ehsan momeni - science and research branch islamic azad university
mohammadhadi parhamvand - science and research branch islamic azad university

we have two kinds of blowout that are underground gas blowout and shallow gas blowout. Underground blowouts involve significant downhole flow of formation fluids from a zone of higher pressure the flowing zone to one of lower prssure the chaarged zone or loss zone. they are the most commonof all well control problems. this phenomenon differs from cross flow wich typecally occurs within a long perforated interval and involves little or no reserves loss or escalation hazard. underground blowouts can occur in drilling wells or producing wells, and are thought to be the most common in the latter because of tubulars corrosion in older completions. two factors make shallow gas drilling a difficult challenge . first unexpected pressure at the top of the gas bearing zone, due most often to the gas effect dictated by zone thickness and / or natural dip, can be significant . this pressure is usually unknown seismic surveys being often unable to give an idea either about thickness or in-situ gas concentration. in more complex situations , deep gas may migrate upwards along faults. gas blowout is one of the dangerous event that may be happen in all of the gas or oil wells. this kind of blow out is one of unknown and uncontrolled event that can be accurate in all fields .

underground gas blowout, shallow gas blowout, recipe