate reservoir plays an important role in the global oil and gas distribution,and its reserves account for a-bout 50% of total oil and gas reserves.Coquina is a kind of important carbonate reservoir,which is characterized by strong het-erogeneity,and the difference of conventional rock physical characteristics between coquina and surrounding rock is not obvi-ous.Therefore,it is difficult to predict its favorable reservoir distribution.On the basis of analyzing the characteristics of rock physics and seismic facies of coquina reservoir,this paper makes clear the difference between the coquina and its surrounding rocks.Then,seismic pseudo-impedance is calculated by predictive deconvolution to characterize the inner seismic refection, which is used to predict coquina distribution by waveform clustering method.Finally,the prediction result is discussed by the sedimentary microfacies and ancient geographical analysis.Meanwhile,the prediction is consistent with the drilling result dem-onstrating the method is reliable and effective.