Simultaneous Production of Oil and Gas Reserves From Single Wellbore

Abstract

Maximising oil recovery in thin and ultra-thin (<30ft) oil columns is a challenge as a result of conning or cresting of unwanted fluids into the wellbore in both vertical and horizontal wells. There is considerable oil left behind, above the well completion in the reservoir. This may also occur in horizontal well when bottom or edge water encroachment or invasion takes place.The development of the gas resources from these reservoirs is a major challenge as regulators want optimal development plan for the oil rim before project approval is made. This can delay upstream gas supply to LNG projects and grind down project value. A smart development strategy has been proposed for the development of these challenging reservoirs. This involves the use of intelligent multilateral well in simultaneous oil and gas development; the first (top) horizontal lateral well legs of the multilateral well will be completed at the crest of the reservoir in the gas cap. The second or lower horizontal lateral well leg will be completed, right above the gas-oil contact.Extensive numerical reservoir flow simulation has been used to demonstrate the ability and possibility of using a single wellbore for simultaneous oil and gas production. This proposed development strategy will provide high impact on the asset of such oil and gas reservoir by providing a cost effective technology solution. The numerical simulation results show that the intelligent multilateral well will significantly improve the overall cumulative production of gas and oil from a thin oil reservoir with large gas cap as compared to conventional wells and also provide opportunity for auto gas lift for low API gravity crude. This paper presents; i) the use of intelligent multilateral wells to simultaneously produce oil and gas from the same wellbore in the thin oil reservoir and ii) provide information on the delay and reduction of excess production of unwanted fluids (water) during oil and gas production from thin oil reservoir using intelligent well technology including cost effectiveness.