http://earthwise-staging.bgs.ac.uk/index.php?action=history&feed=atom&title=OR%2F15%2F066_Fracture_initiation 2026-04-16T15:07:29Z Revision history for this page on the wiki MediaWiki 1.42.3 http://earthwise-staging.bgs.ac.uk/index.php?title=OR/15/066_Fracture_initiation&diff=44310&oldid=prev 2019-12-03T12:38:26Z

<p><span dir="auto"><span class="autocomment">Tensile fracturing</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 13:38, 3 December 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l88">Line 88:</td> <td colspan="2" class="diff-lineno">Line 88:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>|[[Image:OR15066equation4.jpg|frameless|center|225px|    ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>|[[Image:OR15066equation4.jpg|frameless|center|225px|    ]]</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>|-</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>|-</div></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>| Haimson &amp; Fairhurst (1967)&lt;ref name="Haimson 1967"&gt;<del style="font-weight: bold; text-decoration: none;">Haimson, B C, and Fairhurst, C. (1967). Initiation and extension of hydraulic fractures in rocks. ''Society of Petroleum Engineering Journal'', 7, pp.310–318.</del>&lt;/ref&gt;:</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>| Haimson &amp; Fairhurst (1967)&lt;ref name="Haimson 1967"&gt;&lt;/ref&gt;:</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>|[[Image:OR15066equation5.jpg|frameless|center|200px|    ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>|[[Image:OR15066equation5.jpg|frameless|center|200px|    ]]</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>|-</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>|-</div></td></tr> </table>

Ajhil http://earthwise-staging.bgs.ac.uk/index.php?title=OR/15/066_Fracture_initiation&diff=44309&oldid=prev 2019-12-03T12:37:54Z

<p></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 13:37, 3 December 2019</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l130">Line 130:</td> <td colspan="2" class="diff-lineno">Line 130:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The theory introduced above shows that the initiation of fracture formation is dependent on a number of factors. These include: the orientation and size of the borehole; orientation and magnitude of the stress-field; pressure and rate of increase of the hydraulic fracture fluid; pore fluid formation of the shale; elastic properties of the shale, including elasticity, poroelasticity, and tensile strength; and the crack properties, such as stress intensity factor and surface energy. These parameters will dictate where a fracture is initiated and consequently, the direction of fracture propagation.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The theory introduced above shows that the initiation of fracture formation is dependent on a number of factors. These include: the orientation and size of the borehole; orientation and magnitude of the stress-field; pressure and rate of increase of the hydraulic fracture fluid; pore fluid formation of the shale; elastic properties of the shale, including elasticity, poroelasticity, and tensile strength; and the crack properties, such as stress intensity factor and surface energy. These parameters will dictate where a fracture is initiated and consequently, the direction of fracture propagation.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>It should be noted that the theory above is based on a homogeneous elastic medium. Shale is a complex heterogeneous material with strong directional variation in many properties that need to be considered when predicting where fracture initiation will occur. It is also important to consider that the starting shale is not pristine; the action of perforation will create weaknesses within the shale surrounding the well. Perforations need to be directed with respect to the stress-field so that they are in phase with the anticipated fracture direction (Hossain ''et al.'', 2000&lt;ref name="Hossain 2000"&gt;&lt;/ref&gt;). Perforations have been shown to reduce longitudinal fracture initiation pressures when preferentially oriented (Hossain ''et al.'', 2000&lt;ref name="Hossain 2000"&gt;<del style="font-weight: bold; text-decoration: none;">Hossain, M M, Rahman, M K, and Rahman, S S. (2000). Hydraulic fracture initiation and propagation: roles of wellbore trajectory, perforation and stress regimes. ''Journal of Petroleum Science and Engineering'' '''27''' pp.129–149.</del>&lt;/ref&gt;).</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>It should be noted that the theory above is based on a homogeneous elastic medium. Shale is a complex heterogeneous material with strong directional variation in many properties that need to be considered when predicting where fracture initiation will occur. It is also important to consider that the starting shale is not pristine; the action of perforation will create weaknesses within the shale surrounding the well. Perforations need to be directed with respect to the stress-field so that they are in phase with the anticipated fracture direction (Hossain ''et al.'', 2000&lt;ref name="Hossain 2000"&gt;&lt;/ref&gt;). Perforations have been shown to reduce longitudinal fracture initiation pressures when preferentially oriented (Hossain ''et al.'', 2000&lt;ref name="Hossain 2000"&gt;&lt;/ref&gt;).</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>====Fracture mode====</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>====Fracture mode====</div></td></tr> </table>

Ajhil http://earthwise-staging.bgs.ac.uk/index.php?title=OR/15/066_Fracture_initiation&diff=32682&oldid=prev 2017-09-25T14:13:20Z

<p>1 revision imported</p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <tr class="diff-title" lang="en"> <td colspan="1" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="1" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 15:13, 25 September 2017</td> </tr><tr><td colspan="2" class="diff-notice" lang="en"><div class="mw-diff-empty">(No difference)</div> </td></tr></table>

Dbk http://earthwise-staging.bgs.ac.uk/index.php?title=OR/15/066_Fracture_initiation&diff=32681&oldid=prev 2017-08-23T11:03:01Z

<p><span dir="auto"><span class="autocomment">Mineralogy mineralogy</span></span></p> <a href="http://earthwise-staging.bgs.ac.uk/index.php?title=OR/15/066_Fracture_initiation&amp;diff=32681">Show changes</a>

Ajhil