Research On An Environment-friendly High Temperature Resistant Water-based Drilling Fluid

The technology of environmentally-friendly drilling fluid means that the application of environmentally-friendly drilling fluid to meet the requirements of the progress of drilling construction will not bring pollution to the environment and efficient drilling technology.With the rapid development of Chinese petroleum industry,the discharge of heavy metals,organic additives and other harmful substances from waste drilling fluids during drilling construction has caused serious environmental pollution.And because of people's attention to the environment,the environmental protection requirements of drilling fluids are getting higher and higher.Therefore,it is urgent to develop an environmentally friendly water-based drilling fluid to meet the needs of actual oil and gas well drilling fluid.First,the article briefly analyzes the part of environmental protection drilling fluid treating agent,including filtration reducing agent,inhibitor and lubricant.In the discussion of the present characteristics and existing problems of the existing environmental drilling fluid system,including silicate drilling fluid,polyol drilling fluid,synthetic base drilling fluid and polyamine high-performance drilling fluid.Except that,the paper has discussed the evaluation standards about biodegradability and biological toxicity.In order to meet environmental and temperature requirements,solution polymerization has been carried out to modify CMC under the action of initiator to synthesize an environmentally-friendly fluid loss additive.Through a lot of research,the experiment chose AM,AMPS and DMDAAC as grafting monomers.The optimization of the reaction conditions are as follows:the monomer concentration of CMC is 2%,the mass ratio of AM/AMPS/DMDAAC is 6:2:1,the total monomer concentration is 20%,the dosage of initator is 0.2%of the total mass of monomer,the reaction time is 2.5h,the pH is 7,and the reaction temperature is 70?.Using the synthesized graft copolymer as the fluid loss additives of the drilling fluid system,cooperate with anti-sloughing agent,inhibitor and lubricant to develop an environmental drilling fluid system:4%basic mud+3%JHC-4+0.5%CASD+3%TRF-1+1.5%OEM+weighting materials.The systematic evaluation experiment results prove that the drilling fluid system has good rheology characteristic,anti-pollution capability and temperature stability(150?).In addition,It is non-toxic and degradable.