bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Insights on the Characterization of Polymer Adsorbed Layers in Porous Media
Authors: Boujlel J. , Barré L. , Rousseau D. 
Published: March 2018

Abstract
The objective of this work was to bring new insights on Polymer Adsorbed Layers (PAL) in porous media. Irreversible permeability reductions and irreversible polymer retention were firstly determined versus polymer molecular weight, flow velocity and brine salinity and hardness. The presence of PAL was then evidenced by small angle neutrons scattering (SANS). This allowed proposing interpretations of permeability reduction in terms of PAL thickness and density.
This study focused on the adsorption of partially hydrolyzed polyacrylamide (HPAM) polymers on granular packs of silicon carbide (SiC). Polymer solutions were injected at fixed flow rate and concentration. Irreversible permeability reductions (Rk) were determined from changes in pressure drops and irreversible polymer retention (Г) from the difference of volume at breakthrough for two successive slugs. In-situ SANS experiments were performed under flow using the contrast matching technique: the pore space was filled with an H2O/D2O mixture with a scattering length density equal to that of the SiC. This resulted in a two-phase system whose scattering intensity was directly connected to the PAL (meso)structure.
Results showed an increase of Rk and of Г with salinity (0.2 to 80 g/L, with a stabilization trend towards high salinities) and molecular weight. When hardness was increased, Rk was not much affected but Г increased. The SANS experiments revealed a scattered intensity vs. wave vector q typical of PAL with self-similar concentration profile. From these results, it was possible to determine PAL hydrodynamic thicknesses of adsorbed layers (εH) using the Rk values and according to a simple capillary bundle model. εH and Г values were then combined to estimate the PAL density. The impact of salinity could hence be interpreted in view of classical charge screening effect observed for solutions of polyelectrolytes. The impact of molecular weight was found qualitatively consistent with the increase in radius of gyration. Regarding the impact of hardness, stable εH and increased Г translated in an increase of the PAL density: this could be due to the creation of bridges between polymer charged monomers and divalent cations. As for the impact of flow velocity, increases of Rk and hence of εH was generally observed. Such behavior is consistent with a change of conformation of PAL, from coiled to stretched.
This work stand as the first direct experimental evidence of "irreversible" PAL in three-dimensional porous media under flow. It also represents a consistent set of results summarizing the impact on PAL of parameters that are particularly relevant for field operations. The results and corresponding interpretations are meant to be used in reservoir simulation softwares to improve the predictability and economics of polymer flooding EOR.
New Tracers to Measure Residual Oil and Fractional Flow in Push and Pull Tracer Tests
Authors: Huseby Olaf , Galdiga Claus , Zarruk Gustavo A. , Hartvig Sven K. , Dugstad Øyvind 
Published: March 2018

Abstract
The well-established single well chemical tracer test (SWCTT), devised by Deans and co-workers in the 1970ies, has been used extensively to assess oil saturation after water flooding and as a method to measure the effect of EOR. The technique is based on separation of two different tracers; one oil/water partitioning tracer that partly hydrolyses in the reservoir to generate a secondary non-partitioning water tracer. Saturation is found from the time lag of the partitioning vs. the non-partitioning tracer and pre-measured partition coefficients. As an alternative to the commonly used tracers (e.g. Ethyl Acetate), a new family of reactive and partitioning chemical tracers was recently developed and field-tested. The new tracers, as well as their in-situ generated secondary non-partitioning tracer counterparts, are not naturally present in the reservoir, and can be analyzed using highly sensitive analytical methods, either on-site or in an off-site lab. The improved sensitivity implies that the required tracer amount can be reduced to a few hundred grams, i.e. about 1000 times less than in a conventional SWCTT. The reduced tracer amount has operational, HSE and several other benefits. In this paper, we review our field experience using the new tracers and explore how they improve and expand the single well tracer test methodology. Results reported in this paper show that off-site analysis is effective and accurate, which eliminates the requirement for on-site field analysis. The paper demonstrates that injecting several reacting and partitioning tracers can be used to measure saturation gradients in the near well zone. By injecting the new tracers in a well where movable oil is present (i.e. without extensive water flooding), information about the fractional flow of oil and water can also be gained. We explore this option and suggest a procedure for in-situ measurement of fractional flow of oil and water in the near well zone.
Practical EOR Agents - There is more to EOR than CO2
Authors: Dean Elio , French Josh , Pitts Malcolm , Wyatt Kon 
Published: March 2018

