bluuebunny/crossref_metadata_2025 huggingface dataset:
Land Degradation Neutrality Assessment using Geospatial Techniques in North Wello Zone, Northern Ethiopia
Authors: Zeleke Getnet , Zeleke Menberu Teshome , Mersha Lineger Ayele
Published: June 2021

Land degradation a serious and nationwide environmental concern in Ethiopia. The problem is its iterative relationship between land degradation, climate change, and agriculture, exacerbating one another via negative and positive feedback loops. Due to the need for an efficient response to land degradation in the country, different sustainable land management practices have been implemented since the late 1980s. The objective of this study was to analyze land degradation neutrality status using remote sensing data in the study area. We have studied the land degradation neutrality conditions of the North Wello Zone by using indicators data, namely land cover change, land productivity dynamics, and soil organic carbon stock. The result shows that the settlement areas consistently expanded at the fifth speed (2010-2018) from 1995 to 2010. Between 1995 and 2010, forestland declined by 18 percent, while an increasing trend of 26.8 percent from 2010 to 2018. The assessment results also indicate that 52.8 percent of the total area is stable and characterized by less stressed land productivity. The soil organic carbon is comparatively abundant in the high and midland vegetation areas but very thin in lowland areas. Most of the highland and midland parts of the study areas are in the conditions of stable and increasing land productivity with high biomass and soil organic content. However, most lowland areas showed a decline in land productivity conditions.
Returning to Sport: Female Athletes Living With and Beyond Cancer
Authors: Schwartz Anna L , Terry Christopher M
Published: June 2021

Athletes living with and beyond cancer can continue to train and, in some cases, compete during treatment. Following cancer treatment, athletes can return to competitive sport but need to learn to adapt their physical strength and training to lingering effects of cancer. It is critical for oncology healthcare providers to use the principles of assess, refer and advise to exercise oncology programs that are appropriate for the individual. Managing side effects of treatment is key to being able to train during and immediately following cancer treatment. Keen attention to fatigue is important at any point in the cancer spectrum to avoid overtraining and optimize the effects of training.
Construcción de un concepto constitucional de delito con base en los principios de taxatividad, proporcionalidad y dignidad
Authors: Fonseca Luján Roberto Carlos
Published: June 2021

El artículo tiene como objetivo central proponer un concepto constitucional de delito construido con base en los principios constitucionales de taxatividad, proporcionalidad y dignidad de la persona. Este concepto es pertinente en el marco del diálogo entre la dogmática penal y constitucional que ocurre en el proceso actual de constitucionalización del ordenamiento. La metodología emplea el método sistemático, cuya aplicación permite relacionar los principios desarrollados por la interpretación constitucional de la Suprema Corte de Justicia de la Nación con las categorías penales generadas por la Teoría del Delito
Panel laboral general y Mecanismo laboral de respuesta rápida en instalaciones específicas del T-MEC
Authors: Saldaña Pérez Juan Manuel
Published: June 2021

En este trabajo de investigación se analizaron las diversas obligaciones laborales pactadas en el T-MEC, así como los procedimientos arbitrales previstos tanto en el Protocolo por el que se sustituye al TLCAN por el T-MEC del 30 de noviembre de 2018 como en el Protocolo Modificatorio del T-MEC del 10 de diciembre de 2019. Con especial cuidado se examinó lo escrito con letra chica en las Notas al pie de página de este último, donde se incluyeron importantes cambios.
Intelligent Pressure Control System for MPD
Authors: Song Zhao Hui , Li Fu Qiang , Xie Deng Pan , Zhu John , Zeng Liam , Wang Xu Dong
Published: June 2021

MPD (Managed Pressure Drilling) is an important technique for challenging drilling operations especially in narrow operational windows. This paper is to introduce the IPC (Intelligent Pressure Control) system with super compact footprint, unique algorithm and IoT (Internet of Things) feature which bring operator a fresh understanding of MPD operation.

IPC system is equipped with the ultra-compact MPD manifold (L11.75ft × W7.50ft × H9.08ft) with complete functionality of measurement & automatic control, benefit the operators on footprint reducing for limited field space. With the unique algorithm integrated in iPWD (Intellegent Pressure While Drilling) module, the real time downhole pressure data could be generated without any downhole PWD (Pressure While Drilling) sensor, the deviation between iPWD data and real PWD data is within 3%, which was proven in field operations. NEBULA system is an add-on feature for IPC system, using cloud and IoT technologies, it could track the equipment’s specific location, working status and parameters, providing statistical diagnosis based on data collected from field operations, which helps operators to make decisions quickly. The data uploaded to cloud could generate different reports based on end user’s requirements to analyze drilling operation challenges or difficulties. You can receive all data provided by NEBULA system on your cellphone and PC (Personal Computer) at any time anywhere.

