Investigation on the Impact of an Enhanced Oil Recovery Polymer towards Microbial Growth and Microbial Induced Corrosion Rates

Some of the enhanced oil recovery (EOR) techniques involve injection of polymer brine in the formation. Addition of polymer increases the viscosity causing improved sweep efficiency owing to favorable mobility factor. Microbial induced corrosion (MIC) is caused by growth of certain bacterial species in the pipeline system and the reservoir. There is possibility of MIC to occur along the water injection schemes. Sea water is considered bereft of nutrients not allowing much bacterial activity but some sessile consortia may grow on internal line surface and cause corrosion. When the sea water is injected into the formation some anaerobic consortia dominated by sulfate reducing bacteria (SRB) grow in the formation. These bacteria use oxygen present in sulfate for respiration and volatile fatty acids (VFAs) as carbon source. But after some time of water injection the formation may get depleted of VFAs thwarting bacterial growth. This study was taken up to understand impact of EOR polymer on growth of bacterial consortium. A bacterial consortia labelled as consortia II from ATCC which is tough oilfield bacteria consortia was allowed to grow with VFA (lactate or acetate), in absence of VFA and in presence of 1000 ppm of HPAM polymer. Planktonic and sessile counts were monitored over 40 days period. Results from this study showed, microbes utilized the polymer as their secondary nutrient, whenever their preferred nutrient was depleted or insufficient. SRB sessile count which was 102 cells/cm2 in nutrient depleted medium picked up a value of 106 cells/cm2 in presence of polymer. It was observed that the bacteria first utilize the available VFA source, after that a period of lull for about 5 days followed before the growth being picked up.

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Horizontal Versus Vertical Wells: Assessment of Sweep Efficiency in a Multi-Layered Reservoir Based on Consecutive Inter-Well Tracer Tests - A Comparison Between Water Injection and Polymer EOR

10.2118/205211-ms ◽

2021 ◽

Author(s):

Bogdan-George Davidescu ◽

Mathias Bayerl ◽

Christoph Puls ◽

Torsten Clemens

Keyword(s):

Enhanced Oil Recovery ◽

Oil Recovery ◽

Tracer Tests ◽

Horizontal Wells ◽

Operating Conditions ◽

Sweep Efficiency ◽

Flow Paths ◽

Full Field ◽

Polymer Injection ◽

The Impact

Abstract Enhanced Oil Recovery pilot testing aims at reducing uncertainty ranges for parameters and determining operating conditions which improve the economics of full-field deployment. In the 8.TH and 9.TH reservoirs of the Matzen field, different well configurations were tested, vertical versus horizontal injection and production wells. The use of vertical or horizontal wells depends on costs and reservoir performance which is challenging to assess. Water cut, polymer back-production and pressures are used to understand reservoir behaviour and incremental oil production, however, these data do not reveal insights about changes in reservoir connectivity owing to polymer injection. Here, we used consecutive tracer tests prior and during polymer injection as well as water composition to elucidate the impact of various well configurations on sweep efficiency improvements. The results show that vertical well configuration for polymer injection and production leads to substantial acceleration along flow paths but less swept volume. Polymer injection does not only change the flow paths as can be seen from the different allocation factors before and after polymer injection but also the connected flow paths as indicated by a change in the skewness of the breakthrough tracer curves. For horizontal wells, the data shows that in addition to acceleration, the connected pore volume after polymer injection is substantially increased. This indicates that the sweep efficiency is improved for horizontal well configurations after polymer injection. The methodology leads to a quantitative assessment of the reservoir effects using different well configurations. These effects depend on the reservoir architecture impacting the changes in sweep efficiency by polymer injection. Consecutive tracer tests are an important source of information to determine which well configuration to be used in full-field implementation of polymer Enhanced Oil Recovery.

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Synergy of Polymer for Mobility Control and Surfactant for Interface Elasticity Increase in Improved Oil Recovery

10.2118/206164-ms ◽

2021 ◽

Author(s):

Taniya Kar ◽

Abbas Firoozabadi

Keyword(s):

Oil Recovery ◽

Sea Water ◽

Synergistic Effects ◽

Water Injection ◽

Mobility Control ◽

Residual Oil ◽

Sweep Efficiency ◽

Improved Oil Recovery ◽

Low Salinity ◽

Low Salinity Waterflooding

Abstract Improved oil recovery in carbonate rocks through modified injection brine has been investigated extensively in recent years. Examples include low salinity waterflooding and surfactant injection for the purpose of residual oil reduction. Polymer addition to injection water for improvement of sweep efficiency enjoys field success. The effect of low salinity waterflooding is often marginal and it may even decrease recovery compared to seawater flooding. Polymer and surfactant injection are often effective (except at very high salinities and temperatures) but concentrations in the range of 5000 to 10000 ppm may make the processes expensive. We have recently suggested the idea of ultra-low concentration of surfactants at 100 ppm to decrease residual oil saturation from increased brine-oil interfacial elasticity. In this work, we investigate the synergistic effects of polymer injection for sweep efficiency and the surfactant for interfacial elasticity modification. The combined formulation achieves both sweep efficiency and residual oil reduction. A series of coreflood tests is performed on a carbonate rock using three crude oils and various injection brines: seawater and formation water with added surfactant and polymer. Both the surfactant and polymer are found to improve recovery at breakthrough via increase in oil-brine interfacial elasticity and injection brine viscosification, respectively. The synergy of surfactant and polymer mixed with seawater leads to higher viscosity and higher oil recovery. The overall oil recovery is found to be a strong function of oil-brine interfacial viscoelasticity with and without the surfactant and polymer in sea water and connate water injection.

