Systematic Study of Low-Cost, High-Performance Chemical Flooding as EOR for Depleted Oilfields of the Upper Assam Basin

Content Provider	Scilit
Author	Kakoty, Miranda Gogoi, Subrata Borgohain
Copyright Year	2020
Description	Book Name: Advances in Petroleum Technology
Abstract	In this chapter, we present a systematic laboratory study with the aim to develop an alkali-surfactant (AS) enhanced oil recovery (EOR) slug for a depleted oilfield of Barail formation of Upper Assam. A series of experiments such as interfacial tension (IFT), aqueous stability, foam stability and thermal stability have been carried out to optimise the AS formulation. Depending on the anionic nature of most reservoirs of Upper Assam, a natural surfactant, black liquor (BL), and synthetic surfactants sodium dodecyl sulphate ( SDS ), sodium dodecyl benzene sulphonate ( SDBS ) and alpha olefin sulphonate ( AOS ) were screened. A surfactant at its critical micelle concentration (CMC) was mixed with alkalis: $Na_{2}CO_{3}$ and $NaHCO_{3}$ and corresponding CMC values at the lowest IFT were recorded. IFT experiments conducted separately with formation water (FW; containing $K^{+}$, $Ca^{2+}$, $Mg^{2+}$ ) and with laboratory-prepared brine 104(containing $Na^{+}$ only) established that IFT values are lower with FW than with the latter. This study conducted in the temperature range from 30°C to 90°C showed that temperature does not appear to have a significant effect on the IFT. On the basis of IFT-reducing capabilities, a slug comprising BL, AOS, SDBS and $Na_{2}CO_{3}$ was selected for the EOR application in the depleted oilfield under study. Thermal stability tests revealed that both the surfactant system and the alkali did not undergo any thermal degradation upto 90 days. The best chemical formulation was validated in core-flooding experiments. The AS formulation thus developed in the laboratory could lower the oil water IFT to the range $10^{−2}–10^{−3}$ mN/m, and the components were very much compatible with each other at reservoir temperature. The thermal stability study also produced expected results. The results of the core-flooding experiments were encouraging as 50%–76% additional recovery has been achieved.
Related Links	https://content.taylorfrancis.com/books/download?dac=C2020-0-13339-3&isbn=9781003049937&doi=10.1201/9781003049937-6&format=pdf
Ending Page	119
Page Count	17
Starting Page	103
DOI	10.1201/9781003049937-6
Language	English
Publisher	Informa UK Limited
Publisher Date	2020-10-09
Access Restriction	Open
Subject Keyword	Book Name: Advances in Petroleum Technology Petroleum Engineering Surfactant Sodium Reservoirs Alkali Depleted Oilfield
Content Type	Text
Resource Type	Chapter