bluuebunny/crossref_metadata_2025_split huggingface dataset:
Can Sourceless Density LWD Replace Wireline in Exploration Wells? Case Study from Saudi Arabia
Authors: Alakeely Abdullah , Meridji Yacine 
Published: June 2014

Abstract
With the search for hydrocarbon reaching extreme and difficult frontiers worldwide, the use of tools that allow real-time monitoring of operations, such as logging while drilling (LWD) has become increasingly more attractive for both drillers and geoscientists, to safely drill and properly evaluate target formations.
In this paper we examine an alternative where a sourceless density LWD tool was used. It offers the assurance of not using nuclear sources to minimize hazards at the rig site. The tool uses a pulsed neutron generator instead of a chemical source. This allows for safe operation, safe transport and pollution free environment, in particular, in exploration wildcat environment where little is known about the area and the risks are higher.
The objective of this paper is to compare sourceless density LWD tool's performance to wireline using common logs to test the validity of this new technology replacing wireline in exploration wells.
In this investigation, real-time applications of LWD data are presented. First, general factors contributing to differences between LWD and wireline log responses are analyzed. Then, similar curves between LWD and wireline are compared. And, the formation evaluation results based on wireline versus LWD measurements are discussed.
The findings of this study will help reduce the uncertainty associated with the validity of sourceless LWD in replacing wireline in exploration wells. This has many implications for operational efficiency, duration and cost.
Effective Geosteering Using High-Resolution Electrical Images and Deep Azimuthal Resistivity
Authors: Kumar Rohit , Otaibi Saud Faihan , Mumtaz Asim , Saint Craig , Hameed Mahmoud 
Published: June 2014

Abstract
A horizontal producer was planned in Ahmadi limestone crossing two major faults in the curve section of the wellbore. A possibility of small sub-seismic faults associated with these two major faults was a real possibility. The throw of these subseismic faults can be substantial and well placement can become challenging. A geosteering strategy was created to mitigate structural uncertainty and maximize reservoir exposure. This was achieved by constructing a detailed earth model that utilized deep azimuthal resistivity and high-resolution electrical images.
The use of high-resolution electrical images helped in identifying the faults in real time. This information in conjunction with deep azimuthal resistivity signal strength and the distance to bed (D2B) calculation and conventional logging-while-drilling (LWD) formation evaluation data was incorporated in reservoir navigation software to calculate the fault throw. Based on this information, a 2D reservoir navigation model was updated regularly to adjust the wellbore trajectory for optimum well placement.
This paper discusses how above integrated solution was invaluable in placing the wellbore optimally in the zone of interest by using deep azimuthal resistivity signal strength and D2B calculation in conjunction with high-resolution electrical resistivity measurement. In the subjected well, a number of small faults were determined in real time with throws ranging from 9 to 16ft. Based on this information, decisions were made to readjust the well trajectory and the wellbore was placed optimally in 2071ft MD lateral section to achieve 96% net to gross.
Monitoring Residual Surfactant in the Flowback and Produced Water: A Way Forward to Improve Well Productivity
Authors: Rane Jayant P. , Xu Liang 
Published: June 2014

