bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coupled Geochemical-Reservoir Model to Understand the Interaction Between Low Salinity Brines and Carbonate Rock
Authors: Nasralla Ramez A. , Snippe Jeroen R. , Farajzadeh Rouhi 
Published: August 2015

AbstractLow salinity waterflood (LSF) is a promising technology for improving oil recovery. Several laboratory studies have demonstrated the potential of LSF to alter the rock wettability and improve oil recovery in carbonate reservoirs. Some studies have considered calcite dissolution as a mechanism behind the wettability alteration by LSF in carbonates. Moreover, the interaction between rock and injected brine can lead to change in the injected brine composition and pH. Therefore, it is important to better understand the interaction between injected brine and carbonate rock to de-risk the LSF technology for field applications.A numerical model was developed by coupling a reservoir simulator (Shell in-house Simulator, MoReS) with a geochemical model (PHREEQC) to study the interaction between the injected brine and carbonate rock. Calcite is assumed to be the rock mineral to represent most of carbonate reservoirs. Two reservoir rock models are presented: one for coreflood scale and another for field scale. To mimic reservoir condition, the rock is saturated with formation brine (180 g/l) and several brines with different salinity and composition are injected. The model is calibrated to the published experimental data in the literature. Both Local Equilibrium and Kinetic approaches are used to model the interaction between injected brines and rock. Furthermore, the impact on calcite dissolution is examined against various parameters such as brine composition and pH, and temperature.The model results indicate that interaction between calcite and brine can reach equilibrium quickly. As a result, LSF may dissolve calcite from part or the whole core during flooding experiments depending on the kinetics of the interaction. However at field scale, the calcite dissolution occurs only in the area near the injector. This suggests that if calcite dissolution is one of the LSF mechanisms, this mechanism will not contribute to improving oil recovery at field scale. Although calcite dissolution can occur only near the injector, it can still change the composition and pH of the injected brine, which may have an impact on the oil recovery. The increase in salinity due to calcite dissolution in not significant in absence of CO2, but the brine pH may reach 8-9.
Mechanistic Simulation of Polymer Injectivity in Field Tests
Authors: Lotfollahi Mohammad , Farajzadeh Rouhi , Delshad Mojdeh , Al-Abri Khalil , Wassing Bart M. , Mjeni Rifaat , Awan Kamran , Bedrikovetsky Pavel 
Published: August 2015

AbstractPolymer flooding is one of the most widely used chemical enhanced oil recovery methods due to its simplicity and low cost. To achieve high oil recoveries, large quantities of polymer solution is often injected through a small wellbore. Sometimes, the economic success of the project is only feasible when injection rate is high for high viscosity solution. However, injection of viscous polymer solutions has been a concern for the field application of polymer flooding.The pressure increase in polymer injectors can be attributed to (1) formation of an oil bank, (2) polymer rheology (shear-thickening behavior at near well-bore), and (3) plugging of the reservoir pores by insoluble polymer molecules or suspended particles in the water.In this paper, we propose a new model to history match field injection rate/pressure data. The pertinent equations for deep-bed filtration and external cake build-up in radial coordinate were coupled to the viscoelastic polymer rheology to capture important mechanisms. We selected radial coordinate in order to minimize the velocity/shear rate errors due to gridblock size in Cartesian coordinate.We used filtration theory and successfully history matched the field data. We performed systematic simulations and studied the impact of adsorption (retention), shear thickening, deep bed filtration, and external cake formation to explain the well injectivity behavior of polymer. The simulation results indicate that the gradual increase in bottomhole pressure during early times is attributed to the shear thickening rheology at high velocities experienced by viscoelastic HPAM polymers around the wellbore and the permeability reduction due to polymer adsorption and internal filtration of undissolved polymer. However, the linear impedance during external cake growth is responsible for the sharper increase in injection pressure at the later times.The proposed model can be used to calculate the injectivity of the polymer injection wells, understand the contribution of different phenomena on the pressure rise in the wells, locate the plugging or damage that may be caused by polymer, and accordingly design the chemical stimulation if necessary.
Laboratory and Simulation Investigation of the Effect of Thermally Activated Polymer on Permeability Reduction in Highly Permeable Unconsolidated Sand
Authors: Fabbri C.. , Klimenko A.. , Jouenne S.. , Cordelier Ph.. , Morel D.. 
Published: August 2015

