FRACTURE REORIENTATION IN HORIZONTAL WELL WITH MULTISTAGE HYDRAULIC FRACTURING

Transcription

1 SPE Workshop OILFIELD GEOMECHANICS Slide 1 FRACTURE REORIENTATION IN HORIZONTAL WELL WITH MULTISTAGE HYDRAULIC FRACTURING A. Pimenov, R. Kanevskaya Ltd. BashNIPIneft March 27-28, 2017 Moscow, Russia

2 Slide 2 Geomechanical simulation Stress-strain state describes stress, deformation and strain of the rock _ Static equation of equilibrium: Total and effective stress can be expressed in terms of strain: Strain tensor and deformation: Principal stress

3 Growth of hydraulic fracture M.K. Hubert, D.G. Willis Mechanics of Hydraulic Fracturing (1957) He Lui, Zhonxiao Lan & co. в 2008 estimate orientation re-frac (Evaluation of Refracture Reorientation in Both Laboratory and Field Scales) First frac 5 MPa Re-frac 10 MPa 10 MPa 5 MPa Slide 3 First fracture Major factors that control the vertical growth of hydraulic fracture (Warpinski) The contrast in material properties; The contrast in vertical distribution of in situ stress (2.7MPa) Re-frac after stress inversion

4 Slide 4 Multi-Stage Hydraulic Fracturing Fracturing of horizontal well Simultaneous Hydraulic Fracturing; Sequential Hydraulic Fracturing. - Wellbore - fracture port - Swell packers - Shoe guide and Check value Fracturing horizontal well completion

5 Slide 5 Formulation the problem

6 Solving algorithm Slide 6

7 Input parameters Parameter Value and Units Method of parameter definition Major (maximum) principal stress 39.5 MPa Hydraulic Fracturing data, Breakout (FMI) Least principal stress 37.5 MPa Hydraulic Fracturing data, Breakout (FMI), well test (fracture close pressure) Pore pressure 27 MPa Well test, measured directly or estimated from geophysical logs or seismic data Poisson s ratio Young s modulus GPa Compressional and shear velocities and rock density, uniaxial compressive (tensile) stress to the resultant strain Slide 7 Biot s constant 0.8 Compressibility fluid and rock matrix Thickness formation Permeability 11 m 1 md

8 Stress field by first fracture multi-frac 1. How stress anisotropy influence on reorientation second fracture for predetermined first fracture length 2. What distance between frac ports avoids reorientation multistage fractures Crack width is determined from the Perkins-Kern or Khristianovich-Zheltov or Circular fracture model Slide 8 Maximum principal stress 39.5 MPa (effective stress 12.5 MPa) κ=0.98 κ=0.95 κ=0.9 Least principal stress Maximum principal stress

9 Hydraulic fractures in horizontal well Wellbore drilled along the maximum stress Slide 9 The Second fracture growths along the wellbore if distance between frac ports less then 40 m. The Second fracture growths like first if distance between frac ports more then 60 m. System of mutually orthogonal fractures Wellbore drilled along the least stress First and all subsequent fractures growth along the wellbore Least principal stress Maximum principal stress

10 Oil production multi-frac well Slide 10 Length horizontal wellbore - 300m, Thickness formation-11 m, Permeability-1mD Pore pressure atm, bottom hole pressure - 80 atm. Параметры работы a(ky) b(kxy) c(kx) Starting oil rate well with fracs divided starting oil rate well without frac Low pressure area for same total oil production 100% 77.5% 35% a b c

11 SPE Workshop OILFIELD GEOMECHANICS Slide 11 2D plane geomechanical problem of determining the stress-strain state of the formation with hydraulic fractures is described. An algorithm for solving this problem based on the displacement discontinuity method, allowing details to consider the hydraulic fracture. Stress-strain state is calculated for the reservoir in the vicinity of borehole horizontal well with multistage hydraulic fracturing; Demonstrate conditions when the reorientation of cracks multistage hydraulic fracturing is possible; Submitted hydrodynamic simulations allowing to estimate production of horizontal wells with multi-stage fracturing with different wellbore and fracture system configuration. March 27-28, 2017 Moscow, Russia