Research on the Protection Technology of Drilling and Completion Fluid in the Reservoir of Lunnan Area of Tarim Oilfield

The lunnan area of tarim oilfield is of low porosity and low permeability reservoirs. This dissertation describes its geological features and analyses the factors leading to the reservoir damages. The main reason for the reservoir damage is that, the solid phase invasion into microfracture of drilling and completion fluid, or the leak of it, causes solid plugging. All the drilling and completion fluid used in lunnan area is water-based polymer mud system of Lunnan area are used in the polymer water-based mud system. Water-blocking effect, Jamin effect, much too higher pH value of drilling fluid and some other factors result in the damage degree, drilling and completion fluid of lunnan area to the reservoir, increases from medium level to extreme serious level. Considering this case, adding surfactant to weaken water-blocking effect and Jamin effect, promote reservoir permeability and optimize the formula of drilling and completion fluid so that to protect the reservoir.