Environment friendly water-based working fluid for universal drilling and fracturing

Fracturing is a necessary measurement to increase production after drilling and completion well in most low permeability oil field. In order to decrease the total amount of supplies and total emissions of oilfield chemical working fluid in drilling and fracturing treatment, water-based drilling-fracturing universal working fluid was researched. Heter-polysaccharose SJ was chosen as main fluid of current driving fluid, and the performance of drilling-fracturing water-based fluid was evaluated as drilling fluid according to testing procedure of drilling fluid SY/T 5621—1993.The laboratory experiment shows that the rheology behavior, filtration and inhibitive ability could meet the requirement of Changqing Oilfield application. It have well ability of resisting temperature and also could resist the pollution of 2800 mg/L Ca2+, 1900 mg/L Mg2+ and 2500 mg/L K+. Indoor integration process of drilling fluid changing into fracturing fluid was explored. According to SY/T 5107—2005, the property of fracturing fluid was evaluated after it has been transformed. Laboratory result shows that SJ could transform to fracturing fluid which was used as main fluid in water-based drilling fluid, and could achieve the object of drilling-fracturing current driving fluid. the maximum combat temperature was up to 83.3 ℃, after been transformed, and all the rheology, filtration, the ability of taking sand, shear resistance, breaking property, compatibility and the content of caput mortem after gelout could meet the requirement of field application in Changqing Oilfield.