bluuebunny/crossref_metadata_2025 huggingface dataset:
Discussion on the First N2-SAGD Pilot Test in China
Authors: Erpeng Guo , Youwei Jiang , Yongrong Gao , Hongzhuang Wang , Pengbo Yu
Published: August 2015

Injection of non-condensable gas into steam chamber during SAGD (Steam Assisted Gravity Drainage) process is a widely adopted method to improve the efficiency of heavy oil recovery. In Liaohe oilfield, China, a non-condensable gas injection pilot test was initiated since 2011.

This paper describes the operation history of the first N2-SAGD pilot test in China and gives an integrated evaluation based on the field data and history matching results for the first time. The effects of N2 injection was discussed by comparing the production dynamics before and after N2 injection. The steam chamber development process was analyzed on the basis of accurate history matching of production dynamics.

The production dynamic analysis shows that the result of the pilot test was very promising. After N2 was injected, the oil steam ratio increased by 80% with the oil production being enhanced by 20%. Also the water-cut decreased gradually. The results of analysis of steam chamber development indicates that, upon N2 injection, the vertical growth rate of steam chamber is decreased by 30~40%, whereas steam chamber volume expansion rate is increased by 7 times. At the same time the steam chamber grows more steadily and more lateral-preferentially. With N2 injection the life-cycle of SAGD process can be prolonged by 6 years with improved recovery.

The results of this paper show that non-condensable gas injection is an effective method in adjusting the development of steam chamber and improving the efficiency of the whole recovery process. Also this paper could serve as an enlightenment for the exploitation of similar heavy oilfields in China.
Foams with Ultra-Low Interfacial Tensions for an Efficient EOR Process in Fractured Reservoirs
Authors: Chevallier Eloise , Tchamba Oceane , Chabert Max , Bekri Samir , Martin Frederic , Gautier Serge
Published: August 2015

We both evidence a new formulation for ultra-low IFT foams and a new coreflood set-up to demonstrate the efficiency of such a formulation in a model fractured reservoir.

In fractured oil-wet carbonates reservoirs, recovery of oil from the matrix is limited by preferential flows in fractures, and the low permeability and wettability of the matrix. Injection of foams with ultra-low interfacial tension (IFT) may handle these challenges. On the one hand, foam can induce fluid diversion from the fractures to the matrix. On the other hand, ultra-low interfacial tensions with oil (< 10−2 mN/m at optimal salinity) greatly enhance the oil recovery as demonstrated by ASP (Alkali Surfactant Polymer) floodings in homogeneous reservoirs. Ultra-low Ift values can efficiently decrease the entry pressure drop of oil-wet cores. Thus we here investigate the injection of foam with ultra-low IFT properties to mobilize oil in the poorly-swept matrix of oil-wet fractured carbonates.

First, obtaining both ultra-low IFT and stable foams in the same conditions is very often contradictory. Even a foaming solution with a domain of low-IFT generally exhibits a drop of foamability at the vicinity of the ultra-low IFT conditions. This study highlights a key criterion to obtain simultaneously both properties. The formulation requires an outstanding solubility (very low absorbance) at the vicinity of the ultra-low IFT domain. This condition is hardly encountered at the optimal salinity for common surfactant formulations and requires a wide screening of surfactants. From this criterion, we developed a mixture of surfactants which demonstrates simultaneously (60°C, 80g/L NaCl) a good foamability, foam stability and an ultra-low IFT with a crude oil.

Second, we present here a new coreflood set-up - called WFR after Waterflood Fractured Reservoir - designed to model foam flows in fractured reservoirs. The foam is pre-formed by co-injection of nitrogen gas and surfactant solution in a glass bead pack. The foam continuously washes the upper end-face of a vertical core sample. This geometry simulates a foam flowing in a fracture. The resulting flows generated in the matrix and the low-IFT values gives a total oil recovery of 93% OOIP.

The efficiency of the designed ultra-low IFT foam formulation is for the first time evaluated with this set-up to model representative conditions of a fractured system, and gives promising results.
EOR Enhancement Potential Analysis for One Oilfield
Authors: Pang Wei , He Zuqing , Wu Qiong , Hou Qian
Published: August 2015

Girasol oilfield is the first oilfield of Mansarovar Energy Colombia Ltd. (MECL) employing horizontal wells. With first well drilled in 2004 and commercial development started in 2008, this typical heavy oilfield have been produced for 10 years, but the current recovery factor is only 5.09%, and that is much lower than that of similar oilfields.

