The present invention provides improved methods of placing proppant in fractures formed in a subterranean zone to prevent the subsequent flow-back of the proppant with fluids produced from the zone. The methods are basically comprised of the steps of depositing a mixture of hardenable resin composition coated proppant and uncoated proppant in the fractures and then causing the resin composition to harden into stationary permeable masses in the fractures.
Improved hardenable resin compositions and methods of consolidating particulate solids in subterranean zones penetrated by well bores are provided. The improved hardenable resin compositions of the invention are basically comprised of a hardenable organic resin, an aminosilane resin-to-particulate solid coupling agent, a viscous carrier fluid breaker for breaking separating films of viscous carrier fluid between resin coated particulate solids and a surface active agent for causing the resin composition to flow to the contact points between resin coated particulate solids.
Improved methods and compositions for consolidating proppant in subterranean fractures are provided. In accordance with a method of the invention, proppant particles coated with a furfuryl alcohol resin composition are mixed with a gelled liquid fracturing fluid and the fracturing fluid is pumped into a subterranean zone. The fracturing fluid forms one or more fractures in the subterranean zone and deposits the proppant particles coated with the resin composition therein. Thereafter, the hardenable resin composition on the proppant particles is allowed to harden by heat and consolidate the proppant particles into chemical and thermal degradation resistant permeable packs.
New compositions have been discovered which are useful as slurry concentrates to carry solid particles along in a fluid. A non-limiting example would be to carry proppants in a concentrate to a completion fluid being pumped downhole in a hydrocarbon recovery operation. The composition employs both a trivalent salt, such as aluminum chlorohydrate, as a viscosifying agent, and a surfactant. Surprisingly, it has been discovered that a synergistic effect is present between the aluminum chlorohydrate and the surfactant in that less of each component is required when both are used together to suspend the same amount of solids, than if one or the other is used separately. The viscoelasticity of the concentrate may be easily broken by dilution; other mechanisms are also anticipated.
Methods of reducing or preventing particulate flow-back in subterranean zones. In accordance with the methods, a treating fluid having a mixture of reticulated foam fragments and particulate solids are suspended therein. The treating fluid is introduced into a subterranean zone and the mixture of the reticulated foam fragments and the particulate solids are deposited in the subterranean zone whereby the reticulated foam fragments retard or prevent the flow-back of the particulate solids and the transport of formation fines from the subterranean zone upon the flowing-back of fluid from the zone.
Improved methods of coating dry proppant particles with a hardenable resin composition, suspending the coated proppant particles in a fracturing fluid and consolidating the proppant particles after being placed in fractures into high strength permeable masses are provided. As the fractures are formed, a liquid hardenable resin component is continuously mixed with a liquid hardening agent component on-the-fly to form a hardenable resin composition. The hardenable resin composition is continuously coated onto dry proppant particles conveyed from a source thereof on-the-fly to form resin composition coated proppant particles, and the resin composition coated proppant particles are continuously suspended in the fracturing fluid on-the-fly.
