利用逻辑信息法研究断层封闭性

EVALUATION OF FAULT SEALING WITH LOGIC-INFORMATION METHOD

逻辑信息法是数量化理论的一种 ,该方法是以数理逻辑、组合分析及数理统计为基础的一种综合数学分方法。通过比较观测对象结构上的相似性 ,评价这种结构个别元素的作用。文中利用逻辑信息法评价准噶尔盆地断层的封闭性。通过对标准对象(典型的已知封闭性的断层 )影响因素的逻辑运算 ,筛选出主要地质参数 ,根据它们对断层封闭性影响的大小分别赋予权值 ,经计算得出各标准对象的对象权 ,与其封闭性相对照 ,就可以建立断层封闭性判别模型。将此模型应用到准噶尔盆地的 1 0条断层中 ,评价值与实际情况的符合率可以达到 90 %。利用此方法成功解释了五彩湾未能形成整装大气田和呼图壁气田下盘有气 ,上盘无气的原因。这证明利用逻辑信息法评价断层封闭性是有效的。

The Logic-information method is one kind of theories of quantification, and it is a comprehensive mathematical analysis method based on symbolic logic, Comprehensive analysis, and mathematical statistics. By comparing the structural similarity of the objects, this method can evaluate the effect of some special factors. The authors use the logic-information method to evaluate the fault sealing in Junggar Basin. The main geological indexes were filtered by logical calculation of the factors affecting the standard objects (a typical fault whose sealing character is known). According to the affecting capacity of the geological indexes on the fault sealing, some weightings were assigned to them. Then, the object weightings of the standard objects were calculated. Comparing these weightings with the fault sealing, the evaluating model of fault sealing was built up. This model was used to evaluate ten chosen faults in Junggar Basin. The coincidence rate of the evaluated results with the real value is as high as 90%. This method can be used to solve the following two problems in Junggar Basin: Why there is no large scale gas field in Wucaiwan region, and why gas assembleges generate only in the bottom wall of the fault in Hutubi gas field. Both of these prove that the logic-information method can be used to evaluate fault sealing efficiently.