The Unconventional Hydrocarbons Reservoir project aimed to develop mathematical models for unconventional hydrocarbons reservoirs. These types of hydrocarbon reservoirs, like shale gas reservoirs, usually have lower potential for producing hydrocarbons. Petroleum engineers try to increase the potential of these reservoirs by creating fractures in the reservoir through a process called Hydraulic fracturing. Another technology that helps is horizontal drilling. Combining these technologies unlocked and gave us access to hydrocarbon resources that were not feasible before. It started with the study of a practical issue of creating multiple fracture horizontal wells in the reservoir. The impact of inducing the fracturing fluid into the reservoir and its impact on the productivity of the well was studied. The project was published in the SPE Reservoir Evaluation & Engineering. Later, we introduced the incorporation of stress variations in the coalbed methane reservoirs. The Extended volumetric source method was a step forward. Later, we extended the study by considering the bounded dual-porosity reservoirs.