海上油田极限井网密度评价方法研究

Research on Evaluation Method of Limit Well Pattern Density in Offshore Oilfields

井网形式及井距大小是油田形成有效注采井网的基础,也是直接影响油田采收率、投资规模和经济效益的关键。因此,井网的合理性论证是油田开发规划设计中极为重要的一环,特别是对于稀井网、大井距开发的海上油田,显得尤为重要。基于中石油勘探开发研究院经验公式,引入实际油田的驱油效率,同时提出以水平井与直井间的产能比来表征替换比确定井网密度的方法,并通过井网系数的反演计算对公式进行改进,建立了新的采收率与井网密度的关系式;在此基础上结合海上油田井网经济评价模型,对油田井网的合理性进行研究。实例研究表明,该方法适用性强,能很好地反映采收率与井网密度的关系,可为油田加密调整提供理论依据。

The well pattern and well spacing are the basis for the formation of an effective injection-production relationship in the oilfield, and also the key directly affecting the oil recovery rate, the size of the investment and the economic benefits. Therefore, the rationality of the well pattern is an extremely important part of the design of oilfield development plans, particularly for offshore oilfields with sparse well pattern and large well spacing. On the basis of empirical formula of the institute of petroleum exploration and development, a new formula between recovery factor and well pattern density was established respectively by introducing the oil displacement efficiency of actual oilfields, proposing the method of characterizing the replacement ratio to determine the well density by using the ratio of the production capacity between horizontal wells and vertical wells, and using the method of calculating well pattern factor. On the other side, the rationality of oilfields well pattern is studied by combining the economic evaluation model of offshore oilfields. The case study shows that the method is highly applicable and can well reflect the relationship between recovery factor and well pattern density, which can provide a basis for oilfield encryption adjustment.