Breakdown pressures due to infiltration and exclusion in finite length boreholes

Quan Gan, Derek Elsworth, JS Alpern, Chris Marone, Peter Connolly

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The theory of effective stress suggests that the breakdown pressure of a borehole should be a function of ambient stress and strength of the rock, alone. However, experiments on finite-length boreholes indicate that the breakdown pressure is a strong function of fracturing fluid composition and state as well. The reasons for this behavior are explored, including the roles of different fluid types and state in controlling the breakdown process. The interfacial tension of the fracturing fluid is shown to control whether fluid invades pore space at the borehole wall and this in turn changes the local stress regime, hence breakdown pressure. Interfacial tension is modulated by fluid state, as sub- or super-critical, and thus gas type and state influence the breakdown pressure. Expressions are developed for the breakdown pressure in circular section boreholes of both infinite and finite length and applied to rationalize otherwise enigmatic experimental observations. Importantly, the analysis accommodates the influence of fluid infiltration or exclusion into the borehole wall. For the development of a radial hydraulic fracture (longitudinal failure), the solutions show a higher breakdown pressure for impermeable relative to a permeable borehole. A similar difference in breakdown pressure exists for failure on a transverse fracture that is perpendicular to the borehole axis, in this case modulated by a parameter η, which is a function of Poisson ratio and the Biot coefficient. These solutions are used to rationalize observations for mixed-mode fractures that develop in laboratory experiments containing finite-length boreholes. Predictions agree with the breakdown pressure records recovered for experiments for pressurization by CO2 and Ar – higher interfacial tension for subcritical fluids requires higher critical pressures to invade into the matrix, while supercritical fluid with negligible interfacial tension has less resistance to infiltrate into the matrix and to prompt failure. This new discovery defines mechanisms of failure that although incompletely understood, provisionally link lower breakdown stresses with mechanisms that promote fracture complexity with the potential for improved hydrocarbon recovery.
Original languageEnglish
Pages (from-to)329-337
Number of pages9
JournalJournal of Petroleum Science and Engineering
Volume127
Early online date16 Jan 2015
DOIs
Publication statusPublished - Mar 2015

Fingerprint

Boreholes
Infiltration
infiltration
borehole
fluid
Surface tension
Fluids
Fracturing fluids
matrix
fluid composition
Poisson ratio
Supercritical fluids
Pressurization
pore space
effective stress
Experiments
experiment
hydrocarbon
Hydrocarbons
Rocks

Keywords

  • fracture breakdown pressure
  • supercritical fluid
  • Biot coefficient
  • finite borehole length
  • infiltration
  • extraction

Cite this

Breakdown pressures due to infiltration and exclusion in finite length boreholes. / Gan, Quan; Elsworth, Derek; Alpern, JS; Marone, Chris; Connolly, Peter.

In: Journal of Petroleum Science and Engineering, Vol. 127, 03.2015, p. 329-337.

Research output: Contribution to journalArticle

Gan, Quan ; Elsworth, Derek ; Alpern, JS ; Marone, Chris ; Connolly, Peter. / Breakdown pressures due to infiltration and exclusion in finite length boreholes. In: Journal of Petroleum Science and Engineering. 2015 ; Vol. 127. pp. 329-337.
@article{63f92b0f4dad4700a8ac0023eeac1c49,
title = "Breakdown pressures due to infiltration and exclusion in finite length boreholes",
abstract = "The theory of effective stress suggests that the breakdown pressure of a borehole should be a function of ambient stress and strength of the rock, alone. However, experiments on finite-length boreholes indicate that the breakdown pressure is a strong function of fracturing fluid composition and state as well. The reasons for this behavior are explored, including the roles of different fluid types and state in controlling the breakdown process. The interfacial tension of the fracturing fluid is shown to control whether fluid invades pore space at the borehole wall and this in turn changes the local stress regime, hence breakdown pressure. Interfacial tension is modulated by fluid state, as sub- or super-critical, and thus gas type and state influence the breakdown pressure. Expressions are developed for the breakdown pressure in circular section boreholes of both infinite and finite length and applied to rationalize otherwise enigmatic experimental observations. Importantly, the analysis accommodates the influence of fluid infiltration or exclusion into the borehole wall. For the development of a radial hydraulic fracture (longitudinal failure), the solutions show a higher breakdown pressure for impermeable relative to a permeable borehole. A similar difference in breakdown pressure exists for failure on a transverse fracture that is perpendicular to the borehole axis, in this case modulated by a parameter η, which is a function of Poisson ratio and the Biot coefficient. These solutions are used to rationalize observations for mixed-mode fractures that develop in laboratory experiments containing finite-length boreholes. Predictions agree with the breakdown pressure records recovered for experiments for pressurization by CO2 and Ar – higher interfacial tension for subcritical fluids requires higher critical pressures to invade into the matrix, while supercritical fluid with negligible interfacial tension has less resistance to infiltrate into the matrix and to prompt failure. This new discovery defines mechanisms of failure that although incompletely understood, provisionally link lower breakdown stresses with mechanisms that promote fracture complexity with the potential for improved hydrocarbon recovery.",
keywords = "fracture breakdown pressure, supercritical fluid, Biot coefficient, finite borehole length, infiltration, extraction",
author = "Quan Gan and Derek Elsworth and JS Alpern and Chris Marone and Peter Connolly",
note = "This work is the result of support from the Chevron Energy Technology Company. This support is gratefully acknowledged. Originally communicated as paper 13-700 of the 47th US Symposium on Rock Mechanics/Geomechanics, San Francisco. We appreciate the permission of the American Rock Mechanics Association to publish this paper.",
year = "2015",
month = "3",
doi = "10.1016/j.petrol.2015.01.011",
language = "English",
volume = "127",
pages = "329--337",
journal = "Journal of Petroleum Science and Engineering",
issn = "0920-4105",
publisher = "Elsevier",

