Oil field chemical-carrying material and process for making the same
An oil field chemical-carrying material comprising polymeric particles and a process for making the same are disclosed. An oil field chemical is integrally incorporated into the granulated particle. The oil field chemical is in particular a tracer and the particle is in particular a proppant for use in hydraulic fracturing of a subterranean formation. Methods of delivering oil field chemicals, methods of monitoring subterranean formations, methods of tracing flow of fluid from hydrocarbon reservoirs and methods of hydraulic fracturing subterranean formations are also disclosed.
1. A process for producing an oil field chemical-carrying material, the process comprising:
microencapsulating the oil field chemical in a plurality of polymeric microcapsules each comprising the oil field chemical and a polymeric microencapsulant;
distributing the plurality of polymeric microcapsules in a pre-polymeric matrix material to form an oil field chemical carrying mixture;
processing and forming the oil field chemical carrying mixture to produce a precursor formation comprising a distribution of the polymeric microcapsules within a continuous solid matrix phase of polymeric material; and
comminuting the precursor formation to produce a plurality of proppant particles having a size in a range 0.1 to 3 mm, each proppant particle comprising a plurality of the polymeric microcapsules embedded in the solid matrix phase of polymeric material,
wherein the oil field chemical is a tracer, a viscosity modifier, a density modifier, a flow modifier, a gelling modifier, a lubricant, a foaming modifier, a scale inhibitor, a disinfectant, an anti-freeze or a corrosion inhibitor.
2. A process according to claim 1 , wherein the pre-polymeric matrix material is a flowable material into which the polymeric microcapsules are distributed by mixing.
3. A process according to claim 2 wherein the pre-polymeric matrix material comprises a fluid.
4. A process according to claim 2 , wherein the pre-polymeric matrix material comprises a flowable solid powder.
5. A process according to claim 1 , wherein the solid matrix phase of polymeric material comprises a polyethylene, a polypropylene, a polyacrylate, an aliphatic polyamide, a polyurethane, a vinyl ester, an epoxy resin or a polybutylene terephthalate.
6. A process according to claim 1 , comprising screening the particles produced by the comminuting step against a target size range and discarding particles that fall outside the target size range.
7. A process according to claim 1 , wherein the particles are subsequently coated.
8. A process according to claim 1 , wherein the oil field chemical comprises a tracer.