摘要
以归一化处理的典型失重模拟实验结果为依据,研究无滤失情况下水泥浆的沉降失重、沉降—胶凝失重(简称SG失重)和水化体积收缩—胶凝失重(简称HG失重)三者的关系,揭示其内在机理和规律。结果表明:(1)3种失重既相对独立,又相互联系和促进。通常三者的发生依次有“时间差”,并且相邻两种失重有“共存期”。(2)转化期的沉降失重与SG失重的关系总体上是由井眼条件和水泥浆的沉降稳定性能决定的。井眼条件一定时,一般随着水泥浆沉降稳定性能的提高,SG失重将取代沉降失重成为主要失重方式,且V_(pτ)减小,水泥浆的防窜能力提高。(3)转化期的沉降失重和SG失重最多使水泥浆柱孔隙压力降到等高静水柱压力。(4)不同水泥浆沉降失重和SG失重阶段的V_(pτ)与HG失重阶段的V_(pτ)的相对大小不一定一致,这是防窜水泥浆设计中应注意的。(5)用初凝时间归一化处理的失重曲线近似消除了凝结时间不同对失重的影响,失重曲线近似反映了V_(pτ)的变化,可作为直观地比较和评价水泥浆防窜能力的方法。
According to the normalized experimental results, the relationship of cement slurry's three pore Pressure Drops due to Settling (PDS), Settling Gelling (PDSG) and Hydrated volume shrinking - Gelling (PDHG) without filter loss was studied, and the mechanism and law was revealed. The results show: (1) Three pressure drops are both relatively independent and inter - relative and interactive. Their occurrence usually has a time difference in proper order (PDS, PDSG and PDHG), and neighboring two pressure drops have a coexisting period. (2) The relationship between PDS and PDSG in Transformation Period (TP) totally depends on well - hole conditions and the slurry' s settling stability. Under same well - hole conditions and along with the slurry' s stability properties being improved, PDSG will replace PDS and become slurry' s main pressure drop way, at the same time Vpτ reduces and slurry's ability of preventing gas migration increase. (3) PDS and PDSG in TP at most decrease slurry's pore pressure to hydrostatic column pressure. (4) The relative sizes of Vpτ at PDS and PDSG stage and PDHG stage for different slurries are not necessarily identical, which should be noted when designing the slurries for preventing gas migration. (5) The slurry pressure drip curve normalized with the initial setting time approximately e-liminates the influence of setting time on the pressure drop, reflects the change of Vpτ and is a method to directly compare and evaluate slurry's ability of preventing gas migration.
出处
《中国海上油气（工程）》
1999年第3期51-54,共4页
China Offshore Oil and Gas
关键词
水泥浆
压力降
防窜
沉降失重
水化
钻井泥浆
cement slurry, pressure drop, relationship, mechanism, channeling prevention
