Comparison of Different Hydraulic Fracture Growth Models Based on a Carbonate Reservoir in Iran

Abstract

There has been little interest in the application of hydraulic fracture treatment in Iranian oil fields, thanks to the primarily suitable production rates of the vast oil fields. In this paper, hydraulic fracturing treatment was simulated by different models for a carbonate reservoir in the southwest of Iran. Suitable pay zones were nominated based on the lithology, water-oil saturation, geomechanical properties, and finally in-situ stress conditions – with the optimum option chosen based on a pseudo three-dimensional (P3D) model. In this work, modeling with P3D, finite different method (FDM), and the methods proposed by Perkins, Kern, and Nordgren (PKN) and Khristianovic, Geertsma, and de Klerk (KGD) were performed in order to determine and compare fracture growth geometrical aspects and the required pressure. Comparison of the above-mentioned models confirmed that P3D and FDM provides more reasonable results, while neither of PKN and KGD models was suitable for such a complex condition. Eventually, sensitivity analysis of input data, such as in-situ stress, injection rates, and reservoir geomechanical properties, was performed to evaluate the variation influence of these factors on fracture growth aspects, such as required pressures and geometrical specifications. The results showed that successful hydraulic fracturing treatment not only depended on the controllable parameters like fluid and proppant specifications, but also uncontrollable parameters such as reservoir properties and in-situ stress had to be taken into account. This study can help to select the optimum model in future hydraulic fracture design and implement it in carbonate reservoirs with similar conditions.

Keywords

• hydraulic fracturing
• fracture growth
• fracture geometrical aspects
• cracking pressure
• reservoir geomechanical properties