bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Gas Lift-Beam Pump Hybrid Completion Design in Thailand Onshore Field
Authors: Sompopsart Suwin , Toempromraj Wararit , Nadoon Apiwat , Hnuruang Kittithuch , Beokhaimook Chayapod 
Published: September 2019

Abstract
In the onshore field in the Northern part of Thailand, the wells are typically produced with gas lift and converted to beam pump later, using the annulus space for gas separation. In the past, the completion string must be replaced to switch to beam pumps. However, with the new Hybrid completion, the existing completion can be used, and the amount of workover is reduced. In the new Hybrid completion, two sliding sleeves are installed in the tubing string, allowing us to utilize both artificial lift methods without replacing the tubing. To produce the well with gas lift, both sleeves are closed, and the well is produced normally. When converting the well to be produced with a beam pump, both sliding sleeves are opened, a plug is set above the lower sleeve, and a downhole pump installed above the upper sleeve. This forces the wellbore fluid to flow out to the annulus through the lower sleeve. Since the liquid level is higher than the upper sleeve, most of the gas travels up the annulus while the liquid traverses through the upper sleeve from the annulus into the tubing. The liquid is then pumped along the string with a beam pump. This method acts as a gas separation mechanism to prevent gas lock and reduce efficiency problems for beam pumps. The flexibility to switch between the two artificial lift methods allows us to handle the dynamic wellbore and reservoir conditions more efficiently. The Hybrid completion has enabled us to (1) handle a wider well productivity range, (2) significantly lower the cost of workover, (3) decrease the hazards exposure during operations, and (4) produce oil and gas faster, favoring the economic return.
Deep Learning for Well Data History Analysis
Authors: Li Yuanjun , Sun Ruixiao , Horne Roland 
Published: September 2019

Abstract
The rapid development of machine learning algorithms and the massive accumulation of well data from continuous monitoring has enabled new applications in the oil and gas industries. Data gathered from well sensors are a foundation of the oilfield digitization and data-driven analysis. Here, we describe a deep learning approach to predict the long-term well performance based on a moderate duration of well monitoring data.
In this study, we first developed the data processing procedures for oilfield time series data and determined the proper selection of data sampling frequency, parameter combinations and data structures for deep learning models. Then we explored how Deep Learning (DL) models can be employed for well data analysis and how can we combine physics and DL models. Recurrent Neural Network (RNN) is a type of sequential DL model, which can be utilized for time series data analysis. This approach preserves preceding information and yields current response with memory of prior well behavior. Two candidate RNN models were tried to determine how well they were able to improve the accuracy and stability of well performance estimates. These two methods are Gated Recurrent Unit (GRU) and Long Short Term Memory (LSTM). In addition, a novel combination of RNN with Convolutional Neural Networks (CNNs), Long- and Short-term Time-series network (LSTNet), was also investigated.
These various models were tested and compared based on the public production datasets from Volve Field. Both GRU and LSTM achieved higher accuracy in performance prediction compared to the simple RNN. In the case of frequent well shut-in and opening, the failure in capturing fast pressure responses and the extreme fluctuations with the simple RNN ultimately leads to high error. In contrast, LSTNet is more stable to frequent or significant well variations. With advanced deep learning structures, engineers can interpret long-term reservoir performance information from responses estimated by deep learning models, instead of performing costly well tests or shut-ins.
Viscoelastic Characterization Effect of High-Viscosity Friction Reducers and Proppant Transport Performance in High-TDS Environment
Authors: Ba Geri Mohammed , Ellafi Abdulaziz , Flori Ralph , Noles Jerry , Kim Sangjoon 
Published: September 2019

