bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effective Force; Fiction Or Reality?
Authors: Nergaard Arnfinn 
Published: September 2015

Abstract
There are numerous examples of confusion and disagreement in literature and industry in the understanding and implementation of axial force theory for pipe exposed to external and internal pressures. In 1962, Lubinski et al (1) described how tubing exposed to internal or external pressure behaved different to what was expected from calculations. The gap was defined as a fictitious force. In the 50-year period since then, the terms ‘true force’ and ‘effective force’ have emerged from the many discussions and research activities performed to understand pipe behavior. True and effective forces represent certain physical conditions and parameters that are normally easily described and represented in diagrams; however, there is still an ongoing discussion as to what is the mechanical model and explanation, especially for effective forces. The gap between true and effective forces has been subject to many discussions. Several attempts have been made to bridge this gap. Today it is often referred to C.P. Sparks (3, 4) who presented a very simple relation between the true and the effective tension and the influence of internal and external pressure. A classic discussion theme is; will a cylindrical pipe connected to bottom see buoyancy when there is no bottom flat exposed to pressure? It is generally agreed that this pipe see no true axial force from the surrounding water, however, the Sparks equation implies that the pipe see an effective tension equal to the the weight of displaced fluid above a given level. The last contribution to the discussion is Samuel/Kumar's paper “Effective Force and True Force: What are they?” presented at SPE/IADC Drilling Conference, 2012 (2).
The objectives of the present paper are; to offer an understanding of the mechanics of effective forces, to demonstrate the physical effect of effective forces from laboratory tests, to underline the relevance and importance of applying effective forces in design and dimensioning of drill pipe and risers, to give examples of true and effective forces in a few classical well situations and finally to present a method for understanding and assessment of effective compression in a Macondo look alike case.
Novel Laboratory and Field Approaches to Control Halite and other Problematic Scales in High Salinity Brine from the Bakken
Authors: Lu Haiping , Penkala Joe , Brooks Johnathon , Haugen Chris , Harbaugh Chad , McAfee Clyde , Kalfayan Leonard 
Published: September 2015

Abstract
Scale formation during oil and gas production may cause formation damage, pump failure, blockage of tubing or annulus, and deposits in surface lines and equipment that can result in shutdowns or loss of production. Therefore, the prevention of scale is of considerable interest and concern to the oil and gas industry. Control of scale, particularly halite in high salinity Bakken brines (total dissolved solids &gt; 250,000 mg/L), is challenging on two fronts: 1) laboratory evaluation of scale products by conventional dynamic tube-blocking tests or static bottle tests are not optimal for halite scale, and 2) halite formation and high tendencies for carbonate and sulfate scales characterize high-salinity brines, which are difficult to manage with conventional scale control strategies. This paper describes a novel laboratory testing procedure to better evaluate halite/scale inhibition and how to apply this method. Conventional testing is also included to provide a more robust strategy for effective scale control in the high-salinity Bakken brines.
Currently, there is not an industry-recognized method for laboratory testing of halite due to difficulty controlling the amount of halite precipitation and reproducibility during the test. However, a test method was devised utilizing an ultraviolet-visible (UV-Vis) spectrophotometer to monitor dynamic scale formation during product evaluation. This kinetic turbidity test (KTT) uses the information on scale formation kinetics to differentiate various product performances with reproducible testing results. Halite inhibitors and combination products (halite inhibitor + common scale inhibitors) were screened with this method for potential use in field applications. The combination of products exhibited good scale inhibition performance for both halite and other common scales.
The challenges of halite and other scales in Bakken brines cause typical scale inhibitors to be ineffective. Diluting brines with freshwater is the common field treatment to lower scaling ion concentrations and wash out salt deposits. However, this approach is restricted in the Bakken because of the limited fresh water availability, poor fresh water quality (i.e., high bicarbonates and high pH), and remote locations that can impede freshwater treatment. Therefore, more effective treatments are essential for economic oil and gas production.
Mathematical Modeling and Experimental Breakthrough Curves for the Adsorption of Toxic Vapors Emitted from Crude Oil and Condensate Storage Tanks
Authors: Oyelakin Oluwatosin Akintoye , Olabanji Lawal , Ramirez David 
Published: September 2015