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Experimental Studies of Immiscible High-Nitrogen Natural Gas WAG Injection Efficiency in Mixed-Wet Carbonate Reservoir

Energies ◽

10.3390/en13092346 ◽

2020 ◽

Vol 13 (9) ◽

pp. 2346

Author(s):

Mirosław Wojnicki ◽

Jan Lubaś ◽

Marcin Warnecki ◽

Jerzy Kuśnierczyk ◽

Sławomir Szuflita

Keyword(s):

Natural Gas ◽

Enhanced Oil Recovery ◽

Oil Recovery ◽

Gas Injection ◽

Water Injection ◽

Experimental Studies ◽

Carbonate Reservoir ◽

High Nitrogen ◽

The Impact ◽

Wag Injection

Crucial oil reservoirs are located in naturally fractured carbonate formations and are currently reaching a mature phase of production. Hence, a cost-effective enhanced oil recovery (EOR) method is needed to achieve a satisfactory recovery factor. The paper focuses on an experimental investigation of the efficiency of water alternating sour and high-nitrogen (~85% N2) natural gas injection (WAG) in mixed-wetted carbonates that are crucial reservoir rocks for Polish oil fields. The foam-assisted water alternating gas method (FAWAG) was also tested. Both were compared with continuous water injection (CWI) and continuous gas injection (CGI). A series of coreflooding experiments were conducted within reservoir conditions (T = 126 ℃, P = 270 bar) on composite cores, and each consisted of four reservoir dolomite core plugs and was saturated with the original reservoir fluids. In turn, some of the experiments were conducted on artificially fractured cores to evaluate the impact of fractures on recovery efficiency. The performance evaluation of the tested methods was carried out by comparing oil recoveries from non-fractured composite cores, as well as fractured. In the case of non-fractured cores, the WAG injection outperformed continuous gas injection (CGI) and continuous water injection (CWI). As expected, the presence of fractures significantly reduced performance of WAG, CGI and CWI injection modes. In contrast, with regard to FAWAG, deployment of foam flow in the presence of fractures remarkably enhanced oil recovery, which confirms the possibility of using the FAWAG method in situations of premature gas breakthrough. The positive results encourage us to continue the research of the potential uses of this high-nitrogen natural gas in EOR, especially in the view of the utilization of gas reservoirs with advantageous location, high reserves and reservoir energy.

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Improvement of oil field development using enhanced oil recovery methods

Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu ◽

10.33271/nvngu/2021-6/023 ◽

2021 ◽

pp. 23-28

Author(s):

G Moldabayeva ◽

R Suleimenova ◽

N Buktukov ◽

M Mergenov

Keyword(s):

Enhanced Oil Recovery ◽

Oil Recovery ◽

Water Injection ◽

Oil Field ◽

Water Soluble ◽

Sweep Efficiency ◽

Conformance Control ◽

Water Soluble Polymer ◽

Field Development ◽

Water Cut

Purpose. To develop a technology to increase the oil recovery of formations using injection of polymer compositions. Methodology. For this study, practical methods were used such as enhanced oil recovery using stimulating technologies, technology using polymer systems based on a water-soluble polymer acrylamide, and emulsion-polymer technology. To achieve the conformance control, which was a prerequisite for testing, a thorough selection of wells was carried out, as well as an analysis of their hydrodynamic connection. Findings. As a result of using the method for limiting water inflows in the development of oil-bearing formations, redistribution of filtration channels, and a decrease in the production of fossil water as well as stabilisation of water cut were achieved. Originality. The scientific novelty of the study is the withdrawal of wells that are able to redistribute the volume of water injection at perforation intervals. Increased sweep efficiency and pressure at the wellhead at the beginning and at the end of the conformance control indicate a decrease in the conductivity of high-permeability formation intervals. Practical value. Application of the proposed technology for limiting water inflows will make it possible to develop low-permeability interlayers with filtration flows. The wells brought to a stable production rate during the study will ensure a decrease in formation water production and the water cut of the produced products, as well as stabilisation of the water cut over a certain period.

