bluuebunny/crossref_metadata_2025_split huggingface dataset:
Feasibility for the Application of In Situ Combustion in Faja Petrolifera del Orinoco (FPO) Based in a Novel Screening Criteria for the Technology
Authors: Hincapie Rafael , Tovar Francisco , Alvarez Carlos 
Published: July 2011

Abstract
Faja Petrolifera del Orinoco (F.P.O) is by far the largest known heavy and extra heavy oil accumulation worldwide, located at north of Orinoco river in Venezuela contains about 1300 MMMBN of OOIP and 297 MMMBN of recoverable reserves. Exploitation of FPO has been done until present mainly by cold production, reaching recovery factors, is best cases, of about 10% of OOIP. PDVSA in recent years has conducted studies of quantification and certification of reserves, based on recovery factors that consider EOR projects. In situ combustion, the older member of thermal oil recovery family, is a method with a high thermodynamic efficiency that has allowed reaching recovery factors over 50% in some fields, accomplishing technical and economical success. This work presents a state of the art of combustion process and a review of the reservoir characteristics and field performance of successful applications in Venezuela and the rest of the world. These data were used to establish an application window, without weighting the size or significance of the reservoirs. This window, combined with data from reservoir characterization for the first six blocks of the FPO Junín area, was used to visualize the most prospective areas for the application of the process using parameters of thickness and water saturation in a commercial reservoir characterization software, followed by a qualitative evaluation of pressure, viscosity, temperature and depth, calculating this way the volume of oil and associated areal space occupied. Results obtained define Junín Blocks 5 and 6, specifically in areas of Basal Sands and Oligocene as the ones with the most potential, therefore, detailed studies should be performed to assess the technical and economical feasibility of the process implementation in these areas.
Experimental and Numerical Simulation Study on Single Layer Injectivity for CO2 Flooding in Low Permeability Oil Reservoir
Authors: Hongwei Yu , Xinmin Song , Siyu Yang , Dingfeng Chen 
Published: July 2011

Abstract
Supercritical carbon dioxide can keep miscible with crude oil, and eliminating the two-face interface existed in conventional water and gas flooding. The displacement efficiency in laboratory experiment is nearly 100%, so it has the potential to increase oil recovery significantly. However, in practical application of CO2 miscible flooding, severe disaccord appears with injection time increasing between the single layer’s injectivity and its physical property because of many influencing factors, the injection ratio of high permeable layers increases, and the injection ratio of low permeable layers decreases, the injectivity of single layers is unbalanced seriously, so the CO2 swept volume will be influenced, finally leading to the poor EOR result. According to the laboratory experiment of parallel connection cores, injection and production profile in practice and the prediction of numerical reservoir simulation, getting the conclusion that the main influencing factors for the injectivity of single layer are interlayer heterogeneity, mobility ratio, gravity, CO2 molecular diffusion and capillary force, and interlayer heterogeneity influences injectivity most seriously. For avoiding the injectivity disaccord, based on these influenced factors, suggestions have been offered to the CO2 miscible flooding pilot test in Jilin oilfield, these suggestions can provide reliable methods for enlarge CO2 flooding swept volume.
Evaluation of Alkali-Surfactant Effectiveness by Single Well Test Pilot in a Malaysian Offshore Field Environment
Authors: Manap Arif Azhan , Chong Mizan Omar , Sai Rithauddin M. , Zainal Suzalina , Yahaya A. Wafi , Othman Mohamad 
Published: July 2011