AbstractThe in-situ behavior of a Thermally Activated Polymer (TAP) was investigated through laboratory work on a high permeability core (7.5 D) and was interpreted by refined simulation. The experiment, carried out in a 100% water saturated core, aimed at determining the adsorption of the non-activated TAP and the activated TAP Residual Resistance Factor (RRF). The experiment and simulation results led to three observations impacting economic evaluation of TAP/gel treatment.Firstly, unswollen TAP adsorbed, even if the significant values measured (130 µg/g of rock) may be overestimated due to the nature of the sand or to the fact that no residual oil was present in the porous medium. Secondly, in such high permeable sand, the main mechanism for mobility control of the swollen TAP was found to be the viscosity increase of the TAP solution. Indeed, in such high permeability material, permeability reduction estimated after 8 Pore Volumes (PV) of chase water was low (1.3). Refined history matching of the chase water injection in TAP evidenced that the fingering of the chase water through the high viscosity TAP slug should be expected. Therefore, rate variations and a high volume of chase water are required to evaluate the permeability reduction generated by TAP, and not to overestimate it. Finally, the injection of a slug of TAP in a quarter of five spot pattern was simulated with core scale grid blocks. Sensitivities were performed to quantify the dilution of the TAP slug. Results confirmed that the adsorption of the non-activated product and the viscosity of the injected solution affect the TAP distribution. The authors believe that these three observations should be included in the design of TAP treatments, and more generally, for in-depth gel treatments.
Visualization and Distribution of Ions at Fluids/Rock Interfaces: Angstrom Scale Study
Authors: Cha D. K. , Alotaibi M. B. , Yousef A. A. 
Published: August 2015

Abstract
Smart water and low-salinity waterflooding showed encouraging results in carbonate and sandstone reservoirs, respectively, at lab and field scales. Adjusting the injection water salinity and/or composition in either secondary or tertiary mode can positively instigate chemical interactions between reservoir fluids and rock minerals for enhanced oil recovery,. Several macroscopic and traditional laboratory techniques including coreflooding, contact angle, surface charges, NMR, and IFT have been extensively used to understand reaction mechanisms and subsequently optimize the water flooding process.
It is quite challenging to understand the behavior of reservoir fluids and water ions with carbonate minerals at very fine microscopic levels. Advanced technologies are required to comprehend the in-situ interactions at dynamic and static conditions. Cryogenic high resolution transmission electron microscopy (Cryogenic-HRTEM) equipped with energy dispersive spectroscopy (EDS) are utilized in this study to image oil droplets and dissolved salt ions at their native environment. Furthermore, Super-X EDS system? is used simultaneously to image the compositional distribution of multiple elements and to provide elemental mapping of the structures in solution. The experiments have been conducted using two different methodologies involving cryogenic-SEM and cryogenic-TEM. In addition, different fluids as crude oil, seawater and smartwater are observed at interfaces.
Results from this study revealed for the first time the in-situ distribution of mono and divalent ions around crude oil droplets. The elemental maps were shown to be distinct across the fluids and oil droplet interfaces. In comparison to seawater, smartwater reacted differently with crude oil components, and as a result, the interfacial layer thickness determined to be approximately 20 angstroms. This study gives a new insight about the elements’ distribution and interfacial layer's characteristics at different oi/brine interfaces. In summary, the observation at interfaces especially with smart water can alter the carbonate rock wettability towards water-wet for better oil recovery.
Comparison of History-Matched Water Flood, Tertiary Polymer Flood Relative Permeabilities and Evidence of Hysteresis During Tertiary Polymer Flood in Very Viscous Oils
Authors: Fabbri C.. , de Loubens R.. , Skauge A.. , Ormehaug P. A. , Vik B.. , Bourgeois M.. , Morel D.. , Hamon G.. 
Published: August 2015

