Enzyme biotechnology development for treating polymers in hydraulic fracturing operations

Area of Science:

• Biotechnology
• Environmental Science
• Petroleum Engineering

Background:

• Carboxymethyl cellulose (CMC) is widely used in the oil and gas industry as a thickening agent during hydraulic fracturing.
• CMC filter cakes can accumulate at fracture faces, hindering oil and gas recovery.
• Current chemical oxidizer treatments for CMC filter cakes have limitations, driving interest in alternative methods.

Purpose of the Study:

• To investigate the potential of enzyme-based treatments for degrading CMC filter cakes under simulated oilfield conditions.
• To enrich a microbial culture capable of biodegrading CMC under methanogenic conditions relevant to oil extraction.
• To evaluate the efficacy of extracellular enzymes from the enriched culture in reducing CMC viscosity.

Main Methods:

• Enrichment of a methanogenic culture for CMC degradation.
• Characterization of CMC biodegradation under simulated oilfield conditions (temperature, salinity, pH).
• Assessment of CMC viscosity reduction using extracellular enzymes from the enriched culture.

Main Results:

• A methanogenic CMC-degrading culture was successfully enriched.
• Extracellular enzymes demonstrated significant CMC viscosity reduction between 50-80°C, up to 20% salinity, and pH 5-8.
• Viscosity reduction was observed under both oxic and anoxic conditions, indicating broad applicability.

Conclusions:

• Enzyme biotechnology presents a viable alternative to chemical treatments for CMC filter cakes.
• The demonstrated enzymatic degradation of CMC under oilfield conditions shows promise for enhancing oil and gas recovery.
• Further research into enzyme-based solutions could optimize treatments for challenging subsurface environments.