}

TY - JOUR

T1 - Breakdown pressures due to infiltration and exclusion in finite length boreholes

AU - Gan, Quan

AU - Elsworth, Derek

AU - Alpern, JS

AU - Marone, Chris

AU - Connolly, Peter

N1 - This work is the result of support from the Chevron Energy Technology Company. This support is gratefully acknowledged. Originally communicated as paper 13-700 of the 47th US Symposium on Rock Mechanics/Geomechanics, San Francisco. We appreciate the permission of the American Rock Mechanics Association to publish this paper.

PY - 2015/3

Y1 - 2015/3

N2 - The theory of effective stress suggests that the breakdown pressure of a borehole should be a function of ambient stress and strength of the rock, alone. However, experiments on finite-length boreholes indicate that the breakdown pressure is a strong function of fracturing fluid composition and state as well. The reasons for this behavior are explored, including the roles of different fluid types and state in controlling the breakdown process. The interfacial tension of the fracturing fluid is shown to control whether fluid invades pore space at the borehole wall and this in turn changes the local stress regime, hence breakdown pressure. Interfacial tension is modulated by fluid state, as sub- or super-critical, and thus gas type and state influence the breakdown pressure. Expressions are developed for the breakdown pressure in circular section boreholes of both infinite and finite length and applied to rationalize otherwise enigmatic experimental observations. Importantly, the analysis accommodates the influence of fluid infiltration or exclusion into the borehole wall. For the development of a radial hydraulic fracture (longitudinal failure), the solutions show a higher breakdown pressure for impermeable relative to a permeable borehole. A similar difference in breakdown pressure exists for failure on a transverse fracture that is perpendicular to the borehole axis, in this case modulated by a parameter η, which is a function of Poisson ratio and the Biot coefficient. These solutions are used to rationalize observations for mixed-mode fractures that develop in laboratory experiments containing finite-length boreholes. Predictions agree with the breakdown pressure records recovered for experiments for pressurization by CO2 and Ar – higher interfacial tension for subcritical fluids requires higher critical pressures to invade into the matrix, while supercritical fluid with negligible interfacial tension has less resistance to infiltrate into the matrix and to prompt failure. This new discovery defines mechanisms of failure that although incompletely understood, provisionally link lower breakdown stresses with mechanisms that promote fracture complexity with the potential for improved hydrocarbon recovery.

AB - The theory of effective stress suggests that the breakdown pressure of a borehole should be a function of ambient stress and strength of the rock, alone. However, experiments on finite-length boreholes indicate that the breakdown pressure is a strong function of fracturing fluid composition and state as well. The reasons for this behavior are explored, including the roles of different fluid types and state in controlling the breakdown process. The interfacial tension of the fracturing fluid is shown to control whether fluid invades pore space at the borehole wall and this in turn changes the local stress regime, hence breakdown pressure. Interfacial tension is modulated by fluid state, as sub- or super-critical, and thus gas type and state influence the breakdown pressure. Expressions are developed for the breakdown pressure in circular section boreholes of both infinite and finite length and applied to rationalize otherwise enigmatic experimental observations. Importantly, the analysis accommodates the influence of fluid infiltration or exclusion into the borehole wall. For the development of a radial hydraulic fracture (longitudinal failure), the solutions show a higher breakdown pressure for impermeable relative to a permeable borehole. A similar difference in breakdown pressure exists for failure on a transverse fracture that is perpendicular to the borehole axis, in this case modulated by a parameter η, which is a function of Poisson ratio and the Biot coefficient. These solutions are used to rationalize observations for mixed-mode fractures that develop in laboratory experiments containing finite-length boreholes. Predictions agree with the breakdown pressure records recovered for experiments for pressurization by CO2 and Ar – higher interfacial tension for subcritical fluids requires higher critical pressures to invade into the matrix, while supercritical fluid with negligible interfacial tension has less resistance to infiltrate into the matrix and to prompt failure. This new discovery defines mechanisms of failure that although incompletely understood, provisionally link lower breakdown stresses with mechanisms that promote fracture complexity with the potential for improved hydrocarbon recovery.

KW - fracture breakdown pressure

KW - supercritical fluid

KW - Biot coefficient

KW - finite borehole length

KW - infiltration

KW - extraction

U2 - 10.1016/j.petrol.2015.01.011

DO - 10.1016/j.petrol.2015.01.011

M3 - Article

VL - 127

SP - 329

EP - 337

JO - Journal of Petroleum Science and Engineering

JF - Journal of Petroleum Science and Engineering

SN - 0920-4105

ER -