Abstract
CO2 EOR projects have experienced localized success in the United States due to past investments in CO2 infrastructure made possible by no longer existing government incentives. Many countries mistakenly look at these successful cases, along with the environmental benefit of carbon capture, and embarked on a quest for a CO2 EOR projects prior to securing a CO2 source. This paper discusses the available EOR agents beyond CO2.
This paper is based on efforts made to select EOR agents for a Rocky Mountain region reservoir, and uses a 10 MMBBL mechanistic model to assess EOR agents. Sourcing, purchase volumes, costs, infrastructure requirements, and a brief summary of the benefits and challenges are presented for the following EOR technologies: Carbon DioxideEthane + other Hydrocarbon GasesFlue Gas (90% N2, 10% CO2)NitrogenAlkali (different types)Surfactant (different types)Polymer (different types)Combinations of alkali, surfactant, and polymer
The logistic considerations identified in the evaluation of the Rocky Mountain region field are universal and can assist EOR agent selection in North America, the Middle East, and anywhere on Earth.
Chemical EOR in a Strong Aquifer Driven Reservoir: From Concept towards Reality
Authors: Tiwari Sanhita , AL-Mutairi Fahad , Al-Dhuwaihi Abdul-aziz , Al-Ajmi Moudi 
Published: March 2018

Abstract
North Kuwait has vision to increase oil production from its major reservoir and it is planned to be achieved by covering the major reservoirs under the umbrella of enhanced oil recovery (EOR). Sabiriyah Lower Burgan (SALB) is the biggest sandstone reservoir in Sabiriyah field with high permeability and strong aquifer support. Paper describes steps planned from present development strategy of simply infill drilling to EOR to improve the production scenario in future.
Primary recovery from reservoirs like SALB are expected to be good. Performance of the reservoir especially rise in water cut of SALB was analyzed which suggested that though primary recovery would be good but will take longer time to achieve. EOR screening was performed and suitable EOR methods were evaluated using mechanistic model. Screening considered target oil, water quality, permeability, oil viscosity, temperature, aquifer and injection capacity. Lab experiments were performed for the identified EOR processes and most suitable method was selected. EOR pilot area and pilot design performed to take it forward from concept stage towards reality.
SALB Layered part is an acceptable candidate for EOR process due to favorable mobility ratio which reduces the need for mobility control agents, reservoir being mixed wet system which is encouraging for improving unit displacement efficiency and reservoir rock properties are conducive to most forms of EOR. Low salinity water, CO2, N2 and Chemical EOR methods were evaluated. Mechanistic model based Estimated Recovery factor range for these EOR methods indicated Chemical EOR, (A) SP as most effective EOR method. Lab experiments were performed for CO2, N2 and ASP. In Lab, miscible N2 flooding was not found feasible whereas CO2 flooding was feasible for either as CO2 or a blend of CO2/NGL. Coreflood experiments suggested surfactant-polymer or alkaline-surfactant-polymer pilot flood as promising EOR methods for SALB. KOC has planned to proceed with Chemical EOR with its further evaluation through single well chemical tracer test (SWCTT) as first step. A multi-well pilot was also recommended assuming a successful single wells tracer test which would provide a better understanding of chemical solution injectivity, oil recovery potential, chemical retention by the reservoir, effect of the water drive on alkaline-surfactant-polymer flood potential and operational issues. Target layer and likely area was identified for EOR pilot.
EOR in a reservoir with strong aquifer drive has its own challenges but merits of SALB for enhancement of recovery are encouraging. The paper provides an insight of applicability of Chemical EOR in a large reservoir with strong aquifer that will pave the way for similar reservoirs in Kuwait and worldwide.
Evaluation of EOR Chemicals Impact on Topside Operations
Authors: Argillier J.-F. , Henaut I. , Darbouret M. , Jermann C. , Vinay G. 
Published: March 2018

