A mathematical model for solid liquid and mass transfer coupling and numerical simulation for hydraulic fracture in rock salt

Thehydraulicfracturingtechniqueiswidelyused intheoilengineering,naturalgasexploiting,under groundheatextractingandothermineralresources mining,etc.withwelldevelopedhydraulicfracture modelsforordinaryrocks1—3].Inthefieldofsolu tionminingofsaltdeposit,thistechniqueisusedto producefracturealongtheplanelayerofthedeposit,thustoconnecttheinjectionandtargetwells4,5].However,duetothespecialphysicalandmechanical characteristicsofrocksalt,executinghydraulicfrac tureinrocksaltdepositisdifferentfromtha…

A mathematical model for solid liquid and mass transfer coupling and numerical simulation for hydraulic fracture in rock salt

The hydraulic fracture in rock salt is a complicated solid fluid and mass transfer coupling process. Through theoretical analysis, a solid fluid and mass transfer coupling mathematical model of hydraulic fracture in rock salt is established in this work, and numerical simulations are carried out with the model. The simulation results indicate that rock salt cracks in the typical way of wing-crack(or tensile crack) during the fracture, and the relation of fracture aperture (w) with expanding distance (x) and fracture time (t) is w =(0. 0034 0. 0006t )e(0.0007 00018t)x. Furthermore, it has been found that boththe water pressure in the crack and the expanding velocity of the crack decrease gradually as a result of the influence of salt dissolving during fracturing. These numerical simulations well illustrate the process of hydraulic fracture in rock salt and are significantly meaningful in engineering practice.