bluuebunny/crossref_metadata_2025_split huggingface dataset:
Keyless Pigging
Authors: Tharmalingam T. , El-Sawah Mohamed , Sensarma Pradip Kumar , Shabaka Ashraf , Al-Ameri Ali Hamed , Nessim Amr 
Published: November 2017

Abstract
Oil and gas operators are driving towards ‘Digital Oil Field’, injecting best available technologies (BAT) coupled with the modern control systems and networks. This will help to offset a shrinking labour force, higher operational costs and supports the growing demand for improved efficiency and HSE throughout their oil production facilities. Emphasis has been made to explore various innovative schemes, taking the advantage of technology and automation, to provide safe operating environment with minimized OPEX. ‘Keyless’ pigging interlock scheme is one such innovation introduced to overcome the operational difficulties experienced with the existing key pigging interlock schemes without compromising the safety.
Removal of Gas-Condensate by CO2 Huff-n-Puff Injection: A Simulation Study
Authors: Ayub Muhammad , Ramadan Moemen , Bataweel Mohammed A. , Al-Mulhem Abdulrahman A. 
Published: November 2017

Abstract
Accumulation of gas-condensates in near wellbore regions, and consequently reduction of gas production rates, is a well-known phenomenon in most gas reservoirs all around the globe. In this study, injection of CO2 in "huff-n-puff" mode and its potential advantages of removing accumulated gas-condensates are thoroughly investigated. A compositional simulator was used to capture the near wellbore fluid flow physics causing the condensate dropout under various wellbore/field operational conditions. The severity of condensate blockage was evaluated using detailed sensitivity and uncertainty analyses of various key static and dynamic influencing parameters such as porosity, permeability, fluid composition, boundary flux, and flowing bottomhole pressure. Under various scenarios of condensate blockage, studies related to effectiveness and optimization of CO2 slug-size, soaking-time, and flowback rate are conducted. As prove of concept, it is observed that miscibility of CO2 in condensates, and near wellbore re-vaporization of accumulated liquids, are two of the main mechanisms of removing the condensate blockage. It is also concluded that CO2 is relatively more effective in removing near wellbore condensates as compared to far-field regions. Finally, based on various optimization analyses, a viable approach to adopt huff-n-puff CO2 injection scheme is suggested.
An Integrated Approach for Comprehensive Formation Evaluation in Mixed Lithologies using Source-Less Logging While Drilling and Advanced Cutting Analysis: A Case History
Authors: Taher Ahmed , Aki Ahmet , Zeriek Rachad 
Published: November 2017

Abstract
Accurate formation evaluation relies heavily on the quantification of rock matrix constituents. Rock mineralogy identification is commonly based on wireline spectroscopy measurements. Logging while drilling (LWD) techniques traditionally rely on density and neutron data to derive lithology. Historically, density and neutron tools that contain radioactive chemical sources were also the primary sensors used to determine porosity within the reservoir, which is a fundamental petrophysical attribute necessary to accurately quantify reserves. Although the potential irradiation and contamination risks associated with radioactive sources have always been known, the industry is now focusing toward reducing or eliminating their use, where possible.
The alternative source-less sensors for density and neutron tools, such as acoustic and nuclear magnetic resonance (NMR) measurements, were commonly used for porosity calculations. However, calculated porosities from acoustic measurements could contain significant errors arising from the uncertainty associated with the mineralogical composition. In addition, NMR porosity values can contain errors as a result of the effect of density and the hydrogen index of the hydrocarbons in place.
Advanced cutting analysis (ACA), either by X-ray fluorescence (XRF) and/or X-ray diffraction (XRD), provides an independent lithology from downhole tools. The lithology, matrix density, and slownesses computed from the minerals or directly measured by the XRD can, in turn, be used as input data for porosity calculations from sonic and/or NMR data. This helps to provide more accurate porosity measurements, as compared to the traditional calculated porosities, without using density and neutron tools. In addition, scanning electron microscopy (SEM) helps to enable the use of wellsite mineralogy, porosity, grain size distribution, and grain density from cuttings to calibrate the measurements from LWD acoustic and NMR tools.
This paper presents a comprehensive, cost effective method for multimineral formation evaluation using a combination of LWD and advanced mud logging, without the use of radioactive sources. A practical workflow with limitations is also presented.
Assessment of Field Scale Commercial Development for Miscible EOR in a Giant Offshore Carbonate Reservoir
Authors: Willingham Thomas W. , Kohata Akihiro , Al Sowaidi Alunood , Martin John D. , Irwin Drew D. 
Published: November 2017

