高温高压地层漏失控制技术研究与应用

Research and Application of Leakage Control Technology in the Formation with High Temperature and High Pressure

针对南海乐东区块温度高、地层压力大、易发生井漏事故的问题,用复合堵漏剂、诱导剂、悬浮稳定剂配制了密度为2.4 g/cm^(3)的Leakseal堵漏浆,研究了堵漏浆组分的承压强度,堵漏浆的流变性、悬浮稳定性及堵漏效果,并在乐东区块进行了现场应用。结果表明,复合堵漏剂和诱导剂的强度较好,在220℃、50 MPa压力下的破碎率小于25%。堵漏浆具有较好的流变性、高温悬浮稳定性和封堵效果。堵漏浆在180~220℃老化16 h后再静置24 h的沉降率小于10%,在0.69 MPa下在150 s内快速滤失。砂石粒径为4~10、10~20目时,堵漏剂侵入砂床百分比分别为65.6%和52.3%,可承压10 MPa;在缝宽为0.5、1、2 mm的楔形裂缝中注入堵漏浆后形成可承压10MPa的堵漏层,反向承压分别为7、6、6 MPa。堵漏浆在乐东区块某井成功应用,堵漏效果良好。图6表1参11。

In view of the problems of high temperature,high formation pressure and easy lost circulation accident in Ledong block of South China Sea,a plugging slurry with a density of 2.4 g/cm^(3) was prepared by using composite plugging agent,inducer and suspension stabilizer.The component bearing strength,rheology,suspension stability and plugging effect of the slurry were studied.And the slurry was applied in Ledong block.The results showed that the strength of composite plugging agent and inducer was better,and the crushing rate was less than 25%at 220℃and 50 MPa.The plugging slurry had good rheology,high temperature suspension stability and plugging effect.After aging at 180—220℃for 16 h,the settling rate of the lost circulation slurry was less than 10%after standing for 24 h,and it could filter rapidly within 150 s at 0.69 MPa.When the particle size of sand stone was 4—10 mesh and 10—20 mesh,the percentage of plugging agent invading the sand bed was 65.6%and 52.3%respectively,and the bearing capacity was 10 MPa.After injecting plugging slurry into the wedge-shaped fractures with fracture width of 0.5,1 and 2 mm,a plugging layer with pressure bearing capacity of 10 MPa formed,and the reverse pressure bearing capacity was 7,6 and 6 MPa respectively.The plugging slurry was successfully applied on a well in Ledong block,showing good plugging effect.