基于地质统计学反演的缝洞储集体物性定量评价

Quantitative evaluation for porosity of the fracture-cavity reservoir based on geostatistical inversion

塔河油田奥体系发育孔、洞、缝等多种储集体,空间非均质性极强.定量刻画不同类型储集体及其物性在三维空间的展布一直是该类油藏开发的技术难题.本文采用一种基于马蒙算法的地质统计学反演方法,结合地质、测井先验信息,获得表征缝洞储集体类型及反映物性参数的纵波阻抗数据.再通过寻找波阻抗与储集体孔隙度之间的统计关系,利用一种"云变换"手段,协模拟得到缝洞储集体等效孔隙度数据体,以此从物性角度定量评价缝洞储集体的空间非均质性.与常规方法对比说明,该方法评价结果与井点解释物性有较高的吻合程度,井间趋势上更加尊重地震响应特征,是一种地震数据主控的储集体物性评价方法,对于强非均质性油藏的物性发育规律评价具有指导意义.

The Carbonate fractured-vuggy reservoir in Tahe Oilfeild include large caverns,dissolved pores and fractures which are varied in scale and shapes. So its spatial heterogeneity is very strong.Quantitative characterization of different types of reservoirs and its properties in three-dimensional space is a technical problem in the development of this kind of reservoir. Adopt a geostatistical inversion method based on Markov chain Monte Carlo algorithm to get the reservoir types and p-impedance data which has good statistical relationship with reservoir properties, fully integrating prior geology regularity and well logging. By finding the statistical relationship between impedance and porosity of the reservoir,use a＂cloud transform＂means to cosimulate the equivalent porosity of reservoir using which to give a quantitative evaluation of reservoir spatial heterogeneity. The comparison results to the conventional method show： The prediction results from the inversion have good accordance with the borehole data,and consistent with the seismic response away from the well position. The geostatistical inversion is an quantitative evaluation method for the porosity of reservoir with strong spatial heterogeneity. It has an important guiding significance for the geological distribution regularity research of reservoir properties.