致密裂缝性储层水平井中阵列侧向测井正演响应研究

A Research on Forward Response of Array Laterolog in Tight Fractured Reservoir based on Horizontal Well

运用改进三维球状介质模型,利用有限元数值模拟技术,研究水平井中阵列侧向测井仪器在致密裂缝性储层中的正演响应规律。研究表明:在目标地层中的仪器响应与裂缝部分的孔隙度大小密切相关,同时在致密性地层中裂缝倾角也相关。在此基础上,模拟了不同裂缝孔隙度下储层厚度以及其他的相关因素对本仪器响应的影响。结果表明:不同裂缝孔隙度储层中各影响因素对仪器响应的影响程度也不同,明确储层裂缝孔隙度的大小对准确进行影响因素校正工作至关重要。裂缝孔隙度越小,阵列侧向测井响应随层厚变化越剧烈,当层厚达到10m,层厚对仪器响应的影响基本可以忽略;井眼半径越小,不同裂缝孔隙度对应的视电阻率曲线分离度越大,当井眼半径大于0.5m后,裂缝孔隙度的影响基本可以忽略;裂缝性储层中泥浆侵入深度的不同会导致仪器结果出现极性特征。

The improved three-dimensional spherical media model was established in using finite element numerical simulation technique to study the forward response of array lateral logging tools in tight fracture reservoirs.The results show that the instrument response in the target formation is closely related to the porosity of the fractured part,it is also related to fracture dip angle in compact formation.On this basis,the effects of reservoir thickness and other related factors on the response of the instrument under different fracture porosity are simulated.The results show that the influence degree of the influence factors on the response of the instrument in different fracture porosity reservoirs is also different.It is very important to clarify the accuracy of the reservoir fissure porosity before influencing factor correction.The smaller the fracture porosity is,the stronger the array laterolog response change with the change of layer thickness.When the layer thickness reaches 10 m,the effect of layer thickness on the instrument response can be neglected.The smaller the borehole radius is,the greater the degree of separation of apparent resistivity curves corresponding to different fracture porosity.When the borehole radius is greater than 0.5 m,the influence of fracture porosity can be neglected basically.The difference of mud invasion depth in fractured reservoir will lead to polarity characteristics of instrument results.