The compact design of IPC system manifold benefit the operator by minimizing the footprint in limited field space especially for offshore operations; iPWD module provides full time data during drilling operation regardless of connection or any pump off scenarios; also erases the need of PWD sensor on BHA(Bottom Hole Assembly). NEBULA system featured on IPC equipment generates different report based on real-time data received on site after cloud calculation and big data analysis, all data and report could be accessed via cellphone or PC at any time anywhere, which can be an upgraded intelligent features on conventional MPD technology.
A Comprehensive Model for Gas Influx Detection and Control While Managed Pressure Drilling and Its Application
Authors: Fan Hongkang , Jiang Shanhong , Zhou XianHai , Wang Guo , Zhou Haobo , Zhang Hongning
Published: June 2021

The equipment commonly used in managed pressure drilling (MPD) allows alternative responses to kicks that do not need to stop the pump or shut in the well. The pivotal issue of kick control for MPD is the early gas influx detection and the optimal initial response when the kick was detected during drilling. The careful research on gas influx detection and the corresponding control method is very important.

Firstly, the valve opening, bottom hole and well head pressure variation characteristics were analyzed based on the real-time measured data, and then the valve opening and pressure signature of gas influx for different MPD modes (CBHP, CWHP, MFC) was obtained based on the theoretical and model analysis, in which the pressure variation caused by the tripping, ROP and flow rate variation were taken into account, through which the gas kick can accurately detected as soon as quickly. Secondly, the influence factors for initial response selection of kick control was analyzed, and then the comprehensive optimization schedule of response for kick control was established, in which several factors were took into account, such as formation characteristics, drilling conditions, influx intensity and so on, through which the best mode for kick control can be obtained easily. Moreover, integrated software that combined kick detection and gas kick control simulation was developed based on which the best pressure control procedure and kick initial response can be obtained easily.

The gas influx detection and control technique has been applied in Fuling shale gas field of SINOPEC, which is the first large-scale commercial development shale gas field of China. The results show that we can make precisely gas detection based on the new early gas influx detection method and the kick can also be control very well based on the optimization method. Based on the proposed method for kick detection and control, the NPT have been reduced more than 60%.

This study will presented a novel gas kick detection theoretical model for all common MPD modes, and the gas influx control optimal procedure. Through the field application in shale gas drilling, the results show that the NPT has been reduced obviously, and the optimal kick control was designed has successfully prevented the serious kick and reduced the drilling cost.
Resin Squeeze Operation to Successfully Seal Micro-Channels and Eliminate Sustained Casing Pressure of a Sour Gas Well
Authors: Wang Ying , Zheng Xin , Li Li , Yuan Jianbo , Vo Minh , Reading Richard , Zhang Junliang
Published: June 2021

This paper describes the successful resin squeeze operation to seal off a micro-annulus between the 7" and 9-5/8" casings on a sour gas well located in Sichuan Basin, China. Integrated plug and abandonment were also essential to eliminate the risk of potential H2S exposure presented to the residents around this area.

Resin, as a new alternative sealing technology, was technically evaluated, laboratory tested, and then chosen for squeezing into a micro-annulus to stop gas migration for its solids-free and low-viscosity properties compared to a conventional cement. The squeeze job was designed by taking the casing yield strength as the pressure limit (Confirmed by caliper log the casing was in good condition) and determining the resin pumping volume based on estimated resin squeeze volume and the remaining resin plug length. A "Braden-head" squeeze method was selected considering the low injection rate observed during the water injection test. Both stage-up and stage down squeezing techniques (hesitation squeeze of increasing and decreasing wellhead pressure stage by stage) were performed to maximize the injected volume of the resin sealant. A total of 800 L of 9.16 lb/gal resin was placed into a 4 ft milled interval, and 50 L were successfully squeezed into the 7" × 9-5/8" casing annulus. An operational learning was that resin injection is greatly improved during the stage-down process while keeping the casing annulus open. Evidence that the micro-annulus leak path had been sealed was an observation of 0 psi on the 7" × 9-5/8" casing annulus after resin fully set.