Girasol oilfield is at the medium stage of the cyclic steam stimulation (CSS) with 5.3 cycles and remaining reserves of 40.54 MMbbl. Based on characteristics of typical mid-shallow inter-bedded reservoirs with heavy oil in Girasol oilfield, by applying methodology of reservoir engineering and numerical reservoir simulation, the development status of Girasol oilfield is analyzed through full utilization of the geologic, logging and production performance data, and etc. Five potentials for production enhancement are researched including (1) Potential for well pattern improvement: except layer A12 and A9-Upper, other layers exist 30%~70% of uncontrolled regions in transition part between vertical and horizontal wells, nearboundary, low permeability areas; (2) Potential for well infilling: the well spacing is about 150m, while heating radius is about 50m, so there exist oils hard to exploit between wells. Numerical simulation shows the average heating area is only 33.07%. (3) Potential for CSS parameter optimization: compared with other similar blocks, the steam injection parameter is not suitable and the steam injection intensity is too low, and there is a good potential for optimized steam injection parameters; (4) Potential for horizontal lateral optimization: the current horizontal lateral of 600m on average is too long for thermal production because it will leads to high heat loss, un-uniform steam adsorption and poor steam injection effect; (5) Potential for steam flooding: as the reservoir geological conditions meet the screening criteria of steam flooding reservoir, there is a good potential for converting of steam flooding from CSS.

This paper constructs a framework and technical route for fullfield EOR enhancement design of heavy oil reservoir from potential analysis, sector simulation to fullfield scale implementation. Comparison of injection parameters and production performance among similar reservoirs in different countries is another highlight.
A Comprehensive Mathematical Model for Estimating Thermal Efficiency of Steam Injection Wells Considering Phase Change
Authors: Gu Hao , Li Chunlan , Cheng Linsong , Huang Shijun , Lin Menglu , Xiong Wenxue
Published: August 2015

Improving thermal efficiency of steam injection wells is an important goal in the process of steam injection for heavy oil recovery. The main objectives of this paper are to establish a comprehensive mathematical model for estimating the thermal efficiency of steam injection wells and to make some suggestions on how to achieve the above goal.

The mathematical model is composed of four sections. The first one is about prediction of thermophysical properties of injected steam considering phase change. In this section, if wet steam is not cooled to liquid water, slippage between gas and liquid phases is taken into account in calculating pressure drop based on momentum balance principle. In addition, a complete expression for steam quality distribution in wellbores is derived in detail. However, if phase change occurs, we can obtain an implicit equation for fluid temperature by combining energy balance and Coulter-Bardon equations. In the second section, steady-state heat transfer inside the wellbore and transient radial conduction in the formation are coupled at the cement/formation interface, based on which the wellbore heat loss rate is determined. Next, the thermal efficiency is estimated by using both direct and indirect methods. Finally, the mathematical model is solved iteratively for each segment and a detailed calculation flowchart is also provided.

The proposed model is validated by comparing simulated steam pressure, temperature and quality with measured field data from Liaohe Oilfield, and the direct and indirect methods of estimating the thermal efficiency prove to be reliable. Then, using the validated model, we analyze the effects of wellhead steam quality, injection rate and thermal conductivities of insulation materials on thermal efficiency of steam injection wells. The results indicate that enhancing the wellhead injection rate and using low thermal conductivities of insulation materials can greatly improve the thermal efficiency. But it is not a good choice to achieve this goal by improving the wellhead steam quality. Moreover, the paper shows that our methods for estimating the thermal efficiency of steam injection wells can also be applied to concentric-dual tubing steam injection wells.

In this paper, the comprehensive mathematical model for estimating the thermal efficiency of steam injection wells may be worthy of more attention, because it has not been widely reported in the literature. More important, phase change from steam/water two-phase flow to liquid water single-phase flow in deep wells is also considered in our study.
Application of Well Test Information to Judge Blocking and Channeling in Polymer Flooding Unit
Authors: Lin Jiaen , Qiu Kuntai , Guo Xiaoqun
Published: August 2015

Polymer flooding has been extensively applied to oilfields as an effective method for EOR, but along with injected time growing, some wells' bottomhole pressure rose up and oil production dropped, and the formation pressure rose while the reservoir was blocked, and water production of the other wells increased while the reservoir was channeled. An analytical method based on well test analysis is developed to incorporate well test pressure data with production data to verify whether the polymer flooding plays a role in displacing oil into wellbores.

Based on the non-Newton polymer well test analysis models to consider the polymer non-Newton effect, this paper employs two well groups located in Shuanghe polymer flooding pilot unit of Henan Oilfield by using the dynamic performance analysis approach in which the well test information is combined with the production data to judge the blocking and channeling. First qualitative analysis is performed to compare different period pressure history curves of the different period pressure test data by drawing Cartesian coordinate charts and log-log diagnosis charts of pressure change and its derivative of all the well test data with production history data for a well. Secondly we interpret all the well test data from the two well groups with 6 periods' well test data to obtain the formation parameters by using non-Newton fluid well test analysis software.

Blocking and channeling could be judged qualitatively and quantitatively by correlating different period pressure trend and production data trend charts and parameters from the different period well test interpretation. For blockage, oil production flow rate dropped, the formation pressure rose and wellbore skin factors increased for production wells, and reservoir permeability decreased. For channeling effects, both production flow rate and water cut increased, but the formation pressure almost did not change and reservoir permeability did not change. To recognize the geological characteristics and production condition of the two well groups based on the above ideology, Non-Newton composite models with two zones is chosen to analyze the tested wells to acquire the skin factor, internal and external zone flow capacity, internal area radius, formation pressure. Since skin factor and formation pressure increase, both internal and external area zone flow capacity reduce, and internal area radius becomes smaller. It is concluded that the areas around the tested wells have been blocked.