Abstract
Surfactant is a significant component within fracturing fluid additives used for enhancing oil and gas production following stimulation of unconventional reservoirs. To help ensure optimum applications of surfactants, operating and service companies have been searching for tools for tracking surfactant residuals in flowback and produced waters, which can be possibly correlated with well productivity. Conventional wisdom suggests using a dye-based approach (i.e., methylene blue (MB) typically combined with anionic surfactants). The concentration of the combined complex can then be determined using spectroscopic methods. This approach, however, can cause erroneous results because of the presence of anionic friction reducers, scale inhibitor, or gelled fluids. This paper discusses the residual surfactant concentration measured in produced water from example Barnett shale formation wells using a dynamic surface tension technique, which yields much more accurate measurements. A comparison of dynamic surface tension includes comparing the diffusion coefficient to the reaction kinetics of adsorption of a known molecule(s) in produced water. Short time kinetics of adsorption of different molecules vary based on chemical nature and molecular size. UV-Vis spectroscopy is used to confirm the results. An estimate of residual concentrations from UV-Vis appears to be coherent with dynamic surface tension measurement values.
Such measurements can be useful to determine the surfactant concentration during pumping and surfactant performance during and after hydraulic fracturing operations. Additionally, these measurements serve a vital role in tailoring the surfactant additive to specific reservoir conditions to achieve higher oil recovery. Real-time production results from these different wells are analyzed and appear dependent on the corresponding residual surfactant concentrations from produced waters. This unique technique is new to the authors’ knowledge and used to study and analyze produced water for surfactant additive concentration.
Transport of Temperature Nanosensors Through Fractured Tight Rock: An Experimental Study
Authors: Alaskar Mohammed , Li Kewen , Horne Roland 
Published: June 2014

Abstract
The goal of this research was to develop methods for acquiring reservoir temperature data within the formation and to correlate such information to fracture connectivity and geometry. Existing reservoir-characterization tools allow temperature to be measured only at the wellbore. Temperature-sensitive nanosensors would enable in-situ measurements within the reservoir. Such detailed temperature information enhances the ability to infer reservoir and fracture properties and inform reservoir engineering decisions. This study provides the details of the experimental work performed in the process of developing temperature nanosensors. Specifically, particle mobility through fractured media was investigated.
The transport of silica particles through fractured rock was investigated. Experimental results showed that the recovery of the particles was dependent on the particle size and suspension concentration. It was observed that the recovery of the 2 μm particles following their injection into fractured greywacke core was affected adversely by suspension concentrations (decreasing recovery with increasing suspension concentration). Increasing concentration of the 2 μm particles resulted in more pronounced aggregation, which led to trapping by straining. Conversely, the recovery of the 5 μm and polysize particles increased with increasing suspension concentration. The particle size has a direct effect on its recovery. By comparison, the recovery of 5 μm particles was about an order of magnitude higher than that of the large particles (&gt; 5 μm).
The controlling mechanisms for transport of silica particles were also identified. Among all, transport by gravitational sedimentation (gravity settling) was prominent. Results also showed that the existence of the fracture facilitated the particle transport. Particles were found to flow with the fast-moving streamlines within the fracture. The dominance of particle transport by advection or diffusion was examined using the Peclet number. The high Peclet numbers indicated advection-dominated transport.
Integrating Intelligent Field Data into Simulation Model History Matching Process
Authors: Yuen Bevan , Olukoko Olugbenga , Ansah Joseph 
Published: June 2014

Abstract
The advent of digital oil field technology initiated a new era of real-time data acquisition, which facilitated continuous field monitoring and swift intervention. Yesterdays’ or last hour's real-time data is not "real-time" but can be classified as intelligent field data. Raw intelligent field data is usually recorded and stored in second or minute intervals and the size of the data has been continuously increasing. Consequently, the added value of the intelligent field data outweighed the challenges in the storage, validation and summarization of this huge amount of data. While reservoir engineers often struggle with historical well data that are limited in nature, and are measured at different time intervals, the continuous and synchronized data stream emerging from the intelligent field provides unique opportunities to improve the history matching process of reservoir simulation models.
In this paper, we present the data utilization and the workflows adopted to integrate these data into reservoir simulation modeling. The workflow is to manage data quality, consistency, conversion and reconciliation with allocation data. Additional challenges are in selection of intelligent field data to match, and on simulator reported pressure and time stepping. Continuous and synchronized data streaming in real-time means that data is available to the engineer almost instantly or within a short time frame from acquisition. The wealth of data enables the simulation engineer to appropriately diagnose and account for critical reservoir phenomena such as well interference and subsurface well responses to surface well actions. Successful integration of intelligent field data into reservoir simulation significantly enhances the quality and predictability of our models. This builds on the success of our high resolution geological models that attempt to capture all the spatial heterogeneities. Similarly, high resolution temporal data attempts to capture all dynamic actions and reactions within the reservoir to further improve the reservoir simulation models.
Tar Area Development in a Giant Carbonate Field in Saudi Arabia
Authors: Benedek Lajos , Ali Razally , AlGhamdi Humam , Alhuthali Ahmed H. 
Published: June 2014

