Unconventional gas reserves are mainly described by having low permeability which makes these reserves very challenging both technically and commercially to exploit than conventional reserves.Shale gas production is intensifying globally and a lot of the activity is taking place in the United States and Canada,while others countries recently started to intensify the momentum.One of the biggest and important deposits is Marcellus shale.Horizontal drilling and hydraulic fracturing technology gave the technical feasibility of production but there is a fear existing concerning the economics of shale gas production.Some of the worries related to limited production and economic data for shale gas wells.Shale gas is low permeable and porous formations which are both source rock and reservoir.Such formations can be said to have very extreme low matrix permeability.It’s required to carefully examine the properties.Horizontal drilling with multiple hydraulic fracturing along the horizontal well offers successful depletes resources.When modeling unconventional resources it’s necessary to effectively and efficiently model reservoir.The focus of this thesis is mainly in two parts.The first part is the analytical model of finite hydraulic fracture conductivity.The solution procedure is based on the analytical model developed for fractured horizontal wells.In addition,commercial reservoir simulator(CMG)is used to check and compare the result which is obtained from the analytical model.The parameters which affect the productivity of the multiple fractured horizontal wells are studied by using trilinear model.The study shows that productivity of shale reservoirs can increase when the matrix permeability and hydraulic fracture are high.This thesis analysis and compares the sensitivity analysis of the two different models,trilinear model and the commercial reservoir simulator model(CMG).The parameters which were studied include hydraulic fracture half length,hydraulic fracturing spacing and the matrix permeability.In addition,the analysis covers the naturally and hydraulically fractured reservoir.The geo-mechanical influences of natural and hydraulic fractures are also analyzed.The second part of this thesis,we look at the well pattern design which is used to enhance the productivity of the well.Commercial reservoir simulator(CMG)was used to simulate the well pattern design.Three different well pattern designs were simulated which are,Planar Opposed Quadrilateral,Planar offset Quadrilateral and Stacked Tri-lateral to compare and analysis the production output since each of designs penetrating different layers.The result of this study shows that better production performance can be reached if the parameters affecting the reservoir can selected carefully.Production optimization of shale gas is greatly affected by the number of fractures,spacing and the matrix permeability.The natural fractures in shale gas can even contribute higher production rate is considered.In addition,different well pattern designs were chosen in this thesis to study the well optimization performance because choosing well pattern configuration is very important in production and economic.In conclusion,the output results for the two models have shown in agreement even though the analytical model offers better output.