Most innovative aspect of the methodology developed in this paper to judge blocking and channeling effects of polymer flood reservoir in a systematic fashion is by contrasting different periods of tested pressure change trend, flow rate change trend and production water cut change trend with the parameters obtained by non-Newton fluid well test analysis to get a more direct solution of resultant lower uncertainty.
Low-Tension Gas Modeling in Surfactant Alternating Gas and Surfactant/Gas Coinjection Processes
Authors: Beygi Mohammad R. , Varavei Abdoljalil , Lotfollahi Mohammad , Delshad Mojdeh
Published: August 2015

In this paper, we present a framework to model low-tension gas flood process and implement the model into the UT in-house compositional gas reservoir simulator (UT-DOECO2). A gas compositional model is coupled with microemulsion phase behavior to capture important mechanisms in hybrid gas-chemical flood processes in porous media.

Two different surfactant molecules are simultaneously applied: one to lower interfacial tension to ultra-low values and one to keep foam stable as gas mobility control agent. This process cannot currently be modeled using the commercial reservoir simulators. We implemented the option for two surfactants into the existing gas compositional simulator with foam and hysteresis options. A predictive simulator would make it possible to select the best candidates for field application and tailor process design to particular characteristics of each field.

In the field-scale application of the Surfactant Alternating Gas (SAG) process, multiphase fluid behavior in porous media is modeled using three-phase compositional relative permeability and three-phase hysteresis models to include both compositional and saturation history effects. These models represent a more-accurate prediction of the cycle-dependent properties of SAG. The gas entrapment in the foam flow is used to predict the hysteresis effect within each cycle using a dynamic Land coefficient. The in-situ foaming behavior is estimated based on the mechanistic foam models. This study, further, evaluates mobilization and displacement of residual oil in tight reservoirs using the low-tension gas flood and compares the results with other EOR options.

Using a reliable multiphase simulator low-tension gas experiments can be scaled up to the field and to optimize chemical-gas EOR process design. Numerical simulation of the SAG with and without hysteresis is used to assess the effect of the gas-entrapment on oil recovery and gas utilization factor in a field-scale application.
ASP as a Brown Field Re-Development Opportunity - Based on a Case Study
Authors: Anand A.. , van Batenburg D.. , Parker A.. , Eikmans D.. , Boersma D..
Published: August 2015

Predicting Alkaline Surfactant Polymer flood performance at fullfield scale is an interestingly vast subject. Typically, this would comprise of detailed modelling exercises at different dimensions and resolutions to calibrate the model for observed physical and geo-chemical behavior during the fluid flow. Modelling of different physical and chemical phenomena active during the ASP flood offers different complexities. To name a few, the phenomena active during the ASP flood in a reservoir are changing salinity, changing interfacial tension, changing capillary pressure and relative permeability, viscosity modification, chemical transport and retention, residual resistance factor, shear effects and so on. Nonetheless, the degree of areal and vertical heterogeneity in the field has a significant imprint on the ASP flood as an effective recovery process and poses another hurdle in the flood optimization. Also, due to large number of variables associated with the ASP process itself, the number of uncertainty and design parameters increase tremendously in comparison to any conventional recovery technique. The large list of sensitivity variables with increased computational time to model ASP active processes, makes it further restrictive to carry-out a holistic sensitivity analysis.

This paper investigates and addresses the aspects of a field scale development of an ASP flood with the help of full-fledged ASP modelling for our example field. The paper will cover the entire spectrum of the ASP feasibility study from illustrating the approach adopted to simulate the ASP active phenomena to the demonstration of the flood optimization techniques for the field. We will illustrate how the degree of areal and vertical heterogeneity in the field can cause inefficient utilization of chemicals, which in our case was found to have the most limiting effect on ASP field performance. We will discuss some of the ways to optimize the ASP flood in such a heterogeneous reservoir system. The selection of the uncertainty and design parameters and their ranges will be shown and the outcomes of the sensitivity analysis will be presented, including creaming curve analysis. We will also highlight the fullfield 3D effects on some of the conventionally established ASP parameters, for instance slug size.
Low-Tension Gas (LTG) Injection Strategy in High Salinity and High Temperature Sandstone Reservoirs
Authors: Nguyen N.. , Ren Guangwei , Mateen K.. , Cordelier P. R. , Morel D. C. , Nguyen Quoc P.
Published: August 2015