Abstract
Polymer flooding in very viscous oil has been gaining interest since its efficiency has been field proven. Multiple laboratory investigations have evidenced that the incremental oil recovered by the tertiary process increases considerably the recovery reached thanks to water flooding. However, such tertiary injection is made all the more complex that it is preceded by unstable displacement of oil by water. Therefore a better understanding of the physics is needed, in order to better predict and optimize the viscous oil reserves associated with tertiary polymer flooding.
This work presents the interpretation of three similar tertiary polymer flood experiments carried out at the Centre for Integrated Petroleum Research (CIPR, Norway). Each experiment consisted in a water flood followed by a polymer flood. They involved the same Bentheimer outcrop sandstone, 2000 cP oil, 70 cP polymer solution, 2D slab geometry, but different slab lengths (2 slabs are 30cmx30cm, 1 slab is 30cmx90cm). Saturation evolution was monitored by X-ray. On the one hand, provided simple simulation assumptions, the three water floods under study could be history matched (production, pressure). Similar ratios between water and oil relative permeabilities were found, although the water flood relative permeabilities, matched with non Corey-type curves, reflected an important variability. On the other hand, the tertiary polymer floods were found challenging to match consistently. In particular, using classic history matching approaches, the history matching of the long slab experiment could not be reconciled with that of short slab experiments. Simulations were initialized with saturation maps obtained at the end of the water floods. None of the tested approaches enabled us to match consistently the short and long slab experiments together, unless a hysteresis model was implemented. Indeed, a memory effect was observed experimentally from the quantitative analysis of X-ray saturation maps and interpreted as a hysteresis phenomenon. This simple model, with two additional matching parameters, is then further validated by the comparison of 2D simulations with measured in situ saturations.
Impact of Back Produced Polymer on Tertiary Water Treatment Performances
Authors: Jacob Matthieu , Demangel Anne , Goldszalu Alexandre , Rambeau Odile , Jouenne Stéphane , Cordelier Philippe 
Published: August 2015

Abstract
Management of produced water containing back produced polymer (HPAM) is a real challenge since its limited biodegradability and its relatively high concentration in produced water (up to few hundreds of mg/L) make it difficult to discharge into surface water. The preferred option is to conduct Produced Water Re-Injection (PWRI). When PWRI requires stringent water specifications as low as 10 mg/L of dispersed hydrocarbon (HC), 2 mg/L of total suspended solids (TSS) and 5 µm particle cut size (d100), tertiary treatments become mandatory. It is, for example, the case for PWRI in matrix mode for unconsolidated and shallow sand reservoirs. The objective of this study was to better understand the impact of HPAM polymer on tertiary treatment with a focus on ceramic membrane performances in order to optimize the design of produced water treatment facilities.
Maturity assessment of these water treatment technologies highlighted numerous major risks in presence of polymer. A R&D plan was then conducted on labscale prototypes using synthetic Produced Water (PW) containing polymer.
The tests performed with low pore size membrane (&lt; 1 µm) met the specifications but the polymer was retained by the membrane which caused severe fouling and thus low productivity. Inversely, with pore size larger than 1µm, the polymer went through the membrane which strongly enhanced the productivity. However, with such large pores, the specifications are not anymore guaranteed. Two strategies were then identified and tested: (i) combine coagulation and membrane filtration or (ii) combine oxidation and membrane filtration using low pore size membranes. The use of coagulant (FeCl3) was very effective to precipitate the polymer and improve filtration performances but the management of the waste stream containing tons of precipitated polymer turned into a major showstopper. Inversely, the use of oxidation as a pre-treatment breaks polymer chains that become small enough to go through the membranes which (i) strongly improves membrane performances and (ii) enables the polymer re-injection.
This combination was successfully tested in batch but also in continuous mode using commercial membranes. The performances were then compared with other type of tertiary treatment technologies such as media filter (sand and walnut). In the context of PWRI in matrix mode for unconsolidated sand reservoirs (or any case that would require such stringent water specifications), membrane technology combined with oxidation is today a promising option deserving qualification tests at a larger scale.
Advanced Forward Modelling as an Integrated Tool in Seismic Reservoir Monitoring
Authors: Hill David , Lowden Dominic , Sonika Sonika , Paydayesh Mehdi , Bulat Andrej , Truelove Leigh , Chahine Clark , Herrera Adrian Rodriguez 
Published: August 2015

