Primary completion string technology for fracturing and operation of deep gas wells

Deep gas fields in northern Songliao Basin feature in deeply buried reservoir and complicated lithology.There exist a lot microcracks and holes.Higher productivity can be obtained based on fracturing transformation.New fracturing processes and tools are urgently needed to solve such problems as higher fracturing pressure,great change of pressure,and difficult gas well fracturing operation.So primary completion technology for deep gas well fracturing and operation is developed to optimize fracturing processes and strings and to realize multi-interval fracturing and operation on the basis of successive ball throwing.Sealing bore is the key to primary completion string.This paper begins the study of the principle of sealing bores,the stress analysis and calculation of cones.Based on many laboratory tests,it discusses the method to improve the capacity of sealing bores resistant to pressure by perfecting sealing bores,inserted sealed intervals,and sealing rings.According to the real conditions of deep gas wells in northern Songliao Basin,it develops sealing bores of different sizes and their matching inserted sealed intervals,meeting the requirement of deep gas well fracturing production.By improving tools like sand blaster,strings integrating fracturing and operation of deep gas wells are developed.Such strings and downhole tools can be resistant to 150℃ and 80 MPa,which can be used to improve the efficiency of construction and lower damage to reservoir.