Study On Changqing Oilfield Universal Water-based Working Fluig Of Fracturing And Drilling

Fracturing is a necessary measure to increase production after drilling well or completion in most block of Chang Qing oil fieled,in order to decrease total amount of supplies and total emissions of oilfield chemical working solution in drilling and fracturing work.Based on the earlier work of carbohydrate and phenol Oilfield chemicals and working solution, this article aimed to achieve water-based well drilling-fracturing universal working solution in Chang Qing oil field.In view of geologic characteristic of Chang Qing oil field, heter-polysaccharose SJ was choosen as main fluid of current driving fluid, further experiments proved that SJ could increase viscosity and decrease filtration resist temperature and shear repress shale swelland could lubricate wall of hole in water-based drilling fuild;The measurement of proportionality of BOD5/CODCr and Permeability core recovery show that SJ have well biodegradability and could defend reservoir;Phenol-sulfuric acid process quantitative was used to determine the content of polysaccharose in SJ.Through single element experiment,we define fit recuitment of defferent kind of drilling fuild additives,aimd to choose applicable drilling fluid additive according to downhole condition of Chang Qing oil field,research the affection to drilling fuild of the addition order of additive.Through complex test optimize the formilar of drilling fluid,finally,determined drilling-fracture current water-based driving fuild uesd as the drilling field formular: 2.0%SJ+0.2-0.3%gain viscosite fuild ZN-2+0.5-2.5%fluid loss additive JLS-2, We evaluate the performace of drilling-fracture current water-based fuild used as drilling fuild.,according to SY/T5621-1993.The laboratory findings shows that the rheology behavior,filtration and inhibitive ability could meet the requirment of application of Chang Qing oil field.It have well abilty of resisting temperature and could resist the pollution of 2800mg/L Ca2+,1900mg/L Mg2+and2500mg/LK+.Indoor integration process of drilling fuild changing into fracturing fuild was explored.Add proper fracturing fuild treating-agent in current driving fuild(pH conditioner cross linker,clay inhibitor,gel breaker,discharge aiding agent)to make fracture fuild,according to SY/T5107-2005 evaluating the property of fracturing fuild after it have transformed.Laboratory findings shows that SJ use as main fuild in water-based drilling fuild could achieve the trasformation to fracture fuild,and achieve the object of drilling-fracture current driving fuild,the maximum combat temperiture is 83.3℃,after been trasformed.All of rheology,filtration,the ability of taking sand,the ability of combat temperiture,breaking property,compatibility and the content of caput mortuum after gelout could meet the requirement of field application in Chang Qing oil field.