Abstract
Viscoelastic property of high-viscosity friction reducers (HVFRs) was developed as an alternative fracturing fluid system because of advantages such as the ability to transport particles, higher fracture conductivity, and potential lower cost due to fewer chemicals and equipment on location. However, concerns remain about using HVFRs to transport proppant in DI water and harsh brine solution (e.g. 2wt% KCl and 10 lbs. brine). The primary objective of this study is to investigate the viscoelastic property that can help to understand the true proppant transporting capacity of fracturing fluids in high-TDS environment.
To address the evaluation performance of HVFRs, a comprehensive review of numerous papers associated to viscoelastic property of hydraulic fracturing fluids were investigated and summarized. This paper also provides a full comparison study of viscosity and elastic modulus between HVFRs and among fracturing fluids such as xanthan, polyacrylamide-based emulsion polymer, and guar. Moreover, viscosity profiles and elastic modulus were conducted at different temperatures. Better proppant transportation effect though higher viscosity through Stoke's law and the effect on proppant transportation from elastic modulus comparison were also investigated. Finally, HVFR Conductivity test and successful field test result were explained.
The results of the experimental work show that viscoelastic property HVFRs provides good behavior to transport proppant. Viscosity profile decreased slightly as the temperature increased from 75 to 150 when the DI water was used. While using 10 lbs. Brine the viscosity was reduced by 33%. The longer polymer chains of HVFR indicated better elastic modulus in DI water. The elastic modulus also indicated that the highest values at frequency 4.5 Hz from each amplitude, and lower values as amplitude was increased. Although high molecular weight HVFRs were utilized on the conductivity test, the results observed that the regained permeability was up to 110%. Finally, the promising results from the case study showed that using HVFRs could be performed economically and efficiently for the purpose of proppant transportation and pressure reduction in high TDS fluids.
Fracturing Perspectives in Deep HPHT Well: Comprehensive Analysis using High-Frequency Pressure Monitoring, Flowback-Rebound and Step-Rate Tests
Authors: Abdrazakov Dmitriy , Parkhonyuk Sergey , Korkin Roman , Nikolayev Max , Dyussembayev Damir 
Published: September 2019

Abstract
Analysis of production perspectives for very deep wells (below 20,000 ft true vertical depth) is closely related to understanding of the hydraulic fracturing perspectives because at these depths, the overburden stresses and long geological history of the target formations usually result in low permeability. Costs of hydraulic fracturing operations in this type of well is significantly higher than in shallower conditions; however, the risk of nonprofitable outcome is significant.
A workflow, including several key methods, is suggested to mitigate the operational and financial risks of potential hydraulic fracturing operations in very deep environments. These techniques employ cost-effective yet technically strong tools for determination of required reservoir parameters and well information, including fracture closure pressure, reservoir pressure, formation transmissibility, and well tubulars integrity. Suggested methods avoid well intervention and associated rig and services costs. The workflow was applied in a very deep and hot well with target intervals below 21,000 ft and helped in estimating the fracturing perspectives in an efficient manner.
Case Studies: Optimizing BHA Performance by Leveraging Data and Advanced Modeling
Authors: Shahri Mojtaba , James Moisan , Vasicek Alan , De Napoli Roy , White Matthew , Behounek Michael , D'Angelo John , Ashok Pradeep , van Oort Eric 
Published: September 2019

Abstract
Given the intensity of drilling operations in the North American unconventional reservoirs and the quality and amount of data gathered during a drilling operation, leveraging those data along with advanced modeling techniques for optimization purposes is becoming more feasible. In this study, historical data and advanced physical modeling are utilized to better understand and optimize the bottom-hole assembly (BHA) performance in drilling operations. A comprehensive data set is gathered for more than 300 BHA runs in the span of three years. This extensive data set enables thorough examination of the variation in the operational parameters and its effect on the drilling performance.
Different indices are used to determine and evaluate drilling performance, such as rate of penetration (ROP). Excessive tortuosity in a well can have many detrimental effects while drilling such as excessive and erratic torque and drag, poor hole cleaning (cuttings removal), low ROP, along with problematic casing and/or liner runs and associated cementing procedures. In this paper, a tortuosity index (TI) is used to quantify the drilled well quality and correlate it to ultimate drilling performance. In the next step, patterns are extracted and used along with physical modeling for optimizing drilling performance before the well is drilled.
The corresponding tortuosity index can be used as a proxy for the well path smoothness and may be used for quantifying parameters affecting drilling performance. According to historical drilling performance data, there appears to be a strong relationship between wellbore tortuosity and ROP. If drilling operating parameters (e.g., BHA configuration, directional company's performance, target formations, bit specification, mud types, etc.) can be related to the TI based on historical data, such parameters can be modified for optimizing the performance before the well is drilled.
By investigating the historical data, different trends have been extracted. In addition, different models can be built to predict drilling performance (e.g., TI) prior to drilling and according to new well design specifications. Based on data from more than 300 BHA runs and using advanced physical modeling, the most strongly correlated parameters to drilling performance have been determined and shown using different case studies. Such a historical database along with modeling techniques are used to predict well quality and drilling performance during the design phase. Using this method, well design specifications can then be optimized to enhance drilling performance and reduce the cost.
High Molecular Weight Organic Scale; A Sticky Journey in Finding the Solution
Authors: Sidek Sulaiman , M. Hatta Siti Aishah , Goh Hui Lian Kellen , Tan Kok Liang , M. Yusuf M. Hafizi , Tang Ye Lin Catherine , Mawardi M. Hizbullah , Hamzah Haziqah , Masngot Ainul Azuan , M. Jeffry Suzanna Juyanty , Riyanto Latief , Ahmat Kamis Azman 
Published: September 2019