Abstract
Angsi field is located offshore Terengganu, Malaysia. It was identified as the candidate for a pilot project to evaluate the effectiveness of chemical enhanced oil recovery (CEOR). Injection of alkali-surfactant (AS) slug was used to improve recovery factor through the reduction of residual oil saturation (Sor). The pilot project utilized single well chemical tracer test technique (SWCTT) to measure Sor change near well bore due to reactions of CEOR process. The pilot results were later used to update the reservoir dynamic model and to support decision making for potential expanded field application.
The pilot project faced many challenging technical and operational obstacles: offshore location, high reservoir temperature, sea water as injection water, water softening facilities requirement, and unmanned satellite platform with limited space. In addition, compliance to all Health, Safety, and Environment (HSE) requirements is a must, to ensure the pilot operation is carried out in a safe manner.
This paper will focus on the overall pilot design, planning and some results. Operational, HSE and quality control will also be discussed as background to the pilot project.
EEOR Success in Mann Field, Myanmar
Authors: Ott William K. , Nyo Thu , Nyunt Aung Win , Thet Khaing Aung 
Published: July 2011

Abstract
Oil production increased in two test wells in a mature oil reservoir in Mann Field, Myanmar by successfully applying an enzyme-enhanced oil recovery (EEOR) process, a subset of microbial-enhanced oil recovery. A concentrated, water-soluble enzyme preparation made from DNA-modified proteins released from selected microbes was specifically prepared and injected in oil zones of one well and then recycled and applied in a second well.
Mann Field is a brownfield located in Salin sub-basin of the central basin of Myanmar in Southeast Asia and currently is operated by MOGE, with MPRL E&P Pte Ltd as the contractor for the field operations management. The field began producing in 1970, predominately from Oligocene reservoirs that consist of 26 stacked sandstone payzones. More than 667 wells have been drilled and completed, and 118 million stock tank barrels of oil have been produced. Average porosity of the field is 18% with an average permeability of 10–250 md. Oil gravity is typically 36.5°API, which is paraffinic in certain horizons, and the gas gravity is 0.65.
A test well was treated with four drums of enzyme concentrate diluted to 2% in formation compatible, filtered brine. Pretreatment production was 14 bopd and 2 bwpd. Current production is 18 bopd, and some 530 incremental barrels have been produced in 13 months following the 11,000 galtreatment. Pretreatment production from the second well was 10 bopd and 109 bwpd. Current production is 16 to 17 bopd, and approximately 1636 barrels of incremental oil has been produced during nine months since the treatment. Additional enzyme treatments are being designed for wells in Mann Field with higher current oil productivities.
There are unlimited targets for EEOR applications, not only in Myanmar, but throughout the world. These successful initial EEOR applications in Mann Field will allow for treatment design improvements in future wells.
Thermally Active Polymer to Improve Sweep Efficiency of Water Floods: Simulation and Pilot Design Approaches
Authors: Garmeh R.. , Izadi M.. , Salehi M.. , Romero J. L. , Thomas C. P. , Manrique E. J. 
Published: July 2011

ABSTRACTA common problem in many waterflooded oil reservoirs is early water breakthrough with high water cut through highly conductive thief zones. Thermally active polymer, which is an expandable sub-micron particulate of low viscosity, has been successfully used as an in-depth conformance to improve sweep efficiency of waterfloods.This paper describes the workflow to evaluate technical feasibility of this conformance technology for proper pilot project designs supported with detailed simulation studies. Two simulation approaches have been developed to model properties of this polymer and its interaction with reservoir rock. Both methods include temperature triggered viscosification and adsorption/retention effects. Temperature profile in the reservoir is modeled by energy balance to accurately place this polymer at the optimum location in the thief zone. The first method considers a single chemical component in the water phase. The second method is based on chemical reactions of multiple chemical components. Both simulation approaches are compared and discussed.Results show that temperature-triggered polymers can increase oil recovery by viscosification and chemical adsorption/retention, which reduces thief zone permeability diverting flow into unswept zones. Sensitivity analyses suggest that ultimate oil recovery and conformance control depends on the thief zone temperature, vertical to horizontal permeability ratio (Kv/Kh), thief zone vertical location, injection concentration and slug size, oil viscosity, chemical adsorption, and its reversibility, among others. For high flow capacity thief zones and mobility ratios higher than 10, oil recoveries can be improved by increasing chemical concentration or slug size of treatments, or both. Low Kv/Kh (&lt; 0.1) and high permeability contrast generally shows faster incremental recoveries than high Kv/Kh with strong water segregation reservoirs.The presented workflow is currently used to perform in-depth conformance treatment designs in on-shore and off-shore fields and can be used as a reference tool to evaluate benefits of the thermally active polymer in waterflooded oil reservoirs.
Application of Polymer Flooding with High Molecular Weight and Concentration in Heterogeneous Reservoirs
Authors: Xiaoqin Zhang 
Published: July 2011

