High Performance Emulsifier for Carbonate Reservoir Acidizing
Emulsified acids have long been considered beneficial to stimulate oil and gas reservoirs for the dual purpose of protecting equipment and enhancing performance. Emulsified acids improve function by providing deeper penetration of acid into reservoirs, which in turn enhances wormhole development and serves to improve hydrocarbon production. Oil-continuous acid emulsion protects tubulars during pumping by minimizing acid contact and also mitigates acid reaction in the near wellbore during placement.
Used under the recommended conditions, YAQOOT AL SAMA’s EM-5 acid emulsifier allows for the preparation of high-acid emulsions (up to 95 parts acid) with kerosene or diesel fuel (5 parts) that will remain stable under pumping pressure. Rather than inverting or breaking during pumping, the emulsion will liquefy under pressure, only to regain its initial semi-solid consistency when the pressure is relieved. With the help of the correct formation temperature and acid reaction time, as well as the proper dilution of the kerosene/diesel, the acid emulsion progressively becomes resolved and is prepared to react with acid-soluble materials.
Benefit Highlights
- Retards the rate of reaction for deeper penetration of live acid into the formation
- Stable oil external acid emulsifier
- High internal phase concentrations
- Effective in a variety of acid concentrations: 15–28% HCl
- Product can be readily blended either at a central location or in the field
Applications
- Acid treatments on limestone or other acid-soluble materials
- Acid fracturing treatments
- Poorly consolidated sandstones that deposit loose sand into the wellbore
Tailored Treatment Designs
The normal concentration range of acid emulsifier is 10 to 20 gal/1,000 gallons (10 to 20 L/m3) of the total emulsified fluid, depending on the desired stability and the presence and nature of other acid additives. YAQOOT AL SAMA’s EM-5 acid emulsifier should be mixed with kerosene or diesel before slowly adding the acid with sufficient mixing.
Method of Emulsion Preparation
- The emulsifier is added to diesel and mixed
- 20wt% HCl is slowly added to the diesel with high shear mixing
- The final emulsion is sheared for 30 minutes after the complete addition of the 20wt% HCl
- This stable emulsion is ready to be used in testing