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Research progress of viscoelastic surfactants for enhanced oil recovery

Energy Exploration & Exploitation ◽

10.1177/0144598720980209 ◽

2021 ◽

pp. 014459872098020

Author(s):

Ruizhi Hu ◽

Shanfa Tang ◽

Musa Mpelwa ◽

Zhaowen Jiang ◽

Shuyun Feng

Keyword(s):

Enhanced Oil Recovery ◽

Oil Recovery ◽

High Efficiency ◽

Research Progress ◽

Surfactant Flooding ◽

Sweep Efficiency ◽

The World ◽

Washing Efficiency ◽

Viscoelastic Surfactants ◽

Viscoelastic Surfactant

Although new energy has been widely used in our lives, oil is still one of the main energy sources in the world. After the application of traditional oil recovery methods, there are still a large number of oil layers that have not been exploited, and there is still a need to further increase oil recovery to meet the urgent need for oil in the world economic development. Chemically enhanced oil recovery (CEOR) is considered to be a kind of effective enhanced oil recovery technology, which has achieved good results in the field, but these technologies cannot simultaneously effectively improve oil sweep efficiency, oil washing efficiency, good injectability, and reservoir environment adaptability. Viscoelastic surfactants (VES) have unique micelle structure and aggregation behavior, high efficiency in reducing the interfacial tension of oil and water, and the most important and unique viscoelasticity, etc., which has attracted the attention of academics and field experts and introduced into the technical research of enhanced oil recovery. In this paper, the mechanism and research status of viscoelastic surfactant flooding are discussed in detail and focused, and the results of viscoelastic surfactant flooding experiments under different conditions are summarized. Finally, the problems to be solved by viscoelastic surfactant flooding are introduced, and the countermeasures to solve the problems are put forward. This overview presents extensive information about viscoelastic surfactant flooding used for EOR, and is intended to help researchers and professionals in this field understand the current situation.

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Carbonated Water Injection for Recovery of Oil and Wettability Analysis

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.695.499 ◽

2014 ◽

Vol 695 ◽

pp. 499-502 ◽

Cited By ~ 3

Author(s):

Mohamad Faizul Mat Ali ◽

Radzuan Junin ◽

Nor Hidayah Md Aziz ◽

Adibah Salleh

Keyword(s):

Oil Recovery ◽

Oil And Gas ◽

Promising Result ◽

Water Injection ◽

High Mobility ◽

Wettability Alteration ◽

Sweep Efficiency ◽

Gas Flooding ◽

Carbonated Water Injection ◽

Carbonated Water

Malaysia oilfield especially in Malay basin has currently show sign of maturity phase which involving high water-cut and also pressure declining. In recent event, Malaysia through Petroliam Nasional Berhad (PETRONAS) will be first implemented an enhanced oil recovery (EOR) project at the Tapis oilfield and is scheduled to start operations in 2014. In this project, techniques utilizing water-alternating-gas (WAG) injection which is a type of gas flooding method in EOR are expected to improve oil recovery to the field. However, application of gas flooding in EOR process has a few flaws which including poor sweep efficiency due to high mobility ratio of oil and gas that promotes an early breakthrough. Therefore, a concept of carbonated water injection (CWI) in which utilizing CO2, has ability to dissolve in water prior to injection was applied. This study is carried out to assess the suitability of CWI to be implemented in improving oil recovery in simulated sandstone reservoir. A series of displacement test to investigate the range of recovery improvement at different CO2 concentrations was carried out with different recovery mode stages. Wettability alteration properties of CWI also become one of the focuses of the study. The outcome of this study has shown a promising result in recovered residual oil by alternating the wettability characteristic of porous media becomes more water-wet.

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Understanding the Enhanced Oil Recovery Performance of Low Salinity Water Injection: Which Mechanism is Predominant?

10.3997/2214-4609.202113065 ◽

2021 ◽

Author(s):

K. Hassani ◽

A. Saeibehrouzi ◽

B. Rostami ◽

A. Fathollahi

Keyword(s):

Enhanced Oil Recovery ◽

Oil Recovery ◽

Water Injection ◽

Low Salinity ◽

Low Salinity Water ◽

Salinity Water ◽

Recovery Performance ◽

Low Salinity Water Injection

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Modeling to support physicochemical enhancement techniques

Oil and Gas Studies ◽

10.31660/0445-0108-2021-3-79-90 ◽

2021 ◽

pp. 79-90

Author(s):

Т. A. Pospelova

Keyword(s):

Enhanced Oil Recovery ◽

Oil Recovery ◽

Oil And Gas ◽

Chemical Modeling ◽

Comparative Structure ◽

Water Cut ◽

Physical And Chemical ◽

Oil And Gas Companies ◽

The Impact ◽

Selection Of

The article discusses ways to increase the oil recovery factor in already developed fields, special attention is paid to the methods of enhanced oil recovery. The comparative structure of oil production in Russia in the medium term is given. The experience of oil and gas companies in the application of enhanced oil recovery in the fields is analyzed and the dynamics of the growth in the use of various enhanced oil recovery in Russia is estimated. With an increase in the number of operations in the fields, the requirements for the selection of candidates inevitably increase, therefore, the work focuses on hydrodynamic modeling of physical and chemical modeling, highlights the features and disadvantages of existing simulators. The main dependences for adequate modeling during polymer flooding are given. The calculation with different concentration of polymer solution is presented, which significantly affects the water cut and further reduction of operating costs for the preparation of the produced fluid. The possibility of creating a specialized hydrodynamic simulator for low-volume chemical enhanced oil recovery is considered, since mainly simulators are applicable for chemical waterflooding and the impact is on the formation as a whole.

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