High-temperature Low-density Latex Cement Slurry System And Its Application

As the oil and gas field exploitation develops towards complex oil-gas pools, the problems including high temperature and pressure, gas channeling, narrow pressure of window start to show. Low pressure and easy leaking deep wells take up a larger and larger proportion. To solve the problems that the drilling fluid is easy to leak and the strength development of the cement column is slow during the progress of cementing, a low-density cement slurry system which could adapt to the NiuDong area is developed and it is significant to improve the cementing quality and ensure the safety of the well.As far as deep well cementing construction work goes, the cement column it made would be less dense and less evenly-distributed affecting the quality of cementing. In the process of gelation, the free fluid in the cement slurry system will form a channel for oil, gas and water making it inefficient to cementing annulus. From the view of material physical and chemical, the low-density cement slurry was developed by optimizing lightweight additive and reinforcing-material which was based on the particle size distribution. So that not only the density of the slurry was decreased but also the gelling composition of the slurry increased, which could improve the strength and compactness of the cementing paste.The suspension stabilizer agent was used to solve the problem of the lightweight cement slurry system with bad sedimentation stability under high temperature. XT-1L as the transformation of mechanical performances of cement admixture, through the evaluation of different addition on mechanical properties of the cement density, obtained the optimal dosage of XT-1L. Though selecting cement retarders and fluid loss additive, the early strength of cement paste was kept at a high degree which could also satisfy the enough thickening time. The combination properties, engineering adaptability, strength developing, permeability and microstructure of the lightweight cement slurry system or cementing paste was analyzed and discussed in this paper. Finally, the high temperature lightweight latex cement slurry system was successfully applied in practical cementing.Through a large amount of indoor experiments and mechanism studies, a high-temprature, low-density rubber latex cement slurry system with a density range of1.35-1.55g/cm3is developed. The system has a high stability in high temperatures, a better permeability, well resisting pressure and easily adjustable thickening time. The essay will also assess the long-term pressure resistance, anti-corrosion and cementation strength of the cement stone.The high-temperature, low-density rubber latex cement slurry system has already been applied to NiuDong101well, SuTan1H well, NiuDong102well successfully with a90%of success rate. The system successfully avoid the leaking and gas channeling in the process of the cementing, improving the quality of the long cementing section in the deep wells. ensuring the safety and effective exploitation of the gas and oil field.