Study On Drilling Fluid Technology For Protecting Oil Reaervoir In Bozhong25-1 Oilfield

Structural map of four layers in Shahejie group of BoZhong25-1 Oilfield show that there are all complete faulted anticlinal trap. Container rocks in Shahejie group are deeper, higher diagenetic grade, lower porosity and permeability than that in Minghuazhen group. So container rock in Shahejie group should be protected all out effect. Study on drilling fluid technology for protecting Oil Reaervoir in BoZhong25-1 Oilfield were conducted aimed at its geologic feature and reservoir characteristics.Firstly, lithology, layering, reservoir characteristics, type of oil reservoir, properties of liquid, temperature and pressure in stratum of BoZhong25-1 Oilfield were analyzed. Container rocks in sha2 stage of BoZhong25-1 Oilfield are composed of interbedded grey medium-fine sand block and plumbeous mudstone, have good physical property, bigger porosity and higher permeability. While Container rocks in sha3 stage of BoZhong25-1 Oilfield are mainly composed of interbedded grey-offwhite sand block with gravel and taupe-plumbeous mudstone, have worse physical property, smaller porosity and lower permeability. Than aimed at geologic feature and reservoir characteristics of superficial layer of BoZhong25-1 Oilfield, PEM-Ⅰand newly positive ion drilling fluid formula with good temperature resistance, rheological property, inhibition, lubrification and protective property for container rock were obtained. Synthesis based drilling fluid with excellent contamination resistance, inhibition, lubrification and protective property for container rock were obtained to meet the demand of drilling highly-deviated well and horizontal well. Formate drilling fluid with well temperature resistance, inhibition, lubrification and protective property for container rock were optimized aimed at geologic feature and reservoir characteristics of deep layer of BoZhong25-1 Oilfield.