致密砂岩储集层裂缝的双侧向测井响应快速计算方法

Fast computing methods for dual laterolog response of fracture of rigid sandstone reservoir

裂缝性砂岩油气藏是一种极为重要的隐蔽型油气藏,由于其非均质性严重及裂缝分布的复杂性,这类油气藏的测井评价难度较大。双侧向测井被认为是目前常规测井中进行储集层裂缝识别和评价的最有效的测井方法之一。依据平板裂缝模型,按照裂缝的双侧向测井响应特征将裂缝分为低角度裂缝、倾斜角度裂缝和高角度裂缝等3种状态。在进行大量的数值计算的基础上,建立了相应的裂缝性砂岩地层的双侧向测井响应与裂缝孔隙度、裂缝倾角、泥浆电阻率、基岩电阻率之间的函数关系,形成一套适合裂缝性砂岩地层特点的双侧向测井响应快速计算方法,为利用双侧向测井资料快速反演裂缝参数提供有效的支持。实际资料处理表明,根据双侧向测井响应的快速计算方法反演处理得到的砂岩裂缝的参数具有较好的可信度。

As one kind of reservoir in concealment, fractured reservoir is very important, and its evaluation is difficult due to its serious unhomogeneity and complex distribution of fractures. Among the conventional well loggings, the dual laterolog is considered as one of the most effective methods of the identification and evaluation of fractures. Based on the tabulate fracture model, three kinds of fractures are classified according to the responses of the dual laterolog as the low angle fracture, the dip angle fracture and the high angle fracture. On the basis of quantity of digital computation, the equations between dual laterolog responses and fracture porosity, fracture dip, mud resistivity and bulk resistivity of rock were founded. These equations provide a fast computing method of the dual laterolog responses of the fractured rigid sandstone reservoirs, so the parameters of fracture can be more easily calculated. The computing parameters of fractures by the fast computing methods are credible.