Abstract
Water management has always been an important part of production operation but for chemical EOR it becomes one of the critical elements as the whole water cycle needs to be analyzed and adapted to the process. In particular one key aspect that is generally neglected concerns the impact of EOR chemicals on the produced water cycle. After the chemical breakthrough, part of the EOR chemicals (polymers and/or surfactants) will be back-produced and can induce heat exchanger fouling and strongly impact oil/water separation and water treatment surface processes. All these drawbacks may lead to skewed forecasts on economic performance of EOR projects.
Some of the key challenges with produced water treatments, that facility engineers and operators will be facing when preparing a chemical EOR project, will be highlighted in this paper. A focus on some experimental results obtained within the DOLPHIN JIP – supported by 14 oil companies – will be presented. A specific laboratory methodology dedicated to the study of the impact of ASP-type chemicals on heat exchanger fouling, oil/water separation and water treatment efficiency and which mimic actual surface processes, was designed.
Results presented will illustrate the operational conditions that favor deposit on heat exchangers when polymer is back-produced. Impact of having polymers and/or surfactant within produced fluids on oil/water separation (kinetics of separation and quality of both oil and water phases) and water treatment processes efficiency (evaluated by monitoring the concentration of remaining oil in water as a function of time) will also be outlined.
This work emphasizes that water management is a major challenge for chemical EOR that needs an integrated approach and should be studied upfront. Laboratory workflows and procedures could help the de-risking of operations and try to mitigate separation issues that could advantageously be integrated into the design of chemical EOR project.
Experimental Study of Crude Oil Emulsion Stability by Surfactant and Nanoparticles
Authors: Almohsin Ayman. M , Alabdulmohsen Zainab , Bai Baojun , Neogi Parthasakha 
Published: March 2018

Abstract
Surfactants and nanoparticles are materials being widely used for enhanced oil recovery (EOR). Surfactants are mainly used to reduce the interfacial tension between oil and water which could form a stable film of emulsion between these two immiscible fluids. Also, nanotechnology is a potential candidate to offer another solution to improve oil recovery. Nanoparticles can form a solid layer at the droplet's interface and stand as resistant stabilizer under harsh reservoir conditions.
This research investigates whether the combination of surfactants and nanoparticles can form a stable emulsion than surfactants only. Two parts of experimental study have been done in this research. First part was implemented using three types of surfactant: nonionic surfactant with no charge group on its head, an anionic type carrying negative charge, and, cationic surfactant carries positive charge on the hydrophilic portion of the molecules in water. Second part was conducted using combinations of same surfactants mentioned above with nanoparticles. These nanoparticles are aluminum oxide (Al2O3) and silicon dioxide (SiO2). These two parts of experimental work were done using different ratios of water to oil from 1-9.
Results showed that nonionic surfactant through water continuous phase could reach stability with heavy oils up to 40°C reservoir temperature while cationic surfactant through oil continuous phase could form stability reaching more than 60°C reservoir temperature. Meanwhile, anionic type could break the emulsion within a few hours. More emulsion stability could be achieved by adding Al2O3 and SiO2 nanoparticles to nonionic. Adding Al2O3 and SiO2 nanoparticles to anionic and cationic could form emulsion stability based on different water to oil ratio.
Integration of Solar Steam Facilities with Existing Steam Generation Systems
Authors: Nellist M. D. 
Published: March 2018

