52:. The unit has also been used in biophysics and biomechanics, where the flow of fluids such as blood through capillary beds and cerebrospinal fluid through the brain interstitial space is being examined. A darcy has
135:
379:
The unit abbreviation "d" is not capitalized (contrary to industry use). The
American Association of Petroleum Geologists uses the following unit abbreviations and grammar in their publications:
369:. Rock permeability is usually expressed in millidarcys (md) because rocks hosting hydrocarbon or water accumulations typically exhibit permeability ranging from 5 to 500 md.
319:
285:
251:
220:
193:
166:
548:
331:
The darcy is referenced to a mixture of unit systems. A medium with a permeability of 1 darcy permits a flow of 1 cm/s of a fluid with
417:. This conversion is usually approximated as 1 μm. This is the reciprocal of 1.013250—the conversion factor from atmospheres to
458:"Poroelasticity as a Model of Soft Tissue Structure: Hydraulic Permeability Reconstruction for Magnetic Resonance Elastography in Silico"
350:
range as high as 100,000 darcys for gravel, to less than 0.01 microdarcy for granite. Sand has a permeability of approximately 1 darcy.
535:
73:
86:
625:
581:
432:(~ 0.1 bar/m) at a temperature of 20 °C. In this specific setup, 1 darcy is equivalent to 0.831 m/day.
615:
225:
33:
594:
K. N. Duggal, J. P. Soni: Elements of Water
Resources Engineering. Publisher New Age International, 1996, p. 270
526:
640:
555:
372:
The odd combination of units comes from Darcy's original studies of water flow through columns of sand.
645:
635:
347:
45:
479:
53:
29:
620:
630:
469:
300:
266:
531:
507:
424:
Specifically in the hydrology domain, permeability of soil or rock may also be defined as the
497:
487:
235:
204:
177:
150:
483:
502:
457:
77:
572:
609:
340:
429:
409:
336:
366:
37:
418:
414:
492:
343:) under a pressure gradient of 1 atm/cm acting across an area of 1 cm.
332:
256:
511:
602:
Richard Selley's "Elements of
Petroleum Geology (2nd edition)," page 250.
357:
is still in its infancy, is somewhere in the range of 0.01 to 100 darcy.
290:
49:
69:
57:
474:
373:
76:
through rock (or other porous media). The darcy is defined using
425:
549:"The American Association of Petroleum Geologist Style Guides"
396:
41:
376:
has a viscosity of 1.0019 cP at about room temperature.
130:{\displaystyle Q={\frac {Ak\,\Delta P}{\mu \,\Delta x}}}
574:
The SI Metric System of Units and SPE Metric
Standard
524:
Peter C. Lichtner, Carl I. Steefel, Eric H. Oelkers,
386:
millidarcy (plural millidarcys, not millidarcies): md
303:
269:
238:
207:
180:
170:
is the volumetric fluid flow rate through the medium
153:
89:
313:
279:
245:
214:
187:
160:
129:
8:
530:, Mineralogical Society of America, 1996,
501:
491:
473:
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268:
242:
237:
211:
206:
184:
179:
157:
152:
117:
105:
96:
88:
441:
353:Tissue permeability, whose measurement
451:
449:
447:
445:
399:units, 1 darcy is equivalent to
383:darcy (plural darcys, not darcies): d
68:Permeability measures the ability of
7:
527:Reactive Transport in Porous Media
304:
270:
118:
106:
14:
456:Sowinski, Damian (January 2021).