Abstract
In this work we present the evaluation of field scale commercial miscible EOR for a giant offshore carbonate reservoir. The current assessment leverages the prior multi-year evaluation assessing the attractiveness (‘do-ability’) and prize for miscible EOR within each geologic area and reservoir within the field.
Two geologic areas, the "heterogeneous" and "homogeneous" geologic regions of the Crestal area in the largest reservoir were identified as the primary targets for field scale miscible EOR based on the prior multi-year assessment and are the focus of the current assessment. Commercial field-scale miscible development is predicated on a 1-to-1 line drive waterflood with 1km spaced extended reach horizontals with 10,000 ft completions and 500m spaced infills in the more heterogeneous area of the field.
Given the offshore environment, base development utilizes four artificial islands which support facilities for field development and serve as drilling centers. Commercial development with miscible EOR will be implemented in a ‘phased’ (staged) approach where the initial developments will be from the Central Island in the late 2030s followed in succession by the South Island in the early 2040s and North Island in the 2050s.
This assessment uses a novel phased approach where a ‘Tapered WAG’ scheme is used. By utilizing a phased (‘staged’) approach, multiple development concepts can be evaluated expediently. In this work we (i) show an efficient field assessment process for miscible EOR, (ii) illustrate how subsequent patterns can be brought on-line over time as part of a Tapered WAG process and (iii) demonstrate the importance of commercial assessment as part of field development planning and pilot assessment.
The full field assessments included here allows multiple development strategies to be assessed expediently and facilitates the selection of an injection solvent (hydrocarbon gas or CO2). Full field economics have been completed and hydrocarbon gas has been identified as the target solvent. Hydrocarbon gas has the benefit of being commercially attractive and is compatible with existing facilities. Currently two pilots are in preparation to assess the incremental recovery beyond waterflood and assess the commerciality of miscible EOR in a giant offshore carbonate reservoir. Key learnings in this paper include (i) an efficient methodology to assess phased field development for miscible EOR, (ii) incremental recovery of miscible EOR beyond waterflood, (iii) metallurgy and facility requirements for the two solvent schemes and (iv) a preliminary assessment of field scale commerciality including economics for the two solvents, hydrocarbon gas and CO2.
High-Power Mudhammer: A Promising Solution for Hard Formations Drilling
Authors: Souchal R. , Tarek M. , Gerbaud L. 
Published: November 2017

Abstract
A new percussion drilling system, combining a mud hammer with specific hammer drill bits, has been developed to increase drilling performances in hard formations. This system is based on a high-power down-the-hole hammer, capable of delivering high-energy impacts at high frequency. Weighted mud pressure is used as a power source, making it fully compatible with current drilling rigs and existing drilling procedures.
The hammer bits used are specifically designed depending on the formation properties and overburden pressure, using on a semi-empirical model developed from a large series of unitary and full-scale impact tests.
This system was tested extensively, using a full-scale drilling bench capable of accurately simulating deep downhole drilling conditions. Results showed significant performance gains over rotary techniques: ROP improvements from +100% to over +300% were obtained in different hard lithologies. The mud hammer and optimized 6″ bit were then used during a field trial to drill through a hard gneiss formation, increasing the ROP over roller cone bits fourfold, from 1.1 to 4.5 m/hr.
The Case for Requirement Management: How Industrial Design Requirements are Specified and Executed in the Oil Subsea Production Systems SPS vs. Shipbuilding Industries
Authors: Piciaccia Luca A. 
Published: November 2017

Abstract
None of the recent Floating Production Storage and Offloading Unit (FPSO) projects was delivered on time or on budget. This paper, part of a PhD in Systems Engineering at the Norwegian University of Science and Technology (NTNU), endeavors to make visible some Root Causes by comparing the design process in two industries enabling the upstream oil energy value chain, Subsea oil Production Systems (SPS) and shipbuilding. The comparison uses Systems Engineering concepts and techniques to illustrate the current practices and their reliance on different domain specific conventions.
Particular attention is given to possible commonalities and synergies in the design process to enable a more integrated approach to the industry needs. The purpose is to enable seamless requirement transfer between the user of the vessel and the shipbuilder.
The comparison of the two design processes is leveraging on the 25 years subsea oil production experience of the writer and the guidelines established by professor Stein Ove Erikstad at the Department of Marine Technology at NTNU in his course "Introduction to Marine Systems Design Models and Methods".
A Study on the Factors Affecting the Reliability of Laboratory-Measured Gas Permeability
Authors: Salahshoor Shadi , Fahes Mashhad 
Published: November 2017

