bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Simulation Study on the Applicability of Relative Permeability Modifiers for Water-Shutoff in Oil Production Wells
Authors: Alfarge Dheiaa , Wei Mingzhen , Bai Baojun , Almansour Abdullah 
Published: October 2018

Abstract
Disproportionate Permeability Reduction (DPR) is often used as a water-shutoff treatment in production wells when conventional solutions such as mechanical isolations are difficult to perform. Although this property has been well documented by different investigators, the performance of DPR treatments in field applications has varied between success and failure without understandable reasons. This work investigated DPR performance in different scenarios to see when, where and at which conditions DPR treatments can give better results. Numerical simulation methods were used to simulate different scenarios happening in oil and gas fields such as five-spot pattern system and linear-system, with different number of layers, with and without crossflow. The possibility of using DPR treatment in hydraulically-fractured reservoirs was also investigated since many reports indicated that there is an increase in water production after some oil and gas reservoirs being hydraulically-fractured. Moreover, the physical reasoning behind the variations in DPR performance for different scenarios has been extensively discussed.
The results explored that DPR performance was excellent in both of water-cut reduction and oil-recovery improvement when the flow regime was viscous dominated (viscous-gravity number&lt;0.1). On the other hand, when the flow regime was gravity dominated (viscous-gravity number &gt;10), the effective period of DPR treatment was short-term remedy. Secondly, when the high-K layer is existed at the lower-zone of oil or gas reservoir is a good candidate for DPR treatment as compared when the high-K layer located at the upper zone. Furthermore, selecting the correct time to perform DPR treatments generally has a significant role to mitigate water production. Finally, the dimensions of treated fracture are the key components to get a successful DPR-treatment in fractured reservoirs.
Simulation Study of Effects of Surfactant Properties on Surfactant Enhanced Oil Recovery in Fractured Reservoirs
Authors: Cheng Xiaoqian , Kleppe Jon , Torsæter Ole 
Published: October 2018

Abstract
Surfactant addition could improve oil recovery of water flooding in mixed-wet/oil-wet naturally fractured reservoirs by changing wettability or reducing water/oil interfacial tension (IFT). But the mechanisms of surfactant enhanced oil recovery (EOR) in fractured reseroirs are not fully understood. One objective of this work is to analyze the effects of surfactant properties (viscosity, concentration, and adsorption) on surfactant EOR at laboratory scale. The other objective is to obtain the functional relationships between surfactant properties and oil recovery of surfactant flooding.
A core with length of 8 cm and diameter of 4 cm is cut into two parts from the middle to imitate the matrix with a horizontal fracture whose space is 0.1 cm. The middle slide with a width of 0.1 cm is used as the model in this study. Fluid is injected from left side of the fractured and produced from the right side. The original properties of matrix, brine, and oil are from Ekofisk Field. The properties of surfactant are assumed based on literatures. Eclipse is used as the simulator.
The viscosity of surfactant solution has no obvious effect on ultimate oil recovery. But the time to obtain ultimate oil recovery, which is called the ultimate oil recovery time in this paper, is linearly increasing with the increase of viscosity. Since most of surfactants have no significant effect on viscosity of brine, the viscosity of surfactant solution is not a key parameter of surfactant screening for surfactant EOR in fractured reservoirs. The increase of surfactant concentration results in a decrease of oil recovery rate, and an increase of ultimate oil recovery. The ultimate oil recovery at 364 days of surfactant flooding has a negative linear relationship with inverse square root of surfactant concentration. The surfactant concentration has a more significant effect on oil recovery from lower matrix than the oil recovery from upper matrix. The ratio (RC) of the maximum mass of adsorbed surfactant to the mass of surfactant at critical micelle concentration (CMC) is used to describe the effect of surfactant adsorption on oil recovery. Two cases are studied and results imply that the surfactant capability of wettability alteration should be considered first for surfactant screening. If surfactants have the same capability of wettability alteration, then the surfactant adsorption is a key parameter, and the smaller surfactant adsorption concentration leads to a larger ultimate oil recovery.
This work helps to understand the mechanism of surfactant flooding in fractured reservoirs, and could be used as a reference for surfactant screening for surfactant EOR in fractured reservoirs. The functional relationships between surfactant properties and oil recovery help to improve upscaling methods.
Performance and Economic Analysis of a Novel Heavy Oil Recovery Process Using In-Situ Steam and Nitrogen Generated by Thermochemicals
Authors: Moussa Tamer , Patil Shirish , Mahmoud Mohamed 
Published: October 2018

