水平井分段注采产能模型研究

该文针对面积较小或井场开采条件受限的油气藏提出了采用水平井的分段注采的开发方式,它利用水平井的长井段优势,在一定注采管柱条件下实现水平井分段注采,以达到维持地层能量的目的.利用势能叠加原理推导出了定压边界时不同水平井的井段长度、注采封隔间距下的产能模型,并给出了定注入段的注入压力与生产段的生产流压下的产能关系及沿程流量分布,若要保持注采平衡,只需要给定注入压力和生产井流压中的一个即可由注采平衡为约束条件通过迭代进行求解另外一个压力;研究结果表明,注水井对生产井的跟端和趾端干扰不同,生产井流量分布不对称,且井段越长干扰程度越大;注采井段封隔间距对流量分布具有一定影响,封隔间距越大注入段对生产段的干扰越小;当总井长度一定时,产量与注采压差呈正比关系,且随着生产井段长度增加产量逐渐增加,因此对大位水平井进行配产配注时,需要充分考虑注采压差的限制.

Research on deliverability of horizontal well with separated injection and production scheme

This paper presents a new development scheme of separated injection and production in horizontal well for small block reservoirs or restricted reservoirs by production conditions. It is possible to separate the long completion horizontal interval with special pack for injection and production at same time, and the reservoir with pressure maintenance under waterflooding. The model of deliverability has been built based on potential superposition principle for different horizontal well length and block scale with constant pressure outer boundary. Flowing rate distribution along the horizontal well can be gotten for specified injection and production pressure. One of the injection pressure and production pressure will be specified and iteration method will be used to keep the balanced injection and production. It has been also shown that flowing rate distribution is not symmetry because of interference of injection and production, and the more interference the longer production interval. The separate interval has some effect on the distribution, and the less interference the larger separate interval. Production rate is difeet proportion as pressure difference of injection and production with given length of horizontal well, so it is necessary to consider the pressure difference limitation of the packer for production rate dispatching of larger length horizontal well.