bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Molecular Methods (Pyrosequencing) for Evaluating MIC Potential in Water Systems for Oil Production in the North Sea
Authors: Mand Jaspreet , Jack Thomas R. , Voordouw Gerrit , Hoffmann Heike 
Published: June 2014

Abstract
The application of molecular methods, like pyrosequencing of 16S rRNA genes, has now accelerated to the point where identification of microbial communities involved in microbiologically influenced corrosion (MIC) may become routine. We have used this technology to characterize samples obtained from North Sea oil-producing platforms.
Pigging solids were collected from a pipeline that carried a high water content, had a low velocity and cooled rapidly (mesophilic growth conditions), causing high corrosion rates to be expected. A second set of samples was obtained from a platform subjected to produced water reinjection (PWRI). The samples included produced water and PWRI water, a mixture of produced water and seawater. Historically, both locations showed high sulfate-reducing bacteria (SRB) numbers and the system was deemed to be under corrosion threat.
Sulfate concentrations were 2600 ppm in the PWRI water and 170 ppm in produced water, suggesting that sulfate reduction occurred. The pigging solids were found to have high counts of SRB, identified by pyrosequencing to be mostly Desulfovibrio. However, high fractions (13–50%) of sulfur-reducing bacteria (SuRB), of the order Desulfuromonadales were also found. Pyrosequencing indicated that produced water also had more SuRB (48%) than SRB (18%). The PWRI water had a high fraction of the sulfide-oxidizing bacterium (SOB) Arcobacter (25%).
The data suggest that mixing of produced water and oxygenated seawater gives rise to chemical and microbial (Arcobacter) oxidation of sulfide to sulfur, which is then reduced to sulfide by the SuRB using oil organics as electron donor. The predominance of SOB and SuRB indicates that sulfur is prevalent in the system, which indicates that MIC may be involved in this environment. Application of molecular methods greatly facilitates the collection of this information and is thus an important tool in assessing MIC threat.
The Use of Computational Fluid Dynamics to Troubleshoot Excessive Metal Loss in a Carbon Steel Flowline: A Case History
Authors: Marinou Eugenia , de Souza Valdir , Djayapertapa Lesmana , Watson Ken , Moor Craig , Chalmers Frances 
Published: June 2014

Abstract
Greater Kittiwake Area (GKA) well KA-15, while not a significant oil producer anymore, provides large amounts of hot produced water which assists the field's first stage separation process. Historically, there have been numerous records of significant metal loss in the carbon steel flowline, especially at bends and welds, attributed to the line's convoluted configuration, flow rates and associated potential for erosion-corrosion effects.
This paper outlines the investigation process and corresponding findings. For fluid velocity calculations, computational fluid dynamics (CFD) was employed to allow highly accurate determination of the fluid velocity profile as well as the magnitude of localised wall shear stress. This was so as to assess the efficiency of the applied corrosion inhibitor and to provide a means of well management to avoid exceeding erosional velocities. In addition, a thorough review of the input parameters used for the corrosion inhibitor selection was performed; this revealed that erroneous inputs and inadequate testing were used for laboratory qualification of the chemical, with detrimental consequences for the flowline's integrity.
The study eventually concluded that the original material selection for the flowline was not appropriate for at least the current operating conditions and chemical testing was performed on unverified assumptions. This highlights the importance of using accurate methodology to validate inputs and that of periodic in-depth system reviews to ensure that new field parameters are re-evaluated correctly.
Experiences of Polymer Flooding Projects at Shengli Oilfield
Authors: Gao Chang Hong 
Published: June 2014

Abstract
Shengli oil field, located in Northeast China, is one of the largest and oldest oilfields in China. The field production peaked in 1991 and the overall water cut has reached 95% in 2012. The decline in production and the increasing demand for fossil energy have motivated the Shengli Oil Field Company (SLOF) to seek feasible enhanced oil recovery (EOR) methods. Since 1992, more than 60 units at Shengli field have received injection of polymer or a combination of polymer and low-concentration surfactants. Partially hydrolyzed polyacrylamide (HPAM) and petroleum sulfonate were chosen for most polymer flood projects. Field cases demonstrated that polymer flood and surfactant-polymer flood could effectively increase oil rate, decrease water cut and improve oil recovery.
This paper reviews several unique field trials at Shengli oil field. The earlier polymer flood projects targeted relatively ideal reservoirs with low temperature and low water salinity. However the undergoing polymer flood projects and future projects have to face very challenging reservoir conditions. Loss of polymer viscosity and reservoir heterogeneity affect the success of polymer flood projects. Future research at SLOF will focus on developing more tolerant polymers and improving the flow of polymer in reservoirs.
Laboratory Investigation of Miscible CO2 WAG Injection Efficiency in Carbonate
Authors: Duchenne Sebastien , Puyou Gilles , Cordelier Philippe , Bourgeois Marcel , Hamon Gerald 
Published: June 2014

