关键词: 河流相, 沉积单元, 单期砂体, 叠置模式, 储层钻遇率, 水平井, 长庆油田

Abstract: To accurately analyze the spatial configuration of single channel sand bodies, barriers and interbeds in upper Paleozoic fluvial reservoirs in Changqing Oilfield, and then improve the reservoir drilling rate of sand body horizontal wells, marker beds such as coal seam, limestone and high mature paleosoil layer in the study area were used as isochronous surfaces to divide sedimentation units. Isochronous facies-controlled technology was used for comparison, and slice correlation method and isobath correlation method were used to divide sedimentation units. The study shows that the upper Paleozoic fluvial sand bodies in Changqing Oilfield are formed by the superposition of two or multiple stages of single channel sand bodies. The degree of return of the natural gamma and resistivity curves of the barriers in the river channel is related to the thickness of the barriers. The larger the thickness, the greater degree of curve return. The degree of curve return can be divided into the types of stepped, half amplitude and base line. Furthermore, the superimposed patterns of single channel sand bodies in both lateral and vertical directions were summarized. The lateral contact relationships were mainly divided into sand body isolated type, sand body butt-joint contact type and sand body cutting and stacked contact type. The vertical contact relationships were mainly divided into sand body intermittent stacking, sand body complete stacking and sand body erosion truncated stacking. By studying the superimposed patterns of single channel sand bodies, in-depth analysis of the spatial configuration of single channel sand bodies, barriers and interbeds can guide the trajectory control of horizontal wells and improve effective reservoir drilling rate.

Key words: fluvial facies, sedimentation unit, single stage sand body, superimposed pattern, reservoir drilling rate, Changqing Oilfield