Study On The Harmless Treatment Technology Of Waste Oil - Based Drilling Fluid

Because of oil-based drilling fluid which has resistant to high temperature, calcium and salt harassment, make for sidewall stability, good lubricity and lesser degree damage to oil and gas layer,etc.Since then, the oil-based drilling fluid is gradually becoming important means of high difficulty high temperature well, offshore drilling, large angle deviated well, horizontal well, all kings of complex wells and protection for reservoir.But,due to serious pollution for the surrounding environment of the well site,and the backward harmless technology of waste oil-based drilling fluid, which has become a "bottleneck" of our country’s oil exploration and development technologies.Therefore,changing the traditional approach, from the perspective of environmental protection,and strive to progress and breakthroughs to find out the harmless disposal,the principle and processing technology of waste oil-based drilling fluid has important practical significance from the technically and economically feasible.By analysis the factors of impact waste oil-based drilling fluid stability,excellent with the demulsifier,flocculantand thinner,determining the optimum conditions to separation the oil, water and solid phase:taking 25ml waste oil-based drilling fluid and plus thinner ratio of 1:1(40% water/60% ethylene glycol),and plus 57.5mg/L xylene/isopropanol as demulsifier under the conditions of 50℃ and pH is 4.0, adopting centrifugal separation (1200N/600r/min) for disposal the waste oil-based drilling fluid,the oil separation rate reached 80.5%.In order to more thoroughly of oil separator,further processing of residual oily sludge, adopting compoud with demulsifier (xylene/isoproanol) and nekal BX,by synergies to deal with the oily sludge.When the temperature at 45℃,sludge water sludge ratio is 6:l,the pH value of 4.0, the demulsifier dosage of 100mg/L,nekal BX dosage of 2100mg/L,mixing in the blender 180r/min 20min,oily sludge oil recover rate is 45%.The final oil separation is 89.28%, the separation oil moisture is less than 1%.By analysis the factors of affecting the curing effect,excellent with the breaker,curing agent,determine the best curing conditions:under the conditions of pH value of 8.0,40℃ and dry, the breaker SW-A (concentration of 40%) dosage of 9～10ml/100g,lime ratio dosage of 10g/100g, the cement dosage of 30～40g/100g. Determined for leaching toxicity of solid waste, the pollution index of leaching toxicity of solid waste meeting National Integrated wastewater discharge standard (GB 8978-1996) standards.