ABSTRACT
Daqing oilfield is a heterogeneous sandrock oilfield with multilayers. The application of polymer flooding in the field has obtained significantly technological and economic effects. On the bases of numerous lab experiments, it is indicated that polymer solutions of high concentration and molecular weight have better absorption and captation toward the layers than normal solutions do. Besides, the resistance and residual resistance coefficients are much larger. The higher the concentration and molecular weight are, the larger the increment in viscoelasticity is. Once polymer flooding with high concentration and molecular weight is applied, the residual oil saturation will decrease and displacing efficiency will increase. All these lead to higher increment in recovery rate.
Three pilot tests were conducted by means of high concentration and molecular weight. On the bases of the obtained results, industrialized application of the recovery method first began in the N1 block of Sazhong Area in Daqing oilfield in Jan. 2009. In that block, the molecular weight of the polymer solution was 25million Dalton and the concentration was 2000mg/L. Maximum decrement in water cut was 30 percent and enhanced recovery rate was 8.3 %. It was estimated that enhanced recovery rate could ultimately reach 18 percent by the end. The successful application of polymer flooding with high concentration and molecular weight in Daqing oilfield would provide practical experience for the development of similar reservoirs.
Biology Enzyme EOR for Low Permeability Reservoirs
Authors: He Liu , Zhonghong Zhang 
Published: July 2011

Abstract
Biology enzyme may change wettablity of rocks, release surface hydrocarbon of formation rock particles, and reduce interfacial tension. These properties may be used to reduce water injection pressure of low-permeability oil reservoirs, to enlarge swept volume and enhance recovery rate. We applied 4 types of biology enzyme solutions with different concentrations ranging from 0.5% to 5.0%, to conduct depressurization experiments on 6 artificial cores and 3 natural cores. When concentration of biology enzyme was 2.0%, injection pressure dropped significantly by 22.6% to 72.7%, averagely a drop of 51.4%. Pilot tests have been carried out based on indoor experiment results, as well as economic factors and operating convenience considerations, and other oilfield experiment parameters references. When volume multiple of injected biology enzyme was chosen to be 0.6%PV, production declination of connected oil wells was controlled and production rose gradually, showing that formation pressure has been restored and biology enzyme has played a part in enhancing the oil recovery rate.
Large Scale High Viscous-Elastic Fluid Flooding in the Field Achieves High Recoveries
Authors: Demin Wang , Gang Wang , Huifen Xia 
Published: July 2011

Abstract
By conventional mechanism, polymer flooding, due to its high viscosity, decreases the mobility ratio, increases the Volumetric Sweep Efficiency and recovery of the reservoir. When the fluid viscosity reaches a certain value, the decrease in mobility ratio has less effect on further increasing the volumetric sweep efficiency, therefore the practical amount and concentration of polymer that is used is limited.
However, due to the mechanism that the elastic properties of the driving fluid can increase the Displacement Efficiency, Daqing Oil Field started pilot tests of high elasticity driving fluid in the field 9 years ago, the incremental recoveries were all more than 20%OOIP above that of water flooding, about double that of conventional viscosity (40~50 cp) polymer flooding. Due to the very good results, in the recent 3 years, Daqing has rapidly expanded high viscous-elastic fluid flooding to more than 5 thousand wells. From the results of 1000 wells that are using this EOR method and for a sufficient time to predict the results, all these large scale field floods will attain an incremental recovery of more than 20%OOIP. Therefore, in Daqing, high elasticity flooding is taking the place of conventional polymer flooding and alkaline-surfactant-polymer (ASP) flooding to increase the oil field recovery.
Field experience shows the difficulties in solving the technical problems of producing, pumping, gathering and treating produced fluid from high viscous-elastic flooding are about the same as that of conventional polymer flooding and much easier to solve then ASP flooding.
The field results also show that the economics (costs per ton of produce oil) of this EOR method is about the same as conventional polymer flooding.
This is a very promising new EOR method that could significantly increase the recovery in other fields.
The Research on Optimizing the Plan of New Unary Polymer Surfactant Improving the Effect of Development in Thick Oil Pay
Authors: Ma Kuiqian , Cai Hui , Hou Yawei , Lei Yuan , Wang Chuanjun , Zhang Hongyou , Wu Xiaozhang , Zhang Zhanhua , Huang Qin 
Published: July 2011

