Rapid Drilling Technology in Ahdeb Oilfield

Ahdeb Oilfield in Iraq contains abundant recoverable reserves.However,drilling problems have occurred frequently due to the existence of long interval easily-creeping anhydrite formation,easily-collapsing mudstone and argillaceous limestone in Tertiary,and less-drillable anhydrite and lower Cretaceous formations.To accelerate development of the field,several drilling techniques were integrated to a fast drilling technologyy suitable for the oilfield.The technology contains the following aspects: horizontal well structure optimization based on formation pressure profile,profile of horizontal wells optimization to a double build-up with medium curvature radius according to geological characteristics, development requirement and available drilling technology,well trajectory design with unified anti-collision,salt/calcium resisting sulphonated polymer mud with good inhibition capacity optimization through laboratory evaluation,PDC bit selection according to formation drillability profile and PDC bitalong with motor to realize steerable drilling,and slide rail rig move technique in cluster well drilling.Field application shows that tight hole and tight pull are mitigated with the technology,average ROP increase more than 100%,and average drilling period decreased by nearly 50%.Therefore,the fast drilling technology provides effective engineering support for capacity construction in Ahdeb Oilfield.