高温冻胶阀的研制与现场试验

Development and Field Test of High-Temperature Gel Valve

南堡油田潜山裂缝性油气藏水平井目的层温度在150℃以上,钻井过程中存在漏喷同存等问题,完井作业难度大,为此,设计应用了二次交联高温冻胶阀。该冻胶阀设计采用二次成胶方式,第一次交联形成适当结构冻胶,满足泵注要求;第二次交联速度快成胶强度大,完成封隔井筒,保证冻胶阀上部井段顺利施工。RM2100高温高压冻胶检测仪在线检测结果表明,冻胶阀形成过程中冻胶黏度体系一直保持在1 000mPa·s以上,150min时二次成胶开始,最终黏度12 000mPa·s以上。室内模拟试验结果发现,该冻胶阀承压能力在2 MPa/100m以上,150℃高温下72h冻胶黏度基本稳定,可用钻头切割冲蚀方式完成破胶。在NP23-P2016井的试验表明,该冻胶阀成功封隔了井筒,减少了漏失,为回接尾管等完井作业提供了安全的井控环境。研究结果表明,高温冻胶阀技术可有效解决南堡油田潜山油气藏水平井完井作业井控难题。

There are well completion challenges in Nanpu buried-hill fracture reservoirs due to the coexistence of the risk of loss of circulation and blow out combined with formation temperatures over 150℃.To solve the problems,the formula for twice-crosslinking gel valves were developed.In the design,a structural gel was developed to meet operational demands.In the first crosslinking step the gel possesses high strength and quick formation speed.In the second crosslinking step involved insuring proper operations in the isolated borehole section.RM2100 HTHP online gel detector was used to monitor the formation of gel valves.Results showed that viscosity of the gel system could be maintained over 1 000mPa·s.In the secondary crosslinking step,gel formation started at 150 min with ultimate viscosity above 12,000mPa·s.Simulated boreholes were used to determine pressurebearing/load capacitywhich could reach over2 MPa/100 m.In addtion,the gel at 150℃ maintained a satisfactory viscosity for 72 h.Gel-breaking could be done through flushing by using drill bits.Successful application in Well NP23-P2016 indicated effective isolation of hydrocarbons to minimize losses and to provide reliable well-control conditions for deployment of tie-back tailpipes.Research results showed that the high-temperature gel valves could provide satisfactory solutions to challenges in well control encountered during well completion in Nanpu buried-hill reservoirs.