Abstract
Polymer surfactant is a unitary flooding system which be developed in recent years. It has dual characteristics of polymer and surfactant. It has strong solvency even at a lower concentration. It has low molecular weight, counter-mass, high viscosity, anti-shearing force, anti-biodegradation, anti-oxidation degradation, temperature-resistance and salt resistance, and it fits different permeability reservoir. It is also be used to under different mineral degree condition reservoir and be injected with waste water directly. For the situation which not only has the serious invalid injection and production, but also has the oil layer of remaining oil enrichment, the test area carried out comprehensive research on polymer surfactants’ profile modification to improve the development effect of thick oil pay.
In this paper, the viscosity increasing property, stability, viscoelatic property, absorption characteristic, interfacial tension, flow characteristic and molecular coil size of the polymer surfactants is studied through laboratory test. The mathematical model of active constituent qualitative change of polymer surfactants flooding is established. The oil displacement scheme of polymer surfactants flooding in test area is optimized. The latest site implementation shows that polymer surfactants has a good suitability for tap potential in thick oil layer, the cumulative oil has increased 5978.5t, and predicting the enhanced oil rate is 1.7 points.
Challenges in Processing Produced Emulsion from Chemical Enhanced Oil Recovery - Polymer Flood Using Polyacrylamide
Authors: Zheng Frank , Quiroga Pilar , Sams Gary W. 
Published: July 2011

Abstract
Polymer flood using polyacrylamide is an effective way to increase oil production in many aged fields. While extensive research and development and field practices have demonstrated the improvements in oil recovery using this technology, the development on effective methods of processing the produced emulsion from polymer flood lags behind. The polymer in the injection fluid, which alters its physical and chemical behaviors, ultimately breaks out with the produced emulsion and changes its physical and chemical characteristics. This leads to tighter emulsions, increased produced water viscosities, stronger chemical interactions, limitations on the processing methods and process conditions, reduced efficiency on current equipment technologies, and even excessive equipment failures and damages. Adding to the processing difficulties is the uncertainty of the break out fluids. As polymer passes through reservoirs, its physical and chemical properties change due to formation absorption, shearing, and chemical reactions. As a result, the produced polymer is different from the injected polymer, and constantly changing during the production cycle. This requires the emulsion processing technologies to be flexible and stable throughout a large operation envelop.
The Comparative Advantages of a Dedicated CEOR Vessel for Offshore Field Developments
Authors: Wodehouse J.. , Henthorne L.. 
Published: July 2011

Abstract

Description.
Low salinity water floods and chemical enhanced oil recovery (CEOR) injection (Alkali, Surfactant and Polymer) are two technologies which have been applied onshore but are now being studied for use in new and existing offshore field developments. Their application offshore introduces several issues, which can significantly affect the technical feasibility and commercial viability of the project:

Applications.
The results presented in this paper are generic but they provide a basis for further study of the application of a dedicated desalination / CEOR vessel using specific field information. A work sheet has been provided in the paper identifying the most likely design concept(s) of a dedicated CEOR unit for a range of different field location parameters.

