不规则条带状泥质对砂岩电阻率影响的数值模拟

Numerical Simulation to the Influence of Irregularly Banded Argillaceous Composition on Sandstone Resistivity

在分析W油田储层泥质微观分布特征的基础上,基于典型的岩心铸体薄片照片,构建了2类导电模型,并利用有限元数值模拟方法分析了不规则条带状泥质对泥质砂岩电阻率的影响。通过数值模拟结果与实际测井资料的对比分析,验证了有限元数值模拟方法的可行性,明确了泥质对W油田低电阻率储层的影响机理。当岩石含水饱和度较高时,泥质砂岩以纯砂岩区导电为主,泥质砂岩电阻率随着泥质含量的增加而增加;当岩石含水饱和度较低时,泥质砂岩以泥质区导电为主,泥质砂岩电阻率随着泥质含量的增加而降低。高含量且不规则条带状分布的泥质是造成W油田油层低电阻率现象的主要原因之一。所提出的岩石导电特性模拟方法为泥质砂岩导电特性的研究提供了新的思路。

After analyzing the microscopic distribution of the argillaceous composition in the reservoirs and the photographs of typical cast thin sections taken in W oilfield, two types of electrical models were built, and then the influence of the irregularly banded argillaceous composition on the resistivity of the argillaceous sandstone was analyzed. Finally, the simulation results were compared with well logging data to verify the feasibility of the finite element numerical simulation method, and make clear the influence mechanism of the argillaceous composition on the resistivity of the argillaceous sandstone. The results show that: at high water saturation, the argillaceous sandstone is conductive as pure sandstone, and its resistivity increases as the increase of the argillaceous composition;at low water saturation, the argillaceous sandstone is conductive as the argillaceous, and its resistivity decreases as the increase of the argillaceous;the high-content and irregularly banded argillaceous composition is one of the controlling factors on the low resistivity of the reservoirs in W oilfield. The rock conductivity simulation proposed a new idea for researching the electrical properties of the argillaceous sandstone.