Articles

The Laboratory Test of AOS and ABS Surfactant at 60oC for EOR Process

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Background: By 2021, global oil demand is expected to rise by 5.3 million barrels per day (bopd), while oil output is anticipated to decrease gradually. The fall in oil production was attributed to a decline in reservoir pressure and a depletion of oil reserves in the field. Surfactants are employed as a technique in Enhanced Oil Recovery (EOR) to enhance the extraction of oil.

Objective: This study investigates two different forms of surfactant solutions, specifically AOS (alpha olefin sulfonate) and ABS (alkyl benzene sulfonate). The two surfactants were evaluated at five distinct concentration levels, specifically 5%, 6%, and 7%. Both have a salinity level of 7,000 parts per million (ppm). AOS and ABS were selected as research materials because to their capacity to decrease interfacial tension.

Method: A phase behavior test was conducted to assess the durability of the foam throughout a 21-day measurement period at a temperature of 60°C. In addition, the research also seeks to ascertain the efficacy of oil recovery from the surfactant solution under investigation.

Results: This study is a controlled experiment conducted in a laboratory setting to examine the effects of AOS and ABS surfactants on sandstone rocks. The AOS and ABS surfactant solution was prepared by combining AOS powder and 70% ABS surfactant liquid with brine containing a salinity concentration of 7,000 ppm. The research procedure comprises multiple stages, such as density testing and phase behavior testing.

Conclusion: Based on this study, it may be inferred that concentrations beyond 5% did not yield middle-phase emulsions. Nevertheless, the oil recovery rate escalated to 68% as a result of the water flooding injection test and ongoing surfactant injection.

Improving Oil Recovery Efficiency Using Corn starch as a Local Polymer for Enhanced Oil Recovery Processes

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Polymer flooding is a chemical enhanced oil recovery method that improves the recovery of oil by controlling the mobility of water to oil phase. It uses polymer solutions to increase the viscosity of the displacing water thereby decreasing water/oil mobility ratio (Speight, 2013). The volumetric and displacement sweep efficiencies are positively affected by polymer flooding. The viscosity of the aqueous phase is increased due to the molecular size and structure of the polymer used. The main objective of this research was to study the ability of cornstarch (local polymer) to recover additional oil after conventional water flooding. The objective was successfully achieved by injecting four different unconsolidated samples (sand pack) with cornstarch solution at varying concentration of 500ppm, 1000ppm, 3000ppm, and 9000ppm. From the results of the experiment conducted, it was deduced that Cornstarch has the ability to recover an additional volume of oil about half the volume of oil recovered during conventional water flooding (i.e. if 50% of oil initially in place was recovered during water flooding, cornstarch can recover an additional 25% of the residual oil after water flooding). Also, higher concentrations of cornstarch reduce the recovery factor due to polymer adsorption on the rock surfaces which alters the rock wettability. To reduce the adsorption effect of Cornstarch, it is recommended that the concentration of Cornstarch be measured after the flooding experiments for a better understanding of the adsorption mechanism of cornstarch.