塔河油田12区块奥陶系裂缝分布规律研究

Study on the Fracture Distribution and Numerical Simulation of Ordovician Carbonate Reservoir in Block 12 of Tahe Oilfield

通过对露头、铸体薄片、岩性分析和成像测井资料观察和分析发现,塔河油田12区块奥陶系储层内缝洞发育,并且裂缝在一间房和鹰山组的储层中起了至关重要的作用,它既是地层流体的存储空间,又是连通孔洞缝的主要通道。裂缝的发育也增加了储层的非均质性。所以,精细研究裂缝的发育和分布规律,并定量地计算裂缝的相关参数对于识别奥陶系储层和对储层进行精细综合评价是至关重要的。该文重点对12区块鹰山组裂缝性储层进行了研究,分析裂缝测井响应特征以及裂缝发育和分布规律。采用序贯高斯随机建模方法建立裂缝孔隙度、张开度和渗透率等参数的三维分布模型,模拟结果表明,12区裂缝的最大渗透率达到了3 008.781×10-3μm2,平均渗透率为125.788×10-3μm2。模拟的结果说明裂缝对储层物性,特别是渗透性的改造特别明显。

Block 12 Ordovician reservoir is one of the most important exploration and production area of Tahe oilfield in Tarim basin,however,it is a representative extra-low-porosity and extra-low permeability reservoir and,results in much errors in delineating hydrocarbon zones,and so,it is very difficult to identify the reservoir by using conventional well logging data.Investigations of outcrops,cores and scanning electron microscope（SEM） images and well logging images data show that matrix rocks exist lots of fractures and caves.Furthermore,the fracture is a vital important element in Yijianfang and Yingshan groups,which has two primary effects,i.e.one is reserving space for formation liquid,the other is tunnel for hydrocarbon or water migration.The pore morphology,different size and uneven distribution of reserving spaces subsequently result in very strongly heterogeneous property,so it is vital to study the distribution law of fracture.This paper discussed the characteristics of the fractures,and analyzied the reason of fracture occurring,and the distribution law of fractures.This paper used sequence Gaussian randomizing methods to simulate the fracture parameters,such as porosity,permeability and opening.The three-dimensional images of fracture parameters model shows heterogeneous of this reservoir.The simulation result shows that the fractures dramaticlly modify the permeability of the Ordovician reservoir,for the Block 12,the maximum fracture permeability up to 3008.781×10-3 μm2,and average value,125.788×10-3 μm2,The result is in agreement with production data.