The method of locating the optimal spot to squeeze resin involved noise logging to analyze for a potential gas source in the annulus. The post job results confirmed that resin acts effectively as an annular barrier in the repair of gas leaks in the small volume situations where micro-annulus exists in the cement sheath. For large voids such as inside 7" casing, a combination of cement plug plus mechanical barrier is recommended to be placed directly above resin plugs to complete permanent plug and abandonment of the wellbore.
Breakthrough Cementing Technology for Enhanced Well Integrity in Myanmar Offshore Shallow Gas Well
Authors: Li Yi , Ullah Mohammad Solim , Ai Wu Chang , Khumtong Thirayu , Temaismithi Kantaphon , Luo Yu Wei , Xiong Shao Chun , Qi Ying , Ding Xi , Zhang Hao , Xu Qian Fu , Yan Ping
Published: June 2021

In Myanmar offshore, a substantially promising gas reservoir was discovered, the objective of primary cementing is to achieve long term zonal isolation, as any gas migration to surface would cause production loss, as well as significant security issues. Remedial cementing work will cause costly non production time, while the result will be compromised. Shallow gas migration, lost circulation and mud removal, all these factors cause undesired negative effects for cementing design, While the objective is to provide a firm barrier and good zonal isolation, this paper will describe in details the cementing challenge, the methodology, and how the slurry parameter was designed and evaluated for a Fit-For-Purpose solution.
Using Data-Mining CRISP-DM Methodology to Predict Drilling Troubles in Real-Time
Authors: Al Gharbi Salem , Al-Majed Abdulaziz , Abdulraheem Abdulazeez , Patil Shirish , Elkatatny Salaheldin
Published: June 2021

Drilling is considered one of the most challenging and costly operations in the oil and gas industry. Several initiatives were applied to reduce the cost and increase the effectiveness of drilling operations. One of the frequent difficulties that faces these operations is unexpected drilling troubles that take place and stops the operation, resulting in losing a lot of time and money, and could lead to safety issues culminating in a fatality situation. For that, the industry is in continues efforts to prevent drilling troubles. Part of these efforts is utilizing the artificial intelligence (AI) technologies to identify troubles in advance and prevent them before maturing to a serious situation. Multiple approaches were tried; however, errors and significant deviation were observed when comparing the prediction results to the actual drilling data. This could be due to the improper design of the artificial intelligent technology or inappropriate data processing. Therefore, searching for dynamic and adequate artificial intelligent technology and encapsulated data processing model is very essential.

This paper presents an effective data-mining methodology to determine the most efficient artificial intelligent technology and the applicable data processing techniques, to identify the early symptoms of drilling troubles in real-time. This methodology is CRISP-DM that stands for Cross Industry Standard Process for Data Mining. This methodology consists of the following phases: Business Understanding, Data Understanding, Data Preparation, Modeling, Evaluation and Deployment. During these phases, multiple data-quality techniques were applied to improve the reliability of the real-time data.

The developed model presented a significant improvement in identifying the drilling troubles in advance, compared to the current practice. Parameters such as hook-load and bit-depth, were studied. Actual data from several oil fields were used to develop and validate this smart model. This model provided the drilling engineers and operation crew with bigger window to mitigate the situation and resolve it, prevent the occurrence of several drilling troubles, result in big time and cost savings. In addition to the time and cost savings, CRISP-DM provided the artificial intelligent experts and the drilling domain experts with a framework to exchange knowledge and sharply increase the synergy between the two domains, which lead to a common and clear understanding, and long-term successful drilling and AI teams collaboration.

The novelty of this paper is the introduction of data-mining CRIPS methodology for the first time in the prediction of drilling troubles. It enabled the development of a successful artificial intelligence model that outperformed other drilling troubles prediction practices.
Engineered Reinforced Composite Mat Pills to Effectively Combat Losses While Drilling in Qatar
Authors: Muhammad Faraz Khan , Mohammed Karajagi Zahid , Pallapothu Surya , Mohamed Hafez , Klem Pierre , Arshad Umar
Published: June 2021

Drilling into fractures and fissures in carbonate reservoirs with lateral pore pressure variations is a major challenge. Accurately predicting and managing fracture initiation and fracture closure pressure is not practically feasible in naturally fractured carbonate rocks. Local fracture closure pressure (FCP, minimum in situ stress) around fractures are much lower than the mean value of FCP for the area, as observed in the Al Shaheen field. Drilling operators are experiencing massive lost circulation resulting in potential formation damage; and cost overruns. To address these lost circulation instances, modern lost circulation pills must be implemented.

