低成本超低密度水泥浆体系研究与应用

针对低压易漏失、长封固段地层的固井难题，同时适应当前油气勘探低成本战略，开发出一种复合增强材料BCE-650S。该材料具有稳定性好、高活性、高蓄水等特点，且来源广泛、价格低廉。对其辅以适当外加剂，形成了密度在1.20～1.30 g/cm3的超低密度水泥浆体系。该体系在扩大水灰比、降低密度的同时，还具有优良的性能，使低密度水泥浆的成本大幅降低，水泥浆在60℃养护24 h后的抗压强度大于8 MPa，72 h抗压强度在10 MPa以上；浆体稳定性、耐压性能良好；失水量可控，稠化时间可调，满足施工要求。该体系已经应用于吉林油田，现场固井效果良好，具有推广应用前景。 

Study and Application of a Low Cost Ultra-low Density Cement Slurry

By compounding a high water demand material, a high active material and an ultra-fine material, a low cost strengthening light weight material BCE-650S was developed for use in low density cement slurry as a high performance additive. An ultra-low density cement slurry was developed with BCE-650S and other additives and mixed materials selected for use with BCE-650S. This cement slurry has densities adjustable between 1.20 g/cm3 and 1.30 g/cm3, and liquid/solids ratio between 1.07 and 1.23, and therefore has its cost greatly reduced. Laboratory study showed that the 24-hour compressive strength of the ultra-low density cement slurry at 60℃ is greater than 8 MPa, and the 72-hour compressive strength is greater than 10 MPa. The settling stability of the cement slurry is quite good; the difference between the density of the top and the density of the bottom of the cement slurry is only 0.01 g/cm3. The cement slurry has controllable filter loss, adjustable thickening time and high compressive strength, satisfying the need of field operation. This cement slurry is suitable for cementing low pressure long open hole with mud loss zones. Success in applying the cement slurry in Jilin Oilfield indicates that this cement slurry will have good application prospect.