超薄层稠油油藏有效开发方式研究

Research on Effective Development Methods for Ultra-thin Heavy Oil Reservoirs

大庆WE区块萨尔图稠油油藏属于低丰度超薄层稠油油藏,此前仅开展过小规模蒸汽吞吐现场试验,开发程度较低,经济效益不过关,未形成有效的开发技术体系,不同砂体规模布井模式及有效动用方式不明确。为此,基于储层流体渗流特征,通过岩心驱油实验和数值模拟、经济评价研究,对比分析弹性开发、热水驱、蒸汽吞吐、弹性开发转蒸汽吞吐、蒸汽驱的开发效果,建立超薄层稠油油藏开发方式及布井模式优化设计方法,评价不同河道砂体规模下直井和水平井的井控储量,计算不同开发方式技术经济井距。结果表明:弹性开发有效期为240~300d,弹性开发转蒸汽吞吐采收率较高、内部收益率最高。将研究成果用于指导区块分四期编制开发布井方案,设计开发井493口(水平井155口),设计产能32.59×10^(4)t,河道宽度大于250m、有效厚度大于2.3m的区域部署水平井,河道宽度小于250m、有效厚度大于2.7m的区域部署直井,采用140m井距,采取前期弹性开发后期转蒸汽吞吐开发方式。截至目前已完钻并投产292口井,累积产油量32.7×10^(4)t,实现了当年增储、当年建产、当年拿油。

The Saertu heavy oil reservoirs in the WE block of Daqing are low-abundance ultra-thin heavy oil reservoirs.Only small-scale steam stimulation field tests have been carried out before.The degree of develop-ment is low,and the economic benefits are not up to standard,so an effective development technology system is not formed.The well pattern and effective producing mode of different sand body scales are unclear.There-fore,based on the flow characteristics of reservoir fluid,core flooding experiments,numerical simulation,and e-conomic evaluation research are conducted to compare and analyze the development effects of elastic develop-ment,hot water flooding,steam stimulation,elastic development to steam stimulation,and steam flooding.The op-timization design method of development methods and the well patterns of ultra-thin heavy oil reservoirs are established.The well-controlled reserves of vertical and horizontal wells under different channel sand body scales are evaluated,and the technical and economic well spacing of varying development methods is calcu-lated.The results show that the effective period of elastic development is 240 to 300 days,the recovery rate of elastic development to steam stimulation is higher,and its internal rate of return is the highest.The re-search results are used to guide the preparation of a well development plan for the block in four phases,493 development wells(155 horizontal wells)are designed with a designed productivity of 32.59×10^(4)t.The hor-izontal wells were deployed in areas where the river width exceeds 250m and the effective thickness exceeds 2.3m.The vertical wells were deployed in areas where the river width is less than 250m and the effective thickness exceeds 2.7m.A well spacing of 140m is designed,and the development method of early elastic de-velopment and later steam stimulation is adopted.So far,292 wells have been drilled and put into production,with a cumulative oil production of 32.7×10^(4)t,achieving increased reserves,construction of production,and oil production in the same year.