Abstract
Remaining oil saturation, trapped gas saturation, three-phase relative permeability and injectivity are among the many parameters that play a major role in miscible CO2 water-alternating-gas (WAG) injection efficiency. In this work, we present a series of coreflood experiments designed to assess these parameters and investigate the microscopic efficiency of CO2 WAG injection on carbonated reservoirs, far above minimum miscibility pressure (MMP).
Experiments were carried out on intermediate-wet carbonate cores, initially saturated with light oil from a Middle East field, at reservoir conditions. Production was monitored at both reservoir and laboratory conditions providing material balance of each phase and separating the production of flashed oil, condensate and gas. A full compositional analysis was performed on produced volumes using gas chromatography (GC) and liquid analysis of flashed oil and condensate. Differential pressure across the core was also monitored for relative permeability estimation. Finally, a dual energy X-Ray scanner was used to measure three phase in-situ saturations, cross check material balance results and ensure that laboratory artifacts (end effects) do not influence interpretation conclusions. Coreflood data was complemented with PVT experiments including CO2-oil phase behavior characterization through multiple contact test (MCT) and supercritical fluid extraction (SFE).
CO2 WAG injections showed great performance with faster and better recovery than pure CO2 injection. After several cycles of WAG injections, high levels of differential pressure across the core were reached due to a reduction in both water and gas relative permeabilities with injection cycles.
Conformance Control Treatments for Water and Chemical Flooding: Material Screening and Design
Authors: Glasbergen Gerard , Abu-Shiekah Issa , Balushi Sameer , Wunnik John van 
Published: June 2014

Abstract
Heterogeneities in the reservoir can result in poor sweep efficiency during water and chemical floods. In many cases the sweep efficiency is improved significantly when changing to polymer flood. However, in the presence of very high conductive features polymer by itself may not be sufficient and result in undesired polymer production. Diversion of the flow to oil saturated regions and minimization of polymer production is then desired. In the presence of cross-flow the best option is placing a (chemical) plug deep in the reservoir. Adding a second component to the injection polymer stream that can react with the polymer to form a cross-linked gel is then an effective solution. However controlled placement and triggering of the reaction is very challenging.
In this paper we will present the results of static bulk measurements and dynamic core flooding experiments that were performed to identify cross-linked polymer systems. The polymers in the system are the typical high molecular weight partially hydrolyzed polyacrylamide (HPAM) polymers used in polymer flooding projects. The experimental work is focused on understanding and controlling the gelation time to enable proper placement and triggering at any given distance from the injectors. Parameters of investigation included temperature, brine composition, polymer concentration and rock mineralogy. The main parameters affecting the gelation process and possible failure mechanisms were identified. For given conditions, retardation of gelation time varying from few days up to several months could be designed. The learning from the experimental results can be used for improved material selection and design for other chemical and water flooding.
Conformance Control Treatments for Water and Chemical Flooding: Opportunity and Risk Evaluation
Authors: Abu-Shiekah Issa , Glasbergen Gerard , Balushi Sameer , Wunnik John van 
Published: June 2014

Abstract
The volumetric sweep efficiency is an essential factor in the success of any water flooding or EOR project. Volumetric sweep efficiency (VSE) is controlled by the local reservoir geological settings, well patterns and completion design and production and injection strategies.
In this paper we present a numerical modeling methodology to quantify VSE for different well patterns and geological settings independent of fluid types and saturation. The impact of conformance control techniques on VSE is estimated and the results translated to ultimate oil recovery for different driving mechanisms through standard analytical approximations. The methodology is used to evaluate the impact of conformance control techniques during water and polymer flooding for medium to high viscous oil reservoir. The results show that unselective blocking of high permeable layers during water flooding of high viscous oil reservoirs can be counterproductive and narrows the scope of potential chemical EOR opportunities. Polymer-(like) flooding wherever applicable is found to be in itself a very efficient conformance technique to increase the overall sweep efficiency for geological heterogeneities. In general abnormal high conductive features and long induced fractures tend to lower the efficiency of water or chemical flooding and cause excessive water/chemicals production to the surface facilities. Near wellbore mechanical treatments are then effective to minimize polymer production and increase oil production of which examples from ongoing polymer project will be discussed.
A New Modeling Approach to MEOR calibrated by Bacterial Growth and Metabolite Curves
Authors: Büeltemeier Hagen , Alkan Hakan , Amro Moh'd 
Published: June 2014

