Maximizing petroleum production while efficiently managing the operational costs is the oil and gas industry's primary goal which requires innovative engineering approaches and production-enhancing treatments such...Maximizing petroleum production while efficiently managing the operational costs is the oil and gas industry's primary goal which requires innovative engineering approaches and production-enhancing treatments such as hydraulic fracturing(HF).During the HF process,the injected fluid mixed with sands or proppants will create permanent fluid channels to drain more of the reservoir volume.The level of complexity and various constraints involved in real field treatments have made HF even more chal-lenging in layered carbonate reservoirs with the water drive mechanism.A prominent concern is the downward fracture growth to the oil/water contact zone that may cause unfavorable water cut levels.This fracture height confinement criterion necessitates optimization of fracture dimension design.Fracture height development is mainly a function of in-situ stress conditions and stress magnitude differences between geologic layers.In cases with a water table at the proximity of the wellbore,fracture height directly affects the operational success.This paper demonstrates a practical step-by-step approach towards the design of hydraulic fracturing treatment in an offshore carbonate oil reservoir.The modeling process involves optimization of the location,number,and conductivity of the proposed fractures.In-jection of high viscosity fluid causes a bi-wing vertical planar fracture to propagate perpendicular to the direction of minimum horizontal stress in the strike-slip faulting regime.Dimensions of the induced hydraulic fractures are also impacted by the amount and type of proppants.However,as with this case study,the magnitude of vertical stress is in the same range as the maximum horizontal stress;the fracture height growth is the limiting factor.The LGR method is used to define fractures in the dynamic reservoir model which has been built based on a complete set of data ranging from the analyses of logs,core samples,and seismic details,to perform production forecasts and economic evaluation.Then a hydraulic fracture software is implemented to provide a timetable for fracturing fluid volume and mixing proppant concentration for the desired fracture dimensions.The results show that,despite the operator's previous perception,five hydraulic fractures per well would be economical,which include a 150 ft long fracture and four shorter fractures with an approximate length of 75 ft designed to manage the risk of penetration into the water-bearing formations.Due to the reservoir pressure drop by time and more flexible fracture dimension constraints at earlier stages of production,executing such stimulations earlier than later would improve the commercial outcomes.展开更多
文摘Maximizing petroleum production while efficiently managing the operational costs is the oil and gas industry's primary goal which requires innovative engineering approaches and production-enhancing treatments such as hydraulic fracturing(HF).During the HF process,the injected fluid mixed with sands or proppants will create permanent fluid channels to drain more of the reservoir volume.The level of complexity and various constraints involved in real field treatments have made HF even more chal-lenging in layered carbonate reservoirs with the water drive mechanism.A prominent concern is the downward fracture growth to the oil/water contact zone that may cause unfavorable water cut levels.This fracture height confinement criterion necessitates optimization of fracture dimension design.Fracture height development is mainly a function of in-situ stress conditions and stress magnitude differences between geologic layers.In cases with a water table at the proximity of the wellbore,fracture height directly affects the operational success.This paper demonstrates a practical step-by-step approach towards the design of hydraulic fracturing treatment in an offshore carbonate oil reservoir.The modeling process involves optimization of the location,number,and conductivity of the proposed fractures.In-jection of high viscosity fluid causes a bi-wing vertical planar fracture to propagate perpendicular to the direction of minimum horizontal stress in the strike-slip faulting regime.Dimensions of the induced hydraulic fractures are also impacted by the amount and type of proppants.However,as with this case study,the magnitude of vertical stress is in the same range as the maximum horizontal stress;the fracture height growth is the limiting factor.The LGR method is used to define fractures in the dynamic reservoir model which has been built based on a complete set of data ranging from the analyses of logs,core samples,and seismic details,to perform production forecasts and economic evaluation.Then a hydraulic fracture software is implemented to provide a timetable for fracturing fluid volume and mixing proppant concentration for the desired fracture dimensions.The results show that,despite the operator's previous perception,five hydraulic fractures per well would be economical,which include a 150 ft long fracture and four shorter fractures with an approximate length of 75 ft designed to manage the risk of penetration into the water-bearing formations.Due to the reservoir pressure drop by time and more flexible fracture dimension constraints at earlier stages of production,executing such stimulations earlier than later would improve the commercial outcomes.
