Chemical Enhanced Oil Recovery (original) (raw)

Enhanced Oil Recovery: Chemical Flooding

Geophysics and Ocean Waves Studies, 2021

The enhanced oil recovery phase of oil reservoirs production usually comes after the water/gas injection (secondary recovery) phase. The main objective of EOR application is to mobilize the remaining oil through enhancing the oil displacement and volumetric sweep efficiency. The oil displacement efficiency enhances by reducing the oil viscosity and/or by reducing the interfacial tension, while the volumetric sweep efficiency improves by developing a favorable mobility ratio between the displacing fluid and the remaining oil. It is important to identify remaining oil and the production mechanisms that are necessary to improve oil recovery prior to implementing an EOR phase. Chemical enhanced oil recovery is one of the major EOR methods that reduces the residual oil saturation by lowering water-oil interfacial tension (surfactant/alkaline) and increases the volumetric sweep efficiency by reducing the water-oil mobility ratio (polymer). In this chapter, the basic mechanisms of differen...

Polymer Flooding for Improving Oil Recovery

Several methods to enhance oil recovery are encouraging in Indonesia as well as in the world today. In compliance with this, research in the area of enhanced oil recovery (EOR) is still carried out by many examiners. One of the research areas is exploitation of chemicals for seeking the enhancement of oil recovery. Some chemicals have been found for Enhanced Oil Recovery processes. However, in order to determine chemicals used in this experiment, some aspect have been set as follows: it is easily found in Indonesia, it can be produced inexpensively, it has high recoverability and it is not petroleum base. The goal of this research is to investigate the effect of polimer found in the market and developed in the laboratory such as Poly Vynil Alcohol (PVA) and Partially Hydrolyzed Polyacrylamide (HPAM) polymer on the oil recovery which can be used to optimize recovery and minimize residual oil in the reservoir by: lowering the oil / water interfacial tension and improving mobility ratio. The effectiveness of chemicals was tested through micro displacement using artificial reservoir as porous medium. The procedure of operation is as follows: initially the reservoir model was filled with brine until it was 100 % saturated. Then to represent oil migration, oil was injected into the medium until minimum water saturation (S wc) of about 30 % is reached. After this, the medium was flooded by the same brine until minimum oil saturation, S or, was reached, which was about 10 %. The oil remaining in the reservoir model after this water flood was then subjected to the injection of various chemicals for additional oil recovery. A set of mathematical model of oil displacement from porous media using water and polymer flooding has also been developed, based on fundamental theories of two phase flow. Since the model includes the material balance of the water and polymer, the concentration of the polymer at any position and time can be predicted. The oil displacement experiments show that as much as 20 % to 60 % of remaining oil can be recovered by flooding it with the chemical developed in the laboratory. The results also show the oil recovery depends on chemical, chemical concentration, pressure and temperature in the model reservoir, and crude oil. It turns that the mathematical models proposed were in a good agreement with the experimental data.

Chemical flood enhanced oil recovery: a review

Chemical flooding has been found to be one of the major EOR techniques especially for reservoirs where thermal methods are not feasible. The application of chemical flooding is strongly influenced by the current economics, type of reserve oil and crude oil price. In this paper, an up to date status of chemical flooding at the laboratory scale, pilot projects and field applications have been reported. The basic mechanisms of different chemical methods have been discussed including the interactions of different chemicals with the reservoir rocks and fluids. The average recovery of oil after the conventional water flooding is highly encouraging particularly when the demand and price of crude oil is increasing day by day.

Comparative studies on enhanced oil recovery by alkali–surfactant and polymer flooding

Journal of Petroleum Exploration and Production Technology, 2012

Chemical flooding methods are now getting importance in enhanced oil recovery to recover the trapped oil after conventional recovery. In the present study, a comprehensive study has been carried out on alkali, surfactant and polymer flooding. The chemicals with different compositions and combinations were used to recover the oil after conventional water flooding. It has been observed that increase in concentration of alkali, surfactant and polymer increases the additional recovery, but beyond a certain limit, the increase in recovery is only marginal. A series of flooding experiments using the combination of the above methods have been performed with additional recoveries more than 25 %. An analysis has been made on the relative cost of the different chemical slugs injected and the corresponding additional oil recovery. Based on the analysis, an optimum composition of the alkali-surfactant-polymer system has been recommended.