Abstract
Flow assurance has been a big focus of oil and gas operation in ensuring the delivery of the targeted production. A few fields located offshore Malaysia have been experiencing solid deposition inside tubing and stable micro-emulsion from early stage of their life. Oil production from Field W begin in January 2003, unfortunately the wells produced viscous stable emulsion which caused the production decline significantly. Multiple analyses and efforts, including chemical and mechanical treatments, conducted over the years with minimal success. The damaging mechanism was determined to be caused by rare organic deposit that have caused a significant pressure drop in the tubing, which consequently restrict oil production and tested to only disperse at above 90°C. It was suspected that the organic deposit was a naturally occurring component of the crude oil itself, separating from the bulk of the crude as a consequence of the fluids movement towards the wellbore and the consequent drop in fluid pressure.
This paper focuses on the step-by-step workflow developed to identify the solid deposition, laboratory testing, treatments conducted and the result of different chemical treatments in Field W. The ultimate effort was by developing an advanced eco-friendly nano-fluid to remediate the rare issue of High Molecular Weight Organic Deposit (HMWOD) in the fields. The nano-fluid pilot treatment was conducted in 2014 and successfully rejuvenate the well with total of 20,000bbl incremental oil volume. Early 2018, subsequent treatments were conducted that contributed substantial improvement to the field production and at lower total treatment cost. This advanced chemical using nano-fluid technology concept is deemed feasible and will be further replicated in other fields.
This paper is highly beneficial to Operators, Petroleum and Flow Assurance Engineers experiencing flow assurance issue on organic scale such as microcrystalline wax, high molecular weight wax and stable emulsion in the crude production. This paper also promotes the use of nano-fluid technology as part of the solution to flow assurance issue in Oil and Gas industry.
Reservoir Flow Allocation and Quantification Using Spectral Acoustic Data and Temperature Logs: Case Studies in Highly Deviated and Horizontal Wells Equipped with Slotted Liners and Sandscreens
Authors: Alimohammadi Hamzeh , Aslanyan Irina , Minakhmetova Roza , Skutin Vasily , Martin Julian 
Published: September 2019

Abstract
In highly deviated and horizontal wells, focusing on inside wellbore data (flowmeter, hold-up, density, etc.) may not be enough to understand in full the well and particulary reservoir behavior, as most of the time downhole logging tools lack the capacity to reveal reservoir/well interaction, mainly in those cases where flows could occur outside the wellbore (e.g. slotted liner or sandscreen). The objective of this paper is to provide a unique solution following which a thorough understanding of flow inside the wellbore and up to five meters into the reservoir can be obtained by temperature and spectral acoustic logs.
Fluid flows in wells completed with slotted liners or sandscreens, especially those in deviated and horizontal wells, can occur either inside or outside the liner and/or casing. The conventional production logging technique in this type of completion is usually based on results generated by a mechanical flowmeter which measures flow only inside the wellbore but fails to depict flows and entry points behind tubing/casing; for example, when there is flow through cement channels or flow inside the annular section of the wells completed with a slotted liner.
Mechanical spinners have other limitations; 1) they cannot pick up small rates in low potential wells, 2) they can give false response of apparent down flow (heavy-phase recirculation) in deviated wells with 2- and 3-phase flow, 3) they are prone to harsh wellbore conditions, particulary in open-hole completions. The Total Flow analisys (borehole and reservoir flow) uses Chorus spectral acoustic and Cascade temperature logging suite is an innovative addition to conventional single and multi-array PLT tools which are designed to address the above issues. This is done by a combination of hardware and modelling solutions which can be run in highly deviated and horizontal wells with a multi-phase flow and is able to pick up small flows behind multiple barriers.
This paper presents the Total Flow results of spectral acoustics and temperature logging suite run in two horizontal wells equipped with sandscreens, and two highly deviated wells, all completed with slotted liners. These are the most difficult cases where conventional production logging tools usually fail to give vigorous results on fluid entry points as wells as the flow rate at each entry point, whereas spectral acoustic and temperature logs combination can provide detailed results on both entry points and quantity of each phase. The paper also compares the results of production logging and spectral acoustics/temperature logs in three wells to emphasize how using an inappropriate tool for a certain condition could give a wrong result which is far from the actual downhole situation.
A History of Operations Research Optimization in the Petroleum Industry
Authors: DiCarlo Jennifer , Eustes Alfred , Steeger Gregory 
Published: September 2019

