Ketsela Tadesse (PhD)Shiferaw Regassa (PhD)Bisrat Kebede (PhD)Mengistu HaileMariam2024-05-022024-05-022023-06https://etd.aau.edu.et/handle/123456789/2946The economically viable production of oil and gas is a direct function of the geological properties of reservoir rocks. Among these formation properties, permeability is critical for an effective hydrocarbon flow. The flow of fluids from the reservoir to the wellbore can be restricted due to low permeability or damage around the wellbore. Hydraulic fracturing is applied to stimulate the low permeability formation and bypass damaged formation areas, connecting the reservoir to the wellbore. Recently, the most popular layouts for increased production from low permeability reservoirs have been horizontal wells with numerous transverse fractures. Under various studies conducted, it has been proven that there is a significant commercially recoverable gas reserve in the Ogaden basin of Ethiopia that has been identified for development. Hilala Field is located within this basin, and it is considered for gas development and production through domestic and international gas market arrangements outlined in the recent field development plan. This fracture design study is undertaken for the Adigrat sandstone reservoir in Hilala Gas Field, buried at a depth of 3087-3200m and characterized as a low porosity and low permeability reservoir that requires hydraulic fracturing for its economic gas recovery. The aim of the study is to develop an optimum multiple hydraulic fracturing design for the horizontal wells considering the geology, rock mechanics, fracturing fluid, and proppant. This hydraulic fracture design work is based on the Unified Fracture Design (UFD) and selected extension works. Excel sheet is the main tool for the analytical study. OptiFrac and OptiFracMS software are employed to design and analyze results. This study examined well log data from seven wells, well test and production test results from four wells, and the field development plan for the Hilala Gas Field in the Ogaden basin in South Eastern Ethiopia. Understanding reservoir rock‘s physical, geo-mechanical properties is crucial to the stimulation of hydraulic fracturing. The brittleness Index can be determined from well log and core data. Based on the analysis of the Adigrat reservoir rock‘s geo-mechanical properties, the Adigrat sandstone formation in Hilala gas field has a high Young‘s modulus (51.26 MPa) and a low Poisson‘s ratio (0.21), correlating it to a brittle rock suited for fracture propagation. The calculated average closure stress is 50.45 MPa, and the suitable proppant material is intermediate-strength bauxite proppants. An optimum fracture half-length of 310.6m and a fracture width of 2.25 mm are attainable for a given proppant number of 0.87 for a single fracture. An optimum number of twelve (12) transverse fractures can economically attain a dimensionless productivity index of 6.18 for an available proppant number (Np) of 8.92 for the 0.2 mD permeability reservoir and drainage width of 1000m.en-USlow permeability reservoirgas reservoirhydraulic fracturingfracture designfracture geometrybrittlenessclosures stressgeo-mechanical propertyoptimum number of fracturesThesis