提高薄互层低渗透砂岩油藏采收率的有效开发技术

以胜利油田纯41块沙河街组沙四段薄互层低渗透油藏为例,从低渗透油田渗流机理出发,分析了低渗透油田由于存在井距偏大、井网与裂缝匹配不佳、没能适时转注、油藏保护意识薄弱等问题对开发效果的影响。应用渗流机理、地应力场研究成果,提出了低渗透砂岩油藏合理井距确定、井网形式优化、适时增压注水、加强油藏保护等配套开发技术。实施后日产油量、采油速度、日注水量明显提高,含水率、注入压力下降,预测采收率可提高523%。因此,该项配套技术对改善该类低渗透油藏开发效果、提高采收率具有广泛的使用意义。

Technology of effectively enhancing recovery efficiency in thin-interbedding reservoirs of low-permeability sandstone

Taking an interbedded thin sandstone reservoir with low permeability in Chun-41 block in the fourth member of the Shahejie Formation as an example, the factors that affect the development of low-permeability oilfields are analyzed based on their percolation mechanism. Inappropriate well spacing, poor matching of well pattern with fractures, improper timing of waterflooding, and low awareness of reservoir protection, are all considered to be factors contributing to the poor performance of low permeability oilfields. Based on study of percolation mechanism and distribution of earth stress field, several corresponding measures have been proposed to deal with the problem. And the results of field implementation of the measures shows that the daily oil production, oil recovery rate, and daily injection rate of the field are evidently increased and the water cut and injection pressure are lowered. The recovery efficiency is also estimated to be raised by 5.23 %, showing that the measures can effectively improve the performance of low permeability reservoirs.