Comparative Study of Field Development Scenarios of the Elk City Gas Reservoir using Reservoir Simulation

Abstract

Well placement is a critical aspect of Field development planning in order to fully understand the extent of the field to further effectively develop and drain the field. In most cases, the structure of the formation is initially unknown, in addition to other geologic and petrophysical properties that will aid in calculation of GIIP and EUR. The use of analogy alongside decline curve analysis have been great starting points to drill the first few wells while additional data are being collected to enable the use of more advanced tools like reservoir simulation for full-field development study. This paper presents a study on the production of a gas field and the contributions from seven vertical wells that had been drilled. These seven wells are designated wells p1 to p7. Wells p1, p2 and p6 are located on the anticlines, p3 and p7 are located on the front edge of the reservoir, and p4 and p5 are placed at the center between the two domes. Contour, isopach, isopermx, isopermy and isoporosity maps were used for grid generation, while other modeling software were used for reservoir simulation and visualization. Four base cases were simulated to study the effects of grid sizes and use of local grid refinement (LGR). Four additional "experimental" cases were studied to explore alternative well placement and potential benefit for horizontal and hydraulically fractured wells. The two poor performing wells (p3 & p7) were considered as good candidates for hydraulic fracturing. Unfortunately, the results were not promising as both wells showed less than 1% improvement in gas recovery and hence may not justify the investment. The use of alternative well placements scenarios for these wells resulted in about 9% incremental recovery while conversion to horizontal wells added a further 3% in recovery. This last investment will be further justified if a dual lateral is considered rather that two separate wells.