结合地层元素测井和密度测井提高孔隙度评价精度

An Improved Method to Evaluate Porosity with the Combination of Formation Elemental Logging and Density Logging

岩性较复杂的储层中,由于矿物组分及含量的复杂性,利用常规解释方法不能准确计算地层孔隙度。为此,结合地层元素测井和地层密度测井提高孔隙度计算精度。采用基于多目标规划的最优化新方法,将地层元素测井直接测量的元素含量反演得到高精度的矿物含量。根据地层矿物含量准确计算骨架密度值,结合密度测井资料,获取精确的地层孔隙度测井评价结果。将该方法应用到实际测井资料中,并与岩心分析结果对比验证计算结果的准确性。该方法的计算结果与岩心分析结果的相关系数,高于仅利用密度测井以及中子密度测井交会等常规解释方法,证明了该方法提高地层孔隙度评价精度的实用性。

The conventional logging evaluation methods can not accurately calculate porosity in the reservoirs which are characterized by complex mineral components and contents.In order to solve this problem,formation element logging is combined with density logging to improve the evaluation accuracy of porosity.A new optimization method based on multi-objective programming(MOP)is used to obtain high-precision mineral contents by inversing the element contents measured directly from formation element logging.Based on that,the matrix density can be calculated,and the precise porosity can be obtained with the combination of density logging data.Comparing the results of this new method with the core analysis results to validate the accuracy of this method.It is found that the correlation coefficient between them is higher than the conventional methods such as density logging method and the neutron-density crossplot method,which proves that this method can improve the accuracy of porosity evaluation.