Various Techniques for Enhanced Oil Recovery: A review

Iraqi Journal of Oil and Gas Research (IJOGR)

Crude oil can be extracted from the reservoirs by three mechanisms with different amounts of oil depending on the natural conditions of the reservoir. When the reservoir has an enough pressure, the amount of the produced oil is about 20% to 30% through primary recovery mechanism, and this amount can extend up to about 40% using secondary recovery. Because of the massive amount of the oil left behind the two mechanisms, enhanced oil recovery technique (EOR), the third mechanism, is designed to reduce the residual oil, in which, up to 70% of original oil in place can be recovered. Almost 3.0 trillion cubic meter of light oil and 8.0 trillion cubic meter of unconventional oil will be left underground after primary and secondary stages. Therefore, EOR techniques are applied to improve the oil production and extract much of the oil left in the reservoirs. Economics and technology have to be taken into account to choose the appropriate method in the recovery processes. Mainly, this study discusses various EOR techniques used in the enhancement of the oil recovery, including miscible, immiscible, polymer, surfactants, surfactants-polymer flooding as well as thermal methods.

Simulation Study of Enhanced Oil Recovery by Alkaline Flooding in a Mature Oil Field

International Journal of Petroleum and Petrochemical Engineering, 2017

Oil recovery is divided into three stages depending on the producing life of the reservoir. Primary recovery is the first stage where the natural drive of the reservoir is used for recovery and no external mechanisms are introduced into the reservoir. Primary recovery includes different mechanisms such asexpansion of rock and fluid, solution gas drive, water influx from aquifer, gas cap drive, gravity drainage. Secondary oil recovery is done through the injection of external fluid which is water. This method is done mainly to maintain the pressure but at the same time increase the volumetric sweep efficiency(Sheng, 2011). In an oil field with several wells, when the water is pumped alternatively into wells, it is able to either maintain the reservoir pressure or even increase it(Syed Ata Abbas Naqvi, 2012). Tertiary oil recovery is also known as enhanced oil recovery (EOR) where chemicals, gases and thermal energy are injected into the reservoir. EOR is defined as any reservoir process that changes the already existing reservoir rock/oil/brine interactions. It is the injection of fluids other than water or brine into the reservoir(Sheng, 2011). The EOR method of alkaline flooding is a process where chemicals such as sodium hydroxide (NaOH), Sodium Orthosilicate (Na 4 SiO 4) or sodium carbonate, Na 2 CO 3 is injected into the reservoir together with water. The acid in the oil reacts with the alkaline that is injected to form surfactants which then undergoes adsorption that promotes the reduction of interfacial tension (IFT) of oil and water(Abadli, 2012). Besides that, the adsorption also elevates the pH value of the injected fluid. Consequently, this leads to the mobilisation of the trapped residual oils in the reservoir sand(Syed Ata Abbas Naqvi, 2012). EOR is dependent on several reservoir conditions such as, characteristics of reservoir, depth, salinity and pH.

The Efficiency of Polymer Flooding for Oil Recovery

International Journal of Advance Research and Innovative Ideas in Education, 2019

The world keeps on depending intensely on oil for essential vitality. As the extraction of oil turns out to be additionally testing, new systems are set up to build the measure of oil removed. Polymers assume significant job in the Enhanced Oil Recovery; they help remove up to 30% of the first oil set up. Polymers help increment the thickness of the uprooting fluid (water) to drive the dislodged fluid (oil) to the generation well. An assortment of polymers is utilized in various oil fields relying upon working states of that field. Before the correct polymer is picked, a cautious investigation ought to be directed to guarantee that the polymer is powerful amid a broad timeframe. Warm and compound flooding are great choices to recuperate overwhelming oil. Polymer flooding technique is a standout amongst the most essential upgraded oil recuperation (EOR) systems which improve the portability proportion of water and oil. Polymers containing mixes of long chain, for example, polyacrylam...

Formulation of a combined low saline water and polymer flooding for enhanced oil recovery

International journal of ambient energy, 2019

The study aims in formulating a new Enhanced Oil Recovery (EOR) slug comprising of a synthetic polymer, which is Polyacrylamide (PAM) and a biopolymer, which is Xanthan Gum (XG). In this case the EOR will be named XPS, where low saline water flooding was assisted by PAM and XG. The polymer flooding application in depleted oil fields of Upper Assam Basin has faced a number of challenges, as it was unable to enhance the viscosity of the displacing fluid and reduce the effective permeability of the displacing fluid, which led to the failure of the macroscopic sweep efficiency (ES) of the reservoir. The rheological properties were found to be Non-Newtonian mostly shear thinning and followed the Herschel-Bulkley (HB) and Ostwald de Waele power law (OWP) models. The appropriate slugs were further flooded in a core flooding. Low saline water flooding followed by polymer flooding increases the overall recovery efficiency. Keywords XPS,Core Flood, Low saline water flood 1. Introduction The oil recoveries at the end of primary and secondary recovery processes are generally in the range of 20-40% of the original oil in place (OOIP) (Gogoi, 2008, 2009). Work on chemical EOR specially polymer, surfactant flooding, alkali surfactant polymer flooding, micellar alkali polymer flooding showed oil recovery from the depleted oil fields of Upper