Abstract
An ongoing focus area for Saudi Aramco is the optimum field development and depletion of the mobile oil in the tar area, which is limited in extent and occurs mainly along of the periphery of the southeast flank of the field. Unlike many tar mats in other fields, the tar in this field is patchy and has a complex distribution in the reservoir. In addition, areal and vertical tar extensions reveal great variations along with the existence of fractures in the area which imposes difficulties on the reservoir characterization as well as predicting fluid flow behavior.
The objectives of this paper is to present an overview of the tar infected areas, reservoir performance, formation evaluation results, reservoir characterization and modeling workflow to formulate the development strategy. Various tools were utilized such as NMR log, flow-meters, POPI analysis, PVT analysis, Pressure Transient and core analysis to better understand the tar and optimize the development strategy. This paper also documents the results of a recently drilled evaluation well and the proposed horizontal sidetracks performances as actual case studies.
Simulation of Formation Damage in Petroleum Reservoirs
Authors: Ohen Henry A. , Civan Faruk 
Published: June 2014

SUMMARY
A phenomenological model for prediction of petroleum reservoir permeability impairment by porous media, fine particles and liquid interactions is presented. The combined effects of clay swelling, external particles invasion, fines generation, migration and retention involved in permeability impairment are formulated. Deviation from Darcy flow as the flow paths are plugged and the variation of pore size distribution during plugging are considered. The model is tested for a variety of conditions. The magnitudes of the estimated model parameters are used to determine the relative contributions of various damage mechanisms. The estimated parameter values are shown to be valid beyond the range of the data used to estimate them. The successful match between the measured and predicted values of permeability variation and effluent fines concentration demonstrates the validity and the capability of the formation damage model.
Effect of Viscous Crossflow on Miscibility Development in a Two-Layer Flow System: Part I - Ternary Vaporizing Gas Drives
Authors: Pande K. K. , Orr F. M. 
Published: June 2014

SUMMARY
This paper examines the effect of permeability heterogeneity and viscous crossflow on ternary vaporizing gas drive displacements. Material balance equations that describe multicomponent, multiphase flow in a two-layer system are solved by finite differences for the case of maximum (vertical equilibrium) viscous crossflow between layers. The effects of interlayer permeability ratio and operating pressure on composition paths, composition and saturation profiles, and oil recovery are reported.
Fluid mixing due to viscous crossflow is shown to cause significant amounts of two-phase flow in displacements that would be multicontact miscible in the absence of crossflow. Although the induced two-phase flow reduces local displacement efficiency, viscous crossflow improves overall recovery because a decrease in mobility contrast between layers reduces channeling, and because some oil is moved from the low permeability layer to that with faster flow.
Investigation of a Cyclic Countercurrent Light-Oil/CO2 Immiscible Process
Authors: Hara S. K. , Christman P. G. 
Published: June 2014

SUMMARY
In this paper it is shown that CO2 can effectively displace oil from diatomite under countercurrent conditions. A simple model is presented which quantitatively matches the observed oil production. CO2 is postulated to contact the oil due primarily to diffusive transport, and the diffusion coefficient used is consistent with the results of CT scan experiment conducted to measure the liquid phase diffusion coefficient in diatomite.
Effect of Connate Water on Gas/Oil Relative Permeabilities for Water-Wet and Mixed-Wet Berea Rock
Authors: Narahara G. M. , Pozzi A. L. , Blackshear T. H. 
Published: June 2014

