塔河油田碳酸盐岩断溶体刻画技术研究与应用

Fault-karst characterization technology in the Tahe Oilfield,China

碳酸盐岩断溶体是近年来发现的一种重要的碳酸盐岩圈闭,常规断裂检测属性如精细相干、蚂蚁体等方法以表征断溶体内部断裂分布特征为主,不能很好地刻画断溶体圈闭的轮廓特征。引入梯度结构张量方法用于刻画断溶体的轮廓,并对其单一特征值及组合特征值进行断溶体轮廓刻画效果的对比分析。结果表明,梯度结构张量第二特征值的高值区域与断溶体的反射异常区域较为一致,其门槛值可利用实钻井的钻时曲线进行标定。在断溶体轮廓刻画的基础上,融合反演孔隙度数据体及蚂蚁数据体属性,表征其内部溶洞及断裂发育特征,由此形成一套刻画断溶体外部轮廓及内部结构的技术。塔河油田实际地震资料应用表明,该技术在刻画断溶体方面具有很好的效果,可直观体现断溶体在空间上发育的差异性,亦能刻画其内部缝洞结构。

Fault-karst is an important type of trap that was recently discovered.Conventional fracture detection attributes,such as fine coherence and ant body,are mainly used to characterize fracture distribution inside the fault-karst instead of structural characteristics.This study uses gradient structure tensor to characterize the structural characteristics of fault-karst.The application effect of single eigenvalues and combined eigenvalues were analyzed in this paper.The results of contrastive analysis indicated that the high value region of the second eigenvalue is consistent with the reflection anomaly region of fault-karst,and its threshold value can be calibrated by using the drilling time curve.Based on the structural characterization using the proposed technique,porosity inversion and ant attribute can be used to characterize the caves and fractures inside the fault-karst.Therefore a set of techniques for describing the structure and internal structure of fault-karst were developed.Testing on field data showed that the proposed technique could reflect the structural spatial difference and the internal fracture hole.