纯化薄互层低渗透油田开发层系的划分与组合

纯化油田为薄互层低渗透油藏,含油小层多,层间渗透率差异大,储量丰度低,早期采用一套层系开发,层间干扰严重、各小层动用不均衡、储量损失大等矛盾造成开发效果差。为改善油田开发效果,对油田开发层系的技术政策进行研究,确定了油田开发层系划分方案。同一层系内的层间渗透率级差中部地区不宜大于5,边部地区不宜大于3,应尽可能单采3～5个主力小层,射开厚度必须控制在6m左右,单井控制储量一般应大于10×104t,隔层要具有分层卡封的可行性。根据研究结果,在C2块、C23块等5个单元实施,增加可采储量117.8×104t,提高采收率5.2%,表明低渗透薄互层油藏合理划分开发层系可有效改善油藏开发效果。

The division and combination of series of development strata in Chunhua low-permeability Oilfield with thin inter-beds

Chunhua Oilfield is a low permeability reservoir with thin interbeds, which has more small oil -bearing layers, severe vertical heterogeneity, and lower reserves abundance o In early development stage, an old set of series of development strata was adopted. But there were severe vertical heterogeneity, uneven exploitation of every small layer, great reserve loss, these situation caused the bad development effect of the oilfield. To improve the development effect, the re- search of technology strategy for the oilfield development was carried out to determine the division plan of series of develop- ment strata. In same series of development strata, permeability max - min ratio between layers should not exceed 5 in the central region, and not exceed 3 in edge region. The 3 to 5 single layers were produced singly the research results as far as possible, the perforated thickness of reserves must be controlled by about 6 meters. Controllable reserves per well was generally more than 10×10^4 tons, the barrier layer could be sealed by packer. According to the research results, the develop- ment plan was applied in five units, such as Chun 2 block and Chun 5 block, etc , the recoverable reserves were increased by 117.8× 10^4 tons, oil recovery was enhanced by 5.2%. The results showed that reasonable division of series of development strata of the low permeability reservoir with thin interbed can improve effectiveness of oilfield development.