基于Comsol的电位法压裂裂缝监测正演研究

Forward Modeling for Fracture Monitoring Technology Through Electrometric Method Based on Comsol

摘要:

随着我国石油开发的不断深入,大部分油田已经进入了高含水开发期;电位法压裂裂缝监测通过套管向井中供电,地面观测电位分布,监测压裂裂缝形态。该方法简单易行,是一种重要的裂缝监测方法;因此开展相关电位法压裂裂缝监测的正演以及反演研究具有十分重要的意义;首先,文章基于有限单元法,利用comsol软件建立了电位法压裂裂缝监测模型,进行了数学分析,并选取了合适的边界条件;其次,通过建立的模型,研究了裂缝方位与地面电位的对应关系;然后,通过改变测量区域的坡度,研究了坡度对地面测量电位的影响;研究表明,裂缝的方位与异常电位值的极小值相对应；地表坡度将对裂缝方位的监测造成影响;因而,在实际的电位法压裂裂缝监测中,应考虑坡度的影响,并对测量电位进行相应地修正补偿以消除误差。

Abstract:

With the deepening of the oil development in our country,most of the oilfield has entered high water cut development period.Potential method of fracturing fracture monitoring through supplying power for the casing wells,monitoring electrical potential distribution on the ground,to monitor fracturing fracture morphology.This method is simple,so the crack monitoring measure is an important method.So the associated potential method forward modeling and inversion of fracturing fracture monitoring research is of great significance.First of all,based on the finite element method, potentiometry fracturing fracture monitoring model is established by using the software Comsol,the mathematical analysis is implemented,and the appropriate boundary conditions is selected.Second,through the establishment of the model,and studies the fracture azimuth and the corresponding relation of ground potential.And then,by changing the measuring area of the slope,slope is studied to measure the ground potential.Research has shown that the fracture azimuth and the unusual potential value of minimum corresponding;The surface of the slope will affect the fracture azimuth monitoring.Therefore,in the actual potential method of fracturing fracture monitoring,the influence of the slope should be considered and measuring potential compensation be revised accordingly to eliminate the error.