TY - THES

T1 - Fluid-Rock-Fluid Interactions Of Alkali-Polymer in 8 TH & 9 TH Matzen Reservoir

AU - Sidaoui, Ahmad

N1 - no embargo

PY - 2022

Y1 - 2022

N2 - The chemical-enhanced oil recovery market has grown in the past few years. Studies have established that using chemical agents like alkali and polymers together has a synergetic effect in increasing oil production beyond additional recoveries reached by water flooding operations. The mechanisms in play when it comes to chemical-enhanced oil recovery are wettability alteration and interfacial tension reduction between the oleic phase and the injected aqueous phase. The optimal chemical composition is essential because of the unique characteristics of reservoirs. In this work, fluid-fluid and rock-fluid evaluations are carried out in the laboratory to select and optimise the chemical solution to be considered for further pilot testing applications in the 9 TH reservoir of the Matzen field northeast of Vienna, Austria. The evaluations consisted of measuring the IFT reduction effect of alkali and alkali-polymer solutions and analysing the emulsification process and the stability of the emulsions when the chemical agents meet the natural acids present in the oil samples. Spontaneous imbibition experiments were carried out to analyse and quantify the occurance of a wettability alterations mechanisms. Finally, singlephase core flood experiments are carried out to analyse the effect of polymer retention on the core permeability and the additional resistance to flow when polymers are considered in the injected fluids. In the evaluations, two oil types are analysed, an oil sample from the 8 TH reservoir and another from the 9 TH reservoir in the Matzen field. Both oil types have similar TAN and saponifiable acids. The chemicals consisted of different concentrations of two different types of alkalis, sodium and potassium carbonate, along with fixed concentrations of two types of HPAM polymers noted as KA 5265 and SNF 3630S. 1900 and 1850 ppm of SNF 3630S and KA 5265 consecutively were used in some prepared solutions. A sound effect of IFT reduction was noted when an alkali agent was present in the analysed chemical solution. However, the presence of a polymer slightly reduced the IFT slightly reduction effect due to the stability provided by the polymer. The added stability was also noticed in the phase behaviour experiments, the saponification and emulsification process were noticed with all the alkali-containing solutions, and the created emulsion middle phase was stabilised in cases where polymer was also present in the aqueous phase. An additional oil recovery of 7 % and 33 % was recorded for the 9 TH and 8 TH oil samples consecutively in the spontaneous imbibition tests. The low IFT mechanism contributed to the increase in oil production. Moreover, the results were analyzed using the capillary diffusion coefficient. The results showed that the wettability alteration mechanism did not take a role in increasing oil production by spontaneous imbibition for the 8 TH cases. However for 9 TH cases wettability alteration was deduced by an combination of diffusion coefficient increase and IFT decrease.The Single-phase flooding evaluations showed that the concentration of 7500 ppm of sodium carbonate + 1850 ppm KA 5265 yields lower flow resistance factors and has a lower polymer retention capacity when it flows through the porous media.

AB - The chemical-enhanced oil recovery market has grown in the past few years. Studies have established that using chemical agents like alkali and polymers together has a synergetic effect in increasing oil production beyond additional recoveries reached by water flooding operations. The mechanisms in play when it comes to chemical-enhanced oil recovery are wettability alteration and interfacial tension reduction between the oleic phase and the injected aqueous phase. The optimal chemical composition is essential because of the unique characteristics of reservoirs. In this work, fluid-fluid and rock-fluid evaluations are carried out in the laboratory to select and optimise the chemical solution to be considered for further pilot testing applications in the 9 TH reservoir of the Matzen field northeast of Vienna, Austria. The evaluations consisted of measuring the IFT reduction effect of alkali and alkali-polymer solutions and analysing the emulsification process and the stability of the emulsions when the chemical agents meet the natural acids present in the oil samples. Spontaneous imbibition experiments were carried out to analyse and quantify the occurance of a wettability alterations mechanisms. Finally, singlephase core flood experiments are carried out to analyse the effect of polymer retention on the core permeability and the additional resistance to flow when polymers are considered in the injected fluids. In the evaluations, two oil types are analysed, an oil sample from the 8 TH reservoir and another from the 9 TH reservoir in the Matzen field. Both oil types have similar TAN and saponifiable acids. The chemicals consisted of different concentrations of two different types of alkalis, sodium and potassium carbonate, along with fixed concentrations of two types of HPAM polymers noted as KA 5265 and SNF 3630S. 1900 and 1850 ppm of SNF 3630S and KA 5265 consecutively were used in some prepared solutions. A sound effect of IFT reduction was noted when an alkali agent was present in the analysed chemical solution. However, the presence of a polymer slightly reduced the IFT slightly reduction effect due to the stability provided by the polymer. The added stability was also noticed in the phase behaviour experiments, the saponification and emulsification process were noticed with all the alkali-containing solutions, and the created emulsion middle phase was stabilised in cases where polymer was also present in the aqueous phase. An additional oil recovery of 7 % and 33 % was recorded for the 9 TH and 8 TH oil samples consecutively in the spontaneous imbibition tests. The low IFT mechanism contributed to the increase in oil production. Moreover, the results were analyzed using the capillary diffusion coefficient. The results showed that the wettability alteration mechanism did not take a role in increasing oil production by spontaneous imbibition for the 8 TH cases. However for 9 TH cases wettability alteration was deduced by an combination of diffusion coefficient increase and IFT decrease.The Single-phase flooding evaluations showed that the concentration of 7500 ppm of sodium carbonate + 1850 ppm KA 5265 yields lower flow resistance factors and has a lower polymer retention capacity when it flows through the porous media.

KW - IFT

KW - Emulsion

KW - Verbreitung

KW - Spontanes Aufsaugen

KW - Natriumcarbonat

KW - Polymer

KW - 9 TH Matzenfeld

KW - 8 TH Matzenfeld

KW - Chemisch verbesserte Ölrückgewinnung

KW - Kernflutung

KW - Polymerretention

KW - Alkali

KW - Alkaliretention

KW - IFT

KW - emulsion

KW - Diffusion

KW - Spontaneous imbibition

KW - Sodium Carbonate

KW - Polymer

KW - 9 TH Matzen field

KW - 8 TH Matzen Field

KW - Chemical Enhanced Oil Recovery

KW - Core flooding

KW - Polymer retention

KW - Alkali

KW - Alkali retention

U2 - 10.34901/mul.pub.2023.99

DO - 10.34901/mul.pub.2023.99

M3 - Master's Thesis

ER -