Abstract
Heavy oil has attracted global attention due to its huge volume of original oil in place. However, there are numerous operation and economic challenges to the recovery of heavy oil due to its high-viscosity and high-density. Thermal recovery methods such as steam injection is viable and commonly used to recover heavy oil and bitumen primarily by viscosity reduction of heavy oil and improving the displacement of the heavy oil. However, there are significant heat losses before the steam reaches the heavy-oil reservoir, in addition to the concerns of high cost and emission of greenhouse gases. One of the promising new heavy-oil recovery approaches is generating steam with nitrogen gas, in-situ, using thermochemical reaction to reduce oil viscosity, improve the mobility ratio and enhance the heavy-oil displacement. Steam and nitrogen are generated, in-situ, by injecting exothermic reactants downhole with the injected water to create heat and enhance reservoir pressure for mobilizing heavy oil. The exothermic reaction is triggered by either increasing downhole temperature or in the presence of a low pH weak acid.
In this research, a numerical study of the novel heavy oil recovery process using in-situ steam and nitrogen generated by thermochemical reactions in field scale is conducted. Various ratios of nitrogen- steam are studied to identify their effect on the recovery efficiency. In-situ Nitrogen-steam ratio generated by thermochemical is optimized to accomplish the maximum achievable net present value (NPV) after ten years of recovery. The CMG STARS simulator is used to simulate reservoir models with different operational parameters.
The results show that the generated heat from in-situ thermochemical reactions was sufficient to reduce the viscosity of heavy oil, while the generated nitrogen gas provided a good heat insulation effect and reduced steam-oil ratio. Thus, higher NPV was achieved than typical conventional steam-only injection method.
This is the first time NPV and all economic parameters are considered to analyze the performance of an in-situ steam and nitrogen generated by thermochemical reaction. This research shows that the recovery of the proposed method is more suitable and economical for the reservoirs which are not viable for conventional steam flooding methods and it is a step forward to eliminate CO2 emissions associated with thermal recovery process.
High GOR MPFM Flow Loop Testing Evaluation and Pre-Qualification
Authors: Faraj Ali , Benlizidia Imed 
Published: October 2018

Abstract
Multiphase flow metering has become one of the main well testing and reservoir production monitoring for many oil operators. The technological advances in instrumentation and flow modelling has been lately able to address the challenging application in measuring the flow rates of high gas-oil-ratio (GOR) and high gas volume fraction (GVF) with an acceptable accuracy and reliability.
The objective of this paper is to discuss and evaluate the results of a pre-qualification test of three Multiphase Flow Meter (MPFM) technologies conducted in various third party flow loop test facilities mimicking high GOR field conditions. It will also clearly set the procedures and methodologies used to verify the field performance and viability to install those MPFM technologies in a high GOR environment.
Oil fields producing under high GOR flow conditions (more than 90% GVF) pose a technical challenge for in-line MPFM to provide accurate and reliable flow rate measurements. The testing of those technologies in the filed in such harsh environment requires a great deal of planning and careful design and monitoring of the reference measurement that imposes a major time and cost impacts. For this reason, a pre-qualification test of potential MPFM technologies for high GOR environment was conducted in a third party flow loop facility utilizing live hydrocarbons under simulated field operational conditions. These technologies are based on Venturi in association with additional measuring principles to cope with the high GOR conditions including nuclear fractioning, tomography, gamma-ray densitometer and multi-dimensional and multi- frequency electric permittivity measurement system.
This pre-qualification flow loop test was designed to ensure that clear conclusions are reached and that a purely objective evaluation of the results can be performed. Evaluating these MPFM technologies in well controlled and contained flow low loop has enabled a solid assessment of the metrological performance under high GOR. A coherence GVF mapping of each MPFM technology was formulated to help in the assessment in selecting the appropriate technology for the field application.
Technical Feasibility of Concentrated Solar Parabolic Trough Heating for Thermal-Based Desalination Process With Application in Produced Oilfield Water
Authors: Velarde Ruvalcaba , Alejandro Salvador 
Published: October 2018

