Detection and Reuse of the Produced Chemicals in Alkaline-Surfactant-Polymer Floods

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractAlkaline-Surfactant-Polymer (ASP) flood processes have been increasingly applied in the oil fields due to their high ultimate oil recovery. However, a major technical challenge is how to significantly reduce the amount and the cost of chemicals used such that ASP floods can become cost-effective as well. On the other hand, field applications show that the concentrations of alkali, surfactant and polymer remain relatively high in the produced fluids of ASP floods. Thus, successful detection and reuse of these chemicals can substantially reduce the capital cost and the environmental impact. In this paper, several methods are applied to detect each chemical and quantify its concentration in the produced fluids. Also re-injection of the produced chemicals is conducted for further enhancing oil recovery. More specifically, first, the total interactions of each chemical with the oil-brine-rock system are studied. With the developed detection techniques for each individual chemical used in ASP floods, the total loss of each chemical is measured. The chemical loss is caused by its chemical reactions with the crude oil and the reservoir brine, as well as its adsorption onto the rock surface. Secondly, coreflood tests are performed for alkaline floods, surfactant floods, alkalinesurfactant (AS) floods, and ASP floods to determine their respective tertiary oil recovery. Hence, a better understanding of how each chemical contributes to enhanced oil recovery (EOR) is achieved. Thirdly, typical chemical concentrations in the produced fluids are measured and compared with those in the injected slugs so as to determine the potential of reusing these chemicals in practice. The follow-up coreflood tests of reusing these produced chemicals are carried out by directly re-injecting the produced fluids. The test results show that the produced chemicals can still effectively enhance oil recovery by up to 19.7%. It is anticipated that the detection and reuse techniques studied in this work should facilitate the design, optimization and implementation of ASP flood projects.

The Economic Evaluation of the Efficiency of the ASP Chemical Flooding in DERO Field

“… Additional quantity of produced oil added to the quantity of oil produced from the pilot though water flooding is: 71211.5m 3…”

“…This operation can be applied with an increase in the cost of producing one barrel ranges between (1.6-3.5 $/bb). Moreover, researchers Gu and Wang [3], through their experiments, showed that concentrations of polymers, surfactants, and alkaline remain high in the produced fluids when ASP method is applied, therefore, the successful study of these chemicals can dramatically reduce cost of this operation. Also, In a pilot experiment on injecting ASP solution in Daqing oil field, researchers Ang and Huabin [4] evaluated performance of the experiments by achieving the following results: Average of oil production increased in the experiment area from (36.7m3/day) to (91.5 m3/day), while percent of the produced oil decreased from (82.7%) to (59.7%).…”

Effect of ASP Chemical Flooding Efficiency On Displacement Factor and Water Percentage After Exhaustion of Water Flooding Efficiency in DERO Field

“…Thus, ASP can have reduced the cost of the operation, and any loss is due to the adsorption or chemical reaction with the oil. [8] According to Huabin& Shutang, the daily production rate of oil increased from 36.7 m3/day to 91.5 m3/day during a pilot test using ASP in Daqig field, while the water cut decrease from 82.7% to 59.7%. in addition, the daily production rate increased from 3.7 m3/day to 27.1 m3/day in the well surrounded by injectors (5-Spot)and water cut decrease from 87.9% to 45.8% .…”

A Mechanistic Integrated Geochemical and Chemical Flooding Tool for Alkaline/Surfactant/Polymer Floods

“…On the other hand, sufficiently high amount of alkaline should be injected to compensate the consumption of alkaline by the acidic component; divalent ions in the aqueous; and ion-exchange. Including the alkaline in the SP process makes the process cost-efficient not only through generating the soap but also the injected alkali can significantly decrease the surfactant (Wanchao et al, 1995;Al-Hashim et al, 1996;Wang and Gu, 2003;Hirasaki et al, 2004;Liu et al, 2008;Liu, 2008;Mohan, 2009;Sheng, 2013) and polymer (Wanchao et al, 1995) adsorptions to the rock, alter the wettability of the rock (Wyatt et al, 2002;Wang and Gu, 2003;Liu, 2008;Sundstrom, 2011;Sheng, 2013;Fortenberry et al, 2013), and accelerate the equilibrium time, shortening the coalesce time (Jackson, 2006). The dilemma involved in the AP process makes the process impractical most of the times.…”