Research Of The Saliferous Waste Drilling Fluid Innocuous Treatment

《Research of The Saliferous Waste Drilling Fluid Innocuous Treatment》 is the scientific research item which the land managerial department of the financial plan ministry of Sinopec Corp. proposes and the science and technology exploitation ministry of Sinopec Corp. confirms. The contract number is J303020. The study shows how to dispose the saliferous waste drilling fluid and makes it harmless and useful.The saliferous waste drilling fluid is colloid that is made up of the rock bits, clay granules, inorganic salt, disposal chemical, additive, etc. The water content of drilling fluid is commonly between 35%~90%. The drilling fluid is alkalescency which appearance is the ropy fluid state. This ropy colloid has little granules, bad gradation, sizable viscosity, and high water content that is difficultly dehydrated. The contaminations are the salts, deliquescent metallic elements(Cr~6+,Hg~2+,Cd~2+, Pb~2 +,As~2+etc), organic compound, acerbity and alkali pollute the soil and water around the artesian wells. We dispose the saliferous waste drilling fluid by sludge treatment, sludge dehydrate. The high content brine and the low content brine are disposed separately to be harmlessly.The sludge treatment research chooses the kinds and optimal accession proportion through the experimental investigations. In the treatment process, the fly ash (the accession proportion is 3%) is acceded to the drilling fluid as the coagulant aid firstly. Then the polymerization aluminum chloride (the dilution ratio is 5%, and the accession proportion is 10%) as the inorganic coagulant and the cation polyacrylamide (molecular weight ≥12000,000, the dilution ratio is 1%, and the accession proportion is 8%) as the organic coagulant are acceded to the drilling fluid. After the sludge treatment, the drilling fluid is easy to dehydrate and benefits to the subsequent technological process.The disposed drilling fluid is dehydrated by the vacuum tape pressure filter. We confirm the vacuum degree which is 0.03-0.04Mpa in the progress of washing and dehydration .We need wash the drilling fluid for six times. The chlorine ion content in the soak fluid of the mud cake is less than 250mg/l (the water quality standard forfarmland irrigation GB5084-92). The desalinization of the drilling fluid delivers the goods.The saliferous waste drilling fluid is disposed by the sludge treatment, washing, and the vacuum tape pressure filter through the ally examination. After the treatment, the chlorine ion content in the soak fluid of the mud cake is less than 250mg/l (the water quality standard for farmland irrigation GB5084-92) and the water content is 75% in the average level that can be used to build the groundsill and roadbed in the artesian well site. The experiment confirms that the effect of the sludge treatment is good and the accession proportion of the polymerization aluminum chloride, the cation polyacrylamide and the fly ash are right and the washing and dehydration of the vacuum tape pressure filter deliver the goods.The low content brine which is dehydrated from the saliferous waste drilling fluid (saline salinity<35000mg/l) is disposed by the filtration and the reverse osmosis. We leach away the seston and mechanical impurities and debase the turbidity through the mediums filtration and exactitude filtration. Then we wipe off the salinity and organic through reverse osmosis. We choose the super low pressure and high desalinization connected aromatic polyamide composite membrane as the reverse osmosis membrane. Through the middle experiment, the chlorine ion content in the low content brine is not more than 20mg/l , COD is not more than 20mg/l and the seston content is not more than 10 mg/1 after the brine is disposed by the technological process. The disposed water is measure up the water quality standard for farmland irrigation and can be recycled in the well drilling process. The chlorine ion content in the high content brine that is reclaimed is not less than 45000mg/l and is disposed by evaporation.The high content brine that is dehydrated from the saliferous waste drilling fluid and the reverse osmosis is disposed by the double effect ascend membrane evaporation and then produce the crystal salt by the mould. Through the middle experiment, we confirm the vacuum degree which is 0.03— 0.05Mpa in the progress of ascend membrane evaporation, the technological equipments function well and the reclaimed crystal salt can be recycled in the well drilling process.The middle experiment settings are used in the locale experiment at the base of the laboratory and middle experiment. The disposed saliferous waste drilling fluid is followed up the scent and sampling inspection [(2005) Qianjinag environmentinspection (47)]. The disposed mud cake can be used to build the groundsill and roadbed in the artesian well site, the after-treatment water reached the national sewage discharge standard I and can be recycled in the process of drilling. The reclaimed crystal salt can be recycled in the well drilling process. After these, we needn't the mud pit again. These change the conventional drilling technique and cut off the source of pollution from the headstream, economize a good quantity of land resource, achieve the clean produce, amend the image of the environmental protection of the oil field, and have the marked social and economic benefit.