西湖凹陷地层裂缝分布预测模型及应用

Fracture Distribution Prediction Model of Xihu Depression and Its Application

东海陆架盆地西湖凹陷具有走滑构造应力场背景,地层中断层和裂缝发育。常规测井中电阻率测井、声波时差测井、密度测井、中子测井、自然伽马测井等测井数据均能对地层裂缝产生响应。鉴于传统裂缝预测模型采用不同测井数据分析结果的简单加权平均来计算综合裂缝指数,受主观因素影响较大且存在一定误差,因此引入统计学方法,用模糊数学理论对测井数据进行分析,建立了基于隶属度函数的地层裂缝指数预测模型。通过不同模型对西湖凹陷NX区块某井地层裂缝发育情况的预测及与成像测井观察结果的对比,表明基于隶属度函数的裂缝预测模型准确度优于传统模型,预测结果与成像测井一致性高,能够更好的反映裂缝发育情况,为工程实践提供参考依据。

The Xihu sag of the East China Sea has the background of sliding tectonic stress field, and faults and fracture development in the stratum. Some conventional logging data such as resistivity logging, acoustic logging, density logging, neutron logging and natural gamma logging can respond to the cracks in formation. In view of the traditional fracture prediction model using simple weighted average of different logging data analysis to calculate the comprehensive fracture index, the result is greatly influenced by subjective factors and has some errors. Therefore, a statistical method is introduced to analyze logging data with fuzzy mathematics theory, and a prediction model of formation fracture index based on membership function is established. By comparing imaging logging and fracture development prediction results of different models in a well of NX Block in Xihu Depression, it is shown that the accuracy of fracture prediction model based on membership function is better than the traditional model, and the prediction result of membership function model is in better agreement with the imaging logging, which can better reflect the fracture development and provide a reference for engineering practice.