Tracer eluting proppants for hydraulic fracturing

Patent metadata

Field	Value
Publication number	US-2022017815-A1
Application number	US-202117379659-A
Country	US
Kind code	A1
Filing date	Jul 19, 2021
Priority date	Jul 20, 2020
Publication date	Jan 20, 2022
Grant date	—

Abstract

Described are tracer eluting proppants, such as proppants that have polymeric coatings on them that include tracers, such as a fluorescent dye. The tracer eluting proppants can comprise proppant particles coated with a polymeric coating that can elute tracer under some, but not all conditions. For example, the tracer can be eluted at elevated temperature, pH, and/or salinity conditions, but not elute at lower temperature, pH, and/or salinity conditions. Methods of making and using tracer eluting proppants are also disclosed, including methods for characterizing subterranean reservoirs.

First claim

What is claimed is:

1 . A proppant composition comprising:
a proppant particle; a coating on a surface of the proppant particle, the coating comprising a tracer and a polymer, wherein the coating is activatable under temperature, pH, and salinity conditions within a subterranean reservoir.

2 . The proppant composition of claim 1 , wherein the coating encapsulates the proppant particle.

3 . The proppant composition of claim 1 , wherein the tracer is releasable from the coating to an aqueous solution over time.

4 . The proppant composition of claim 3 , wherein the aqueous solution has a temperature greater than 25° C., greater than 30° C., greater than 35° C., greater than 40° C., greater than 45° C., greater than 50° C., greater than 55° C., or greater than 60° C.

5 . The proppant composition of claim 3 , wherein the aqueous solution has a pH greater than 8 or greater than 9.

6 . The proppant composition of claim 3 , wherein the aqueous solution has a pH less than 8.

7 . The proppant composition of claim 3 , wherein the aqueous solution has a salinity greater than 10000 ppm or greater than 50000 ppm.

8 . The proppant composition of claim 3 , wherein the aqueous solution has a salinity less than 10000 ppm.

9 . The proppant composition of claim 1 , wherein the coating has a thickness of from 1 μm to 20 μm.

10 . The proppant composition of claim 1 , wherein a concentration or loading of the tracer in the coating is from 0.05 wt. % to 5 wt. %.

11 . The proppant composition of claim 1 , wherein the tracer is homogeneously distributed in the polymer in the coating.

12 . The proppant composition of claim 1 , wherein the tracer comprises a dye, a rare earth organometallic complex, fluorobenzoic acids, nanoparticles, radioactive tracers, or any combination of these.

13 . The proppant composition of claim 1 , wherein the polymer comprises a methacrylic acid polymer, an acrylate polymer, methacrylic acid-ethylacrylate copolymer, or any combination or copolymers of these.

14 . The proppant composition of claim 1 , wherein the coating is activatable upon contact with an aqueous solution having one or more of: a temperature greater than 25° C., a pH greater than 8, or a salinity greater than 10000 ppm.

15 . The proppant composition of claim 1 , further comprising one or more additional proppant particles lacking the coating.

16 . A method of identifying a proppant position in a subterranean reservoir, the method comprising:
providing a proppant composition, the proppant composition comprising:
a proppant particle;
a coating on a surface of the proppant particle, the coating comprising a tracer and a polymer, wherein the coating is activatable under temperature, pH, and salinity conditions within the subterranean reservoir;
injecting the proppant composition into the subterranean reservoir; producing a fluid from the subterranean reservoir; detecting a concentration of the tracer in the fluid produced from the subterranean reservoir as a function of time; and analyzing the concentration of the tracer to identify a position of the proppant composition in the subterranean reservoir.

17 . The method of claim 16 , wherein injecting the proppant composition into the subterranean reservoir includes positioning the proppant composition within fractures in the subterranean reservoir.

18 . The method of claim 16 , further comprising identifying temperature, pH, or salinity conditions in the subterranean reservoir and identifying the proppant composition based on the temperature, pH, or salinity conditions in the subterranean reservoir.

19 . The method of claim 16 , wherein analyzing the concentration of the tracer includes using a numerical model for tracer transport

20 . The method of claim 19 , wherein the numerical model includes a dispersion coefficient, a mass transfer coefficient, a fracture porosity, a coating volume factor for the proppant particle, and a tracer partitioning factor.

21 . The method of claim 19 , wherein the numerical model includes temperature, pH, or salinity conditions in the subterranean reservoir.

22 . The method of claim 16 , further comprising:
providing a second proppant composition, the second proppant composition comprising a second tracer; injecting the second proppant composition into the subterranean reservoir; detecting a concentration of the second tracer in the fluid produced from the subterranean reservoir as a function of time; and analyzing the concentration of the second tracer to identify a position of the second proppant composition in the subterranean reservoir.

23 . The method of claim 16 , wherein injecting the proppant composition into the subterranean reservoir comprises activating the coating by contacting the coating with an aqueous solution having one or more of: a temperature greater than 25° C., a pH greater than 8, or a salinity greater than 10000 ppm, wherein the tracer is released from the coating to the aqueous solution upon activation.

24 . A method of making a proppant composition, the method comprising:
providing a proppant particle; contacting the proppant particle with a polymeric solution to form a solution coated proppant particle, the polymeric solution comprising a polymer, a tracer, and a solvent; subjecting the solution coated proppant particle to conditions to evaporate solvent from the solution coated proppant particle to form a tracer coated proppant particle, the tracer coated proppant particle comprising:
the proppant particle;
a coating on a surface of the proppant particle, the coating comprising the tracer and the polymer, wherein the coating is activatable under temperature, pH, and salinity conditions within a subterranean reservoir.

25 . The method of claim 24 , wherein the tracer comprises a dye, a rare earth organometallic complex, fluorobenzoic acids, nanoparticles, radioactive tracers, or any combination of these.

26 . The method of claim 24 , wherein the polymer comprises a methacrylic acid polymer, an acrylate polymer, methacrylic acid-ethylacrylate copolymer, or any combination or copolymer of these.

27 . The method of claim 24 , wherein the solvent comprises acetone, dichloromethane, methyl ethyl ketone, dimethyl formamide, or any combination of these.

28 . The method of claim 24 , further comprising mixing the tracer coated proppant particle with one or more additional proppant particles lacking the coating.

29 . The method of claim 24 , further comprising preparing the polymeric solution.

30 . The method of claim 24 , further comprising identifying temperature, pH, or salinity conditions in the subterranean reservoir and preparing the polymeric solution based on the temperature, pH, or salinity conditions in the subterranean reservoir.

31 . The method of claim 24 , further comprising contacting the tracer coated proppant particle with an aqueous solution to release the tracer to the aqueous solution over time.

32 . The method of claim 31 , wherein the aqueous solution has a temperature greater than 25° C., greater than 30° C., greater than 35° C., greater than 40° C., greater than 45° C., greater than 50° C., greater than 55° C., or greater than 60° C.

33 . The method of claim 31 , wherein the aqueous solu

Assignees

• Univ Texas

Inventors

• Mohanty Kishore K
• Zhao Bochao
• Panthi Krishna
• Singh Robin

Classifications

• E21B43/267

  reinforcing fractures by propping · CPC title

• C09K8/805 Primary

  Coated proppants · CPC title

• C09K2208/10

  Nanoparticle-containing well treatment fluids · CPC title

• C09K8/882

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• E21B2200/20

  Computer models or simulations, e.g. for reservoirs under production, drill bits · CPC title