基于多元回归分析的致密油可采资源评价方法

由于非常规油气的特殊聚集特征，常规资源评价方法已很难获得较为可靠的致密油可采资源。以北美二叠盆地狼营组B₁₂段成熟致密油区为基础，提出一种基于多元回归分析评价致密油可采资源的新方法。该方法通过致密油井产层地质参数与实际产量数据的关系，建立评价致密油可采资源的评价模型，利用相关性分析和多元回归方法确定各地质参数及对应的影响系数，获得研究区致密油可采资源丰度的计算模型，进而计算出研究区内的致密油可采资源量。实例解剖结果表明，SJ区地质因素对狼营组B₁₂段致密油可采资源的影响从大到小依次为：脆性矿物含量、成熟度、孔隙度、含油饱和度；建立的模型预测的产量与实际产量的相关系数可达0.788 5，区内致密油可采资源总量为4 615×10⁴ t。由于多元回归的致密油评价模型与产量直接对应，增加对产量的约束，即可获得区内致密油可采资源Ⅰ类为44×10⁴ t，Ⅱ类为2 483×10⁴ t，Ⅲ类为1 869×10⁴ t。基于多元回归分析的致密油评价结果更为有效，应用范围更为广阔。

Method to assess recoverable tight oil based on multiple regression analysis

It is hard to reliablely estimate recoverable resources of tight oil by means of conventional resource evaluation methods due to the abnormal features of unconventional oil and gas accumulation.Through the study of the productive tight oil play in the B₁₂ interval of Wolfcamp Formation in the Permian Basin of North America,we proposed a new me- thod for evaluating recoverable tight oil resources in the Permian Basin based on multiple regression analysis.In line with the correlation between the geological parameters of pay zones and the actual production of the tight oil play,a model for evaluating recoverable tight oil was established;then,the geological parameters and their corresponding influence coefficients were determined by correlation and multiple regression analyses,so as to get the calculation model for recoverable tight oil abundance in the study area.Finally,the volume of recoverable tight oil in the study area was worked out.After the detailed analysis of SJ area in the Permian Basin,the geological factors affecting the recovery of tight oil can be graded in terms of significance as follows: brittle mineral content,maturity,porosity and oil saturation,with the degree of significance decreasing from the beginning.Meanwhile,the correlation coefficient between the predicted yield by the model and the practical yield reaches 0.7885,signifying the reliability of the model,and the total volume of recoverable tight oil is 46.15 million tons.Since the tight oil evaluation model based on multiple regression corresponds directly with the production,after setting the constraints on production,we can also get to know that the recoverable volumes of Type Ⅰ,Ⅱ and Ⅲ tight oil are 0.44,24.83 and 18.69 million tons,respectively.In summary,the new model based on multiple regression analysis is more effective for assessing recoverable tight oil resources and thus its scope of application is broader.