基于斯通利波能量衰减的裂缝渗透性评价方法研究

Research on evaluation method of fracture permeability based on stoneley wave energy attenuation

塔里木库车地区气藏目的层主要为致密砂砾储层,裂缝是流体主要的运移通道.该地区多采用油基泥浆钻井,导致电成像效果差,降低裂缝有效性评价精度.斯通利波对井中流体运动的敏感性,为利用斯通利波评价裂缝渗透性提供了可能:阵列声波资料提取的斯通利波能量经归一化后计算衰减系数,然后根据实验得到的衰减系数与裂缝宽度的关系反演出裂缝宽度,同时根据裂缝宽度、裂缝倾角反演得到裂缝渗透率.结果表明,水基泥浆井中利用该方法反演得到的衰减系数、裂缝宽度、裂缝渗透率曲线与电成像解释成果图对应良好,在裂缝发育段曲线呈现明显高值,在裂缝不发育段呈现低值;同时与试油结果吻合,可以用来评价裂缝渗透性.最后将该法推广到油基泥浆井中,结合电成像测井可提高裂缝有效性评价的精度.

The target stratum of Kuche area in Tarim is main of fractured dense sand reservoir.The main migration pathway of fluid is effective fracture.It’s hard to use routine logging data accurate to evaluate the fracture effectiveness.The sensibility of The stone wave energy to the fluid motion in well makes the evaluate of fracture permeability possible.Article uses the normalized stone wave energy from array acoustic wave data to calculate the attenuation coefficient.Then we invert the crack width from the relation between the attenuation coefficient of the experiment and the crack width.At the same time,we can invert the fracture permeability from crack width and fracture dip.It turned out that the attenuation coefficient,crack width and fracture permeability curve are good corresponding to the electric imaging interpretation graph in water-base mud well.In the period of fracture development,the curve is significantly higher,and in the period of fracture non-development,the curve is significantly lower.Meanwhile the result coincides with actual potential test result.It can be sued to evaluate the fracture permeability.