Study on the Permeability Evolution and Its Formation Mechanism of Xiaojihan Aquifer Coal Seam under Plastic Flow

<table class="table-group" id="tab11"><tr><td><table class="table"><tr><td class="thead-hr" colspan="5"><hr/></td></tr><tr class="thead"><td class="align_left" rowspan="2">Axial strain (%)</td><td class="align_center" colspan="4">Confining pressure influence coefficient <svg height="16.4744pt" id="M187" style="vertical-align:-3.908299pt" version="1.1" viewbox="-0.0498162 -12.5661 18.1326 16.4744" width="18.1326pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M648 625C638 644 619 665 597 665C518 665 445 585 404 489C377 436 359 379 345 309H340C335 367 324 448 296 515C263 599 214 665 123 665C83 665 33 649 1 632L6 606C19 608 32 609 44 609C124 609 186 567 230 473C270 390 283 308 283 200V122C283 42 274 33 184 27V0H468V27C376 33 368 42 368 122V194C368 293 402 401 461 492C512 573 576 611 629 611C634 611 636 611 642 610L648 625Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.519,-6.049)"><path d="M309 -142C211 -61 151 99 151 271S210 601 309 683L288 710C141 611 75 451 75 272V271C75 90 141 -72 288 -169L309 -142Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,11.777,-6.049)"><path d="M135 536C164 536 186 560 186 587C186 617 164 639 136 639C109 639 85 617 85 587C85 560 109 536 135 536ZM252 0V26C188 32 181 38 181 106V451C138 433 90 420 39 412V388C99 379 102 374 102 312V106C102 38 95 32 32 26V0H252Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,14.225,-6.049)"><path d="M283 271C283 451 220 610 70 710L48 683C146 603 207 443 207 271S149 -59 48 -142L70 -169C220 -67 283 90 283 271Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,7.41,3.858)"><path d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z"></path></g></svg></td></tr><tr class="thead"><td class="align_center"><span style="width: 20.133ptpx;"><svg height="16.4744pt" id="M188" style="vertical-align:-3.908299pt" version="1.1" viewbox="-0.0498162 -12.5661 20.133 16.4744" width="20.133pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M648 625C638 644 619 665 597 665C518 665 445 585 404 489C377 436 359 379 345 309H340C335 367 324 448 296 515C263 599 214 665 123 665C83 665 33 649 1 632L6 606C19 608 32 609 44 609C124 609 186 567 230 473C270 390 283 308 283 200V122C283 42 274 33 184 27V0H468V27C376 33 368 42 368 122V194C368 293 402 401 461 492C512 573 576 611 629 611C634 611 636 611 642 610L648 625Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.519,-6.049)"><path d="M309 -142C211 -61 151 99 151 271S210 601 309 683L288 710C141 611 75 451 75 272V271C75 90 141 -72 288 -169L309 -142Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,11.777,-6.049)"><path d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,16.209,-6.049)"><path d="M283 271C283 451 220 610 70 710L48 683C146 603 207 443 207 271S149 -59 48 -142L70 -169C220 -67 283 90 283 271Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,7.41,3.858)"><path d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z"></path></g></svg></span></td><td class="align_center"><span style="width: 20.133ptpx;"><svg height="16.4744pt" id="M189" style="vertical-align:-3.908299pt" version="1.1" viewbox="-0.0498162 -12.5661 20.133 16.4744" width="20.133pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M648 625C638 644 619 665 597 665C518 665 445 585 404 489C377 436 359 379 345 309H340C335 367 324 448 296 515C263 599 214 665 123 665C83 665 33 649 1 632L6 606C19 608 32 609 44 609C124 609 186 567 230 473C270 390 283 308 283 200V122C283 42 274 33 184 27V0H468V27C376 33 368 42 368 122V194C368 293 402 401 461 492C512 573 576 611 629 611C634 611 636 611 642 610L648 625Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.519,-6.049)"><path d="M309 -142C211 -61 151 99 151 271S210 601 309 683L288 710C141 611 75 451 75 272V271C75 90 141 -72 288 -169L309 -142Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,11.777,-6.049)"><path d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,16.209,-6.049)"><path d="M283 271C283 451 220 610 70 710L48 683C146 603 207 443 207 271S149 -59 48 -142L70 -169C220 -67 283 90 283 271Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,7.41,3.858)"><path d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z"></path></g></svg></span></td><td class="align_center"><span style="width: 