周志军 暴赫

摘      要：在辽河油田超稠油油藏SAGD开发后期，受低物性段隔夹层阻挡作用，蒸汽腔发育迟缓、纵向扩展受限导致产量下降。针对这一问题，可采用直井辅助水平井SAGD开发和对低物性段酸压等手段改善渗透率、促使蒸汽突破低物性段从而进一步提高采收率。本文结合现场数据建立数值模型，采用正交设计法分析不同裂缝参数对产能的影响顺序，依次为裂缝长度、裂缝数量、裂缝宽度、裂缝间距。同时采用控制变量法分析不同裂缝参数对产能的影响并优选出适合目标区块的最佳裂缝参数，裂缝长度160 m，裂缝数量5条，裂缝宽度9 mm，裂缝间距90 m。并对优化方案进行了模拟预测，结果表明：目标区块累计产油量增加5 928.6 t，采收率提高12.2%，累计油气比达到0.228，含水率平均降低8%～12%，研究成果对直井辅助水平井SAGD低物性段开发和提高后期采收率提供了理论指导。

关  键  詞：SAGD;低物性段;直井水平井;裂缝参数;正交设计;参数优化

中图分类号：TE 341        文献标识码： A        文章编号： 1671-0460（2020）08-1745-05

Abstract： In the late stage of the SAGD development of super-heavy oil reservoir in Liaohe oilfield， due to the blocking effect of low-physical interlayer， the steam chamber was stunted and the vertical expansion was limited， resulting in the production decline. To solve this problem， vertical Wells can be used to assist the development of SAGD in horizontal wells and acid fracturing in low physical properties section to improve permeability and promote steam breakthrough in low physical properties section so as to further enhance recovery. In this paper， a numerical model was established based on the field data， and the influence order of different fracture parameters on productivity was analyzed by using the orthogonal design method， which was fracture length， fracture number， fracture width and fracture spacing. At the same time， the control variable method was used to analyze the influence of different fracture parameters on productivity and to optimize the optimal fracture parameters suitable for the target block. The optimal fracture parameters were determined as follows： the fracture length 160 m， the number of fractures 5， the width of fractures 9 mm， and the spacing of fractures 90 m. The results showed that the cumulative oil production in the target block increased by 5 928.6 t， the recovery rate increased by 12.2%， the cumulative oil/gas ratio reached 0.228， and the water content decreased by 8%～12% on average. The research results provide theoretical guidance for the SAGD development of low-physical section and the improvement of the recovery rate in the later period.

Key words： Steam assisted gravity drainage; Low physical property segment; Vertical well and horizontal well; Fracture parameters; Orthogonal design; Parameter optimization

辽河油田属超稠油油藏，同时存在低物性段，原油黏度高、凝固点高、埋藏浅、地层温度低，初期采用蒸汽吞吐方式进行开采。随着吞吐周期的增加油井暴露出许多问题，如产量递减快、油气比低等特点，转水平井辅助SAGD后蒸汽腔突破低物性段，产量得到提升，但后期含水较高，开发效果变差，随后开展了直井辅助水平井SAGD开发低物性段方面的研究，取得初步成效。但是目前国内外对开发参数优化的研究主要采用单变量控制法，不能得出各因素对生产结果的影响顺序，难以准确地指导现场实际生产及后期进行措施调控[1-7]。……