Methodology for Calibration of Geomechanical Field Model for Assymetric Hydraulic Fracture Design Based on Actual Data

Abstract

This paper discusses an approach to the static Young's modulus calibration on the basis of fracturing statistics from one of the West Siberian fields. The relevance of this work is due to the fact that there are many fields in the region where multi-stage fracturing is en masse carried out in horizontal wells, but laboratory tests of mechanical and strength properties are lacking. The procedure is based on reiterated matching of estimated fracture closure time to the actual values obtained during interpretation of data-frac test (or calibration or minifrac test) results in the course of the sequential search over the pairs of Young's modulus and leakage factor values. Then simulation of main fracturing is carried out, and simulation result is compared to the actual results of the works (whether fracture was successful or finished with emergency shutdown of pumps). From the entire set of experiments, the multiplier that satisfies all accidents and describes successful operations is chosen. Calibration of mechanical properties and stress model was successfully carried out in this field using the field data of more than hundred fracturing operations, which is evidenced by the similar values obtained in fracturing simulation and half-lengths of hydraulic fractures matched with field development data in one of the hydrodynamic model implementations.

This work is a continuation of research [1, 2] and includes comparison of field development parameters in both calibration methods, which led to the final decision on the repeated laboratory studies, because none of the calibration methods used allowed creating a single universal model of mechanical properties. One of the models more reliably describes the situation of fracture development within the rock mass, the other relates to fracture development along the fault. In addition, the geomechanical model analysis also revealed that in most cases where fracture intersects the fault it would develop along it.