Abstract
The history of closed-loop seismic reservoir monitoring (CL-SRM) dates back to early 2000's with the History Matching Using Time Lapse Seismic (HUTS) project; the authors noted at the time that the proposed forward modelling step was too costly (Gosselin 2003).
From 2003 the technologies used in the forward modelling step of the CL-SRM workflow have developed in line with the availability of computing resources. Three groups of methods are currently in common use: a) direct analytical transformation of reservoir properties to seismic properties, b) variations on well log based fluid-substitution and petro-physical modelling, and c) simulation-to-seismic modelling (Gjøystdal, 2007). Both a) and b) are typically 1D and neglect realistic noise, overburden and acquisition configuration effect, while c) models noise free seismic data attributes, incorporating overburden and acquisition configuration effects via ray-tracing, but still neglects realistic noise. In all three cases the modelling is largely confined to the reservoir interval. More recent advances in computer architecture have now enabled large-scale finite difference acoustic and elastic modelling.
In parallel, research increasingly indicated the 4D-response associated with production was not restricted to the reservoir, but radiates into the over-burden, side-burden, and under-burden driven by geomechanical effects. Consequently to robustly predict a 4D-response related to production, field-scale modelling has to fully describe the acoustic and elastic response to both reservoir and field-wide changes. This complex interaction incorporates the reservoir dynamics component - which encompasses fluid properties, fluid flow characteristics, field performance history and pressure distributions and profiles over time, and also the changes in stress induced by the pressure changes during production. It is the stress changes that induce strains and deformations not only within the reservoir but also around it. Understanding the complete reservoir dynamics is not possible from studying the individual geologic, reservoir simulation, and reservoir geomechanical models in isolation – it requires they be integrated into a full-field coupled Dynamic Integrated Earth Model (DIEM)
On the Road to 60% Oil Recovery by Implementing Miscible Hydrocarbon WAG in a North-African Field
Authors: Maffeis I.. , Mogensen K.. , Rinaudo M.. , De Simoni M.. , Scarfato F.. , Galli G.. , Tripaldi G.. , Belaid F.. , Hachelaf H.. 
Published: August 2015

Abstract
A WAG injection project is foreseen in a North-African field, which was first brought on stream in 2004 with production coming from two separate hydrocarbon columns within the Upper and Middle TAG-I Triassic sandstone reservoirs. The crude oil is light (44°API) and develops multi-contact miscibility with its own solution gas. The current development strategy centers on gas injection as well as water injection for pressure maintenance. Recently, the maximum gas separation capacity was reached, and because the operator respects a zero-flaring policy, a key element of the development strategy involves active gas management which may influence a number of smaller satellite fields that also tie in to the same production facilities.
This paper describes efforts to further increase oil recovery in the considered field by means of miscible hydrocarbon gas injection implemented as a tapered WAG. We describe our monitoring plan which involves, among other things, systematic use of diagnostic plots to constrain and assist history matching of the field performance. Some gas breakthrough data indicate arrival of a methane bank ahead of the main gas front, which suggests that the multi-contact miscibility may not be entirely preserved due to dispersion effects. The pattern performance analysis is inspired by earlier gas injection projects and its main purpose is to enable the operator to benchmark patterns and make efficient use of the available injectant. Current gas utilization ratio is around 25–30 Mscf/stb for continuous gas flooding. It is estimated that full-field implementation of a tapered, miscible hydrocarbon WAG will lower the gas utilization ratio further and push the recovery factor towards 60%.
Esthetic Challenges in Rehabilitating the Anterior Maxilla: A Case Report
Authors: Miranda ME , Olivieri KA , Rigolin FJF , de Vasconcellos AA 
Published: August 2015