Abstract
Toxic vapor emissions (TVEs) from crude oil and condensate storage tanks contain volatile organic compounds which are precursors for ground level ozone formation. Vapor recovery units have been proposed for the control of TVEs but come with high energy cost and no liquid recovery. Thermal swing adsorption (TSA) was experimentally and theoretically studied for the capture and recovery of TVEs from crude oil and condensate storage tanks. Benzene, toluene, ethylbenzene, m, p and o-xylene (BTEX) were selected as the TVEs from the analyzed mixture of crude oil and condensate sample, API 54.2. Experimental adsorption breakthrough curves of BTEX on a commercially available granular activated carbon (GAC) were obtained from a bench scale TSA system. A non-steady state, mathematical model was developed to simulate concentration breakthrough curves for the adsorption cycle. The GAC showed high removal efficiencies with equilibrium adsorption capacities for toluene, benzene, m, p-xylene, o-xylene and ethylbenzene on GAC of 215 ± 7 mg/g, 183 ± 5 mg/g, 56 ± 2 mg/g, 9 ± 2 mg/g, and 3 ± 0.3 mg/g, respectively at 25°C. Liquid recoveries of BTEX ranged from 30–35%. Results from the mathematical model were compared to the experimental values. The non-steady state mathematical model predicted the experimental data very well. The model simulation results were further used to study column dynamics adsorption and evaluate the process efficiency of the TSA system.
Case Study of Soft Particle Fluid to Improve Proppant Transport and Placement
Authors: Sun Hong , Zhou Jia , Brannon Harold , Satya Gupta D. V. , Ault Marshall , Carman Paul , Wheeler Richard 
Published: September 2015

Abstract
The primary objective of hydraulic fracture stimulation is to use “ideal” fracturing fluids to initiate and propagate fractures, transport proppant and place a conductive proppant pack in the created fracture. Resident hydrocarbons may be more easily produced in the created fracture broadways. Thus, optimization of conductive fracture area is perhaps the most critical tenets of fracture stimulation. The effective fracture area is characterized by the conductive fracture height and length, and is often compromised by the inability to place the proppant throughout the created fracture area. Several attempts have been implemented to improve the effective fracture area, such as hybrid fracturing, ultralightweight proppant (ULWP) delivery, channel fracturing, and slug fracturing. The techniques are all based on viscosity-governed proppant transport mechanisms.
This paper proposes a new fluid system for nearly perfect proppant suspension to improve proppant transport and vertical distribution in fractures. It improves effective fracture height by placing proppant across the complete productive interval under downhole conditions when properly applied. This leads to better transverse and vertical placement of proppant in the fracture and significantly increases the fractured surface area. The degradability of the fluid can lead to non-damaged fracture conductivity with time by internal or external stimulus.
Criteria and considerations for successful applying such fluids to optimize proppant placement and maximize fracture conductivity are discussed. Job design is elaborated in terms of fluid mechanics and proppant transportation mechanics differences and benefits over traditional crosslinked gel systems. The execution, experiences, and subsequent well performance of treatment applications results are compared to offsets treated with a traditional crosslinked gel system.
Coupling Nanoparticles with Waterflooding to Increase Water Sweep Efficiency for High Fines-Containing Reservoir - Lab and Reservoir Simulation Results
Authors: Huang T. , Han J. , Agrawal G. , Sookprasong P. A. 
Published: September 2015

Abstract
Waterflooding is an established conventional method to improve oil recovery. When water flows into pores in a rock formation occupied by hydrocarbons, clays and other formation fines are released and flow with the injection water. Left unaddressed, the released formation particles can accumulate and plug the pore throats in the flow channels, which cause higher water injection pressure, lower water sweep-efficiency and lower oil recovery. Chemical additives in the injection water to stabilize formation clays and fine particles during waterflooding operations are partially helpful. Several major operators established a goal for 70% oil recovery, motivating the research of higher performing waterflooding formulations. As the nanoparticle-loaded water drives hydrocarbons toward the producers, the nanoparticles fixate formation fines at their sources in the water flow channels, resulting in fewer fines accumulating at the near-wellbore region of the producers (causing less choking to the production of hydrocarbons) and resulting in water-sweep-efficiency increases. This paper presents the results with and without using nanoparticles in simulated waterfloodings. In addition to cleaner water effluent, lower pressure drop occurs across the porous media containing nanoparticles under the same flow rate of 5%KCl and the same porous media compositions of sand and simulated formation fines. Full reservoir simulation details the benefits of coupling the nanoparticles and waterflooding in high fines-containing reservoirs with various reservoir properties.
This paper presents the use of select nanoparticles in waterflooding to significantly improve oil recovery in reservoirs susceptible to formation fines migration. The research shows the unique ability of select nanoparticles in stabilizing formation clays and fines in waterflooding operations. The lab results demonstrate a much higher performance of the new nanoparticle-blended waterflooding than the currently used technology of stabilizers for formation clays and fine particles. Lab tests, even visually, show a clear improvement of the water-effluent quality (less fines) when the nanoparticle-blended waterflooding is pushed through the lab-constructed permeable media. The simulation resulted in 37% more production than regular waterflooding in a higher permeability reservoir case and 95% greater production in a lower permeability reservoir scenario. The paper includes the scientific principle behind the nanoparticle functioning, detailed lab results and the reservoir simulations.
Innovative New Frac Manifold Trailer Offers Step Change in Slickwater Pumping
Authors: Gusek Ronald , Farshad Ghasripoor 
Published: September 2015

