高密度水泥浆沉降稳定性评价方法探讨

针对高密度和超高密度水泥浆设计中凝结沉降稳定性迄今仍无依据的问题,研制出了水泥浆凝结沉降稳定性指标确定装置,依据凝结水泥石的纵向抗压强度满足固井质量要求的思想,提出了高密度和超高密度水泥浆的凝结沉降稳定性指标的确定方法。该方法将顶部一段水泥石的抗压强度刚好满足工程对水泥石抗压强度要求的最低值所对应水泥石柱顶部与底部的密度差值,作为水泥浆沉降稳定性密度差值的指标。模拟实验结果表明,利用该装置确定水泥浆的凝结沉降稳定性指标的方法简单易行,可靠性好。用该装置,根据模拟条件下水泥石纵向抗压强度满足固井环空封固要求为前提,提出了高密度和超高密度水泥浆凝结沉降稳定性指标的方法,为施工设计提供了理论依据。

Determination of Parameters Controlling Sedimentation Stability of High Density Cement Slurries

A testing device has recently been developed as a tool to determine parameters governing the sedimentation stability of cement slurry.Based on the idea that the longitudinal compressive strength of set cement should satisfy the need of well cementing, a method of determining the parameters controlling the sedimentation stability of cement slurry is presented.In this method, when the compressive strength of a section of the top set cement just satisfies the need of engineering for the minimum compressive strength of set cement, the corresponding difference between the density of the top and bottom of the set cement is taken as the control parameter for measuring the sedimentation stability of cement slurry.Simulation test shows that this device is easy to operate and gives reliable results.