Fracture Mechanics Models for Sensivity Analysis of Hydraulic Fracturing

Abstract

Most hydrofrac data interpretation for stress derivation only use singular pressure values of characteristic pressurization phases such as breakdown, fracture reopening or shut-in values. This paper presents an algorithm for automatic sensitivity analysis of hydraulic fracturing parameters on the basis of fracture mechanics. The algorithm can be separated into tow parts. The first part consists of calculating synthetic pressure records for random model assumptions of the underground. The second part compares the measured pressure records with the synthetic pressure records by a least square fit. The result of these calculations are presented in the form of intervals for horizontal and vertical stresses, rock mass density, fracture toughness, fracture height and initial fracture length, given by the model parameters with the best fit of synthetic and measured pressure records.