Abstract
In the petroleum industry, references to a new science called Operations Research appeared in the literature in the late 1950s; however, over the last 60 years, use of Operations Research optimization techniques in the petroleum industry has been sporadic, resulting in vast untapped optimization opportunities. Some subsets of the petroleum industry have successfully used Operations Research optimization techniques for specific applications; however, when these techniques were not used by the industry, the stated reasons involved difficulty dealing with non-linearities and stochastic elements, insufficient computational power to solve realistic models, and the necessity for specialized knowledge of Operations Research optimization software and solvers. In this paper we provide a history of the use of Operations Research optimization methods in the petroleum industry by presenting a comprehensive review of papers that use these techniques. We focus on linear, non-linear, integer, and mixed-integer optimization methods and the evolution of these models in the petroleum industry over time. Finally, we provide examples of sub-optimal optimization schemes and explore reasons for the lack of Operations Research optimization use in the petroleum industry.
Mitigation of Paraffinic Wax Deposition and the Effect of Brine
Authors: Kar Taniya , Firoozabadi Abbas 
Published: September 2019

Abstract
Wax deposition in wells from shale oil production is a major challenge. Crystal modifiers and dispersants may mitigate wax deposition via steric hindrance and wettability alteration, respectively. Interaction of reservoir brine coproduced with oil and the chemicals may increase mitigation efficiency. This study investigates quantitative effect of brine on inhibitor performance, at three different flow rates, representing different field conditions.
Two dispersants and two crystal modifiers at low concentrations (500-1000 ppm) are selected among eight chemicals after screening. In our work, pressure drop in flowlines is a measure of mitigation efficiency. Three light crude oils are investigated; they are from shale formations which have high wax content. Brine effect on chemical performance is investigated from high flow rate to low rates. To select chemicals and provide a guide for flow experiments, we include optical microscopy with polarized light, rheology, and particle size measurements as part of the study.
Crystal modifiers are observed to delay pressure build up from deposition significantly compared to dispersants. For dispersants, the effect of brine is found to improve efficiency. At the intermediate flow rate, brine is found to increase efficiency of two dispersants, AO4 and PARA, by 70% and 21%, respectively, in terms of total fluid transported before blockage. For crystal modifiers, there is practically no increase in flow throughput by brine. Dispersant and brine have a synergistic effect, leading to decrease in adsorption of wax crystals on the surface of pipeline. Crystal modifiers do not have an appreciable effect on surface wettability in the presence of brine and no significant improvement is observed in inhibitor efficiency. The observation is the same for all four crystal modifiers in the screening tests at three different flow rates in the flow experiments. The eight chemicals used in this work were provided from different companies. The basis of their selection was on reduction of viscosity in vials from the addition of small amount of chemicals. We find that viscosity reduction alone is not a measure of effectiveness of chemicals. All the chemicals supplied by various companies reduce viscosity of the shale oil sample at the conditions of wax formation. However, deposition in dynamic flow tests do not relate to bulk viscosity reduction.
Our investigation includes a comprehensive set of particle size and flow measurements of low dosage crystal modifiers and dispersants in wax mitigation over a range of flow rates. There is a significant synergistic action of dispersants and brine. Chemical inhibitor performance is a strong function of flow rate and metal surface.
Enhanced Problem Solving Approach to Tackle Repetitive System Failures
Authors: Mukhamediyeva Assel , Sutcliffe Francesco Gigli , Kaitupov Sezim 
Published: September 2019

Abstract
The paper describes an innovative approach to performance improvement using Causal Learning (CL), a method based on the general observation that a business performance is largely the outcome of the organization, processes and procedures, ways of working, constraints and norms – the systems that the business applies to itself. These system causes are often remote from physical causes of equipment failures and as such remain hidden until revealed by appropriate analysis. The objective of CL is discovering these system causes that ultimately lead to an undesired outcome or event. CL helps us "learn" the performance system, develop insights from these discoveries and recognize the specific aspects of a system that require change to shift business performance.
The Company adopted this approach to improve problem solving and root cause analysis of machinery failures. The initial decision to apply CL followed several outages of power generation systems that continued to occur after previous analyses of similar events in the past.
An Enhanced Problem Solving Team (EPST) was established and trained to apply Causal Learning principles to reveal the underlying system causes of these outages. In the time since that first analysis the tools and techniques of CL have been applied to other undesired or unexpected business outcomes including HSE and project work with little or no direct technical content.
CL reveals the contribution of well-intended human behaviours behind unwanted outcomes (e.g. hardware failures), and importantly the underlying system causes of these human behaviours. This is predicated on the basis that people do their best to achieve the goals they believe they need to achieve. When it is revealed why those goal were important and why the actions taken were "their best" with the time, tools, processes available to the individual at that time at that place the systems causes can be properly understood. These findings often surprise the organization, particularly when it is made visible to Leaders at all levels how they created, or are responsible for, the systems that influenced those human behaviours.