Evaluating Unconventional Reservoir Based on DFIT Analysis, Actual Field Cases

Reservoir properties become critical key parameters to optimize the hydraulic fracture treatment which play an important role to develop unconventional reservoirs. The most valuable and commonly tool used to quantify the reservoir and hydraulic fracture characterizations is Diagnostic fracture injection test (DFIT). The pressure decline response of DFIT test reflects the process of fracture closure and the flow capacity of the reservoir. DFIT test could be provide valuable estimation of reservoir properties and fracturing parameters, including interaction with natural fractures and heterogeneous rock properties. This result could be used to build simulation model to forecast these reservoirs before performing the actual frac job. The objective of this paper is to investigate and analyze the behavior of non- ideal DFIT and factors which affect the DFIT data. The paper also explains the analysis of DFIT before and after closure and how to identify the flow regimes under complex reservoir conditions. The fall-off period is analyzed using the diagnostic plots and leak-off modeling to determine the reservoir and fracture characterization such as pressure, reservoir permeability, mobility, and transmissibility, flow regime before and after closure and fracture half-length …etc.). This result could be used to build simulation model to forecast these reservoirs before performing the actual frac job and predict the reservoir productivity index. The paper explains different mechanisms affecting the pressure behavior during DFIT and leak-off process in order to observe the reservoir response and get more realistic reservoir and fracture properties.