A SIMULATION OF MANAGED PRESSURE DRILLING IN IRANIAN DARQUAIN OIL FIELD

The narrow operating window between pore pressure and fracture pressure makes drilling difficult in some operations. A feasibility study of managed pressure drilling (MPD) is carried out on Iran Darquain oil field. The previous wells drilled in this field showed that mud returns were lost during drilling Gadvan formation. The present work addresses this problem by means of surface back pressure application in Darquain oil field. The methodology employed in this study is based on hydraulic analysis calculations and comparative drilling operation pressures. The DZxION MPD software performs hydraulic analysis using the API RP ۱۳D rheological model and calculates the annular pressure drop to compare the pressures and the required back pressure, if needed. Using a mud weight of ۱۴.۳۱ ppg and exerting ۱۰۰ psi static back pressure, the wellbore pressure profile got slightly overbalanced. When the mud pumps are in service, no back pressure is required. The problem is resolved and no kick or loss is observed using a MW of ۱۴.۳۱ ppg and a static back pressure of ۱۰۰ psi. As a result, the managed pressure drilling technology is useful in Iran Darquian oil field through using a lower mud weight in order to overcome the circulation loss in Sarvak formation. This study is based on hydraulic analysis calculations and comparing the drilling operation pressures in Darquain oil field. For analyzing the pressure regimes throughout the well, DZxION managed pressure drilling software performs hydraulic analysis. This software calculates annular pressure drop and equivalent circulating density to compare the pressures and required back pressure, if needed. By using this method to drill the well, some advantages were gained: the mud weights used to drill the well, the number of casing strings, and the number of changing mud weights were reduced.