Abstract
This paper reports on the start-up of Phase 1 of a Solar Steam Generation facility (SSG) and its export to the existing steam headers of the Amal oil field, located in the south of Oman. Significant considerations within the SSG are reviewed and the impacts on the client's systems identified and discussed.
Operational performance indicators on SSG and Client facilities are studied, primarily based on process operating data and equipment stability records, to ensure that the supply of variable steam from solar generation does not create any detrimental effects on the existing facilities. Of particular interest is to assess the success of a variable rate steam injection mode and the impact this has on Client facilities: system pressures, conventional steam generator operation, and wellhead steam injection rates.
Previous simulation work has demonstrated that this mode of operation is essentially equivalent to fixed steaming rates provided the same daily equivalent of steam is injected in both cases. However, this has never been demonstrated in the field for extended periods.
Operational data showed that, as anticipated, the Client's systems were able to accomodate the cyclic swings in header pressure and the induced variable flows through their fixed, manual chokes. Data showed that the Client's conventional steam generators (HRSGs) continued to operate as normal without noted issue.
The changing pressure in the Client's steam header propagated back to the solar steam generation facility which was able to easily manage its operations automatically, causing no disruptions to its operations. No safety-related incidents arose, and all processes were well-managed on-site.
This study demonstrates for the first time the performance of large-scale solar steam generation facilities operating alongside conventional steam generation and distribution systems with the two disparate systems seamlessly integrated. It also demonstrates that variable rate steaming has practical application within this field. This highly dynamic process has been sympathetically and successfully added to an existing large, steady-state operation without introducing significant issues to either system.
Polymeric Surfactant for Enhanced Oil Recovery- Microvisual, Core-Flood Experiments and Field Application
Authors: Li Binhui , Liu Zheyu , Fei Chunguang , Lv Jianrong , Chen Xin , Li Yiqiang 
Published: March 2018

Abstract
Phase separation, which decreases the synergistic effect, are observed during amount of surfactant/polymer (SP) or alkali/surfactant/polymer (ASP) flooding field applications and laboratory experiments. The idea of adding hydrophobic groups to a water-soluble polymer is to make polymeric surfactant that could be applied in Enhanced Oil Recovery (EOR). However, pole-scale displacement mechanisms and field performances of polymeric surfactant have not been investigated throughtly. In this work, we synthesized two types of polymeric surfactants and evaluated their physi-chemical properties, including chemical structure, rheological characteristic, emulsification and salt tolerance. Beside these physi-chemical property tests, a micro-visual model and core-flooding tests were performed to investigate the efficiency of polymeric surfactant flooding to recover the bypassed or trapped residual oil after water flooding. Finally, field performances of polymeric surfactant were estimated by monitoring the production dynamics and development index from a pilot test in Daqing oilfield. Results show that the polymeric surfactant has characteristics of strong viscosity, salt-resistance and emulsification. The high viscosity of the polymeric surfactant gurantantees a better mobility control than the ordinary polymer. What's more, the enhanced swept volume, emulsifiability and high elasticity makes the polymeric surfactant flooding has higher recovery factor than traditional polymer during chemical flooding. The heterogeneous core flooding experiments show that extra 10% overall recovery can be obtained with polymeric surfactant flooding after traditional polymer flooding. The application of the two types of polymeric surfactants in the pilot area shows that polymeric surfactants make the middle and low permeability zones absorb more water than traditional polymer flooding. If the surfactants were injected after water flooding, oil recovery can be improved by more than 20%, and significant reduction in water cut. With these unique properties and good performances for trials in the pilot test, polymeric surfactants can be considered as a replacement to the traditional polymer in highly heterogeneous reservoirs after water flooding or polymer flooding.
Feasibility Study of a Steam-Foam Process Application in Kuwait
Authors: Al-Murayri M. T. , Al-Sabah H. M. , Kamal D. S. , Hassan A. A. , Cuenca A. , Suzanne G. P. , Batot G. , Chabert M. 
Published: March 2018

