Thermoset nanocomposite particles, processing for their in oil and natural gas drilling applications
Use of two different methods, either each by itself or in combination, to enhance the stiffness, strength, maximum possible use temperature, and environmental resistance of thermoset polymer particles is disclosed. One method is the application of post-polymerization process steps (and especially heat treatment) to advance the curing reaction and to thus obtain a more densely crosslinked polymer network. The other method is the incorporation of nanofillers, resulting in a heterogeneous “nanocomposite” morphology. Nanofiller incorporation and post-polymerization heat treatment can also be combined to obtain the benefits of both methods simultaneously. The present invention relates to the development of thermoset nanocomposite particles. Optional further improvement of the heat resistance and environmental resistance of said particles via post-polymerization heat treatment; processes for the manufacture of said particles; and use of said particles in the construction, drilling, completion and/or fracture stimulation of oil and natural gas wells are described.
1. A method for fracture stimulation of a subterranean formation having a wellbore, comprising:
injecting into the wellbore a slurry containing a nanocomposite spherical bead proppant at sufficiently high rates and pressures such that said formation fails and fractures to accept said slurry, said spherical bead proppant comprising:
a polymer matrix; and from 0.001 to 60 volume percent of nanofiller particles possessing a length that is less than 0.5 microns in at least one principal axis direction,
wherein said nanofiller particles comprise at least one of fine particulate material, fibrous material, discoidal material, or a combination of such materials; and
wherein said nanofiller particles are selected from the group of nanofillers consisting of: natural nanoclays, synthetic nanoclays or mixtures thereof, said nanofiller particles being dispersed throughout said polymeric nanocomposite spherical bead proppant, wherein said spherical bead proppant has a diameter ranging from 0.1 mm to 4 mm and wherein said spherical bead proppant has about neutral buoyancy relative to water; and emplacing said nanocomposite spherical bead proppant within a fracture network in said formation in a packed mass or a partial monolayer of said spherical head proppant, which packed mass or partial monolayer props open the fracture network; thereby allowing produced gases, fluids, or mixtures thereof, to flow towards the wellbore.
2. The method of claim 1 , wherein said polymer matrix comprises a styrene-divinylbenzene copolymer or a styrene-ethylvinylbenzene-divinylbenzene terpolymer.
3. The method of claim 2 , wherein said polymer matrix contains divinylbenzene in an amount ranging from 3% to 35% by weight.
4. The method of claim 1 , wherein said nanofiller comprises natural nanoclays, possessing a length that ranges between 100 and 500 nanometers in at least one principal axis direction and present in an amount from 0.1% to 15% of said nanocomposite spherical bead proppant by volume.
5. The method of claim 1 , wherein said nanofiller comprises synthetic nanoclays, possessing a length that ranges between 100 and 500 nanometers in at least one principal axis direction and present in an amount from 0.1% to 15% of said nanocomposite spherical bead proppant by volume.
6. The method of claim 1 , wherein said packed mass or said partial monolayer exhibits a static conductivity of at least 100 mDft after 200 hours at a temperature greater than 80° F.