Method and Compositions for Hydraulic Fracturing and for Tracing Formation Water
A method of hydraulic fracturing, and tracer composites for use in the fracturing procedure, for tracing the production of formation water from one or more fractured zones. The tracer composites preferably include a formation water tracer material adsorbed onto a solid carrier material.
1 . A tracer composite for use in tracing production of formation water, comprising:
a solid carrier material which is substantially non-soluble in water; and
a tracer on the solid carrier material;
wherein the tracer is held on the solid carrier material to substantially prevent the tracer from being eluted from the solid carrier material at a detectable level in water having a salinity level of less than 1 part per thousand by weight but permit the tracer, at least when the salinity level of the water reaches a value of 5 parts per thousand by weight, to be eluted from the solid carrier material at detectable levels which increase as the salinity level of the water increases; and
wherein the solid carrier material comprises catalytic sites that, in the presence of water, convert aldehydes adsorbed on the solid carrier material to acids.
2 . The tracer composite of claim 1 , wherein the tracer comprises a halogenated benzoic acid adsorbed to the solid carrier material.
3 . The tracer composite of claim 2 , wherein at least a portion of the halogenated benzoic acid adsorbed to the solid carrier material has been converted from a halogenated benzoic aldehyde by catalytic sites of the solid carrier material during manufacture of the tracer composite.
4 . The tracer composite of claim 3 , wherein at least 50% of the halogenated benzoic aldehyde adsorbed on the solid carrier material has been converted to the halogenated benzoic acid.
5 . The tracer composite of claim 1 , wherein the solid carrier comprises diatomaceous earth, silica gel, alumina, calcined clay, porous ceramics, or granular carbon.
6 . The tracer composite of claim 5 , wherein the solid carrier comprises silica gel or a porous ceramic.
7 . The tracer composite of claim 6 , wherein the solid carrier material is silanized.
8 . The tracer composite of claim 6 , wherein the solid carrier material has been silanized by contacting with a silanizing agent comprising hexamethyldisilazane, chlorotrimethylsilane, or poly-(dimethylsiloxane).
9 . The tracer composite of claim 6 , wherein the silanizing agent is delivered in a solvent comprising acetonitrile or hexane solution.
10 . The tracer composite of claim 5 , wherein the hydrophilic groups on surfaces of the solid carrier material have been deactivated.
11 . The tracer composite of claim 1 , wherein the tracer adsorbed onto the solid carrier material is about 10% to about 30% by weight of the total weight of the tracer composite.
12 . A method of manufacturing a tracer composite, comprising:
contacting a solid carrier material which is porous and substantially non-soluble in water with a tracer to adsorb the tracer onto the solid carrier material;
wherein the tracer is held on the solid carrier material to substantially prevent the tracer from being eluted from the solid carrier material at a detectable level in water having a salinity level of less than 1 part per thousand by weight but permit the tracer, at least when the salinity level of the water reaches a value of 5 parts per thousand by weight, to be eluted from the solid carrier material at detectable levels which increase as the salinity level of the water increases.
13 . The method of claim 12 , further comprising silanizing the solid carrier material prior to contacting the silanized solid carrier material with the tracer.
14 . The method of claim 13 , further comprising draining and drying the silanized solid carrier material prior to contacting the silanized solid carrier material with the tracer.
15 . The method of claim 13 , wherein the silanizing comprises contacting the solid carrier material with a silanizing agent comprising hexamethyldisilazane, chlorotrimethylsilane, or poly-(dimethylsiloxane).
16 . The method of claim 15 , wherein the silanizing agent is delivered in a solvent comprising acetonitrile or hexane solution.
17 . The method of claim 12 , wherein the tracer comprises a halogenated benzoic aldehyde that is liquid at room temperature, and is adsorbed onto the solid carrier material without use of a solvent.
18 . The method of claim 17 , wherein the tracer is sprayed onto the solid carrier material while the solid carrier material is tumbled under vacuum conditions.
19 . The method of claim 12 , wherein the tracer comprises a halogenated benzoic acid and is adsorbed onto the solid carrier material by combining the tracer with a solvent, contacting the tracer-containing solvent with the solid carrier material, and evaporating the solvent to leave the tracer on surfaces of the solid carrier material.
20 . The method of claim 19 , wherein the solvent comprises methanol, hexane, dichloromethane, isopropyl alcohol, or acetone, and wherein the evaporating is conducted under vacuum conditions.