Flushing Fluid System And Related Theoretical Research To Improve Interface Replacement Efficiency

The cementing quality is directly related to the life of oil and gas wells. A good cement displacement efficiency can fully ensure the casing wall and the cementing quality of the borehole wall. Improve the displacement efficiency is one of the keys to increase oil and gas well life. According to laminar boundary effect has little research in the cementing operation on displacement efficiency, field application measures are not clear, based on the engineering fluid mechanics theory of edge of laminar flow, the flushing fluids'thickness of the laminar flow are simulated, combined with the indoor rinses displacement efficiency evaluation method devised a isolation type of flushing fluid, and has carried on the experimental analysis simulation displacement efficiency, designed to draw rinses edge thickness of laminar flow and its effect on displacement efficiency. The main research contents and the main achievements were as follows:(1) Using the materials provided by oil field and new rinses evaluation device and its method, the optimization of anionic, ionic and nonionic surfactants in surfactants was carried out by using flush efficiency simulation, a new type of surfactant CMY is developed. And CMY gives priority to material, combining with the soluble salt, and other materials, a new isolation type of flushing fluid system named CMY with density 1.01?1.10 g/cm3 is developed And its determining method is also put forward.(2) Using the theory of laminar flow and while the thickness of the laminar flow mode, and oil field's drilling fluid, and water simulation experiment to analyze the drilling fluid boundary laminar thickness how to effect the displacement efficiency. The results showed that: Drilling edge laminar thickness thinner, drilling can be replaced and cleaned more easily, the shorter time was used for clean, used the less dosage of flushing fluid to replace.(3) With the density of 1.01?1.10 g/cm3 CMY isolation rinses, combined with indoor rinses displacement efficiency simulation experiment, the isolation rinses edge thickness of laminar flow influence on the displacement efficiency is analyzed. The results showed that: Rinses'thickness of the laminar flow is smaller, the displacement efficiency is higher, the shorter the time used for clean, less dosage of flushing fluid. This result is similar to water's rinsing.(4) Based on the edge thickness of the laminar flow model and the model of the fluid flow around, the influence of wall roughness on the displacement efficiency is studied. Through designing two kinds of simulation of the borehole wall roughness and the indoor displacement efficiency simulation experiment results show that:The caliper is more regular, the higher the wall displacement efficiency of mud cake, used the less dosage of flushing fluid. The return rate of the rinses is bigger, the rules wall displace mud cake cleanly used the shorter time. And under the condition of the same roughness, wall displacement to simulate roughness particles of mud cake spread length is greater, the wall mud cake displacement efficiency is higher. Namely, rough arrangement spacing is 3 times of the absolutely simulated grain roughness height, the wall mud displacement efficiency is higher than the spacing for 2 times.