The Research And Application Of Underbalance Drilling Technology In Huabei Oil Field

The main reservoir of Huabei Oilfield mainly in Jizhong Depression,the buried hill stratigraphic pore,hole,fracture are very abundant,clay concentration of low permeable sandstone reservoir are more than the other. With conventional drilling techniques prone to lost circulation , borehole collapse incidents and other underground complex while drilling, and the reservoir produces injury. Application of underbalanced drilling technology can effectively avoid the occurrence of such incidents, to protect the reservoir, the purpose of improving rate of penetraion.This thesis analyzes the geological features of buried hills and low permeability sandstone reservoirs in Jizhong Depression of Huabei Oilfield , The reserch of well and layer selection is from three key hands include geological,engineering and construction capabilities. According to the outstanding problems of the reservoir to determine the appropriate under-balanced pressure differential, the final design underbalanced drilling technology for Huabei Oilfield. Optimized the formulation of Oil-in-water Drilling Fluids, and Conducted field application in 5 wells, the results of leak protection are obvious, reaching the purposes of reservoir protection.The successful drilling of Xi73X used the whole-process underbalance drilling technology,overflow 8.6m3 in the drilling process,discovered oil and gas shows,improve 100.35% than the adjacent wells on the rate of penetraion.It has very important meaning for valid development of outer oil field and hydrocarbon stimulating of HuaBei oil field,it also offered powerful technical support for sustainable development of HuaBei oil field.