辽河断陷盆地西部凹陷西斜坡中南段欢曙上台阶齐40块高倾角(＞10°)油区在蒸汽驱试验区中占比例较大,目前已进入开发后期,产量持续递减,开采成本升高,探索倾斜油藏蒸汽驱后期有效的接替开发方式、进一步提高采收率具有理论意义和实用价值.选取齐40块西部高倾角区4个典型井组,应用Petrel软件和STARS软件分别建立了三维地质模型和数值模拟模型,进行蒸汽驱后期接替开发方式优化设计研究.数值模拟结果表明,莲Ⅰ油层组动用程度较高;莲Ⅱ油层组动用程度较低,剩余油饱和度在60％以上,构造高、低部位剩余油分布差异较小.根据莲Ⅰ和莲Ⅱ油层组剩余油分布特点,蒸汽驱后期可采用分层注汽技术,采用分层注汽技术可提高采收率4.0％.齐40块倾斜油藏蒸汽驱后期接替开发方式优化结果表明,间歇蒸汽驱提高采收率幅度最大,达5.2％;连续蒸汽驱提高采收率4.6％;汽水交替驱和蒸汽空气复合驱提高采收率幅度较小,分别为1.8％和3.2％.采用间歇蒸汽驱开发莲Ⅰ油层组的动用程度大于连续蒸汽驱;间歇蒸汽驱的累计油汽比高于蒸汽空气复合驱及汽水交替驱.因此,综合考虑建议使用间歇蒸汽驱作为后期的接替开发方式.%High dip-angle(＞ 10°) oil area in the Block Qi 40,located in the middle-southern part of the western slope in the Western sag of Liaohe rifted basin accounts for a large proportion of the steam flooding pilot areas.The high dip-angle oil area has entered the late development stage,which is characterized by continuous decline of oil production and rising production cost,so that to explore effective successive development method at the late steam drive stage for inclined reservoirs and to further enhance oil recovery have theoretical and practical significance.4 typical well groups are selected in the high-dip angle area of western Qi 40 block,and 3D geological model and numerical model are established by using Petrel and STARS softwares,respectively,then study on optimization of successive development methods at the late steam flooding stage is carried out.Numerical simulation result shows that the producing degree of Lian I oil member is relatively high;that of Lian Ⅱ oil member is relatively low with the residual oil saturation higher than 60％,and small differences exist in residual oil distributions at the high and low positions of the structure.According to the characteristics of residual oil distributions in Lian Ⅰ and Lian Ⅱ oil members,it is considered that separate layer steam injection technology can be used and the oil recovery factor by the technology can increase by 4.0％.The optimization result of the successive development methods at the late steam flooding stage for the inclined reservoirs in the Block Qi 40 shows that the oil recovery inproved by intermittent steam flooding is the highest,reaching 5.2％;that improved by continuous steam flooding is 4.6％;those improved by alternate steam-water flooding and steam-air combination flooding are 1.8％ and 3.2％,respectively.The producing degree by intermittent steam flooding is larger than those by continuous steam flooding in Lian Ⅰ oil member;the cumulative oil-steam ratio by intermittent steam flooding is higher than those by steam-air conbination flooding and alternate steam-water flooding.Therefore,it is suggested that intermittent steam flooding should be the optimal successive development method at the late steam flooding stage.
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