Drilling through the natural fractures within parts of the Shuaiba limestone reservoir usually results in significant drilling fluid losses, up to 50 m3/h. Lateral pore pressure variation causes dynamic inflow conditions within the wellbore, which make plugging fractures difficult. In addressing these lost circulation challenges, various approaches were previously used, notably reducing the hydrostatic pressure of fluids column, utilizing lighter weight drilling fluids, reducing the penetration of fluids into fractures with the use of various lost circulation materials, and the use of thixotropic cement slurries and lightweight high-solids-content cement slurries. Conventional lost circulation treatments provided very limited success under these conditions.

An engineered composite fiber-based lost circulation pill with an innovative blend of fibers and sized solids to bridge and plug thief zones has been developed to address these lost circulation challenges. This pill was designed to be pumped through either a dummy bottomhole assembly (BHA) or through bypass circulation ports above the BHA with total flow area of 1.571 in2. These pills have been successfully used to mitigate losses while drilling as well as to achieve an incremental equivalent static density up to 144 kg/m3 to drill and cement the section. An impermeable grid created by this system was able to withstand the additional pressures. As a result, all the wells treated with these pills in the field were successfully drilled and cemented.

After establishing the field specific guidelines over 2 years, continuous success was replicated in other wells for all the operator's rigs in Qatar.
A Blowout Accident Causative Model of Hydrogen Sulfide Oil and Gas Wells using DEMATEL and ISM Algorithms
Authors: Han Chao , Guan Zhichuan , Xu Yuqiang , Hu Huaigang , Wu Desong
Published: June 2021

Blowout is one of the most serious accidents in the drilling process of hydrogen sulfide (H2S) oil and gas wells, often accompanied by the leakage of H2S and other toxic gases, which easily causes casualties and huge economic and environmental losses. Therefore, this article uses DEMATEL and ISM hybrid algorithms to establish a blowout accident-causing network model for oil and gas wells with H2S content, thus strengthening the risk management.

In this model, firstly, the general causative factors of blowout accidents are extracted by accident statistics. Secondly, expert knowledge is adopted to determine the correlation matrix among factors. Thirdly, based on the DEMATEL algorithm, the degree of the relationship among the factors is analyzed. The importance degree (centrality) of each factor and its status as well as role (causality) in the accident-causing system are given. Finally, the ISM algorithm is used to classify the factors and establish an accident-causing network diagram with hierarchical relationship.

The proposed model has been applied in a gas field containing H2S in East Sichuan, China. The results show that causative factors of blowout accidents can be divided into cause group and effect group according to the influence relationship among them. The cause group implies the meaning of the causative factors, and the effect group denotes the meaning of the causative factors. Hence, it would be necessary to control and pay great attention to the cause group factors beforehand. The key causative factors of blowout accidents are geological exploration technology, safety monitoring facilities and on-site safety culture, which belong to the cause group and are at the basic level of the accident-causing network diagram. This model has provided effective decision-making guidance for HSE work in gas field and reduced the incidence of blowout accidents.

This model uses a combination of qualitative and quantitative methods to analyze the causes of blowout accidents, not only considering the relationships between factors and accidents, but also considering the relationships between factors and factors. As a result, it provides decision-making basis for the prevention and control of blowout accidents in H2S oil and gas wells.
Fracture Treatment Design in the Lower Miocene Reservoir, Offshore Viet Nam
Authors: Nguyen Huu Truong
Published: June 2021