323:is the thickness of the medium
582:Society of Petroleum Engineers
44:, but they are widely used in
1:
80:, which can be written as:
662:
314:{\displaystyle \Delta x\,}
280:{\displaystyle \Delta P\,}
197:is the area of the medium
365:The darcy is named after
493:10.3389/fphy.2020.617582
315:
281:
247:
246:{\displaystyle \mu \,}
216:
189:
162:
131:
626:Hydraulic engineering
316:
282:
248:
217:
190:
163:
132:
46:petroleum engineering
616:Units of measurement
462:Frontiers in Physics
430:hydrostatic pressure
301:
267:
236:
205:
178:
151:
87:
484:2021FrP.....8..637S
215:{\displaystyle k\,}
188:{\displaystyle A\,}
161:{\displaystyle Q\,}
413:or 0.9869233
346:Typical values of
311:
277:
243:
212:
185:
158:
127:
327:
326:
125:
54:dimensional units
653:
595:
592:
586:
585:
580:(2nd ed.).
579:
569:
563:
562:
560:
554:. Archived from
553:
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539:
522:
516:
515:
505:
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477:
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412:
407:
404:
320:
318:
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252:
250:
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221:
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194:
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186:
167:
165:
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159:
145:
144:
136:
134:
133:
128:
126:
124:
112:
97:
661:
660:
656:
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652:
651:
650:
606:
605:
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571:
570:
566:
558:
551:
547:
546:
542:
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519:
455:
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438:
428:of water under
405:
402:
400:
393:
363:
299:
298:
289:is the applied
265:
264:
255:is the dynamic
234:
233:
203:
202:
176:
175:
149:
148:
113:
98:
85:
84:
66:
40:. They are not
28:(md or mD) are
12:
11:
5:
659:
657:
649:
648:
643:
641:Soil mechanics
638:
633:
628:
623:
618:
608:
607:
604:
603:
597:
596:
587:
564:
561:on 2011-08-09.
540:
517:
440:
439:
437:
434:
392:
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362:
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329:
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321:
309:
306:
295:
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272:
261:
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228:of the medium
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210:
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156:
138:
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123:
120:
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101:
95:
92:
65:
62:
36:, named after
13:
10:
9:
6:
4:
3:
2:
658:
647:
644:
642:
639:
637:
634:
632:
629:
627:
624:
622:
619:
617:
614:
613:
611:
601:
600:
591:
588:
584:. June 1984 .
583:
576:
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568:
565:
557:
550:
544:
541:
537:
536:0-939950-42-1
533:
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459:
452:
450:
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427:
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416:
411:
398:
395:Converted to
390:
385:
382:
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368:
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358:
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351:
349:
344:
342:
338:
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297:
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288:
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263:
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259:of the fluid
258:
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239:
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208:
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174:
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109:
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63:
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55:
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47:
43:
39:
35:
31:
27:
23:
19:
646:Soil physics
636:Hydrogeology
590:
573:
567:
556:the original
543:
525:
520:
465:
461:
423:
394:
378:
371:
364:
354:
352:
348:permeability
345:
330:
226:permeability
139:
67:
34:permeability
25:
21:
17:
15:
391:Conversions
367:Henry Darcy
293:difference
78:Darcy's law
38:Henry Darcy
621:Hydraulics
610:Categories
475:2012.03993
436:References
64:Definition
26:millidarcy
22:darcy unit
631:Hydrology
333:viscosity
305:Δ
271:Δ
257:viscosity
240:μ
119:Δ
115:μ
107:Δ
512:36340954
408:10
291:pressure
42:SI units
538:, p. 5.
503:9635531
480:Bibcode
468:: 637.
355:in vivo
224:is the
140:where:
50:geology
534:
510:
500:
361:Origin
70:fluids
58:length
24:) and
578:(PDF)
559:(PDF)
552:(PDF)
470:arXiv
401:9.869
374:Water
341:mPa·s
30:units
18:darcy
532:ISBN
508:PMID
426:flux
419:bars
74:flow
48:and
20:(or
16:The
498:PMC
488:doi
403:233
339:(1
72:to
56:of
32:of
612::
506:.
496:.
486:.
478:.
464:.
460:.
444:^
421:.
415:μm
397:SI
337:cP
335:1
60:.
514:.
490::
482::
472::
466:8
410:m
406:×
308:x
274:P
209:k
182:A
155:Q
122:x
110:P
103:k
100:A
94:=
91:Q
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