Abstract
In wet-crude handling facilities, a desalting system requires wash water to reduce salt content of crude before shipping it to a stabilization plant. Produced water could be treated and used as wash water instead of consuming groundwater resources. Due to the high produced water salinity, this treatment could be done via thermal desalination method, such as humidification-dehumidification (HDH) distillation process.
One heat source available for thermal desalination is solar energy. Concentrated solar parabolic trough technology uses a heat transfer fluid to absorbe solar energy resource and provide heat to process fluids via a heat exchanger. The technology can be applied to heat produced water to the desired temperature at the HDH inlet. In this study, the technical feasibility of using concentrated solar parabolic trough heating for HDH process with application in produced oilfield water in Saudi Arabia is conducted. Concentrated solar parabolic trough performance is modelled and simulated via a public released renewable energy software. Also, technical considerations for process potential application are elaborated upon.
The results presented show the capability and overall scheme blocks in which concentrated solar parabolic trough contributes towards achieving heat requirements to HDH desalination process.
The approach studied in this paper tackles both energy and water conservation. It provides an overview on the use of alternative energy source for heat transfer fluid in an oilfield produced water desalination process with the potential to displace diesel or associated gas consumption. At the same time, the produced water treatment process displaces groundwater consumption.
Research on Interfacial Rheology of Chemical Flooding Systems
Authors: Tie Leilei , Yu Meng , Zheng Yufei , Li Xiang , Zhang Bo , Liu Wenhui , Xue Xinfang , Zhang Zhonggang 
Published: October 2018

Abstract
There are various interface phenomena in the process of foam flooding, so the interfacial rheological technique has a broad application prospect in the field of foam flooding. We can obtain the micro process information of interface through the study of interfacial rheological properties, which contributes to obtain a better explanation of the mechanism of foam generation, foam stability, and the effect of foam flooding. In this paper, the interfacial dilational rheological technology was used to investigate surface rheological properties of foam flooding systems. At the same time, the relationship between interfacial rheology and foam flooding recovery was also studied. To study the relationship between foam performance and surface parameters, sodium dodecyl sulfate (SDS)/long chain alcohol systems and long chain alkyl three methyl ammonium chloride systems were investigated.
Results show that due to different matchings of long chain alcohol molecules and SDS molecules, foaming volume and foam half-life of SDS solution increase at first then decrease with addition of lauryl alcohol, myristyl alcohol, cetyl alcohol and stearyl alcohol. Results show very slight variations in surface tension, while dilational modulus, elastic modulus, and surface viscosity of the systems increase at first then decrease. With the growth of hydrophobic chain, foaming volume and foam half-life of LTAC, TTAC, CTAC and OTAC decrease in turn, surface tension shows subtle changes, dilational modulus and elastic modulus decrease in turn. However, we obtain relatively low value for the viscous modulus of all the four long chain alkyl three methyl ammonium chloride systems. Foaming ability of foam flooding systems is controlled by surface viscoelasticity. Stability of foam flooding systems is mainly affected by surface rheological properties, and there is significant linear relationship between foam half-life and elastic modulus. Combining with the displacement experiment, a greater interfacial dilational elasticity results in a higher oil recovery. The conclusion is consistent with results of injection pressure in the macro core-flooding experiment and the change of sweep efficiency in the microscopic displacement experiment.
The results will provide insights in understanding the mechanism of foam flooding from the point of interfacial rheology.
Superheated Steam-Air Coupled With Toe-Point Injection Technique for Heavy Oil EOR: A Numerical Study on Horizontal Wellbore Mass and Heat Transfer Characteristics
Authors: Feng Naichao , Cheng Shiqing , Yu Haiyang , Shi Wenyang , Qin Jiazheng , Zhang Jia , Sun Fengrui , Du Changhao , Liu Xin 
Published: October 2018