Abstract
Currently there is no commercial reservoir simulator used to model the growth phase of microbial enhanced oil recovery (MEOR), due to process complexity and significant dependency on laboratory data. One of the work packages of the project "MEOR Studies" being conducted by Wintershall is dealing with the modeling of MEOR to allow the reservoir simulation of the planned pilot. The reaction kinetics option of STARS/CMG is applied as analogy to Monod equation, which is usually used to model bacteria lifetime. One reaction is applied for bacteria growth and metabolite generation, mainly using the stoichiometric coefficients, whereas a second reaction is used to simulate decay of used substances. The parameters are calibrated by matching batch experiments measuring optical density (OD) of an enriched culture consisting of various strains isolated from one of the screened Wintershall fields.
All components of MEOR are modeled as tracer in water and/or oil phases. The EOR effects are modeled as function of the produced metabolites. Using this concept following primary MEOR effects are successfully modeled: reduction of oil viscosity by generated CO2, IFT reduction by bio-surfactant and increase in water viscosity by bio-polymer. Furthermore, the adsorption option of STARS is used for modeling the selective plugging effect created by biomass.
The validation of the new MEOR modeling approach is performed by using the results of sandpacks and coreflood experiments. In homogeneous sandpacks the additional 5–9 % oil of OOIP due to IFT reduction and rheology change in displacing phase was successfully modeled.
Chemical EOR in Low Permeability Reservoirs
Authors: Delamaide Eric , Tabary Rene , Rousseau David 
Published: June 2014

Abstract
Low permeability reservoirs contain a significant and growing portion of the world oil reserves, but their exploitation is often associated with poor recovery even after waterflood. Miscible or immiscible gas injection is usually the first choice in terms of EOR methods but it is not always feasible for instance due to lack of adequate supply. In such cases chemical EOR is often considered.
In this paper we propose to examine the specific challenges of chemical EOR in low permeability reservoirs by reviewing the well documented chemical EOR field operations that were implemented in reservoirs ranging from conventional low permeability (around 100 mD) to so-called tight reservoirs (few mD). Shale plays where permeability is in the µD range and which only produce when simulated by hydraulic fractures are not considered in our investigation.
We show that what works at the lab scale in low permeability plugs cannot be automatically transposed to the field scale. In particular low permeability can lead to injectivity issues and uncontrolled fracturing due to near wellbore plugging or simply to the high pressures required to propagate the injected chemical over large distances. Another challenging aspect of chemical EOR in low permeability reservoirs is the high chemical adsorption due to important surface to volume ratio and specific mineralogy, as in the case of carbonates (fractured or not). Success and failures of chemical EOR pilots in such challenging reservoirs, including innovative approaches such as wettability alteration, are reviewed.
Overall, this review will provide the reader with an updated view of past and on-going developments in chemical EOR applied to low permeability reservoirs. It should help operators determine whether a given low permeability reservoir is eligible to such processes or not.
A Novel Method to Model Low Salinity Water Injection in Carbonate Oil Reservoirs
Authors: Al-Shalabi Emad W. , Sepehrnoori Kamy , Delshad Mojdeh , Pope Gary 
Published: June 2014

Abstract
There are few low salinity water injection models proposed for carbonate rocks mainly because of incomplete understanding of complex chemical interactions between rock-oil-brine. This paper describes a new empirical method to model the low salinity water injection (LSWI) effect on oil recovery from carbonate rocks, based on the history matching and validation of recently published corefloods. In this model, the changes in water and oil relative permeability curves, as well as residual oil saturation, due to the LSWI effect are considered. The proposed model is implemented in the UTCHEM simulator to match and predict the multiple cycles of low salinity experiments. The screening criteria for using the proposed LSWI model are addressed in the paper. The developed model and the simulation results give more insight into the oil production potential of future waterflood projects using a modified water composition for injection.
Longitudinal Heterogeneity Effects in Alkaline Surfactant Polymer Flooding Enhanced Oil Recovery
Authors: Shahri Hamid Ghafram , Liu Keyu , Clennell M. B. , Liu Jishan , McKinley Allan 
Published: June 2014

Abstract
This paper describes experimental work to study the impact of longitudinal heterogeneity of porous medium (in terms of permeability) on the efficiency of ASP flooding that has been practiced in Enhance Oil Recovery (EOR). EOR becomes increasingly important as the globally proved crude oil reserves are being depleted. Chemical flooding is one of the tools to increase recovery; however, is still an active area for integrated research as it involves geochemistry, pore structure, microemulsion, fluid flow and chemical transport in porous media.
This present study is based on the use of carefully designed heterogeneous sand packs and monitors the effect of heterogeneity on the enhanced oil recovery by ASP slug. Oil recovery measurements were made based on mass measurements.
Results include the chemical profiles and its relation to EOR. The results indicate that longitudinal heterogeneities can impact EOR and the flooding of ASP slug from lower-to-higher permeability transition can mitigate the heterogeneity influence on EOR. In this experimental investigation, an enhancement of 5% (Original Oil in Place) was found when the ASP flood goes from lower-to-higher permeability transition as compared to that from higher-to-lower permeability transition. This finding can be of great importance to operators interested in implementing ASP floods.
Maximising Steam Project Value in South Oman through Flexible Development Phasing and Integrated Reservoir Surveillance
Authors: Al-Hinai S. M. , Tromp J. P. , Al Manahali M. O. , Belghache A. , Koning M. , Rabaani A. O. , Al-Adawi R. S. , Brissenden S. J. , Duggan T. , Alwazeer A. , Qi Chen Z. 
Published: June 2014