SUMMARY
Gas and oil relative permeabilities were measured on water-wet and mixed-wet Berea sandstone at various connate (initial) water satura- tion values, including zero, using the gasflood method. The centrifuge method was used to extend the measured oil relative permeability curves to lower total liquid saturations than could be achieved by gasflood. Composite cores were used in the gasfloods, whereas individual plugs were tested in the centrifuge.
The results show that gas and oil relative permeabilities are indepen- dent of the connate water saturation in water-wet and mixed-wet Berea sandstone provided certain conditions are satisfied.
Representation of a Horizontal Well in Numerical Reservoir Simulation
Authors: Peaceman Donald W. 
Published: June 2014

SUMMARY
The derivation of Peaceman's equation for the equivalent wellblock radius of a well in an anisotropic medium assumes that the grid is uniform and that the well is isolated, i.e., far from the grid boundaries. For a horizontal well, the assumption of being isolated may not be valid. The range of validity of Peaceman's equation is explored, using recent work of Babu and Odeh. If the reservoir is stratified or if the grid is not uniform, the assumptions underlying the equations of either Peaceman or Babu and Odeh are not valid, and a special program must be used to calculate the equivalent radius.
A Cellular Automaton Model for Flow in a Heterogeneous Reservoir
Authors: Lee S. H. , Chung E. Y. 
Published: June 2014

ABSTRACT
This paper reports on the development of a 2-dimensional cellular automaton (CA) model to simulate fluid flow in porous media. In CA, simple rules of particle interactions at a lattice are used to simulate complex flow phenomena. Since the numerical operations involved are largely bit manipulation, CA can be potentially more efficient in memory usage than conventional methods, such as finite difference or finite element methods.
While other research on the use of CA to model porous media flow primarily focuses on Stokes flow at the pore level, with the intent of understanding flow at the core scale, this work concentrates on modeling Darcy flow in large heterogeneous fields. Permeability variations and anisotropy are modeled by a distribution of "soft scatterers" and "directional scatterers". Collision of incoming particles with scatterers is a stochastic process. Anisotropy is modeled via a preferred direction of collision between the directional scatterers and incoming particles
The CA model is verified through the study of single-phase flow in porous media. Simulation results obtained from this CA model show that particle flow rates are linearly proportional to pressure gradient (pressure is modeled through particle density in CA), and permeability is linearly correlated with scatterer density over a certain domain. Therefore, the CA model can be used to predict Darcy-like flow. It is shown that heterogeneity is modeled properly by varying the density of scatterers.
In addition to the single fluid model, a model with two fluids with identical physical properties has also been developed to study dispersion characteristics of a CA model. In the numerical simulation results, the transverse diffusivity converges to the theoretical constant, but the longitudinal diffusivity increases with time. Finally, extension of the current model to a more general case (i.e., three-dimensional, multiphase flow) is also discussed.
Orthogonal Adaptive Grid Generation with Fixed Internal Boundaries for Oil Reservoir Simulation
Authors: Sharpe H. N. , Anderson D. A. 
Published: June 2014

SUMMARY
The generation of boundary conforming, orthogonal, smooth curvilinear grid systems for regions containing internal boundaries, which can also cluster dynamically to physical solution gradients, is of major importance to reservoir simulation. This paper develops a practical methodology for achieving these objectives for two dimensional problems, with extensions to three dimensions. It is based on extending elliptic mapping methods to parabolic ones and the use of equidistribution schemes.
An Adaptive Variational Finite Element Method for Computing Coupled Porous-Media Problems with Moving Fronts
Authors: Kececioglu Ifiyenia 
Published: June 2014

