Study On High Temperature Foam Drilling Fluid

In the process of drilling deep well, drilling ultra-deep well and drilling geothermal well, often met complicated geological condition, especially due to its complex geological structure and ultra-high stratum temperature, which cause a series of complicated drilling technical problem such as high circulating temperature, keep borehole clean, slow mechanical drilling rate and completely lost circulation. Foam drilling can prevent lost circulation effectively, protect the reservoir, keep foam system stability and owns a good shear performance, thus foam drilling can be the best choose to overcome the above problems while drilling. However, conventional foam drilling fluid has limited capacity to resist high temperature while in deep well drilling/ultra-deep well drilling and geothermal well drilling. For the complex problems encountered in ultra-high stratum temperature while drilling with foam drilling fluid, research is carried out by the following aspects.In-depth analysis of foam fluid characteristics and the related theory, the performance of the different kinds of foaming agent is been evaluated, and one kind of foaming agent is optimized to match it for the purpose of improving the ability of integral foam fluid to resist the high temperature, through compounding different foam agents in order to has good foaming property and high tolerance to fight pollution. The ability of self-healing of foam membrane by using surface tension analysis, the foam structure of foaming agent under different temperature by using microscopic observation analysis, focus on the performance of thermal stability.Using aqueous solution polymerization in the quaternary copolymerization reaction, synthesis of high temperature foam stabilizing agent, and through the orthogonal test and single factor experiment to optimize the best preparation conditions, verify the copolymer molecular structure by using infrared spectrum analysis, the XRD analysis is carried out on foam stabilizing agent by using X-ray diffraction techniques, the characterization of the synthesis of the molecular structure also combined with viscosity analysis.The synthetic performance of this foam drilling fluid has been evaluated and reveals positive effect to high temperature drilling, high tolerance to fight pollution and good performance thermal stable (230℃), this provides a scientific basis for safe deep well drilling/ultra-deep well drilling and geothermal well drilling.