Abstract
It has been more than 15 years since the idea of slickwater fracturing was proposed as an effective means of stimulating unconventional reservoirs. Since then, the use of slickwater treatments has grown to represent a significant portion of hydraulic fracture treatments pumped in North America today. The growth in the use of low viscosity fluids has not been without its challenges, specifically around equipment. Historically, lower pumping rates and higher viscosity fluid protected many of the wear surfaces in a pump from the erosive properties of sand. Today, repair and maintenance of fracturing pumps due to erosion from proppant pumped at high rates in low viscosity fluids is a major expense, and can be a significant contributor to operational downtime for that equipment.
This paper examines an innovative new technology that enables a step change in how slickwater fracture treatments are pumped. The unique manifold trailer, or “missile”, allows for proppant-laden fluid to be pumped downhole at fracturing pressures without passing through a frac pump. This process of pressurizing the slurry is accomplished using a device called a pressure exchanger. The pressure exchanger functions by taking energy from high pressure clean fluid and transferring that energy to low pressure slurry, the outcome being a high pressure slurry stream and a low pressure clean stream of fluid. It accomplishes this function using only one simple rotating component within an outer housing. It has no bearings or valves, and is manufactured from tungsten carbide to maximize durability and minimize wear. By utilizing the unique pressure exchanger technology, fracturing pumps are no longer required to pump slurry laden fluid, but simply to pressurize a clean fluid stream from which the energy is subsequently extracted. By removing proppant from the fluid stream that passes through the pumps, wear and tear on the pump, and specifically on components such as valves and seats, is expected to be reduced significantly.
The paper will discuss the design and function of the new missile and its key component, the pressure exchanger. It will also examine the results of the yard test and the potential impact on the life of pump components as a result, as well as highlight operational differences vs current technology.
Real-Time Monitoring of Health Hazards During Hydraulic Fracturing
Authors: Uyanik Ilyas , Dursun Serkan 
Published: September 2015

Abstract
Hydraulic fracturing processes can use hundreds of thousands of pounds of fracturing sand or “frac sand,” which may result in airborne silica dust. Although the use of hydraulic fracturing techniques provides many benefits in the production of natural gas and oil resources, there are concerns about possible health, environment, and safety (HE&S) effects associated with silica dust. In fracturing processes, frac sand can produce breathable crystalline silica dust, which is a potential exposure hazard. Long-term exposure to or breathing excessive amounts of crystalline silica can result in silicosis, which is a respiratory disease that causes scarring in lung tissue. Consequently, the proper handling of the frac sand to avoid overexposure to silica dust is important. This paper presents an initial experience in the design and development of a real-time monitoring and surveillance system, consisting of desktop and smartphone applications with mobile and stationary sensors. The system is designed to monitor and report spatio-temporal evolution of airborne silica clouds on the drilling site. The purpose of the proposed system is to monitor the silica cloud movement and exposure to silica by workers on the drilling site in real time and to provide information about actions required for a safe drilling operation. The quantitative monitoring of airborne crystalline silica exposure has been distinctly difficult because the infrastructure framework has not been available until now. With the proliferation of environmental sensor networks installed, real-time, quantitative, and localized information becomes available. The system assesses airborne silica exposures quantitatively, rather than speculatively, for both workers and managers on the drilling site.
Velocity Tracking for Flow Monitoring and Production Profiling Using Distributed Acoustic Sensing
Authors: Paleja Rakesh , Mustafina Daria , in ‘t panhuis Peter , Park Timothy , Randell David , van der Horst Juun , Crickmore Roger 
Published: September 2015