20.133ptpx;"><svg height="16.4744pt" id="M190" style="vertical-align:-3.908299pt" version="1.1" viewbox="-0.0498162 -12.5661 20.133 16.4744" width="20.133pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M648 625C638 644 619 665 597 665C518 665 445 585 404 489C377 436 359 379 345 309H340C335 367 324 448 296 515C263 599 214 665 123 665C83 665 33 649 1 632L6 606C19 608 32 609 44 609C124 609 186 567 230 473C270 390 283 308 283 200V122C283 42 274 33 184 27V0H468V27C376 33 368 42 368 122V194C368 293 402 401 461 492C512 573 576 611 629 611C634 611 636 611 642 610L648 625Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.519,-6.049)"><path d="M309 -142C211 -61 151 99 151 271S210 601 309 683L288 710C141 611 75 451 75 272V271C75 90 141 -72 288 -169L309 -142Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,11.777,-6.049)"><path d="M290 377C321 398 342 415 358 430C378 450 389 473 389 502C389 578 329 635 238 635H237C184 635 137 610 109 578L64 515L88 493C112 529 154 573 208 573S303 542 303 482C303 409 233 370 141 341L149 308C165 313 190 319 215 319C272 319 341 283 341 193C342 98 292 43 222 43C163 43 122 72 96 94C88 101 79 100 70 94C61 87 47 73 46 60C44 47 48 37 62 23C76 10 118 -12 165 -12C238 -12 430 62 430 223C430 297 379 359 290 375V377Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,16.209,-6.049)"><path d="M283 271C283 451 220 610 70 710L48 683C146 603 207 443 207 271S149 -59 48 -142L70 -169C220 -67 283 90 283 271Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,7.41,3.858)"><path d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z"></path></g></svg></span></td><td class="align_center"><span style="width: 20.133ptpx;"><svg height="16.4744pt" id="M191" style="vertical-align:-3.908299pt" version="1.1" viewbox="-0.0498162 -12.5661 20.133 16.4744" width="20.133pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M648 625C638 644 619 665 597 665C518 665 445 585 404 489C377 436 359 379 345 309H340C335 367 324 448 296 515C263 599 214 665 123 665C83 665 33 649 1 632L6 606C19 608 32 609 44 609C124 609 186 567 230 473C270 390 283 308 283 200V122C283 42 274 33 184 27V0H468V27C376 33 368 42 368 122V194C368 293 402 401 461 492C512 573 576 611 629 611C634 611 636 611 642 610L648 625Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.519,-6.049)"><path d="M309 -142C211 -61 151 99 151 271S210 601 309 683L288 710C141 611 75 451 75 272V271C75 90 141 -72 288 -169L309 -142Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,11.777,-6.049)"><path d="M462 177V227H365V632H320C217 496 116 350 21 208V177H284V109C284 43 280 38 190 31V0H451V31C369 38 365 43 365 108V177H462ZM284 227H88C155 336 218 430 282 519H284V227Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,16.209,-6.049)"><path d="M283 271C283 451 220 610 70 710L48 683C146 603 207 443 207 271S149 -59 48 -142L70 -169C220 -67 283 90 283 271Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,7.41,3.858)"><path d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z"></path></g></svg></span></td></tr><tr><td class="thead-hr" colspan="5"><hr/></td></tr><tr><td class="align_left">X-1.61</td><td class="align_center">0.26</td><td class="align_center">0.09</td><td class="align_center">0.068</td><td class="align_center">0.052</td></tr><tr><td class="align_left">X-1.72</td><td class="align_center">0.24</td><td class="align_center">0.12</td><td class="align_center">0.052</td><td class="align_center">0.043</td></tr><tr><td class="align_left">X-1.79</td><td class="align_center">0.21</td><td class="align_center">0.10</td><td class="align_center">0.046</td><td class="align_center">0.029</td></tr><tr><td class="align_left">X-1.81</td><td class="align_center">0.065</td><td class="align_center">0.019</td><td class="align_center">0.011</td><td class="align_center">0.0061</td></tr><tr><td class="align_left">X-2.01</td><td class="align_center">0.067</td><td class="align_center">0.023</td><td class="align_center">0.012</td><td class="align_center">0.0059</td></tr><tr class="table-tr"><td colspan="5"><hr class="tbody-hr"/></td></tr></table></td></tr></table>

<div>The confining pressure influence coefficient of water-bearing specimen.</div>

Geofluids

tab11

Table 11

Table 11: Study on the Permeability Evolution and Its Formation Mechanism of Xiaojihan Aquifer Coal Seam under Plastic Flow 