Acid stimulation of oil and gas production wells with Self-Diverting Acid Stimulation fluids
The technology of oil and gas production stimulation with self-deviating acid stimulation fluid FLUXOCORE® 210 grade C (or its concentrated form FLUXOCORE® 210 grade N) with gelling agent SURFOGEL® grade A/grade AT is designed for the treatment of wells in carbonate fractured and porous fractured reservoirs with high heterogeneity of layers.
Gelling agent SURFOGEL® grade A is applied at normal formation temperatures, gelling agent SURFOGEL® grade AT is applied at higher temperatures.
The process of oil production stimulation in carbonate porous fractured reservoirs with high-permeability zones in the producing formation is complicated with the fact that acidic compounds tend to acidize mainly the zones with high-permeability.
The most effective way to increase the acid stimulation coverage is to divert acidizing fluids with the help of temporarily blocking compound based on gelling agent SURFOGEL® grade A/grade AT. Blocking gel is formed directly in-place conditions while the process of acid spending with the reaction between acid formation rock. This allows to divert selectively the acid fluid to a less permeable area where the net of wormholes is formed. The wormholes are formed not only due to the heterogeneity of the reservoir but also due to redirecting the vector of effect on the rock by increasing the resistance of the gel.
In the presence of oil the gels destruct themselves.
- Self-diverting acid stimulation fluids do not cause formation damage with colmatating comparing to polymer-based flow-diverters.
- Possibility of creating a wide network of wormholes in the matrix not only due to the heterogeneity of the reservoir but also due to redirecting the vector of effect on the rock by increasing the resistance of the gel.
- Enhancing the efficiency of usage of hydrochloric acid, for the acid is not spent on cavity creation.
- No need in keeping high speed of injection of self-diverting acid stimulation fluids, and thus no need in expensive specialized equipment.It is possible to use self-diverting acid stimulation fluids when the coiltubing technologies are applied.
- The viscosity of acid stimulation fluid FLUXOCORE® 210 grade C (grade N) with diverting agent SURFOGEL® grade A/grade AT in its original state is about 20-30 mPa·s at the temperature of 20 °С.The possibility of regulating the ultimate viscosity of self-diverting acid stimulation fluids containing gelling agent SURFOGEL® grade A/grade AT by changing its concentration depending on the geological conditions and objectives.
To select the optimal design of application of self-diverting acidizing fluid it is recommended to contact the specialists of Sales and Service Department of Polyex company.
Chemicals are certified for the application in oil-and-gas industry.