Abstract
In this paper, we will share the recent work that was done to understand how bulk flow rates and fluid composition may be derived in single-phase and multi-phase flow by tracking the slopes (velocities) of coherent features detected using Distributed Acoustic Sensing (DAS). Both laboratory experiments and real field examples will be presented to demonstrate how velocity features can be detected and attributed to events such as slug flow or sound waves. Speed of Sound (SoS) analysis can in principle be used for determining changes in the fluid composition in multiphase flows, which provides opportunities to detect fluid interfaces and water or gas breakthrough. On the other hand, slowly moving features such as slugs or turbulent eddies can be used to derive bulk flow velocities, which may be used for injection or production profiling. The evaluation method directly derives velocities by Fourier transforming the raw DAS data in the temporal and spatial domains without applying any calibration steps. It can therefore be used to monitor flow in wells on a drive-by or continuous basis without a need for reference flow data.
Obtaining Operational Efficiencies by Applying Process Safety KPIs Developed for Offshore Production Installations
Authors: Infortunio Fred A. , Bedford Grantt V. , Vacas Francisco 
Published: September 2015

Abstract
The authors of this paper use Process Safety Key Performance Indicators (KPIs) to improve safety and operational efficiency by studying Safety Critical Equipment (SCE) reliability on Exploration & Production (E&P) offshore installations. This gives E&P Operations and Maintenance Departments the ability to optimize operational safety and production efficiencies. Details of the methods utilized and the process of selection of SCE and KPIs and the study and findings are presented in this paper. The authors used recognized international recommended practices as suggested by The American Petroleum Institute (API), (Process Safety Performance Indicators for the Refining and Petrochemical Industries, RP-754, April 2010), The Oil and Gas Producers (OPG), (Process Safety-Recommended Practice on Key Performance Indicators, Report No. 456, November 2011) and The Center for Chemical Process Safety (CCPS), (Guidelines for Process Safety Metrics, ISBN 978-0-470-57212-2, October, 2009). However, the identification of risks associated with high hazard operations, usually conducted upfront (HAZIDs, HAZOPS, FMEAs, etc.), do not necessarily show the whole picture. Advanced targeted analyses into some of the leading KPIs helps eni improve its Operations and Maintenance Departments.
Process Safety Tier 1 and Tier 2 events are well known, but they are lagging indicators and do not predict failure. This study focuses on Tier 3 and Tier 4 events that are statistically valuable and provide insight to eni's activities. These KPIs capture the number of demands on emergency shut-down systems, abnormal safety system and permissive overrides for operational purposes, asset integrity stressing, and corrective and preventive maintenance activities.
Analyses and control chart comparisons of the process as it reaches or exceeds the process control limits gives an understanding of the functioning of the SCE and an understanding of the sensitivities of the processes changing conditions. Identifying process variations that exceed control limits helps eni to improve process safety, reduce production downtime, and increase profitability.
Experimental Study on Mechanisms of Wax Removal During Pipeline Pigging
Authors: Wang Wenda , Huang Qiyu , Liu Yangjin , Sepehrnoori Kamy 
Published: September 2015

Abstract
Pigging is widely used in pipelines for wax removal. However, pigging operation relies heavily on “rule-of-thumb.” Because of its complexity and lack of methods, the wax removal mechanism is still poorly understood. This work aims to reveal the nature of the wax breaking process and thus promote understanding of wax removal physics. A unique experimental setup is designed and constructed to perform a series of wax removal experiments. The test section consisting of a 50-mm-ID, 600-mm-long, horizontal pipe has an accurate temperature control for wax casting and removal process. Different types of polyurethane pigs without oversize against the test section were used for the experiments to eliminate the influence of friction force between the pig and the pipe wall. Mixtures of crude oil and field wax deposit were cast inside the test section to carry out the experiments. In particular, a novel yield stress measurement was introduced into this study to characterize the wax hardness.
The effects of wax thickness, mixing ratio of wax deposit to oil, pipe wall temperature, shape and aggressiveness of polyurethane pig on wax breaking force were investigated comprehensively. In particular, the dependences of wax breaking force on the pig aggressiveness and pipe wall temperature are clarified for the first time. In addition, it is found that the relationship between wax failure stress and yield stress can be well fitted as a linear relation. Furthermore, the dependences of wax breaking force on the wax hardness and pig design being used are revealed quantitatively. Subsequently, it is concluded that there is an overwhelming effect between wax failure stress and yield stress, where the wax failure stress exceeds the yield stress of the same wax deposit during the wax removal process. The findings of this paper are beneficial in determining the optimal de-waxing frequency and evaluating the pigging risks.