利用常规测井资料识别裂缝方法研究

On Fracture Identification with Conventional Well Logging Data

通过小波变换、分形维数和裂缝敏感参数的加权概率指数可从常规测井曲线上提取微弱的裂缝高频响应信号,识别储层裂缝发育程度。加权概率指数的计算关键是提取对裂缝敏感的特征参数,如孔隙结构指数、地层因素比值、三孔隙度比值、等效弹性模量差比、电阻率侵入校正差比、龟裂系数等24个裂缝特征参数。将小波变换、分形维数和加权概率指数的方法编制成程序,并对6口取心井的实际资料进行处理验证。验证结果表明这3种方法均有效,加权概率指数法更具有实用性。该研究为油气田无成像测井资料的井进行裂缝评价提供了方法和工具。

The wavelet transform, fractal dimension and the index of synthetic probability conception are adopted to draw out the weak high frequency signal of fracture from the conventional well logging data and then the signal is used to identify the fracture of formation. The important step of the index of synthetic probability method is to construct the fracture sensitive characteristic parameters. These are twenty-four parameters mentioned in this article, such as the index of porosity structure, the ratio of formation factor, the ratio of the three- porosity, the ratio of difference of equivalent elastomeric module, the ratio of the difference of dual laterolog resistivity, the flexural strength, etc. The fracture identification method of wavelet transform, fractal dimension and the index of synthetic probability is written to a procedure and verified in six well logging data. The result indicates that all the three method are available. The index of synthetic probability method is more efficient and universal than the others. This research could offer a methodology and tool for oilfield to evaluate formation fracture without image well logging data.