TY - JOUR

T1 - A Mini-Frac Analysis Using a Direct Hydraulic Fracture Simulation via the Fully-Coupled Planar 3D Model

AU - Baykin, A. N.

AU - Lgotina, E. V.

AU - Shel, E. V.

AU - Paderin, G. V.

N1 - Funding Information: Authors would like to express gratitude to Polina Kabanova from Gazpromneft Science and Technology Centre for the help in gathering the experimental field data, to Sergey Golovin from the Lavrentyev Institute of Hydrodynamics SB RAS for the fruitful discussions and comments on the results,?to the anonymous reviewer who suggested to use DDM method for sensitivities calculation that made it possible to obtain more stable and interesting results, and to Siberian Supercomputer Center of SB RAS for providing the computational resources. The reported study was funded by RFBR, Russia according to the research project no. 18-31-00410/19. Funding Information: Authors would like to express gratitude to Polina Kabanova from Gazpromneft Science and Technology Centre for the help in gathering the experimental field data, to Sergey Golovin from the Lavrentyev Institute of Hydrodynamics SB RAS for the fruitful discussions and comments on the results, to the anonymous reviewer who suggested to use DDM method for sensitivities calculation that made it possible to obtain more stable and interesting results, and to Siberian Supercomputer Center of SB RAS for providing the computational resources. The reported study was funded by RFBR, Russia according to the research project no. 18-31-00410/19. Publisher Copyright: © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.

PY - 2021/9

Y1 - 2021/9

N2 - In this work we propose a method for mini-frac analysis via the direct numerical modeling for permeability and closure stress determination. The idea is to adjust the model parameters to match the simulated and field pressure curves by the virtue of the optimization algorithm to automatize the routine. To this end, the Planar 3D hydraulic fracturing model is improved to take into account the wellbore storage, fracture initiation and pumping through a finite perforation interval. The reservoir mechanical behavior is based on Biot’s equations naturally coupled with the mass conservation law and force balance in the fracture and wellbore. This model is capable to describe all the pressure curve features from the fracture initiation up to the after closure filtration. The optimization workflow is based on Levenberg–Marquardt algorithm with Jacobi matrix calculated via a direct differentiation method. The numerical stability and performance of the inverse problem solution is verified. The pressure curve sensitivity analysis is conducted and the impact of the parameters’ uncertainties on the pressure change is calculated. The proposed method is applied to a field case and compared with classical mini-frac methods. We demonstrate that the wellbore storage impact governs the pressure increase during the fracture initiation and prevents the steep pressure decline after closure. We also show that the shortening of the perforation length generates additional pressure support at the end of and after the fracture closure. The recovered permeability and closure stress appears to be stable in presence of uncertainties in Young’s modulus and Biot’s coefficient.

AB - In this work we propose a method for mini-frac analysis via the direct numerical modeling for permeability and closure stress determination. The idea is to adjust the model parameters to match the simulated and field pressure curves by the virtue of the optimization algorithm to automatize the routine. To this end, the Planar 3D hydraulic fracturing model is improved to take into account the wellbore storage, fracture initiation and pumping through a finite perforation interval. The reservoir mechanical behavior is based on Biot’s equations naturally coupled with the mass conservation law and force balance in the fracture and wellbore. This model is capable to describe all the pressure curve features from the fracture initiation up to the after closure filtration. The optimization workflow is based on Levenberg–Marquardt algorithm with Jacobi matrix calculated via a direct differentiation method. The numerical stability and performance of the inverse problem solution is verified. The pressure curve sensitivity analysis is conducted and the impact of the parameters’ uncertainties on the pressure change is calculated. The proposed method is applied to a field case and compared with classical mini-frac methods. We demonstrate that the wellbore storage impact governs the pressure increase during the fracture initiation and prevents the steep pressure decline after closure. We also show that the shortening of the perforation length generates additional pressure support at the end of and after the fracture closure. The recovered permeability and closure stress appears to be stable in presence of uncertainties in Young’s modulus and Biot’s coefficient.

KW - Fracture closure pressure

KW - Hydraulic fracture

KW - Mini-frac analysis

KW - Numerical optimization

KW - Permeability estimation

KW - Planar 3D model

UR - http://www.scopus.com/inward/record.url?scp=85107814581&partnerID=8YFLogxK

U2 - 10.1007/s00603-021-02523-x

DO - 10.1007/s00603-021-02523-x

M3 - Article

AN - SCOPUS:85107814581

VL - 54

SP - 4455

EP - 4482

JO - Rock Mechanics and Rock Engineering

JF - Rock Mechanics and Rock Engineering

SN - 0723-2632

IS - 9

ER -