Methods for using reversible phase oil-based drilling fluid
A method of fracturing a subterranean formation, the method including injecting a fracturing fluid into the well, wherein said fracturing fluid includes: an oleaginous fluid; and an amine surfactant having the structure wherein R is a C 12 -C 22 aliphatic hydrocarbon; R′ is an independently selectable from hydrogen or C 1 to C 3 alkyl; A is NH or O, and 1≦x+y≦3; and oil-wet proppant material. Additionally, the method includes pressurizing the fluid so as to cause the subterranean formation to fracture and allow the proppant materials to enter the crack, adding acid to the fluid so as to change the oil-wet proppant materials into water-wet proppant materials, and washing the well with an aqueous based wash solution.
1. A method of fracturing a subterranean formation, the subterranean formation being in fluid communication with the surface via a well, the method comprising:
a) injecting a fracturing fluid into said well, wherein said fracturing fluid includes: an oleaginous fluid; and an amine surfactant having the structure
wherein R is a C 12 -C 22 aliphatic hydrocarbon; R′ is an independently selectable from hydrogen or C 1 to C 3 alkyl; A is NH or O, and 1≦x+y≦3; and oil-wet proppant material;
b) pressurizing said fluid so as to cause the subterranean formation to fracture and allow the proppant materials to enter said crack;
c) adding acid to said fluid so as to change the oil-wet proppant materials into water-wet proppant materials and;
d) washing said well with an aqueous based wash solution.
2. The method of claim 1 wherein said oleaginous fluid comprising from 5 to about 100% by volume of the oleaginous fluid of a material selected from a group consisting of esters, ethers, acetals, di-alkylcarbonates, hydrocarbons, and combinations thereof.
3. The method of claim 1 wherein the fracturing fluid further includes a non-oleaginous liquid.
4. The method of claim 3 wherein said non-oleaginous liquid is selected from the group consisting of sea water, a brine containing organic or inorganic dissolved salts, a liquid containing water-miscible organic compounds, and combinations thereof.
5. The method of claim 1 wherein said amine surfactant is selected from diethoxylated tallow amine; diethoxylated soya amine; N-aliphatic-1,3-diaminopropane wherein the aliphatic group is a C 12 to C 22 hydrocarbon; or combinations thereof.
6. The method of claim 1 wherein the proppant material is selected from the group consisting of quartz gravel, sand, glass beads, ceramic pellets, and conbinations thereof.