Gas fracturing method and system
Gas fracturing methods and systems utilizing a gas treatment fluid, which may contain a dispersed phase of fluid loss control agent particles. Also, treatment fluids suitable for use in the methods and systems are disclosed.
1. A method for treating a subterranean formation penetrated by a wellbore, comprising:
injecting into a fracture in the formation a gas treatment fluid stage above a fracturing pressure, wherein the gas treatment fluid stage is substantially free of proppant and wherein the gas treatment fluid stage is a mist that comprises a continuous gas phase and a mist phase, wherein the continuous gas phase is present at a concentration above 95 percent by volume, and the mist phase comprises particles in an amount below 5 percent by volume;
depositing the mist phase particles onto a face of a fracture within the formation to inhibit fluid loss into a formation matrix; and
reducing the pressure in the fracture to form a network of flow paths in the formation,
wherein the mist phase particles are smaller than 100 microns.
2. The method of claim 1 , wherein the mist phase comprises a hydrocarbon.
3. The method of claim 1 , wherein the mist phase comprises a hydrolyzable compound.
4. The method of claim 1 , wherein the mist phase comprises a degradable oil.
5. The method of claim 1 , wherein the mist phase comprises a material selected from the group consisting of esters, polyamines, polyethers, and any combination thereof.
6. The method of claim 1 , wherein the mist phase comprises a foaming agent.
7. The method of claim 1 , wherein the mist phase comprises fine solids.
8. The method of claim 1 , comprising degrading the mist phase particles deposited on the formation surface to facilitate conductivity.
9. The method of claim 1 , wherein the mist phase comprises mist phase particles at a concentration of at least 0.5 percent and below 5 percent by volume.
10. The method of claim 1 , wherein the gas treatment fluid stage is injected as a pad or pre-pad stage and the method further comprises:
injecting one or more proppant stages into the fracture following the gas treatment fluid stage prior to fracture closure.
11. The method of claim 1 , comprising:
filling a micropore within the formation with the gas treatment fluid, wherein the gas treatment fluid forms a foam in situ.
12. A gas fracturing system, comprising:
a treatment fluid supply unit configured to inject a treatment fluid stage into a formation, wherein the treatment fluid stage comprises:
a continuous gas phase at a pressure above a fracturing pressure to form a fracture in the formation, wherein the gas phase is present at a concentration higher than 95 percent by volume, and
a mist phase that comprises mist phase particles present at a concentration of at least 0.5 percent and below 5 percent by volume, and having a particle size smaller than 100 microns,
wherein the mist phase particles are deposited on a fracture face within the formation; and
a fluid loss control system present in the mist phase in an amount to inhibit fluid loss into the formation.
13. The gas fracturing system of claim 12 , wherein the treatment fluid stage is substantially free of proppant.
14. The gas fracturing system of claim 12 , wherein the treatment fluid fills a micropore within the formation, wherein the fluid forms a foam in situ.
15. A method for hydraulic fracturing comprising:
injecting a gas treatment fluid stage in a formation at a treating pressure above a fracturing pressure, wherein the gas treatment fluid is a mist that is substantially free of proppant, and comprises a continuous gas phase at a concentration higher than 95 percent by volume, and a mist phase dispersed in the continuous gas phase as a discontinuous phase in an amount of less than 5 percent by volume;
depositing liquid or foam particles from the mist phase onto a face of a fracture within formation to inhibit fluid loss into a matrix of the formation; and
reducing the pressure in the fracture to form a network of conductive gas-fractured flow paths in the formation;
wherein the mist phase particles are smaller than 100 microns.
16. The method of claim 15 , wherein the mist phase comprises a foaming agent.
17. The method of claim 15 , wherein the mist phase comprises from 0.5 to 5 percent by volume based on the total volume of the gas treatment fluid stage.
18. The method of claim 15 , wherein the mist phase further comprises fine solids, and the method further comprises depositing the fine solids onto face of a fracture within the formation.
19. The method of claim 15 , comprising:
filling a micropore within the formation with the gas treatment fluid, wherein the gas treatment fluid forms a foam in situ.