陆上稠油油田多轮次聚合物驱提高采收率方法

Enhancing oil recovery by multi-cycle polymer flooding for onshore heavy oilfields

采用聚合物驱技术提高稠油油藏原油采收率已经在国内外海上油田得到成功实践,而陆上稠油油田的开采目前却主要依赖于热力采油。为探究陆上稠油油田聚合物驱开采的可行性及相应技术对策,以我国西部某油田的ZH区块普通稠油油藏为研究对象,采用聚合物驱数值模拟技术,从参数优化的角度对陆上稠油油田聚合物驱的合理实施界限进行了研究,明确了聚合物驱核心技术参数注入量、注入速度、聚合物溶液浓度、注入时机对聚合物驱效果的影响规律,在此基础上,形成了陆上稠油油田多轮次聚合物驱提高采收率技术。多轮次聚合物驱中,5个独立段塞发挥不同功效,组合协同增油作用明显。对ZH区块的模拟计算结果表明,多轮次聚合物驱可提高水驱采收率达11.78%,吨聚增油量达到168.97 m3。陆上普通稠油油田聚合物驱的成功探索为该类油田提供了一条提高采收率的新途径,特别是对热力采油技术应用具有局限性的油田有较强实用性。

The technology of polymer flooding to enhance oil recovery in heavy oil reservoirs has been successfully applied to domestic and foreign offshore oilfields. However, the development of onshore heavy oilfields mainly depends on thermal methods. In order to investigate the feasibility and technical strategy of polymer flooding for onshore heavy oilfields, the polymer flooding simulation method is implemented in ZH Block, a regular heavy oilfield in western China. The reasonable implementary strategy is studied through parameter optimization, and the variation law of polymer flooding effectiveness with paramount parameters（injection volume,injection rate, concentration of polymer solution, injection time,） is then delineated. The technology of enhancing oil recovery by multicycle polymer flooding is developed based on the research results above. Each of the five polymer slugs plays a distinct role in the process of multi-cycle polymer flooding, which contributes to the wonderful effect of increasing oil production. Numerical simulation results for ZH Block show that multi-cycle polymer flooding can increase the water flooding recovery by 11.78%, and the oil increment per ton of polymer powder is 168.97 m^3. The validation of feasibility and technical research of polymer flooding for onshore regular heavy oilfields provides a new way of enhancing oil recovery for these reservoirs. In particular, it possesses strong practicality for reservoirs limited to thermal development methods.