SUMMARY
An adaptive deforming-grid mixed-variable finite element method for solving two-dimensional porous-media transport problems governed by a system of coupled nonlinear partial differential evolution equations, is presented. The advantages of this methodology over standard fixed-grid formulations in improving solution accuracy and yielding better computational stability characteristics are discussed and demonstrated through solution of a representative set of problems. Accordingly, extremely accurate solutions were computed not only for the primary variables but also their fluxes, with a very small fixed number of deforming and moving finite elements, for a set of transient high Péclet number porous-media convection-diffusion (continuous moving front) problems and also for the front motion (discrete moving front) during resaturation by water of a porous rock.
Reinfiltration in Fractured Porous Media: Part 1 - One Dimensional Model
Authors: Firoozabadi Abbas , Ishimoto Koichiro 
Published: June 2014

SUMMARY
Conventional fractured reservoir simulation models often neglect some fundamental aspects of multiphase flow in fractured porous media. Reinfiltration of the drained liquid from the upper blocks to the lower blocks is a key process which is often neglected. In this study, we present a theory of reinfiltration in fractured porous media in a one-dimensional (1-D) space. Based on this theory, it is established that the rate of drainage in a matrix block is always less than or equal to the reinfiltration rate. This implies that the drained liquid (for a gas-liquid system) from an upper block, rein-filtrates to the lower block and does not flow through the fracture network.
Transport Coefficients for Compositional Simulation with Coarse Grids in Heterogeneous Media
Authors: Barker J. W. , Fayers F. J. 
Published: June 2014

SUMMARY
Novel transport coefficients (α-factors) are introduced in the flow terms of a compositional simulator to model the interaction between phase behaviour and reservoir heterogeneity within coarse grid blocks. They are successfully used to model both lean and rich gas injection in stochastically-generated, heterogeneous reservoir cross-sections.
On the Effect of the Electroless Nickel-Phosphorus(Ni-P) Coating Defects on the Performance of This Type of Coating in Oilfield Environments
Authors: Mainier Fernando B. , de Araújo Marcelo M. 
Published: June 2014

SUMMARY
In the eighties the use of electroless nickel-phosphorus(Ni-P) coatings was largely increased in many industrial segments. In the oil industry this kind of coating has a particularly large applicability due to its outstanding resistance to CO2, H2S and aqueous brines. Therefore, it has been largely applied to valves, section pumps, production tubings, and other equipment. Nevertheless, laboratory tests performed have shown that it is essential to evaluate the quality of the coating in order to assure its field performance for it is dramatically affected by surface defect. In this paper several problems that occasionally occur in Ni-P coatings are presented. The following items of the coating are evaluated: nickel and phosphorus content, hardness, adherence, porosity, discontinuities, thickness and uniformity.
Numerical Simulation Study of Cyclical Processes of In-Situ Combustion and Steam Injection
Authors: Colonomos P. , Rodriguez H. , Villalba M. , Zerpa L. 
Published: June 2014

ABSTRACT
This paper presents a conceptual study of the numerical simulation of thermal stimulation processes such as the injection of steam and the in situ combustion using oxygen. A comparison is made of the production behavior of a representative well of heavy crudes in the Venezuela Orinoco Belt under an intermittent regime of in-situ combustion and a cyclic steam injection scheme. The production mechanisms responsible for the additional recovery are analyzed, as well as the effects of various parameters on the recovery of oil. The purpose of the study was to determine the technical feasibility of a cyclic in-situ combustion processes with oxygen to increase the production potential of heavy oil reservoirs.
A compositional thermal simulator with a tridimensional model was used for the study. This was done under conditions comparable with those existing in cyclic steam injection projects in the Hamaca field of the Orinoco Belt.
The results show that in both cyclic processes, under a constant energetic base, there is a similar increment in the production of oil. The sensitivity analyses show that on incrementing the rate of injection there is an increase of production although the process efficiency decreases. In the case of in situ combustion, the pressure of injection and temperature of injection did not affect the recovery obtained during the process. Furthermore, one of the principal mechanisms of production which acted during the cyclical combustion process is the dissolution of the carbon dioxide in the crude.
Our study point to the technical feasibility of the cyclic combustion process with oxygen as an alternative when the injection steam cannot be applied in heavy crude reservoirs.