Research On Reservoir Protection Drilling Fluid Of Qianan Area In Jilin Oilfield

Though the basic reasons of formation damage have been profoundly understood, due to differences in geological characteristic and formation condition and so on, detailed analysis of each oilfield should be carried out. There are a lot of technical problems in drilling fluid of Jilin oilfield, the remarkable one is that low-inhibiting drilling fluid damages formation to a large degree and is harm to formation discovering and protection and influences development rate and effects of oilfield. Therefor, how to advance the inhibition of drilling fluid and induce liquid and solid contents that invade into formation becomes the chief problem of formation protection in Jilin oilfield. According to standard test procedure, research on formation sensitivities of Yingtai area have been conducted, the results are as follows: Acid sensitivity (medium), Stress sensitivity (medium), rate sensitivity (medium to low or (medium), alkali sensitivity (low or medium), water sensitivity (medium to low or low), Salt sensitivity (low to medium or low). On the basis of sensitivity analysis, research onformation damage mechanism of Jilin oilfield has been conducted, damage simulating test proves that the main reason causing formation damage is invasion of exotic fluid into formation.On the basis of original drilling fluid of Jiling oilfield, formation protection drilling fluid-water-based drilling fluid has been developed, a lot of tests indicate that the system has high permeability recovery which is in favor of formation discovering and protection.