Abstract
In this paper, a novel model is proposed to characterize superheated steam-air (SSA) pressure and temperature distribution in horizontal wells with toe-point injection technique. Firstly, the mathematical model of SSA flow in both tubing and annulus is established based on the mass, momentum and energy conservation equations, and it is solved by employing finite difference method. The mass and heat transfer are coupled with injection of SSA into formation and heat exchange between tubing and annulus by iterative technique. Then, the proposed model is validated by field data. Finally, the effect of mass fraction of air and injection temperature on SSA temperature, pressure, mass flow rate in annulus and heat transfer rate from annulus fluid to formation are conducted.
Results indicate that: (1). The SSA temperature in tubing decreases while flowing from heel point to toe point and the temperature gradient decreases with distance to heel point. (2). The SSA temperature in annulus first decreases and then turns to increase while flowing from toe point to heel point. (3). The SSA pressure in tubing decreases linearly from heel point to toe point, while the SSA pressure gradient in annulus decreases with the distance to toe point. (4). The SSA temperature in both tubing and annulus decreases with the increasing of mass fraction of air. This is because the enthalpy of air is smaller than superheated steam. (5). Increasing injection temperature can decrease the SSA pressure in both tubing and annulus by reducing SSA density and increasing frictional loss.
Based on the presented model, the SSA pressure and temperature in both tubing and annulus can be accurately predicted with the relative error less than 5%. The theoretical studies in this paper can be taken as a reference for engineers in optimization of injection parameters and provide following researchers with the very basic theory for the application of toe-point injection technique.
The Effect of Salt-Laden Degraded MEG on Gas Hydrate Inhibition
Authors: Alef Khalid , Barifcani Ahmed 
Published: October 2018

Abstract
The formation of gas hydrates in pipelines continues to be a major challenge in gas production. Conventionally, thermodynamic hydrate inhibitors (THIs) are used to inhibit hydrate formation. Mono- ethylene glycol (MEG) is commonly utilized as a hydrate inhibitor due to its recoverability. However, during the recovery process, MEG may undergo multiple phases of thermal exposure which may lead to the degradation of MEG. In this study, MEG solution with realistic brine composition was tested for its gas hydrate inhibition performance.
The typical lean-MEG solution was prepared by combining pure MEG in a brine solution based on common formation water salt composition. The degraded samples were extracted from a MEG recovery pilot plant that had undergone a complete recovery operation (~13 h). Samples were then taken for gas hydrate testing using a high-pressure PVT cell. The isobaric hydrate testing method was employed for accurate hydrate equilibria results.
The new hydrate equilibria data revealed a hydrate promotion effect amongst the degraded MEG samples as opposed to pure non-degraded MEG. Although salt in the MEG solution improved hydrate inhibition, the results show that the inhibition effect was decreased as the extent of MEG degradation increased. Furthermore, MEG degradation products were identified to be acetic, formic, and glycolic acid. Observations reveal a color change from colorless to slightly yellow depending on the extent of thermal degradation of the MEG samples.
Design of a Pipeline Pre-Activation Inspection Robot for Pipeline Tap Detection
Authors: Idachaba Francis Enejo 
Published: October 2018

