The Luohe Formation in the upper part of the horizontal well of Longdong shale oil has low pressure bearing capacity and active formation water,resulting in cementing problems.The existing light bead system has problems such as poor pressure resistance,deterioration of rheology after pressure and lack of resistance to water intrusion.For this reason,the low-cost waterproof penetration pressure resistance low friction slurry system was developed.Compared with the glass micro-bead system of the same density,the 1m3 slurry cost of the system is reduced by about 50%,the underwater cement loss is less than 0.5%,the water-land strength ratio is higher than 0.85,the pressure density difference is not higher than 0.03g/cm3.After the cement slurry is pressurized,n＞0.5,k＜1.5Pa·sn,the cement stone's compressive strength is greater than 7MPa after 48h of atmospheric pressure curing at 45℃.Under the condition that the cost of cement slurry is similar to that of the light bead system,the performance of cement slurry is greatly improved.In the application of 60 shale oil horizontal wells in the Longdong area,the field construction pressure is significantly reduced,no leakage occurs,the cement slurry return height meets the design requirements,and the sealing pass rate of the Luohe water layer is 100%,providing solid technical support for the cementing of low-pressure and leakage-prone layers.
shale oilwell cementinglow-costwaterproof invasionwithstand pressurelow-frictionLongdong area
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