基于常规测井资料的裂缝概率模型及其应用

A conventional log-based fracture probability model and its application

准确预测裂缝的分布发育是碳酸盐岩储层研究中的重要内容,目前已发展了许多先进的技术和方法,但都需要地震和先进测井技术的支持,而老区块通常只有常规测井资料,因此,利用常规测井资料对裂缝进行预测有着重要的意义。为此,利用现有岩心资料和常规测井资料(GR、AC、DEN和RT曲线等),采用曲线元的方法计算裂缝存在概率,进而采用序贯高斯方法建立了裂缝存在概率的三维模型,从而展示出老区块裂缝的纵、横向发育状况及分布规律。现场应用结果表明:研究区裂缝平面上在主构造高点区和主构造西南倾伏端附近较发育,纵向上各单元体的裂缝发育情况分带明显,这与现有地质认识相符合,为常规测井资料进行裂缝预测提供了新的技术方法。

The accurate prediction of fracture distribution and development is the main content in the research of carbonate reservoirs.Many new techniques and methods have been developed at present,but all have to depend on the advanced seismic and logging techniques.However,in those mature blocks where only conventional wireline logging data are available,it will be crucial to predict fracture distribution with the conventional log data.In view of this,based on the available core data and conventional log data including GR,AC,DEN and RT curves,the fracture existence probability was calculated by the curve unit method.Then,a 3D model of fracture existence probability was built by the Symmetric-Gauss-Seidel(SGS) method to reveal the vertical and lateral development and distribution of fractures.This model was successfully applied to predict the distribution of fractures in a mature block.Laterally,fractures were mainly distributed in areas near the structural high and near the southwestern plunging end of the major structure.Vertically,fracture development showed significant zonation in each stratigraphic unit.These prediction results are in accordance with geologic understandings.This model provides a new method for fracture prediction based on conventional log data.