Abstract
Crude oil pipeline vandals have been known to insert taps on new pipelines as they are being laid or when the pipelines are inactive. These insertions in the pipelines also known as taps allow the vandals to steal and continue to steal crude oil from the pipeline as long as it is pumped through the line. This approach is difficult to detect using the available leak detection technologies as the crude is not leaked into the environment and does not cause a sudden reduction in the pipeline pressure. The Pre-activation Inspection robot is a battery powered self-actuated robot deployed into the lines to inspect the pipeline and provide a video feedback of the pipeline internal surface before crude oil is pumped. This robot can be deployed as the last stage of the handover process to ensure that the lines are free of taps before the pipeline is activated. It will enable operators determine if their lines have been tapped and also enable the localization of such taps. This deployment is capable of minimizing the volume of crude oil theft from pipelines and also providing information on the state of the pipeline internal surface.
A Realistic Kick Simulator for Casing Design - Part 2: Well Design and Execution
Authors: Chukwudi Ohaegbulam , Stanley Ibeh , Boniface Obah , Stanley Onwukwe 
Published: October 2018

Abstract
This paper is a continuation of SPE paper 189167 (A realistic kick simulator for casing design-part 1). A transient kick simulator that is based on kick tolerance concept using the drillers’ method was developed for well design. The purpose of this work is to demonstrate how the formulated model was used in well design. Supplementary models was developed to assist the drilling engineer to make the right decisions in the events of uncertainty and well control incidents during drilling thereby minimizing downtime. During well design, the casing seat points must be placed at a competent formation that must be able to withstand the hydrostatic pressure exerts by the drilling mud column as well as the kick imposed pressure and frictional pressures that will arise during the secondary well control operations. As the drilling operation is moving to more challenging fields (tight windows between pore and fracture pressure, HPHT wells, depleted fields, deep water wells) the importance of incorporating kick tolerance in the well design programme cannot be overemphasized. Hence, a realistic optimization of casing seat points using the proposed kick model and pore-fracture pressure gradients was implemented in this work. The casing seat point is a function of a pre-design kick volume, kick intensity, and the well geometry. A method to estimate the internal burst load for surface and intermediate casing using the proposed model with a design kick volume (limited kick) and kick intensity was demonstrated in this work. These methods were compared with the conventional methods and their advantages/disadvantages were analyzed. Results show that the use of kick simulator/incorporation of kick tolerance in well design programme translate to cost reduction and increased safety over conventional methods.
Pressure Transient Behavior of Horizontal Wells in Naturally Fractured Reservoirs with Formation Sensitive Properties
Authors: Emeli Hilary U. , Igbokoyi Alpheus O. 
Published: October 2018

Abstract
Production of fluids from petroleum reservoirs reduces the pore pressure, increases the net overburden stress, and consequently, reduces the total porosity and permeability of the reservoir rock. This effect is much more significant in low permeability geo-pressured and naturally fractured reservoirs. For well test purpose, the assumption of constant permeability in the diffusivity equation will yield inaccurate estimates of the reservoir properties for any reservoirs in geo-pressured zone. To study the pressure transient behavior in a stress dependent porous media, it is assumed that permeability of the formation is stress dependent. Hence, a new parameter known as the permeability modulus is introduced.
In this study, the effect of stress-sensitivity was incorporated by expressing the permeability as an exponential function of pore pressure in the derivation of a three-dimensional diffusivity equation required to describe the flow of fluid for a horizontal well in a naturally fractured reservoir. The matrix-fracture fluid transfer model considered was the pseudo-steady state flow model. Since pragmatic values for the dimensionless permeability modulus ranges between zero and unity, it was possible to apply the theory of perturbation to develop and solve a system of linear boundary value problem subject to an infinite lateral and bounded vertical boundary condition. Applying the Laplace and finite Fourier cosine transform, an approximate analytical solution in Laplace space was obtained which was inverted numerically. Pressure response curves were generated and analyzed for certain vital parameters.