The work presented in this paper evaluates the potential of Low-Tension Gas (LTG) as an alternative to polymer flood for displacing the surfactant slug in a chemical EOR process in ultra-high salinity (above 189,000 ppm TDS), high temperature (above 85°C) sandstone reservoirs. The LTG process involves the use of surfactant and gas to achieve the mobility control required to displace the micro-emulsions and the crude oil. The optimal formulation of surfactants is identified to obtain good oil/water microemulsion phase behavior and desirable high optimum salinity. The latter feature allows the LTG process to work with a wide variation of injection brine salinity or in-situ salinity gradient. The optimal injection strategies are then determined through a series of oil recovery core floods with co-injection of gas and the surfactant solution. Tertiary recovery of up to 90% of the residual OIP was achieved for cores with 150–400md air permeability. The high optimum salinity that is closest to the formation brine salinity was found to give the highest incremental oil recoveries. Macroscopic stability of displacement fronts was studied via pressure derived mobility ratios. Approximate parity of relative mobility of injected fluids was observed with respect to relative mobility of displaced water at true residual oil saturation and interpreted relative mobility of a formed oil bank. These results indicate that in-situ foam propagation was present which enabled mobility control, and that stable displacement of in-situ fluids was achieved during flooding. By replacing polymer with foam, chemical EOR methods can be expanded into formations where the use of polymer is impractical.
Building an Enhanced Oil Recovery Culture to Maximise Asset Values
Authors: Rotondi M.. , Lamberti A.. , Masserano F.. , Mogensen K..
Published: August 2015

Global energy demand is forecasted to rise by over one-third from now until 2035. As the relatively easy oil reserves deplete, focus will shift to development of extremely complex reservoirs in challenging environments including those in ultra-deepwater and the Arctic. Another source of supply to fill the void will be from Enhanced Oil Recovery (EOR) techniques applied to existing fields. The current global ultimate average recovery factor for oilfields is roughly 35%. This means that about two-thirds of the already discovered oil is left within the reservoir. Pushing the recovery factors from 35% up to 45% would bring an additional one trillion barrels of oil to an energy-hungry world. Even though the EOR prize is high, many oil companies are still struggling to build an EOR culture. The lack of a systematic approach, costs and time-to-market of EOR projects and the general belief that EOR should only be applied to mature fields are preventing a wider spread of EOR deployment. In order to promote a new wave of EOR applications, it was decided at Top Management level to restructure the EOR Unit by creating a multidisciplinary team of laboratory, subsurface, production, project and procurement personnel. New best practices were also circulated in order to force reservoir engineers to evaluate the benefits of EOR techniques for every new green and brown field reservoir study. This was a breakthrough that facilitated the changing mindset of company professionals as EOR may be applied from the beginning of a field's life and not only in maturity stages. The EOR workflow from laboratory to field implementation was duly revised in order to try to shorten the time-to-market of EOR projects by means of: a faster screening phase due to a new in-house tool; the deployment of a quicker and high resolution simulator for full field cases and ad-hoc simulators for more detailed sector models; the use of single well chemical tracer tests to promptly prove the effectiveness of EOR agents; and finally, standard practices for pilot implementation and monitoring. A strong focus on containing costs was proposed to explore cheaper and more promising EOR techniques such as Low Salinity. The whole company reservoir portfolio was screened at a high level to identify the most prominent EOR techniques to focus on and the unconstrained additional EOR RF calculated. Finally, some interesting cases on water-alternate-gas projects for mature fields, chemical EOR and water conformance by means of thermally activated particles will be presented. The adoption of the new workflow showed a great time reduction from screening to pilot phase and that in some cases EOR techniques are still viable even in a low oil price scenario.
Progress of Microbial Enhanced Oil Recovery in China
Authors: Guo Hu , Li Yiqiang , Yiran Zhao , Wang Fuyong , Wang Yansheng , Yu Zhaoyan , Haicheng She , Yuanyuan Gu , Chuyi Jin , Xian Gao
Published: August 2015

Compared with other EOR technique like gas flooding, chemical flooding, and thermal production in heavy oil, the prominent advantages MEOR has environment-friendliness and lowest cost. MEOR has various applications not only in sandstone but also carbonate reservoirs, light oil reservoirs as well as heavy oil reservoirs.

This paper mainly reviewed progress in laboratory studies and MEOR field tests including six big successful field tests in China. Present focus on MEOR has been changed from qualitative analysis to quantitative characterization, and high-tech like 16S rDNA and advanced method has being tried to investigate its mechanism on molecular level. The mechanism of microbial effects on making oil emulsification and wettability alternation was the main interest of recent study. Application of high resolution mass spectrum (HRMS) on MEOR mechanism has revealed the change of polar compound structures before and after oil degradation by the microbial on molecular level.

MEOR could be divided into indigenous microorganism and exogenous microorganism flooding. The key of exogenous microorganism flooding, was to develop effective production strains, and difficulty lies in the compatibility of microorganism, performance degradation and high cost. Indigenous microorganism flooding, has good adaptation but no follow up process on production strains development, thus it represents the main direction of MEOR. China has some of the most complex and diversified reservoirs and was notable for the scale of MEOR field tests since there has been six big MEOR field tests since 1998 after many precious small-cale tests. All field tests have shown positive results in incremental oil and water cut reduction. The combination of indigenous microorganism and exogenous microorganism flooding was adopted because of the cost and difficulty of exogenous microorganism flooding.

