Nano Technologies for Improved Oil & Gas Recovery

Nanoparticle perspective…. SARS virus human T-cell lymphotropic virus

Nano Scale Chemical Delivery System for Oil & Gas Applications* Evolved from drug delivery technologies developed in pharmaceutical industry. Using nanoparticles (polyelectrolyte complexes) to entrap oil & gas field chemicals. Able to penetrate deep into formation rock (particle size in nanometer range). Change of nanoparticle surface charge by altering mixing sequence. Controlled release of chemicals achieved by engineering compositions of nanoparticles. * KU Patent Pending

Potential Applications for Oil & Gas Industry Any active agent capable of generating a binding event with nanoparticles. Examples: Metal ions (single and multivalent) Gel Breakers (Enzymes, Oxidizers) Scale inhibitors Corrosion inhibitors Surfactants Etc.

What are we looking for in nano-carriers and other nano systems? Environmentally friendly - non-toxic - biodegradable Cost effective Compatible with hostile underground environments - pH - temperature & pressure - salinity Compatible with reservoir rock and fluids Able to control propagation in reservoir rock Able to entrap and protect active during placement Able to control/delay the release of active Able to scale up to field scale

Example Application in Improved Oil & Gas Recovery Polymer gels have been used extensively to improve sweep efficiency by blocking high conductivity channels during enhanced oil recovery operations. Cr(III) crosslinks with Partially Hydrolyzed Polyacrylamide polymer (HPAM) to form a strong gel. Once gelled, can no longer propagate in formation rock. Gelation time too short (< 30 min.) to place gel deep into formation rock. Polyelectrolyte complex nanoparticles can entrap and control the release of Cr(III) to delay the onset of gelation.

PolyanionPolycation Cr(III) MIX Nanoparticles + Cr(III) Process of Entrapping Active Agents in Nanoparticles

Characterization of Nanoparticles SampleDiameter nm Zeta Potential mV Entrapment Efficiency % Cr(III) - Nanoparticles 140.6± ± Laser Particle Size & Zeta Potential Analyzer

Controlled Release of Crosslinking Agent (Delay Gelation of Cr(III)-HPAM Gel) Gelant Composition 5,000 ppm HPAM (Mw = 6,000 kDa) + Nanoparticles loaded with 100 ppm Cr(III) + 1%(w/w) NaCl +100 ppm NaN 3, pH=9.45 HPAM Gelant HPAM 5,000 ppm Cr(III) 100 ppm Nanoparticles + Cr(III)

Delayed Gelation of HPAM Gel Using Entrapped Cr(III) Gelation time at 40 C was up to 10 days In contrast Control gelants consisting of 5,000 ppm HPAM and 100 ppm Cr (as CrCl 3 ·6H 2 O) formed gels in less than 5 min Top of scale

Other Example Application for Oil & Gas Industry Fracturing fluid cleanup Entrap breaker with nanoparticles and pump with fracturing fluid Electrostatic repulsion between like-charged nanoparticles insure suspension and even distribution in fracturing fluid. Evenly distributed breaker insures effective breakdown of fracturing fluid when released Breaker release can be controlled until desired elapsed time (e,g., 1 day)