利用数字岩芯评价疏松砂岩气藏渗流特征

Evaluating the Seepage Characteristics of Unconsolidated Sandstone Gas Reservoir by Digital Core

针对疏松砂岩气藏岩石物理性质的测试存在取芯难、岩芯易水化和出砂,传统的岩芯驱替实验无法准确评价其渗流特征的问题,利用数字岩芯技术对其开展了渗流特征的研究。研究中以涩北疏松砂岩气藏某井岩芯为研究对象,首先利用CT扫描仪扫描岩芯样品,获取岩芯的三维图像,抽取数字信息,将多孔介质的孔隙结构直接映射至网络,并利用分形几何原理建立数字岩芯,再从中抽提出三维孔隙网络模型;然后将模型计算结果与真实岩芯实验值进行对比和校正,获取客观有效的数字岩芯模型;最后利用该数字岩芯模型计算了不同有效应力、不同地层水伤害时间以及不同泥质含量状态下的渗流物理参数和相对渗透率,为疏松砂岩气藏的开发提供了重要的岩石物理基础数据。

To solve the problems of hardicoring,easy hydration foricore and sand prodiction during the test of physical properties of rick in uiconsolidated sandstone gas reservoir,Weicarried out the study of the seepageicharicteristics by digitalicore tichnology while the traditionalicore displicement experimenticannot evaluate its seepageicharicteristics pricisely. Based on theicore of a well in Sebei uiconsolidated sandstone gas reservoir,firstly,we ican theicore samples to get their 3D images withicT icanner,and extrict digital information,put the pore stricture to dirictly map onto the network model,establish the digitalicore and extrict the 3D pore network model from it iccording to the frictal priiciple. And then,we put the modelicaiculation results and realicore experimental results inicomparison andicorriction,and get the effictive model of digitalicore.Finally,use this model of digitalicore toicaiculate the physical seepage parameters and relative permeability in various states of effictive stress,formation water damaging time and shaleicontent so that iticould provide important basic data physical of rick for the uiconsolidated sandstone gas reservoir development.