基于OVT域HTI介质衰减各向异性的储层裂缝预测方法及应用  

Reservoir fracture prediction based on OVT domain HTI medium attenuation anisotropy and its application

作　　者：李创[1] 程冰洁[1] 徐天吉 王啟 华豪 LI Chuang;CHENG Bingjie;XU Tianji;WANG Qi;HUA Hao(Key Laboratory of Earth Exploration and Information Techniques(Chengdu University of Technology),Ministry of Education,Chengdu,Sichuan 610059,China;School of Resources and Environment,University of Electronic Science and Technology of China,Chengdu,Sichuan 611731,China;Yangtze Delta Region Institute,University of Electronic Science and Technology of China,Huzhou,Zhejiang 313000,China)

机构地区：[1]成都理工大学地球勘探与信息技术教育部重点实验室,四川成都610059 [2]电子科技大学资源与环境学院,四川成都611731 [3]电子科技大学长三角研究院(湖州),浙江湖州313000

出　　处：《石油地球物理勘探》2024年第6期1340-1352,共13页Oil Geophysical Prospecting

基　　金：国家自然科学基金项目“基于应力诱导各向异性与岩石力学性质的深层页岩储层可压裂性评价方法研究”(42074160);四川省自然科学基金项目“深层—超深层页岩储层‘甜点’要素智能预测与一体化表征方法研究”(2023NSFSC0255)联合资助。

摘　　要：品质因子Q是表征地震波衰减的一种重要参数,广泛应用于储层裂缝发育特征及含油气性识别。然而,在各向同性、各向异性、黏弹性等不同介质模型的约束下获取的Q值具有不同的储层表征能力。为了精确描述裂缝型、裂缝—孔隙型、孔隙—裂缝型等储层的各向异性及裂缝发育特征,基于HTI介质模型和地震波衰减各向异性理论,提出了一种基于OVT(Offset Vector Tile)域HTI介质衰减各向异性的储层裂缝预测方法。首先,利用广义S变换(GST)对OVT矢量片叠前道集进行高精度时频分析;然后,通过T-K(Teager-Kaiser)能量算子计算地震波的单频T-K能量;最后,计算抽样波长距离内的相对衰减量,获得衰减拟Q值进行椭圆拟合,并以椭圆扁率表征衰减各向异性强度和预测裂缝发育密度。该方法不仅充分发挥了OVT叠前道集较叠后数据包含了更丰富的储层流体和裂缝信息的优势,而且将衰减属性与储层裂缝表征联系在一起,提供了一种裂缝预测新思路。该方法在川西坳陷XC气田的应用中取得了地震资料预测结果与岩心分析、测井资料解释成果吻合度较高的裂缝识别效果。Quality factor Q is an important parameter to characterize seismic wave attenuation,which is widely used in reservoir fracture development characteristics and oil&gas bearing identification.However,under the constraints of different media models such as isotropic,anisotropic,and viscoelastic models,the obtained Q values have different reservoir characterization capabilities.To accurately describe the anisotropy and fracture development characteristics of fracture type,fracture‑porosity and porosity‑fracture reservoirs,we propose a new method for reservoir fracture prediction based on the HTI medium medium model and seismic wave attenuation anisotropy theory in the OVT(offset vector tile)domain.Firstly,we use generalized S‑transform(GST)to perform high‑precision time‑frequency analysis of OVT pre‑stack gather.Then,we calculate the single frequency T‑K energy of seismic wave by Teager‑Kaiser energy operator.After that,we calculate the relative attenuation within the sampling wavelength distance to obtain the attenuation Q‑value for ellipse fitting.Besides,we utilize ellipse oblateness to characterize attenuation anisotropy strength and to predict fracture development density.This method not only gives full play to the advantage that OVT pre‑stack gather contains more reservoir fluid and fracture information than post‑stack data,but also links attenuation attributes with reservoir fracture characterization,providing a new approach for fracture prediction.In the application of XC gas field in Western Sichuan Depression,the method has achieved the fracture identification effect with high consistency between core analysis,logging interpretation and seismic prediction.

关 键 词：裂缝预测 衰减各向异性 品质因子 HTI介质 OVT地震数据 

分 类 号：P631[天文地球—地质矿产勘探]