基于等效介质模型和频变AVO反演的裂缝储层参数估算方法

由于裂缝性油气藏具有突出的资源潜力和经济效益,利用地震方法对裂缝储层进行精细的定量描述逐渐成为勘探地球物理的关键任务之一。为了克服以往数据驱动类反演方法无法直接获得裂缝参数、而基于静态等效介质模型驱动的反演方法无法描述孔隙内部结构和流体信息的缺点,笔者提出一种基于动态等效介质模型的储层定量描述新方法。该方法通过频变AVO(amplitude variation with offset)理论建立目标函数并使用全局最优化算法反演裂缝参数。一维和二维模型测试证实,由于充分利用了反射系数频变响应对裂缝密度和时间尺度因子的敏感性,反演方法可以对裂缝储层实现有效描述。     

岩性油气藏地震保幅处理技术及其应用--以东部某油田岩性气藏为例

地震数据保幅性处理是一项复杂的系统工程。笔者分析了实际地震数据处理流程中各个关节点模块的保幅性,重点评价了反褶积和振幅补偿的保幅性,并论述了俞氏子波统计反褶积比预测反褶积有更好的保幅性,而剩余振幅补偿需要用叠前弹性阻抗或者叠后反演结果来检验其保幅性。根据上述的保幅性分析结论,对目标区进行了保幅性的地震数据处理,运用叠前弹性参数反演的方法预测了该区的含油气性,其预测的结果与钻井结果相符合,说明了该文采用的保幅处理流程和方法能够提供一套保幅性比较可靠的基础数据。     

Stratal Carbonate Content Inversion Using Seismic Data and Its Applications to the Northern South China Sea

Data on the carbonate content in marine sedi-ments are one of the most i mportant proxies to paleo-ceanography,paleoenvironment,and paleocli mate.Itis directly related to the changes in the global carbonreservoir and has unique significance and wide appli-cations in both scientific research and resource explo-ration(Huang et al.,2003;Chen et al.,2002;Trentesaux et al.,2001).The data on the carbonatecontent in sedi ments are pri marily acquired by meas-uring core samples(Fabricius,2003;Kenter…     

塔西南坳陷甫沙构造带正反转构造及其石油地质意义

塔西南坳陷甫沙构造带褶皱冲断强烈,古近系膏泥岩下层构造变形复杂,具有正反转构造变形特征。侏罗纪—白垩纪区域伸展环境发育大量正断层,后期在喜马拉雅运动中受挤压反转。南部发育高角度基底卷入正反转断层,中部发育叠瓦式逆冲断层,北部边缘变形微弱。相应地将甫沙构造带划分为反转断隆背斜带、楔状叠瓦构造带和逆冲前缘构造带;反转程度南强北弱、西强东弱。对区域构造变形环境的分析表明,西昆仑山隆升引发水平挤压叠加垂直向上的剪切作用,使先存高角度正断层容易被迁就利用进而发生正反转。对正反转相关构造圈闭评价认为:反转断隆背斜带发育的圈闭规模大,幅度低,埋藏浅,落实程度高,但上覆膏泥岩层薄,被断层破坏强烈,油气散失严重;楔状叠瓦构造带发育的圈闭规模小,幅度大,埋藏深,落实程度低,上覆膏泥岩层厚,有利于油气保存;逆冲前缘构造带发育低幅度隆起和地层岩性圈闭。     

Stress-Dependent Fluid Flow and Permeability in Fractured Media: from Lab Experiments to Engineering Applications

Summary. Permeability is a physical property in rocks of extreme importance in energy engineering, civil and environmental engineering, and various areas of geology. Early on, fractures in fluid flow models were assumed to be rigid. However, experimental research and field data confirmed that stress-deformation behavior in fractures is a key factor governing their permeability tensor. Although extensive research was conducted in the past, the three-dimensional stress-permeability relationships, particularly in the inelastic deformation stage, still remain unclear. In this paper, laboratory experiments conducted on large concrete blocks with randomly distributed fractures and rock core samples are reported to investigate fluid flow and permeability variations under uniaxial, biaxial and triaxial complete stress-strain process. Experimental relationships among flowrate, permeability and fracture aperture in the fractured media are investigated. Results show that the flowrate and stress/aperture exhibit “cubic law” relationship for the randomly distributed fractures. A permeability-aperture relationship is proposed according to the experimental results. Based on this relationship, stress-dependent permeability in a set of fractures is derived in a three-dimensional domain by using a coupled stress and matrix-fracture interactive model. A double porosity finite element model is extended by incorporating such stress-dependent permeability effects. The proposed model is applied to examine permeability variations induced by stress redistributions for an inclined borehole excavated in a naturally fractured formation. The results indicate that permeability around underground openings depends strongly on stress changes and orientations of the natural fractures.