Abstract
Laboratory measurements of gas permeability are used in many petroleum engineering studies, from core analysis for reservoir formation characterization to research work on reservoir engineering, formation damage, and various enhanced recovery techniques. The value of this data depends on how well they translate from one measurement condition to another. In this study, several factors affecting laboratory permeability measurements are investigated. Experimental results show that negligence of these factors may result in errors exceeding fifty percent.
Permeability measurements are performed for limestone and sandstone samples using a conventional steady-state technique. The effect of variations in core length, gas type, pressure of gas supply, and the flow rate and pressure of the flowing gas is systematically studied. An accurate mass flow meter for gas is built in-house to eliminate the calibration error of commercially available flow meters that depend on the gas type. Nitrogen, helium, and ethane are used in these measurements. Temperature variations of the flowing gas are recorded, and gas slippage and inertia effects are also taken into account.
Our study shows a significant reduction, bordering 25%, in permeability values measured for some shorter cores compared to the permeability value of the original whole core. This difference is more pronounced in highly permeable sandstone samples but is till significant in low permeability carbonates, bordering 20%. Permeability values measured using helium are higher than those measured using nitrogen. The difference is more pronounced in shorter cores, bordering 50%. It is important to note that this variation in permeability between nitrogen and helium exists even when corrections for the gas slippage or Klinkenberg effect are considered. Gas slippage effects are more pronounced for helium compared to nitrogen and for shorter samples compared to longer ones. The effect of length on the non-Darcy permeability and the high-velocity coefficient can also exceed 50% even when the same gas type is used. To the best of our knowledge, almost all laboratory permeability measurements neglect the temperature effect by considering an isothermal process. The effect of length on measured permeability is hinted in a few publications but no systematic study is reported. Our data show that models accounting for the effect of gas type are not accurate. We conclude that permeability measurements need to be corrected for the core length and flowing gas type effects, which vary with rock type and experimental conditions.
Risk Assessment for Groundwater Contamination from Hydraulic Fractured Shale to Aquifers
Authors: Li Weirong , Dong Zhenzhen , Wang Cai 
Published: November 2017

Abstract
Using hydraulic fracturing in shale gas and oil reservoirs to develop natural oil and gas has caused concern regarding the risk of groundwater contamination. Failed well casing, bulk media and fractures are three potential pathways that allow the transport of contaminants from the fractured shale to aquifers. Models built and simulated by CMG are used to investigate the potential risk of water contamination from hydraulic fractured shale to aquifers. This study focuses on the role of vertical fractures permeability/failing casing, aquifer permeability, reservoir permeability, distance between reservoir and aquifer, distance between fracture and water well in aquifer in controlling the contamination risk at environmentally sensitive locations.
The results show that risk strongly depends on well casing quality, initial water saturation, and fracture parameters. Furthermore, the measured risk value is more sensitive to leakage depth and leakage rate through well casing/permeable fracture when compared to the hydrogeological properties. The study shows that transport could require up to tens of thousands of years to move contaminants to the surface when well casing is integrity and without fractures/fault in the overburden layers, but also that fracking the shale could reduce that transport time to tens or hundreds of years. Conductive faults or fracture zones could reduce the travel time further. Well casing failure would reduce the travel time to months. The study identifies the important of well integrity for minimal risk to water contamination in fracturing, also the finding requires that monitoring systems be employed to track the movement of contaminants when fractures and faults appear in the overburden layers.
Simulator and Controller Tuning/Testing Rig for Artificial Gas Lift
Authors: Matraji Imad , Wang Weiliang , Boiko Igor , Al-Durra Ahmed , Abushawish Ibrahim Y. 
Published: November 2017

Abstract
Artificial Gas Lift (AGL) technology is used in mature oil wells to increase the oil production rate. Improper control of this system can produce casing heading instability resulting in slug flow and problems in downstream equipment. The AGL system has very complex nonlinear dynamics, which makes the tuning of the controller parameters difficult on a real system. In this paper, an AGL simulator is developed to test and tune the controllers before installation in the field. The simulator uses the concept of Hardware-In-the-Loop (HIL) which emulates the real behavior of gas lift system and connects to a Programmable Logic Controller (PLC) or Distributed Control System (DCS) to design and optimize control algorithms. The AGL simulator uses accurate model and high performance processing. It is equipped with a Human Machine Interface (HMI), which displays the status of AGL system using animation and trending so that slugging can be easily identified. The HIL can be operated in two modes: real time and accelerated time. An example of control tuning method using Modified Relay Feedback Test (MRFT) is used to demonstrate controller gain tuning in accelerated mode, based on its performance on the AGL simulator. The proposed HIL simulator can prove to be a convenient practical tool used for testing automation solutions before connecting them to real gas lift process in the field.
Unlocking Egypt’s Unconventional Potential
Authors: Zaher Amr , Loubens Etienne , Zayed Mohamed , Gill Nicholas , Sadhu Oneil , El Hares Layla 
Published: November 2017

