Aplicação de sistemas microemulsionados ácidos em acidificação de poços

Stimulation operations have with main objective restore or improve the productivity or injectivity rate in wells. Acidizing is one of the most important operations of well stimulation, consist in inject acid solutions in the formation under fracture formation pressure. Acidizing have like main purpose remove near wellbore damage, caused by drilling or workover operations, can be use in sandstones and in carbonate formations. A critical step in acidizing operation is the control of acid-formation reaction. The high kinetic rate of this reaction, promotes the consumed of the acid in region near well, causing that the acid treatment not achive the desired distance. In this way, the damage zone can not be bypassed. The main objective of this work was obtain stable systems resistant to the different conditions found in field application, evaluate the kinetic of calcite dissolution in microemulsion systems and simulate the injection of this systems by performing experiments in plugs. The systems were obtained from two non ionic surfactants, Unitol L90 and Renex 110, with sec-butanol and n-butanol like cosurfactants. The oily component of the microemlsion was xilene and kerosene. The acqueous component was a solution of HCl 15-26,1%. The results shown that the microemulsion systems obtained were stable to temperature until 100ºC, high calcium concentrations, salinity until 35000 ppm and HCl concentrations until 25%. The time for calcite dissolution in microemulsion media was 14 times slower than in aqueous HCl 15%. The simulation in plugs showed that microemulsion systems promote a distributed flux and promoted longer channels. The permeability enhancement was between 177 - 890%. The results showed that the microemulsion systems obtained have potential to be applied in matrix acidizing

Aplicação de sistemas microemulsionados ácidos em acidificação de poços

Stimulation operations have with main objective restore or improve the productivity or injectivity rate in wells. Acidizing is one of the most important operations of well stimulation, consist in inject acid solutions in the formation under fracture formation pressure. Acidizing have like main purpose remove near wellbore damage, caused by drilling or workover operations, can be use in sandstones and in carbonate formations. A critical step in acidizing operation is the control of acid-formation reaction. The high kinetic rate of this reaction, promotes the consumed of the acid in region near well, causing that the acid treatment not achive the desired distance. In this way, the damage zone can not be bypassed. The main objective of this work was obtain stable systems resistant to the different conditions found in field application, evaluate the kinetic of calcite dissolution in microemulsion systems and simulate the injection of this systems by performing experiments in plugs. The systems were obtained from two non ionic surfactants, Unitol L90 and Renex 110, with sec-butanol and n-butanol like cosurfactants. The oily component of the microemlsion was xilene and kerosene. The acqueous component was a solution of HCl 15-26,1%. The results shown that the microemulsion systems obtained were stable to temperature until 100ºC, high calcium concentrations, salinity until 35000 ppm and HCl concentrations until 25%. The time for calcite dissolution in microemulsion media was 14 times slower than in aqueous HCl 15%. The simulation in plugs showed that microemulsion systems promote a distributed flux and promoted longer channels. The permeability enhancement was between 177 - 890%. The results showed that the microemulsion systems obtained have potential to be applied in matrix acidizing

Comparative study between the effects of hyaluronic acid and acid galactan purified from eggs of the mollusk Pomacea sp in wound healing

To compare the effect of hyaluronic acid (HA) and of AG on the healing of intestine wounds. Methods: The semi-purified extract of the eggs of the mollusc was obtained by fractionation with ammonium sulfate and purification for ion-exchange chromatography. The obtained galactans were eluted in water (neutral galactan) and in 0.1 and 0.2M NaCl (acidic galactans). The in vivo study was performed with 45 “Wistar” rats, separated in three groups (n=15). Solutions containing HA 1%, GA 1% or saline solution 0,9%, was placed topically on the sutures of wounds in the small intestine of the rats. After 05, 10 and 21 days the animals were sacrificed and biopsy of the healing tissue was done. Results: The hystologic grading was more significant for HA and AG groups when compared to the group C. AG stimulated the appearance of macrophages, giant cells and increase in the concentration of collagen in the area of the wound when compared to HA. Conclusion: The topical use of GA in intestinal wounds promoted the anticipation of events that are important in the wound healing

Comparative study between the effects of hyaluronic acid and acid galactan purified from eggs of the mollusk Pomacea sp in wound healing

To compare the effect of hyaluronic acid (HA) and of AG on the healing of intestine wounds. Methods: The semi-purified extract of the eggs of the mollusc was obtained by fractionation with ammonium sulfate and purification for ion-exchange chromatography. The obtained galactans were eluted in water (neutral galactan) and in 0.1 and 0.2M NaCl (acidic galactans). The in vivo study was performed with 45 “Wistar” rats, separated in three groups (n=15). Solutions containing HA 1%, GA 1% or saline solution 0,9%, was placed topically on the sutures of wounds in the small intestine of the rats. After 05, 10 and 21 days the animals were sacrificed and biopsy of the healing tissue was done. Results: The hystologic grading was more significant for HA and AG groups when compared to the group C. AG stimulated the appearance of macrophages, giant cells and increase in the concentration of collagen in the area of the wound when compared to HA. Conclusion: The topical use of GA in intestinal wounds promoted the anticipation of events that are important in the wound healing