摘要
Abstract
In light of the characteristics of long cementing section(about 2 000 m) of Ø244.5 mm casing in high-pressure salt-anhydrate bed in HFY Oilifeld of Iraq, high pore pressure (2.15~2.20 g/cm3), narrow safe cementing window (0.08 g/cm3)and low cementing section temperature (30~70 ℃), as well as the problems existing in previous cementing operation, the test and research have been carried out, the optimal salt concentration for salt-tolerant high-density cement slurry of which the density is 2.28 g/cm3 has been determined as 10%~15%(BWOW). In light of the characteristics of weighting and close packing compressible packing model and through calculation and evaluation of solid-phase water demand, the reasonable composition of weighting hematite and BCW500S (4∶1) as well as the concentration (80%~83%(BWOC) ) under such density have been determined. The salt-tolerant carboxylate based dispersant has been introduced, the concentration of ifltration loss reducer has been optimized from 10%to 6%~8%(BWOW), and the HFY high-density salt-tolerant cement slurry system so formed has the characteristics such as high slurry stability, good rheological property, controllable thickening time, and quickly-developing early-stage compression strength at low temperature. On the basis of the optimization of cementing program, the cementing of Ø244.5 mm casing is simpliifed from double-stage cementing to single-stage cementing, and the cementing quality is obviously improved. The successful application in 28 wells indicates that, this technology settles the cementing dififculty in high-pressure salt-gypsum bed with narrow-density window.关键词
固井/高压盐膏层/窄密度窗口/水泥浆优化/盐掺量/加重剂Key words
cementing/high-pressure salt-anhydrate bed/narrow-density window/cement slurry optimization/salt concentration/weighting agent分类
能源科技
