CO2-Energized-Acid Treatment Reduces Freshwater Use, Boosts Well Performance

Topics: Carbonates Stimulation/acidizing
Source: Getty Images.

Carbon dioxide (CO2) with 30% foam quality (FQ) has been introduced for the first time during acid fracturing treatments in a tight, sour, high-pressure/high-temperature carbonate gas reservoir in Saudi Arabia to reduce consumption of fresh water, minimize reservoir damage, reduce the flowback period, and eliminate the need for nitrogen lifting with coiled tubing. The addition of liquid CO2 to hydrochloric acid (HCl) in quantities sufficient to produce emulsion allows live acid to retard and penetrate much deeper than HCl alone.


Gases were introduced to the oil and gas industry primarily as an aid to recover pumped stimulation fluids. This application still accounts for the majority of use of nitrogen and CO2. Special applications, such as foaming stimulation fluids, have reduced consumption of the liquid phase significantly.

Stimulation activities have been increasing dramatically in Saudi Arabia. During each stage of fracturing stimulation in Saudi Arabia, up to 3,000 bbl of groundwater is used. Up to 70% of that groundwater consumption can be reduced through the CO2-foam fracturing treatment. The application of CO2 also reduces the flowback period and eliminates the need to perform coiled-tubing nitrogen lifting, which is a unique requirement for tight and depleted reservoirs. The addition of liquid CO2 to HCl in quantities sufficient to produce viscous foam (emulsion) is one of the more significant improvements in recent years.

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 172620, “Successful Implementation of CO2-Energized-Acid Fracturing Treatment in Deep, Tight, and Sour Carbonate Gas Reservoir in Saudi Arabia That Reduced Freshwater Consumption and Enhanced Well Performance,” by Ataur R. Malik, SPE, Alaa A. Dashash, Saad M. Driweesh, SPE, and Yousef M. Noaman, SPE, Saudi Aramco, and Eduardo Soriano, SPE, and Alfredo Lopez, Halliburton, prepared for the 2015 SPE Middle East Oil and Gas Show and Conference, Manama, Bahrain, 8–11 March. The paper has not been peer reviewed.
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CO2-Energized-Acid Treatment Reduces Freshwater Use, Boosts Well Performance

01 June 2016

Volume: 68 | Issue: 6