Selection of Appropriate Zones for Hydraulic Fracturing Operations in the Ilam and Sarvak Formations of an Oil Well in the Southwestern Oil Fields of Iran
Subject Areas :Mehran Kalhori 1 * , S. Gharechelloo 2 , S. Yasami Khiabani 3
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Keywords: Hydraulic Fracturing, Hierarchical clustering, Rock Mechanical Zonation Stress Barriers, Hydraulic Fracturing Zone Candidate,
Abstract :
Abstract
Hydraulic fracturing is one of the most widely used well stimulation methods in oil and gas reservoirs worldwide. Economically, selecting the appropriate zone for hydraulic fracturing operations is highly critical. Geomechanical parameters play a significant and influential role in identifying candidate zones. Among the most important geomechanical parameters are the magnitude and orientation of the minimum horizontal stress and the rock mechanical properties of the formation. In this study, the process of zonation and selecting the optimal zone is investigated using stress zone identification based on minimum horizontal stress, rock mechanical zonation based on rock mechanical parameters, and integrating these results with acceptable thresholds for porosity and permeability. First, rock mechanical parameters such as Young’s modulus, Poisson’s ratio, Uniaxial Compressive Strength, fracture toughness, and rock brittleness index were extracted from well logs using various empirical correlations. Hierarchical clustering, as an unsupervised machine learning method, was then applied to these data, resulting in six clusters. Based on these clusters, the reservoir interval was divided into 13 zones labeled A to M. By calculating the principal stresses and pore pressure, the minimum horizontal stress was used to determine stress zones bounded by stress barriers, identifying six stress zones within the studied interval in the well.
Finally, by analyzing and integrating the results of rock mechanical zonation, stress zonation, and reservoir parameters (porosity and permeability), appropriate zones for hydraulic fracturing were selected. Stress zones 6, 3, and 5 were identified as the most suitable zones for hydraulic fracturing operations.
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