Horizontal well development technology in low oil saturation bottom reservoir——by taking Ng6,Ng7,Ng9and Ng10layers in northern Gaoqian as examples

Ng6,Ng7,Ng9 and Ng10layers in northern Gaoqian of Jidong oilfield belong to low oil saturation bottom reservoir,with the characteristics of low amplitude structure,small oil column height and porous reservoir,and the conventional directional well can't be used for normal production.By applying horizontal well and sidetracking horizontal well in three steps can effectively develop such reservoirs.Firstly,to deploy an oil well on the top of oil layers with the thickness of more than 5 m and avoid bottom water fast ridge into.Secondly,to apply horizontal well chemical water plugging technology of oil wells in high water cut,block high waterflooded interval and force the bottom water flow around so as to enlarge sweep volume of water drive.Finally,when the bottom water comprehensively cresting,by using CO2stimulation technology to enhance the capacity of oil flow and further displace residual oil around the wellbore.Horizontal well design is the core,water plugging and CO2stimulation provide the guarantee for water control and increased oil in high water cut stage.