适宜海水钻井液体系新前置液实验和现场试验

INVESTIGATION OF THE PERFORMANCE OF A NEW RECIPE OF SPACER FOR SEA-WATER DRILLING FLUIDS BY MEANS OF LABORATORY AND IN-SITU EXPERIMENTS

前置液是影响固井质量的重要因素之一,对于海水钻井液体系,如何选用前置液是一个新的课题．提出了一种适宜于海水钻井液体系的新型前置液,对其在固井过程中的各种性能进行了室内实验研究,结果表明:新型前置液与海水钻井液、固井水泥浆及盐水等环境流体有良好的相容性,对井壁具有稳定作用,其中的固体颗粒及表面活性剂有利于冲刷海水钻井液形成的泥饼．在此基础上,将新型前置液应用于胜利油田的固井作业,进行现场试验,发现:应用新型前置液后,环空水泥浆界面清晰,混浆段长度缩短,第2界面的胶结质量有明显提高．

Spacer is one of the cruciM factors influencing the quality of well cementing. It is particularly important to choose right ingredients of the spacer for well cementing in sea-water drilling fluid. The paper proposes a new recipe of spacer and studies its performance in laboratory. The experimental results demonstrate that the new spacer works well with the environmentM fluids, such as sea-water drilling mud, cement slurry and salty water. It can stabilize the wall of the well. And, with carefully chosen solid particles and surfactazats in the recipe, the spacer fluid can efficiently used to wash the wall of the well, especially, for the mud cake. Furthermore, in-situ experiments were conducted in Shengli Oilfield, Shangdong Province, China. The results show that the new spacer fluids can shorten the mixing length of the drilling mud and the cement slurry, and can evidently improve the quality of the second interface of the cement annulus.