一种高压内封堵井口增注保护装置的研制与应用

Development and Application of A High Pressure Internal Sealing Wellhead Injection Protection Device

随着油田开发进入中后期,常规的注水补充能量已无法满足“补能、增油”的动态开采要求,尤其是针对部分高压低孔低渗油藏缺少有效开发手段,普遍面临“压力高、注不进、采不出、动用程度低、生产成本高”的困境,在经济极限井距下难以实现有效驱替。目前大港油田主要采用增能注水增注工艺,利用压裂车组对目标井组进行“超高压、大排量”增强注水,在短期内补充老区地层亏空,能够达到提高采收率目的。但是增能注水工艺主要应用于高压低孔低渗油藏埋藏深、温度高,且施工压力高(70MPa)、压力波动频繁、排量大,需要配套高承压级别井口,为解决常规注水井口即可满足增能注水需要的问题,研制了一种高压内封堵井口增注保护装置,可以在不进行作业更换高压井口的情况下实现高压增能注入,减少作业成本和施工时间,已实施2口井增注,实现日增注69m^(3),累计增注11752m^(3),井组增油1358.7t,效果显著,具备推广应用价值。

With the oil field development entering the middle and late stage,conventional water injection energy supplement has been unable to meet the dynamic production requirements of"energy supplement and oil increase",especially for some high-pressure lowporosity and low-permeability reservoirs,which lack effective development means,and generally face the dilemma of"high pressure,no injection,no production,low utilization degree,high production cost",and it is difficult to achieve effective displacement under the economic limit well spacing.At present,Dagang oilfield mainly adopts the process of enhanced energy water injection,and uses the fracturing truck group to enhance the water injection of"ultra-high pressure and large displacement"to the target well group,which can supplement the formation deficit in the old area in a short time and achieve the purpose of enhanced oil recovery.However,the enhanced energy water injection process is mainly applied to the high pressure low porosity and low permeability reservoir with deep burial,high temperature,high construction pressure(70 MPa),frequent pressure fluctuations,and large displacement,which requires a high pressure level wellhead.In order to solve the problem that the conventional water injection wellhead can meet the needs of energy enhanced water injection,a high pressure internal wellhead injection protection device is developed in this study,which can realize high pressure energy injection without replacing the high pressure wellhead,and reduce the operating cost and construction time.Two wells have been implemented to increase injection,achieving a daily increase of 69 m^(3),a cumulative increase of 11,752m^(3),and an oil increase of 1358.7 t in the well group,with remarkable results.It has the value of popularization and application.