MEOR screening criteria for reservoirs has been improved. The parameters include temperature, salinity, oil viscosity, permeability, porosity, wax content, water cut, and microorganism concentration in which production fluid, temperature, and salinity were the most important three parameters. MEOR was suitable in reservoirs of which temperature lower than 80°C, salinity less than 100,000 ppm, and permeability above 50 mD. MEOR experience and study in reservoirs of 120°C, salinity more than 350,000ppm and permeability of 10 mD has expanded the reservoirs range suitable to carry out MEOR.
Logistic Considerations for Safe Execution of Offshore Chemical EOR Projects
Authors: Baginski Victor , Larsen Dan , Waldman Tom , Manrique Eduardo , Ravikiran Ravi
Published: August 2015

Chemical EOR technologies used offshore can either be short term reservoir conformance treatments such as Marcit Gels for near-wellbore and BrightWater® for in-depth permeability modifications or long term floods such as mobility control improvements utilizing polymers (latex emulsion or powder). Each offshore EOR technology has significant logistical challenges for successful implementation that ultimately impacts the oil recovery performance. This paper will present a project management plan and logistics using existing offshore facilities, which needs to be considered well in advance of project execution for a successful field implementation for both conformance and mobility control programs.

Synthetic polyacrylamides for offshore mobility control applications are limited in practice but interest in offshore applications is increasing rapidly. Polyacrylamides are commercially available in two forms, latex emulsion (liquid) and powder. Each product form has unique benefits and challenges for effective field execution that will be discussed here. The project execution management plan encompasses global supply chain activities (logistics, imports, regulatory) as well as design, construction, and installation of custom facilities. In addition, field execution requires detailed project management including safety and HazID visits, pre-job site visits, pumping services, and surveillance programs. This management plan can be furhter complicated by the type of completion (i.e., dry or wet tree), chemical tie-in location to water injection, neat or slipstream chemical injection, deck space for injection equipment and chemical base tanks, hydration or inversion equipment, and size of transport vessel for chemical transfer offshore.

Offshore EOR projects are not generally planned during initial field development. Rather, EOR projects are considered add-on technologies that have to fit existing facilities and operations. This add-on approach increases the complexity and risks of EOR projects and Offshore Operations. Lessons learned and some tools that we have utilized to plan and implement offshore chemical EOR projects are discussed.
Dalia/Camelia Polymer Injection in Deep Offshore Field Angola Learnings and In Situ Polymer Sampling Results
Authors: Morel D. C. , Zaugg E.. , Jouenne S.. , Danquigny J. A. , Cordelier P. R.
Published: August 2015

The Polymer Injection Project on Dalia field, one of the main fields of Block 17 in deep offshore Angola, is a world first for both surface and subsurface aspects. Thorough geosciences and architecture integrated studies led to decide to phase the project, with a polymer injectivity test on one single well, followed by a continuous injection of polymer on one of the four subsea lines delivering water to the field.

The single well injectivity test on DAL-710 was completed first quarter of 2009, just two years after first oil. Very successful results led to launch a polymer injection pilot on the full injection line of the Camelia reservoir.

The main objectives of the single line Camelia pilot were to confirm long term operability and injectivity of polymer in the specific conditions of this deep-offshore development, and measure the in situ viscosity (sampler well) of the injected polymer solution away from the injector, as key inputs to the evaluation of an extended project.

From February 2010 to August 2012, a 900 ppm polymer solution was injected through the three wells of the line. In summer 2012, a sampler well was drilled 80 m far from one of the injector, located behind the polymer front thanks to 4D seismic monitoring. MDT and bottom hole samples were done and analyzed.

The paper describes the main results of the pilot phase on injectivity, operability and polymer sampling. The pilot answered its objectives, but still a lower viscosity than expected was measured in the sampler well. Key deliverables were: How to operate the whole process chain of viscosified water at topsides levelBetter knowledge of polymer degradation from topside to deep into the reservoirData required to properly size an extended polymer project.
Workflow Application for Advanced Well Completions to Meet IOR/EOR Challenges in Malaysia
Authors: Masoudi Rahim , Chan Keng Seng , Karkooti Hooman , Soni Sumit , Jalan Shlok , Shahreyar Noman , Kalyani Tejas , Finley Douglas
Published: August 2015

Advanced well completions in Malaysia have been installed since 2003. Recently, advanced well completions have been gaining increased attention for possible deployment in improved oil recovery/enhanced oil recovery (IOR/EOR) projects. This attention has resulted from recognition of values, such as reduced capital cost, improved productivity, operational flexibility, well/reservoir management/monitoring, and increased ultimate recovery.

Controlled and selective injection and production through advanced well completions improve the conformance control and the sweep efficiency in IOR/EOR projects. The technology implies the application of an inflow control device (ICD) or intelligent completion or a combination of both. Application of intelligent and ICD completions have been identified and evaluated by multiple operators for multiple fields under IOR/EOR in Malaysia.

