How is CO2 used for hydraulic fracturing?
CO2 is pumped as a liquid. Once it reaches the reservoir, down-hole conditions cause it to become a super-critical fluid. This phase change results in a significant increase in fluid volume, further extending fractures.
CO2 reduces the pH of water, which helps to break polymers and eliminate clay swelling in water sensitive formations. Since CO2 remains a liquid throughout the wellbore portion of the treatment, it is suited to high fracture gradient reservoirs where additional hydrostatic pressure is required.
Why use Liquid CO2?
Fracturing with a CO2 and liquid mix is very common within the oil and gas industry, and has been instrumental in the economic development of many oil and gas fields. CO2 can be applied by itself as the fracturing fluid for a completely damage-free frac, as an energizer where approximately 10% to 52% CO2 is added or as an emulsion or foam where 52% to 90% CO2 is added.
What are the benefits of CO2?
Liquid Carbon Dioxide has many benefits including:
- Minimized relative permeability effects and lowering surface tension between the fracturing and reservoir fluids
- Reduced liquid portion of the fracturing fluid
- Greater drawdown pressure in the fracture, which better mobilizes liquids and thus improves fracturing and reservoir fluid flow back
- CO2 dissolution from the fracturing fluid during drawdown generates an expandable gas phase that assists movement of fluids through pore throats
- Increased effective fracture length.
Visit Ferus’ Completions site to learn about the benefits of using CO2, and N2 as energized fluids for hydraulic fracturing, or enhanced oil recovery (EOR).
Find out how you can reduce costs on your wells by 20%, increase production by 15%, and reduce the reliance of freshwater by up to 80%.