致密储层可压裂性测井评价方法研究

以×区致密砂岩储层为研究对象,利用蕴藏在测井资料中的储层完井品质信息,对影响致密储层可压裂性的脆性指数、层内水平最小主应力差异系数、层间应力差及裂缝发育特征进行系统分析,给出了适用于×区致密砂岩储层的可压裂性评价标准。基于该标准,开展了致密储层可压裂性评价研究。研究结果表明,致密储层的脆性指数、层内水平最小主应力差异系数对可压裂性影响较大,层内应力差异系数越小,且储层发育微裂缝和层理时,越容易形成复杂网状缝;储层与围岩层间的应力差小,且围岩厚度小,单层压裂时易于沟通相邻的含油层,否则,层间应力差大、泥岩隔夹层较厚时,难以沟通主力含油层相邻的其他含油层,需要采用多层合压方式获得高产。

On Evaluation Method of Fracturing Tight Reservoir Using Log Data

Accurately evaluating the fracturing tight reservoir is of vital importance in the development of the reservoir's fracturing design.This paper assessed the tight oil reservoir in × area.Utilizing the information of reservoir completion quality from logging,the brittleness index,difference coefficient among the minimum horizontal major stresses in the reservoir,stress difference between the reservoir and surrounding bed and microfractures are systematically analyzed,and the evaluation criteria for the fracturing tight sandstone reservoir in × area are proposed.Based on this standard,a study was conducted to evaluate the fracturing tight reservoir.The results show that the brittleness index of the tight reservoir and difference coefficient among the minimum horizontal major stresses in the reservoir have a strong influence on fracability.When the stress difference coefficient in the reservoir is smaller and the reservoir develops microfractures and bedding,the development of complex mesh fractures is easier.When the stress difference between the reservoir and the surrounding bed is small and surrounding rock has small thickness,it is easy to reach neighboring oil-bearing formations with single-layer fracturing.When the stress difference between layers is large and the mudstone interbed is thick,it is difficult to reach neighboring oil-bearing formations of the major formation.Multi-layer pressing may be required to achieve a high yield.