SUMMARYThe rehabilitation of an unesthetic smile in the anterior maxilla is always a clinical challenge, especially when an improper shape and size, old restorations, and unesthetic shading are present. In addition, an irregular gingival zenith contour in the anterior maxilla can affect the smile's harmony. Thus, detailed treatment planning is needed to define a functional and esthetic prosthetic rehabilitation. This study describes a clinical case in which a 55-year-old woman was rehabilitated using Digital Smile Design planning and full ceramic crowns (metal free) in the anterior zone of the maxilla and mandible. To normalize the gingival zenith, a dynamic compression technique was performed using provisional restorations to condition the gingival tissues and harmonize the proportional length of the anterior upper teeth.
Phanerotoma libertinecida (Hymenoptera: Braconidae), a new species of parasitoid of Grapholita libertina (Lepidoptera: Tortricidae) associated with lingonberry (Ericaceae)
Authors: Goulet H. , Hillier N.K. , Dixon P.L. , Larson D.J. 
Published: August 2015

AbstractPhanerotoma libertinecidanew species (Hymenoptera: Braconidae: Cheloninae) is described and put in context with the latest North American revision of the genus. The species has been reared repeatedly from Grapholita libertina Heinrich (Lepidoptera: Tortricidae), which is found on lingonberry (Vaccinium vitis-idaea var. minor Loddiges, Loddiges, and Loddiges (Ericaceae)). Its natural history is also described.
Convex Functions on Discrete Time Domains
Authors: Atıcı Ferhan M. , Yaldız Hatice 
Published: August 2015

AbstractIn this paper, we introduce the definition of a convex real valued function f defined on the set of integers, ℤ. We prove that f is convex on Z if and only if Δ2 f ≥ 0 on ℤ. As a first application of this new concept, we state and prove discrete Hermite–Hadamard inequality using the basics of discrete calculus (i.e., the calculus on Z). Second, we state and prove the discrete fractional Hermite–Hadamard inequality using the basics of discrete fractional calculus. We close the paper by defining the convexity of a real valued function on any time scale.
A Multilevel Correction Method for Steklov Eigenvalue Problem by Nonconforming Finite Element Methods
Authors: Han Xiaole , Li Yu , Xie Hehu 
Published: August 2015

AbstractIn this paper, a multilevel correction scheme is proposed to solve the Steklov eigenvalue problem by nonconforming finite element methods. With this new scheme, the accuracy of eigenpair approximations can be improved after each correction step which only needs to solve a source problem on finer finite element space and an Steklov eigenvalue problem on the coarsest finite element space. This correction scheme can increase the overall efficiency of solving eigenvalue problems by the nonconforming finite element method. Furthermore, as same as the direct eigenvalue solving by nonconforming finite element methods, this multilevel correction method can also produce the lower-bound approximations of the eigenvalues.
An Approximation of Three-Dimensional Semiconductor Devices by Mixed Finite Element Method and Characteristics-Mixed Finite Element Method
Authors: Yang Qing , Yuan Yirang 
Published: August 2015

AbstractThe mathematical model for semiconductor devices in three space dimensions are numerically discretized. The system consists of three quasi-linear partial differential equations about three physical variables: the electrostatic potential, the electron concentration and the hole concentration. We use standard mixed finite element method to approximate the elliptic electrostatic potential equation. For the two convection-dominated concentration equations, a characteristics-mixed finite element method is presented. The scheme is locally conservative. The optimalL2-norm error estimates are derived by the aid of a post-processing step. Finally, numerical experiments are presented to validate the theoretical analysis.
The PrinceAgainst Prudence:
Authors: Bush Randall 
Published: August 2015

ABSTRACTThis article explores an alternative logic of imprudence at work in Machiavelli's The Prince, a text seemingly defined by its prudence. Arguing that crucial engagements with The Prince by Eugene Garver and Robert Hariman operate as “prudent” readings, I note that the text offers durable resources for radical political and rhetorical imagination. Such resources are recoverable, however, only in and through an alternative, imprudent, reading strategy. Following the work of Maurice Merleau-Ponty, I read The Prince—particularly in its aesthetic and rhetorical articulation of “the people”—neither as a manual for princes or realpolitik but as both irreducible plurality and differential network, reflecting a political imagination at work in the text beyond modern calculation. Reading The Prince imprudently, I explore the necessary interconnection between rhetorical reading and political thinking—and the subsequent importance of understanding political theory as an aesthetic and textual practice.