Method for optimizing conductivity in a hydraulic fracturing operation
A method of distributing proppant in a spatial arrangement throughout a created or enlarged fracture by pumping into a subterranean formation penetrated by a well multiple stages of fracturing fluid wherein a fluid laden with proppant is pumped into the well and a fluid substantially free of proppant is then pumped into the well; the fluid of the fluid laden with proppant and the fluid substantially free of proppant being the same. Vertically extending pillars are created within the formation. Fluid produced from the hydrocarbon-bearing reservoir is then flowed at least partially through channels between the vertically extending pillars.
1. A method of hydraulically fracturing a hydrocarbon-bearing formation with fluids which comprises:
(a) pumping into the formation a first fluid laden with proppant disposed in a superabsorbent polymer;
(b) pumping into the formation a second fluid substantially free of proppant;
(c) breaking the superabsorbent polymer with a breaker and releasing the proppant therefrom;
(d) creating vertically extended pillars from the released proppant and creating conductive flow channels between the pillars; and
(e) flowing fluids produced from the hydrocarbon-bearing reservoir at least partially through the channels between the vertically extending pillars.
2. The method of claim 1 , wherein the superabsorbent polymer comprises a plurality of crosslinks.
3. The method of claim 1 , wherein the superabsorbent polymer includes a repeat unit which comprises a polysaccharide, an acrylate, an acrylamide, a poly vinyl acetate, a derivative thereof, or a combination thereof.
4. A method of hydraulically fracturing a hydrocarbon-bearing subterranean formation which comprises:
(a) pumping into the formation a fluid containing a breaker, the fluid being laden with proppant disposed in a crosslinked superabsorbent polymer;
(b) pumping into the formation a fluid substantially free of proppant;
(c) reacting the breaker with the superabsorbent polymer and breaking a bond in a polymer chain of the superabsorbent polymer, a bond in a crosslink of the superabsorbent polymer, a bond between a crosslink and a chain of the superabsorbent polymer or a mixture thereof;
(d) releasing the proppant from the reaction product of step (c) and forming pillars from the released proppant; and
(e) flowing fluids produced from the hydrocarbon-bearing reservoir at least partially through the channels between the vertically extending pillars.
5. The method of claim 4 , wherein the superabsorbent polymer is a polysaccharide or contains repeating units of an acrylate, an acrylamide, a vinylpyrrolidone, vinyl acetate, vinyl alcohol, 2-acrylamide-2-methylpropanesulfonic acid or a derivative thereof crosslinked with a crosslinker.
6. The method of claim 4 wherein the rate of pumping of the fluid containing proppant and the fluid substantially free of proppant is substantially the same.
7. The method of claim 4 wherein the volume of the fluid containing proppant and the volume of fluid substantially free of proppant are substantially the same.
8. The method of claim 4 , wherein the fluid containing proppant is an ultra lightweight proppant having an apparent specific gravity less than or equal to about 2.45.
9. The method of claim 4 , wherein at least one of the following conditions prevail:
(a) the proppant of the fluid with proppant is coated with a resin; or
(b) the proppant of the fluid with proppant is a plastic bead.
10. The method of claim 4 , wherein the relative permeability of the reservoir is less than about 1 mD.
11. The method of claim 10 , wherein the permeability of the reservoir is less than about 0.1 mD.
12. The method of claim 4 , wherein the proppant of the fluid with proppant is a coated plastic bead and further wherein the bead comprises a polystyrene divinylbenzene or a polyamide or a derivative thereof.