Experimental study on the effect of fillers on fracture closure in fault-karst reservoir

Abstract

Fracture is an important percolation channel in fault solution reservoir, and its closure law under geostress has an important influence on reservoir permeability.The physical simulation experiments of carbonate rock samples were carried out to study the influence of fracture occurrence (vertical fracture and high angle fracture) and filling on the law of fracture closure.The fracture specimen is prepared by Brazilian splitting experiment and wire cutting method, and the fracture deformation analysis method based on CT scanning gray image is constructed.The fracture closure is characterized by core permeability and fracture width.The results show that the fracture width and specimen permeability decrease gradually with the increase of pressure; the stronger the ductility of the filler is, the more obvious the fracture closure under pressure is, and the greater the decrease of permeability is; for quartz-filled cracks, the fracture permeability is different under different filling methods, and the supporting effect on the fracture is as follows: single layer fine sand > thick layer fine sand > medium sand and fine sand mixed.

Keywords

• tahe oilfield
• fault-karst reservoir
• fracture closure law
• ct scanning
• digital core