延145-延128井区致密储层单砂体分布特征及开发潜力

针对鄂尔多斯盆地延145-延128井区主力气层山₂段、山₁段、盒₈段产量递减快,开发效果不佳的问题,利用精细地质研究手段,对主力气层的地质特征以及砂体接触关系开展储层综合评价,进一步明确储层沉积微相展布特征,刻画优质单砂体储层分布范围,落实井位部署潜力区。研究结果表明:延145-延128井区储层为三角洲前缘亚相沉积,砂体基本上呈现连片发育特征,厚度一般为4~6 m;多层叠加砂体垂向厚度和横向规模较大,砂体连通性较好;孤立型砂体垂向厚度和横向规模有限,砂体连通性一般;横向上单砂体存在孤立型、叠加型等接触关系,对于孤立型砂体,未射孔动用则基本为原始气藏状态,剩余气富集,孤立型砂体可以作为下一步重点挖潜对象;根据剩余气分布特征,可采用加密、补孔、扩边等措施提高储量动用程度,计划部署加密井12口、扩边井15口,补孔36井次,预计增加可采储量83×10⁸m³。该研究可为同类气藏的开发调整提供重要的参考依据。

Distribution Characteristics and Development Potential of Single Sand Bodies in Tight Reservoirs,Well Blocks Yan 145-Yan 128

In response to the problem of rapid production decline and poor development effectiveness of the main gas reservoirs in Shan2 Member, Shan1 Member and He8 Member, Well Blocks Yan145-Yan128, Ordos Basin, a comprehensive reservoir evaluation was performed on the geological characteristics of the main gas reservoirs and the sand body contact relationship by means of refined geologic studies to further definite the distribution characteristics of sedimentary microfacies in reservoirs, characterize the distribution range of high-quality single sand body reservoirs, and identify the potential area of well deployment. The study results showed that the reservoirs in Well Blocks Yan 145-Yan 128 were delta front subfacies deposits, and the sand bodies basically were continuously developed, with a general thickness of 4 to 6 m; the vertical thickness and horizontal size of multi-layer superimposed sand bodies were large, and the connectivity of sand bodies was preferable; the vertical thickness and horizontal size of the isolated sand bodies were limited, and the connectivity of sand bodies was average; single sand bodies were isolated and superimposed in the horizontal direction; for isolated sand bodies, the unperforated production was basically at the original gas reservoirs, with abundant remaining gas, so isolated sand bodies might be the key target for further tapping the potential; according to the characteristics of residual gas distribution, measures such as infilling, re-perforating and set-out, could be taken to increase the production of reserves; it was planned to add 12 infilling wells, 15 set-out wells and 36 re-perforating wells, and it was expected to increase the recoverable reserves by 83×10⁸ m³. The study provides an important reference for the development and adjustment of similar gas reservoirs.