低滤失双膨胀水泥浆体系的室内研究与应用

油井水泥浆体固有的体积收缩和高滤失量是造成固井窜槽事故的根本原因。针对江苏油田老区调整井地层压力系统紊乱、固井质量无法保证的技术难题，研制开发出了油井水泥低滤失双膨胀材料(F17C)，对其在不同条件下的膨胀量、滤失量、胶结强度和工程性能进行了评价。结果表明：F17C可使油井水泥浆产生足够的塑性膨胀和硬化膨胀，还能有效控制水泥浆的滤失量。掺入该材料后水泥浆的其它性能也满足现场施工的技术要求。低滤失双膨胀材料的双膨胀性能来自于多膨胀源的综合作用，其膨胀驱动力源于膨胀性成分反应产物的结晶生长压；其优异的降滤失效果得益于对滤饼渗透能力的控制。江苏油田138口调整井的固井实践证明：低滤失双膨胀水泥浆具有显著的抗窜作用，能够大幅度提高固井优质率。

Improving the Cementing Quality Using a Novel Additive with Double-expansion and Fluid-loss-control Action

The intrinsic shrinkage of oilwell-cement slurry causes fluids-migration and poor bond quality in cementing. One of the major problems in Jiangsu Oilfield is fluid migration in cementing wells of multi-pressure system as well as poor bonding quality in sheath/formation and sheath/casing. A novel anti-channeling mechanism was proposed and a controllable fluid-loss double-expansive material for oil well cement studied in this paper. The experimental findings indicated that the slurry with double-expansive material shown not only significant expansion both in plastic and set conditions but also lower filtration. In addition, other engineering properties of the slurry, such as thickening time, compressive strength and rheology, also satisfied API specification. The double-expansion of the additive chould is due to comprehensive function of multi-expansive crystal materials, and the expansive force comes from the crystal growth pressure of the expandant. The excellent capacity of control filtration should be result of reduce permeability of the filter cake. The additive was applied over 138 wells and showed excellent cementing quality. It proved to be a successful material for improving the cementing quality in channeling easy wells.