Research Of High-temperature Deep Well Water-based Drilling Fluid

The deep and ultradeep well drilling fluid technology was considered to be significant sign of the drilling fluid and drilling technology. Developing new drilling fluid additives and drilling fluid system with good performance is the primary problem in the deep and ultradeep well drilling. A fluid loss agent and a thinner are synthetised upon the treating chemical action mechanism through radical polymerization with molecular structure design,suited for high temperature and high density water-based drilling fluid system in deep well. Analysing the influence factors of product performance,such as reaction temperature, the initiator amount, the solid amount,the reactant allocated proportion, the reaction time, the reaction pH and so on, the optimal synthetising technological conditions are obtained. The availabilities of temperature resisted, salt resisted, calcium resisted and effect used in drilling fluid system have been appraised and compared with similar products.Based on the two synthesized treating chemical, a set of water-based drilling fluid system which can resist high tempreture(220℃～240℃) with high density(2.2g/cm3) was founded. The rheology and the HTHP filtration have been tested. The experimental results show the ability of the new products that can resist high temperature, alcium and salt, and they also have good rheological and the HTHP filter loss performance with good compatibility with sulfonated agent. With good HTHP rheology and filtration, the drilling fluid system has extensive prospect of application.