Abstract
EOR is key to the longer term business performance of Petroleum Development Oman (PDO). The "A" Steam Project in Southern Oman is a large scale EOR project currently being executed by PDO. It comprises the re-development of the "A" West Field, which has a significant prior cold oil development history, and the new development of the nearby "A" East Field.
The heavy viscous oil in both fields is contained in high net-to-gross braided river, aeolian and alluvial fan sandstones of the Cambrian Haima Group. Both fields were discovered in the 1970's. The "A" West Field has lower oil viscosity and was first produced in 1976. "A" East oil is significantly more viscous than "A" West oil and was believed to be too viscous to be produced by cold production, so "A" East Field was not developed. By 2008, after some 30 years of cold oil production, an estimated 18% of the STOIIP had been recovered from "A" West and the water cut steadily increased to 95%.
A field study was initiated in 2008 to evaluate re-development options based on EOR technologies. The selected Phase I (re-)development concept comprised a steam flood with fifty 10-acre / 7-spot patterns in "A" West and initial cyclic steam soak (CSS) with 74 wells on a regularly spaced 92 × 92 m grid in "A" East, with conversion later to a 8 acre / 9 spot steam flood. The two sub-surface developments were to be managed as an integrated project with shared surface facilities and operations. The project received FID for Phase I in 2009 and this is currently being executed. After the successful testing of cold production in selected new "A" East wells, a change to the Phase I FDP was implemented with the decision to cold produce the 32 most crestal wells prior to CSS in "A" East.
To de-risk the project, the more complex "A" West Field is being re-developed in a phased manner. Following field trials, initial CSS is now used to improve the gross rate of poorly performing producers, which constitutes a change to the FDP. To investigate the economic benefits of alternative patterns in areas of the field where steam flooding efficiency appears to be low, injection has recently started in two patterns which will become 10 acre / 10 spot trials. Additionally seven 3.3 acre / 7 spot trial patterns are being drilled on the western edge of the 10 acre / 7 spot development area.
Advanced time-lapse surveillance data acquisition techniques – DTS, DAS 3DVSP and HT optical pressure gauges - are deployed to support WRM optimization of the Phase I development, and to prepare the Phase II field (re-)development plan for the down-flank areas.
Implementation of Enhanced oil Recovery Techniques in India: New Challenges and Technologies
Authors: Baskaran Vijai Kumar , Dani Kamal Chandra , Kumar Krishna Pavan , Urkude Ashish Manohar 
Published: June 2014

Abstract
India's crude oil reserves tend to be light and sweet, with specific gravity varying from 38° API in the offshore Mumbai High field to 32° API at other onshore basins. India produced roughly 880 thousand barrels per day (bbl/d) of total oil in 2009 from over 3,600 operating oil wells. Enhanced oil recovery (EOR) is a term applied to methods used for recovering oil from a petroleum reservoir beyond that recoverable by primary and secondary methods. Primary recovery normally refers to the production using the energy inherent in the reservoir from gas under pressure or a natural water drive. Secondary recovery refers to usually refers to injection of water or water flooding thus, enhance oil recovery is often synonymous with tertiary recovery. Four group of methods –thermal recovery, gas miscible recovery, chemical flooding and microbial flooding are included in this collection. Implemented EOR techniques in India include alkaline surfactant flooding (ASF) in Jhalora-Rajasthan, Kalol-Gujarat, and Ankleshwar-Gujarat, immiscible hydrocarbon water alternating gas injection (HC-WAG) in Gandhar fields- South Gujarat, in-situ combustion/air Injection and simultaneous water and gas injection (SWAG) in Mumbai High. Some of the EOR pilots on anvil are immiscible CO2, microbial in-situ stimulation, and paraffin control microbes in western onshore regions of India. The planned techniques include air injection in light oil in western offshore, immiscible flue gas in western onshore and immiscible CO2 in eastern onshore. The Indian government and other oil E&P organizations expects this geographical dependence to rise in light of limited prospects for domestic production and hence, interested in Enhanced oil recovery techniques.