Results, Observations, and Conclusions.
In many cases the lowest risk and most cost efficient design is to locate the desalination / CEOR facilities on a separate vessel. This paper addresses the comparison of these issues in a qualitative manner for different design scenarios. The concept selection comparison is based upon engineering studies and typical offshore industry cost metrics.

Technical Contributions.
This paper presents a basis for considering a dedicated CEOR vessel for offshore projects. This is a novel concept and by initiating further detailed analysis for specific field developments this paper could provide the impetus for the recovery of a significant amount of additional offshore field reserves.
Improving Chemical EOR Economics by Optimizing Water Quality
Authors: Henthorne Lisa , Hartman Meghan , Hayden Andrea 
Published: July 2011

Abstract
Chemical enhanced oil recovery (CEOR) is emerging as a vital method to increase recoverable oil from aging reservoirs, but economics and the achievable incremental recoverable oil will dictate its widespread adoption. Water chemistry of the injectant plays an important role in the effectiveness and cost of CEOR. For instance, in polymer floods using partially hydrolyzed polyacrylamides (PHPAM), it is well established that the realizable viscosity for a given polymer concentration is a function of the injection water salinity, with divalent cations having a more detrimental impact than monovalent ions. Studies have shown that five to ten times less PHPAM is required using desalinated or lower salinity water when compared to seawater, resulting in an equivalent cost savings related to polymer consumption. In surfactant flooding, the relationship between the injectant water chemistry and the effectiveness of the flood is a more complex equation. Considerable research is ongoing to predict optimal salinities for surfactant flooding and the added benefit of using salinity gradients through the life of the surfactant flood. And lastly, alkalinity addition to either a surfactant and/or polymer flood dictates the injectant water be softened to prevent calcium and magnesium carbonate precipitation if sodium carbonate is the source of cost-effective alkalinity. Further complicating matters, the injection water salinity must be kept at a level sufficient to prevent clay swelling in the reservoir, and sulfate levels must be low enough to prevent precipitation of the sparingly soluble salts of barium or strontium, if present.
This paper analyses the economics associated with an alkalinity-surfactant-polymer (ASP) flood using general characteristics of an ASP flood project and demonstrates how optimizing the water quality of the injection water can change the project economics. Creating customized water chemistries of optimal blends throughout the CEOR flood is possible by carefully choosing membrane and polishing technologies which allow for a range of possible chemistries. Reducing the cost of CEOR through optimized water chemistries may further enhance oil recovery on a global scale by expanding the number of reservoirs in which CEOR is economically attractive.
Uncertainty in MMP Prediction from EOS Fluid Characterization
Authors: Dzulkarnain I.. , Awang M. B. , Mohamad A.. 
Published: July 2011

AbstractPublished results on modelling crude oils by equation of states (EOS) showed the importance of tuning the equation to fit experimental data closely. Usually various parameters relating to C7+ such critical properties are altered to obtain an equation with a high regression correlation. Although current oil samples may be analysed up to C60+, the presence of isomers for each component may still cause a high degree of uncertainty in the averaged properties. The use of different tuning factors can also cause variations in the equation of states. In practice, the fluid model after tuning does not always give good prediction for all properties. For example, a good fit for saturation pressure and viscosity may give considerable difference in the density prediction. Another set of tuning may be excellent for another property and poor fit for another. Since the prediction of the minimum miscibility pressure (MMP) depends on the EOS model, variations in the model will result in differences in the MMP value. Therefore the priority set on each property during tuning may result in widely differing MMP values.This research aims to find a relationship on the effects of each property of a crude oil on the MMP predicted. Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK), five properties and key tuning parameters are varied. The impact of using different combinations of the critical properties correlations on MMP calculation are tested on gas/oil systems.The best fit that is chosen from a tuning process may not always give a good fit to all properties. Our results may be used to list the priority of each property during tuning and will allow an estimation of the uncertainties in each property.