This paper addresses field-wide challenges and proposes advanced completion technology solutions for productivity enhancement and improvement in ultimate recovery from these fields. The focus of completion technologies’ evaluation was to determine the need for zonal flow control requirements for multizone and multilateral applications for producer and injector wells. Further evaluation was performed to determine fit-for-purpose flow control equipment for individual well applications. Detailed well and reservoir modeling was performed to demonstrate added value with application of advanced well technologies (Kokal and Al-Kaabi 2010). Moreover, a quantitative value screening was performed to assess productivity/injectivity gain and estimated ultimate recovery (EUR) from the fields.

A selection and design methodology is presented for advanced well completion with flow performance modeling and anticipated results with proposed completion technologies. Two advanced completion designs were proposed for these offshore wells that intercepted stacked or compartmentalized reservoirs, thin-oil rims, and water zones being used for IOR. Additional consideration was given during completion design for water injectors to accommodate switching to water-alternating-gas (WAG) flooding techniques during later well life if required. The need for appropriate sand control methods were identified and presented to meet sand control challenges in these fields.
Treatment Technology of Steam Breakthrough for Offshore Heavy Oil Reservoirs Developed by Huff and Puff with Multi-Component Thermal Fluid
Authors: Liu Yigang , Zou Jian , Meng Xianghai , Han Xiaodong , Sun Yongtao , Zhang Wei , Zhou Fayuan , Fang Jichao
Published: August 2015

The multi-component thermal fluid huff and puff pilot for offshore heavy oil has been conducted in Bohai Oilfield since 2008. Currently, part of the wells has entered the second cycle of the huff and puff. With the increase of the stimulation cycles, the steam breakthrough becomes serious due to the steam fingering and overlapping.

In order to further improve the oilfield development performance, technology that could impede the steam breakthrough is developed. Experiments are designed and carried out for selection of suitable foam systems and the optimization of injection parameters in laboratory. And the temperature-sensitive gel is also developed for the steam breakthrough treatment which presents as liquid at normal conditions, begins to solidify at about 70°C and could become liquid again when the temperature decreases below 70°C. Then technology based on these two plugging agent are applied in the actual wells.

The experimental results indicate that the selected foam system could meet the requirement of high temperature resistance and plugging strength. The injection mode of the foam system are all studied and optimized. Based on the experimental results and reservoir simulation, a project for steam breakthrough treatment in Bohai Oilfield has been designed by using both the selected foam system and the temperature-sensitive gel. The simulation prediction shows that this technology could achieve high oil increment for single cycle which indicates that this technology is efficient for impeding the steam breakthrough and improving the oil production rate. The actual field implementation has been conducted.

This is the first time that this technology is applied for steam breakthrough treatment in Bohai Oilfield. This technology could provide useful guidance for treatment of steam breakthrough in offshore heavy oil reservoirs.
CDG in a Heterogeneous Fluvial Reservoir in Argentina: Pilot and Field Expansion Evaluation
Authors: Diaz D.. , Saez N.. , Cabrera M.. , Manrique E.. , Romero J.. , Kazempour M.. , Aye N..
Published: August 2015

The Loma Alta Sur (LAS) field is a multi-layer fluvial sandstone reservoir in the Neuquén Basin, Argentina. Reservoir heterogeneities and adverse mobility ratio (30 cp oil) led to an early water breakthrough short after water injection started. After the evaluation of different IOR/EOR methods, the evaluation of Colloidal Dispersion Gel (CDG) was considered as a strategy to improve oil recovery in the field.

CDG pilot started in July 2005 in well pattern LAS-58. Pilot considered the injection of two slugs (≈ 190,000 bbls each) separated by one year of water injection at the same injection rate (≈ 1,000 bbl/d). Injected CDG used 300 ppm of an HPAM and Chromium as a crosslinker with a polymer:crosslinker ratio of 40:1. CDG pilot was concluded in October 2007. Pilot monitoring was supported by a comprehensive injection/production data analysis, tracer and injection profiles before and after CDG injection.

Projected ultimate incremental oil recoveries estimated in 2008 were approximately 62,000 m3 (2.9 % of the OOIP). Incremental recoveries were reasonably validated as October 2014. Oil production response in some of the wells of pattern LAS-58 can be correlated with tracer injection before and after the first CDG slug. These changes were also corroborated by time-lapse injection profiles run over the period of the pilot tests. Most recent injection profiles suggest that possible permeability reduction generated by CDG was removed after several years of water injection. Based on the pilot reassessment, CDG injection is under evaluation in the same and different patterns of LAS field. Ongoing CDG evaluation is supported by detailed laboratory and field scale numerical simulation studies.

This study provides an updated evaluation of LAS CDG pilot validating projected ultimate recoveries, recent laboratory evidences of size distributions of CDG injected, rheologic measurements, and preliminary results of pilot history matching. Lessons learned during pilot evaluation and monitoring strategies will be also presented.
Markers of β-Cell Failure Predict Poor Glycemic Response to GLP-1 Receptor Agonist Therapy in Type 2 Diabetes
Authors: Jones Angus G. , McDonald Timothy J. , Shields Beverley M. , Hill Anita V. , Hyde Christopher J. , Knight Bridget A. , Hattersley Andrew T.
Published: August 2015

OBJECTIVE

To assess whether clinical characteristics and simple biomarkers of β-cell failure are associated with individual variation in glycemic response to GLP-1 receptor agonist (GLP-1RA) therapy in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We prospectively studied 620 participants with type 2 diabetes and HbA1c ≥58 mmol/mol (7.5%) commencing GLP-1RA therapy as part of their usual diabetes care and assessed response to therapy over 6 months. We assessed the association between baseline clinical measurements associated with β-cell failure and glycemic response (primary outcome HbA1c change 0–6 months) with change in weight (0–6 months) as a secondary outcome using linear regression and ANOVA with adjustment for baseline HbA1c and cotreatment change.

