Type Curve Techniques for Hydraulically Fractured Wells in Tight Gas Reservoir

Abstract

Tight gas sand is characterized for having low productivity and permeability in which low gas flow rate is provided. The application of hydraulic fracturing known as stimulation technique has been used to produce gas at economic rates. However, a common problem in tight gas reservoir simulation is the representation of hydraulic fracture in reservoir modelling. This is a crucial challenge for numerical simulation in which erroneous values of pressure distribution are generated, resulting in the calculation of unrealistic cumulative gas production. As a reliable solution, the use of Local Grid Refinement (LGR) simulation technique is applied around the wellbore and parallel to the fracture increasing the resolution of pressure behavior to adequate properly the hydraulic fracture in the reservoir modelling. In this paper, the results of simulation for Whicher-Range (WR), a tight gas field in Western Australia, were analyzed and used to generate the type curves for finite flow capacity in vertical fractured wells. Although the curves behavior was completely different to the type curves in conventional reservoirs, the development of engineering plot generated based on the same simulation results matched perfectly on the type curves predicting the gas production as well as validating the effectiveness of LGR method in numerical simulation of tight gas reservoir. The generation of type curves for hydraulic fractured wells in tight gas reservoir has never been presented and proven for Whicher Range field before. Also, the reformulated method based on the research by Argawal, Carter and Pollock of type curves are much faster than using numerical simulator which is time consuming and high CPU cost. In this paper, the successful method proven is a fast and effective way to predict the gas production for a single hydraulic fractured well in tight gas reservoir without any problem of using any commercial software.