Abstract
Steam foam processes can improve the thermal efficiency and overall economics of steam-based oil recovery methods. Foam reduces steam mobility, thus mitigating steam channelling and energy loss, particularly in presence of thief zones. This paper describes an integrated EOR study to develop a steamfoam process for the Ratqa Lower Fars (RQLF) heavy oil reservoir in Kuwait with more focus on chemical selection, formulation design and reservoir simulation.
A variety of foaming surfactants were extensively evaluated in the lab based on the reservoir properties and operating conditions of the RQLF reservoir. This involved lab evaluation of thermal stability, adsorption, foam generation ability and foam rheology to select appropriate foaming surfactants. In parallel, multi-well/pattern steam-flooding simulations were performed to investigate the benefits of injecting foaming surfactants with steam. Different scenarios were considered and simulated mainly by varying the timing, duration and foaming surfactant concentration.
A fit-for-purpose foaming formulation was successfully developed for the RQLF reservoir. Thermal stability of the selected chemicals was validated. Furthermore, the adsorption of the selected foaming formulation on reservoir rock using injection water was found to be very low. Long-term foam stability was also confirmed in the presence and absence of crude oil. Based on these results, high foam apparent viscosity is expected in the planned core-flood experiments that will be performed to validate the ability of the selected surfactants to generate robust foam.
Simulation results showed that using foaming surfactants with steam can delay steam breakthrough and increase oil production, thus reducing steam-to-oil ratio. Furthermore, simulation results showed that it is beneficial to inject foam shortly prior to steam breakthrough rather than injecting it at the onset of steam injection. Basic economic evaluation was performed and the results indicate that foam addition to steam makes steam-flooding more cost-effective.
This paper discusses, for the first time, the results of an integrated study to evaluate the application of a steam-foam process for the RQLF reservoir in Kuwait. Valuable insights are presented on the design and simulation of foaming surfactants that can be used to improve the performance of steam-based oil recovery methods. The findings of this study are expected to pave the way for potential field trials in the future.
Experimental Study of Urea-SAGD Process
Authors: Erpeng Guo , Hongyuan Wang , Oilfield Liaohe , Youwei Jiang , Yongrong Gao , Junhui Shi 
Published: March 2018

Abstract
Improving recovery factor and heat efficiency of SAGD process has always been the main pursuit of EOR technology. This paper will provide the experimental study results of urea assisted SAGD process in reducing the steam consumption and improving the sweeping efficiency of SAGD process.
Based on previous 1-D flooding test results, this paper futher discussed the advantage of urea-SAGD process with series of 2-D experiment. After evaluation of heat loss effect for SAGD with numerical simuatoin approach, 2-D high experimental study on urea-SAGD process experiment plan were carefully designed. 3 groups of 2-D SAGD experiment with different additives (including ammonia, CO2, urea) were run to evaluate the influence to SAGD process. The performance of different additives were compared. The effects of different products from urea were analyzed in detail.
Study reveals that SAGD process can be greatly influenced by urea. Urea can gradually decompose into ammonia and CO2 over 150℃. Great solubility of ammonia in water can effectively increase sweeping efficiency and decrease residual oil saturation. CO2 is soluble in crudes and can improve the oil water mobility ratio. The 2D experimeint results shows that CO2 can stay in the higher position of the model and drive the oil down to the producer. And ammonia-SAGD experiment also shows that the ammonia can imrove steam efficiency when pure steam can not sustain production in the experiment. Urea SAGD process shows and comprehensive advantage over conventional SAGD process. The decomposed CO2 and NH3 can jointly improve the sweeping volume and sweeping efficiency in SAGD process. The recovery factor of urea-SAGD process can as high as 75% while other runs (including CO2-SAGD, ammonia-SAGD and pure steam SAGD) of experiment no more than 50%. The improvement of ammonia to SAGD process is comparable with CO2, both of them can improve about 10~12% comparing to conventional SAGD process. With the result of this paper, urea can reduce the consumption of steam by 1/3 and improve the oil production by 30% when it was co-injected with steam in SAGD process.
This study provides a new and effective approach of improving SAGD performance with inexpensive chemical products.