RESULTS

Reduced glycemic response to GLP-1RAs was associated with longer duration of diabetes, insulin cotreatment, lower fasting C-peptide, lower postmeal urine C-peptide–to–creatinine ratio, and positive GAD or IA2 islet autoantibodies (P ≤ 0.01 for all). Participants with positive autoantibodies or severe insulin deficiency (fasting C-peptide ≤0.25 nmol/L) had markedly reduced glycemic response to GLP-1RA therapy (autoantibodies, mean HbA1c change −5.2 vs. −15.2 mmol/mol [−0.5 vs. −1.4%], P = 0.005; C-peptide <0.25 nmol/L, mean change −2.1 vs. −15.3 mmol/mol [−0.2 vs. −1.4%], P = 0.002). These markers were predominantly present in insulin-treated participants and were not associated with weight change.

CONCLUSIONS

Clinical markers of low β-cell function are associated with reduced glycemic response to GLP-1RA therapy. C-peptide and islet autoantibodies represent potential biomarkers for the stratification of GLP-1RA therapy in insulin-treated diabetes.
Classroom Video Data and the Time-Image: An-Archiving the Student Body
Authors: de Freitas Elizabeth
Published: August 2015

Video data has now become the most common form of data for educational researchers studying classroom interaction and school culture. Software protocols for analysing vast archives of video data are deployed regularly, allowing researchers to annotate, code and sort images. These protocols are often applied by researchers without reflection or reference to the extensive philosophical work in film and media studies. Without exception, this research treats the video image as movement-image or picture, a recording of ‘raw data’, indexical of a given time-space relationship. In this article I situate this kind of research within the history of scientific cinema, drawing on Deleuze's books on cinema, as well as his ideas on colour and figure from The Logic of Sensation, to propose an alternative way of analysing video data. One of the central claims of Deleuze in Cinema 2 is that the time-image reconfigures bodies as expressions of force – the body becomes a ‘shock of forces’. I argue that such an approach allows us to study the student body as less a phenomenological organism with built-in ‘I can’ cognitive and motor capacities, and more an indeterminate crystalline contraction and expansion of intensity. I present an example of how to study classroom video data as time-image, and explore the implications of such work for education research.
Slave to the Rhythm: The Problem of Creative Pedagogy and the Teaching of Creativity
Authors: Russell Francis
Published: August 2015

Since the mid-twentieth century the concepts ‘creativity’ and ‘innovation’ have become increasingly significant within a host of fields, such as education, medicine, engineering, technology and science. Moreover, such terms appear to have become ubiquitous, if not hegemonic, within the contemporary discourses that inform debates that surround the allocation and cultivation of the social capital that is native to education, both tertiary and otherwise. Given that the thinking of creativity appears increasingly to be possible only within the contemporary logics of utility and productivity that inform the discussion of the ‘knowledge economy’, the philosophical works of Gilles Deleuze are perhaps now more vital than ever, at least insofar as he is able to provide the possibility of approaching an ‘otherwise’ to the contemporary thinking of ‘creativity’. This paper discusses the possibility for Deleuze's discussion of rhythm – as can be located in his text A Thousand Plateaus and his work on the twentieth-century painter Francis Bacon – as providing the means for better posing the question of the conditions for the emergence of a fundamentally creative approach to teaching creativity to be conceptualized within our present situation.
Development of Biocomposites with Antioxidant Activity Based on Red Onion Extract and Acetate Cellulose
Authors: De Dicastillo Carol , Navarro Rosa , Guarda Abel , Galotto Maria
Published: August 2015

Antioxidant biocomposites have been successfully developed from cellulose acetate, eco-friendly triethyl citrate plasticizer and onion extract as a source of natural antioxidants. First, an onion extraction process was optimized to obtain the extract with highest antioxidant power. Extracts under absolute ethanol and ethanol 85% were the extracts with the highest antioxidant activity, which were the characterized through different methods, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2ʹ-azinobis(3-ethylbenzothiazoline-6-sulphonate)), that measure radical scavenger activity, and polyphenolic and flavonoid content. Afterwards, the extract was incorporated in cellulose acetate as polymer matrix owing to develop an active material intended to oxidative sensitive food products packaging. Different concentrations of onion extract and plasticizer were statistically studied by using response surface methodology in order to analyze the influence of both factors on the release of active compounds and therefore the antioxidant activity of these materials.
Extracellular Vesicles from Ovarian Carcinoma Cells Display Specific Glycosignatures
Authors: Gomes Joana , Gomes-Alves Patrícia , Carvalho Sofia , Peixoto Cristina , Alves Paula , Altevogt Peter , Costa Julia
Published: August 2015

