The Unayzah-A in field T is an Aeolian sandstone formation with high sanding tendency requiring stimulation using the frac pack technique. Modified Isochronal Tests (MIT) and pressure buildups (PBU) were conducted on several wells in field T, to assess the reservoir and to evaluate the frac pack technique. During the analysis of the MITs and PBUs, several consistent trends were observed in the pressure derivative plots of field T wells, such as the absence of the fracture signature and the decrease of reservoir quality away from the wellbore. This consistency in the behavior of the pressure derivative was investigated in this study. Analytical and numerical well testing models, reservoir characterization, and fracturing analysis assisted in investigating the observations in PBUs. The investigation showed that to capture a fracture in the pressure derivative plot of high permeability formation, the fracture half length has to be extremely long, and there should be significant contrast between the fracture and the formation conductivities. The investigation also showed that the created fracture and the reservoir heterogeneity due to changes in geologic facies dictate the shape of the pressure derivative plot.

This paper will discuss how the reservoir characterization and the fracturing analysis were used to help in analyzing the pressure transient response of frac packed wells. Two pressure buildups (PBUs) and four MITs were used in this study. This paper will also shed some light on the frac pack results, and the non-Darcy flow effect.

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