Abstract
The objective of this paper is to discuss the journey of developing the first unconventional gas opportunity in Egypt. The transformation of the development concept through successful appraisal and pilot phases will be discussed, emphasizing the key learnings and outcomes from the first pilot project including a horizontal well with a multi-stage hydraulic frac. The integration of the early results from the pilot into some stochastic techniques to evaluate a range of EUR/well and range of production forecasts will also be discussed.
The Apollonia gas-bearing chalky carbonate reservoir has been appraised by 6 vertical wells. Initial attempts to evaluate Apollonia reservoir potential have relied on either natural flow or relatively small scale propped sand frac jobs with limited success. In early 2012, foam fraccing was performed to improve well productivity and ultimately project economics. Whilst significant productivity improvement was observed, the higher production rates could not be sustained.
The key uncertainties were establishing a reliable long term production profile and achieving sustainable production flow to make the development commercially viable. Estimated well ultimate recoveries from vertical wells are uneconomic. An alternative well concept was therefore required that could deliver an economical development.
A pilot phase was designed in 2015 to deploy and test 3 long reach horizontal wells, stimulated with multi-stage hydraulic fracs. Two pilot wells were drilled in 2016 and currently in production with a data acquisition program in place to determine the technical viability and commerciality. Learnings from the 2 pilot wells are being assessed to optimse the design concept for the planned 3rd pilot well.
Enumeration Approach in Condensate Banking Study of Gas Condensate Reservoir
Authors: Fuad Iqmal Irsyad , Lee Jang Hyun , Akhir Nur Asyraf , Zulkifli Izzati 
Published: November 2017

Abstract
In this paper, enumeration method was developed to simulate gas condensate reservoir behavior based on the different condensate banking zones. Sharp increment of pressure drawdown near wellbore and description of condensate bank away the wellbore are still part of challenges in simulating gas condensate reservoir. This method allows prediction on how pressure behavior near and away wellbore and how the condensate banking will evolve in future due to the simultaneous flow of gas and condensate in the reservoir.
A single well model has been developed to investigate the effect of condensate bank on pressure behavior in gas condensate reservoir. Upon production, gas condensate reservoir creates different zones based on different phase mobility, resulting from condensate banking. Enumeration initialization approach is to divide the simulation explicitly for the multiple stages. During the stops, condensate bank parameters have been modified at each zone to describe drastic change of well performance due to condensate banking. A representative matured gas condensate reservoir from Malay Basin has been selected for the purpose. The effect of the mobility changes to pressure behavior is then investigated.
Comparison of pressure behavior between enumeration ways with conventional approach have been presented. It was found that enumeration method shows better prediction in investigating the pressure behavior and condensate saturation near and away wellbore during stabilized production. It is due to its ability to predict mobility changes at every zones. The change of relative permeability to variations in fluid saturation, velocity, and interfacial tension cause increment of pressure drawdown. In analytical analysis, the increment of pressure drawdown mostly demarcated as positive skin to a factor of 30 – 90. With enumeration method in place, pressure behavior can be quantified without defining the positive skin, thus improve the condensate bank characterization.
This paper improves accuracy in defining complex physics of condensate banking phenomena, also providing key tool in quantifying the condensate bank. Enumeration approach screens the potential condensate banking in later well life and appropriate mitigation technique can be selected – optimize drawdown or change wettability as the positive skin term in simulation has been replaced.
Integrated Workflow of GOR Management Towards Sustainable Oil Production
Authors: Sarsekov Arlen , Al Neaimi Ahmed , Saif Omar Yousef , Abed Abdalla 
Published: November 2017

Abstract
Most of the oil fields in Middle East are carbonate bearing rocks including onshore and offshore environment. GOR Management is critical aspect in light oil fields where strict guideline of GOR value can cause production losses.
Integrated GOR Management is a workflow of solutions of different techniques which can be applied in order to manage gas production and stay below SH's guideline.
Integrated GOR Management will consist of the following aspects: Reservoir dynamic analysis and water/gas injection balanceEfficient VRR calculation methodologyRigless intervention such as Gas shut off with chemicals and cement squeeze.New completion technologies which can delay Gas BreakthroughSurface facility optimization.
The Real case study has been applied in giant offshore carbonate field to manage GOR value and mitigate gas movement and balance injection/production offtake.
GOR management is a critical aspect in most of the field to maximize recovery factor. Most of the time this subject is treated as a single subsurface challenge; however integrated approach which takes into account subsurface and surface optimization, rig and rigless intervention can bring the tremendous value towards sustainable oil production.