Study On Harmless Treatment Technology Of Waste Sulfonated Drilling Fluid In Green Exploration Of Sichuan Tibet Railway

In the exploration of Sichuan Tibet Railway with bridge tunnel ratio up to 96.4%,there are many drilling holes and complex geological conditions,which put forward higher performance requirements for the commonly used solid free and low solid-phase drilling fluid treatment agents.When drilling the deep tunnel hole,it is often accompanied by high temperature and ground pressure.When drilling the broken stratum,it is easy to have problems such as borehole wall instability and borehole collapse,which seriously affects the progress of the investigation ? In the process of drilling,the sulfonated drilling fluid has small filtration,compact mud cake and good compressibility,and has good anti collapse and wall protection performance.At the same time,sulfonated drilling fluid also has good thermal stability,and can maintain good rheological property under high temperature and pressure.Therefore,sulfonated drilling fluid is more used in actual drilling.However,a large number of waste sulfonated drilling fluid will be produced after the survey.If it is discharged directly without treatment,it will pollute the environment.In accordance with the principle of green exploration,this paper makes a systematic study on the harmless treatment of waste sulfonated drilling fluid produced in the exploration process of Sichuan Tibet railway.Focusing on the research purpose of harmless treatment of waste sulfonated drilling fluid and environmental protection,the following research results are achieved in this paper:(1)This paper analyzes the source and harm of the pollutants in the waste sulfonated drilling fluid.The pollutants mainly come from the invasion of drilling fluid additives,inorganic salts in the formation and heavy metal ions.It also analyzes the main ways of the pollutants polluting the environment,and expounds the difficulties and steps of the harmless treatment of the sulfonated drilling fluid.(2)The stability of waste sulfonated drilling fluid is analyzed by physical method(particle size analysis of drilling fluid)and chemical method(analysis of the influence of treatment agent on colloidal stability).The systematic research on the treatment of waste sulfonated drilling fluid by gel breaking flocculation is carried out.The newly developed gel breaking agent GB-1 is selected,which can achieve better gel breaking effect when the dosage is 2%.The flocculant(0.5% Cationic PAM(molecular weight 12 million))and coagulant aid(0.2% nc-1 type coagulant aid)were optimized.Through gel breaking and flocculation,most of the suspended solids,some organic pollutants and a large number of heavy metal ions in the waste sulfonated drilling fluid were removed.The concentration of heavy metal ions after flocculation has reached the national secondary discharge standard.(3)In terms of solid-liquid separation methods,the effects of centrifuge dewatering and pressure filtration dewatering are studied respectively,and the efficiency and effect are compared.Combined with the construction site conditions,the centrifuge dewatering method is selected,and the solid-liquid separation equipment is preliminarily designed.(4)The harmless treatment of filtrate after solid-liquid separation was studied,and the applicability of different harmless treatment methods to the exploration of Sichuan Tibet railway was compared.In the process of screening oxidants,it was found that monomer oxidants could not effectively treat filtrate.The compound oxidant was determined as 2% potassium permanganate + 4% CA-1 type oxidant + 1% sodium hypochlorite by orthogonal test and range analysis.The oxidation effect of the compound oxidant was compared with that of the monomer oxidant,and it was concluded that the compound oxidant had better oxidation effect than the monomer oxidant.(5)Using the high cohesiveness of soluble cellulose and sodium carboxymethylcellulose,a new type of sf-100 curing agent was made by ourselves.Compared with the common curing agent,the best curing agent was sf-100,and the best dosage and influencing factors of sf-100 curing agent were analyzed.