Cells release vesicles to the extracellular environment with characteristic nucleic acid, protein, lipid, and glycan composition. Here we have isolated and characterized extracellular vesicles (EVs) and total cell membranes (MBs) from ovarian carcinoma OVMz cells. EVs were enriched in specific markers, including Tsg101, CD63, CD9, annexin-I, and MBs contained markers of cellular membrane compartments, including calnexin, GRASP65, GS28, LAMP-1, and L1CAM. The glycoprotein galectin-3 binding protein (LGALS3BP) was strongly enriched in EVs and it contained sialylated complex N-glycans. Lectin blotting with a panel of lectins showed that EVs had specific glycosignatures relative to MBs. Furthermore, the presence of glycoproteins bearing complex N-glycans with α2,3-linked sialic acid, fucose, bisecting-GlcNAc and LacdiNAc structures, and O-glycans with the T-antigen were detected. The inhibition of N-glycosylation processing from high mannose to complex glycans using kifunensine caused changes in the composition of EVs and induced a decrease of several glycoproteins. In conclusion, the results showed that glycosignatures of EVs were specific and altered glycosylation within the cell affected the composition and/or dynamics of EVs release. Furthermore, the identified glycosignatures of EVs could provide novel biomarkers for ovarian cancer.
High Levels of IL-10 and CD4+CD25hi+ Treg Cells in Endemic Burkitt’s Lymphoma Patients
Authors: Futagbi Godfred , Gyan Ben , Nunoo Harriet , Tetteh John , Welbeck Jennifer , Renner Lorna , Ofori Michael , Dodoo Daniel , Edoh Dominic , Akanmori Bartholomew
Published: August 2015

Background: The interplay between Epstein-Barr virus infection, malaria, and endemic Burkitt’s Lymphoma is not well understood. Reports show diminished EBV-specific Th1 responses in children living in malaria endemic areas and deficiency of EBNA1-specific IFN-γ T cell responses in children with endemic Burkitt’s Lymphoma (eBL). This study, therefore, examined some factors involved in the loss of EBNA-1-specific T cell responses in eBL. Methods: T-cell subset frequencies, activation, and IFN-γ- or IL-4-specific responses were analyzed by flow-cytometry. Plasma cytokine levels were measured by ELISA. Results: CD4+ and CD8+ cells in age- and sex-matched healthy controls (n = 3) expressed more IFN-γ in response to all immunostimulants than in pediatric endemic BL (eBL) patients (n = 4). In healthy controls, IFN-γ expression was higher than IL-4 expression, whereas in eBL patients the expression of IL-4 by CD4+ cells to EBNA-1 was slightly higher than IFN-γ. Moreover, the blood levels of TNF-α was significantly lower (p = 0.004) while IL-10 was significantly higher (p = 0.038), in eBL patients (n = 21) compared to controls (n = 16). Additionally, the frequency of CD4+CD25hi+ T cells was higher in both age-matched acute uncomplicated malaria (n = 26) and eBL (n = 14) patients compared to healthy controls (n = 19; p = 0.000 and p = 0.027, respectively). Conclusion: The data suggest that reduced Th1 response in eBL might be due to increased levels of IL-10 and T reg cells.
Photohydrogenation of Acetophenone Using Coumarin Dye-Sensitized Titanium Dioxide under Visible Light Irradiation
Authors: Kohtani Shigeru , Mori Mizuho , Yoshioka Eito , Miyabe Hideto
Published: August 2015

The use of coumarin dyes adsorbed on titanium dioxide (TiO2, P25) successfully extended the photocatalytic UV response of TiO2 toward visible light region. The hydrogenation of acetophenone (AP) using TiO2 modified with coumarin dyes proceeded with good chemical efficiencies under visible light irradiation. The role of sacrificial reagents on this dye-sensitized system is also reported.
Conspiratorial Beliefs Observed through Entropy Principles
Authors: Golo Nataša , Galam Serge
Published: August 2015

We propose a novel approach framed in terms of information theory and entropy to tackle the issue of the propagation of conspiracy theories. We represent the initial report of an event (such as the 9/11 terroristic attack) as a series of strings of information, each string classified by a two-state variable Ei = ±1, i = 1, …, N. If the values of the Ei are set to −1 for all strings, a state of minimum entropy is achieved. Comments on the report, focusing repeatedly on several strings Ek, might alternate their meaning (from −1 to +1). The representation of the event is turned fuzzy with an increased entropy value. Beyond some threshold value of entropy, chosen by simplicity to its maximum value, meaning N/2 variables with Ei = 1, the chance is created that a conspiracy theory might be initiated/propagated. Therefore, the evolution of the associated entropy is a way to measure the degree of penetration of a conspiracy theory. Our general framework relies on online content made voluntarily available by crowds of people, in response to some news or blog articles published by official news agencies. We apply different aggregation levels (comment, person, discussion thread) and discuss the associated patterns of entropy change.