In the past decades, most oil explotation in the White Tiger oil field was produced from the basement reservoir. However, in recent years, these pay zones consist of basement reservoirs, Oligocene reservoirs, and Miocene reservoirs of which oil field s have been declined in oil production rate due to several issues such as complex fracture network, high heterogeneity formation, high water cut, and the reduction of reservoir pressure. The huge issues in the most production wells at basement reservoir were high water cut and it has been significantly increasing during oil production yearly. Therefore, the total amount of oil production in all pay zones sharply decreased with time. At present, the lower Miocene reservoir is one of the best tight oil reservoirs to produce oil extractrion. The lower Miocene reservoir has been faced some issues such as high heterogeneity, complex structure, catastrophic clay swelling, low connectivity among the fractures, low effective wellbore radius and the reservoir that is hig h temperature up to 120°C, the closure pressure up to 6680psi, reservoir pressure up to 4500 psi, reservoir depth up to 3000m. Another reason low conductivity consists of both low reservoir porosity ranging from 1% of the hard shale to 10% of the sandstone formation, and the low permeability raining from 1md to 10md. By considering the various recovery methods, the integrated hydraulic fracturing stimulation is the best tool to successfully stimulate this reservoir, which method allows an increase in oil production rate. In the post fractured well has been shown an increase in productivity over 3 folds in comparison with the base case with fracture half-length nearly 75m, and fracture conductivity about 5400md.ft, which production rate is higher than the production rate of the base case. In addition, the proppant mass is used of 133,067 lbs of which the first main stage is to pump sinter lite bauxite proppant type of 20/40 into the fractures and the next big stage is to pump sintered ball bauxite proppant size of 16/30 into the fractures, which not only isolate proppant flow back but also increase fracture conductivity at the near wellbore as wel as high productivity rate after fractured well. To improve proppant transport, fract uring fluid systems consist of Guar polymer concentration of 11.2 pptg with these additives to form a total leak-off coefficient of 0.00227 ft/min0.5.
Integrated Geomechanics, Geology, Petrophysics and Mineralogy Model for Successful Deep HPHT Gas Well Drilling
Authors: Moid Farrukh
Published: June 2021

Drilling high pressure gas wells requires special consideration and precautions. The main goal is to analyze wellbore stability to plan drilling fluids and best drilling practices to minimize drilling risks. Ultimate objective is to provide a stable and smooth borehole environment for wireline logging runs and completion of a deep high pressure high temperature gas wells. Continuous collaboration and integration among all disciplines including Drilling, Geology, Geo-steering, Production Engineering and Reservoir Management is deemed key to a successful well.
On the Influence of the Equivalent Circulent Density Fluctuations on the Development of the Wellbore Natural Fracture
Authors: Kamgue Lenwoue Arnaud Regis , Deng Jingen , Feng Yongcun , Songwe Selabi Naomie Beolle
Published: June 2021

Wellbore instability is one of the most important causes of Non-Productive Time during drilling operations causing billions of dollars of losses every year. During the drilling stage, the Equivalent Circulent Density (ECD) is subjected to fluctuations caused by some factors such as the drill string vibrations cyclic loads. The fluctuating ECD applied on the fractured formation progressively modifies the initial parameters of the fractured formation such as its length and its width and this process finally results into wellbore instability.

In this research, a poroelastic model based on a finite element method has been established to analyze the influence of the drill string vibration cyclic loads on the development of the wellbore natural fracture. The analysis was conducted with a two-dimensional plane strain model. A traction-separation law based on energy has been proposed for the Cohesive Zone Model. A nonlinear finite element software ABAQUS was utilized as the numerical simulator.

The numerical results showed that the profiles of the fracture width as a function of time follow a sinusoidal behavior similar to the behavior of the drill string vibration cyclic loads profile. For different values of the Weight On Bit (WOB) and constant drill string Revolution Per Minute (RPM), an increase of the fracture width with the fracture length is observed in the near wellbore region. In the region far away the wellbore, the fracture width globally decreases with an increase of the fracture length for each fracture profile. the investigation of the effect of some drilling operational parameters on the development of the wellbore natural fracture also demonstrated that the drillstring vibration cyclic loads lead to an increase of the fracture length, fracture width, the loss circulation and the Bottom Hole Pressure.

This study couples the integration of the fracture rock development with the continuous cyclic load generated by drill string vibrations. This aspect has been rarely discussed in the literature. The study indicates that the cyclic loads significantly affect the development of the wellbore natural fracture during drilling operations, and therefore has an important impact on the wellbore stability analysis.
Maximizing Injection Performance Through Fit-for-Purpose Dynamic Underbalance Perforation Using Unconventional Gun System in Offshore Well, Sarawak, Malaysia
Authors: A'akif Fadzil Nurul Aula , Sapian Nik Fazril Ain , Tusimin Fuziana , Latief Riyanto Latief Riyanto , M Zaki Shazana , Abu Bakar Asba Madzidah , Sadan Nur Syazana , Bakar M Faris , Adhi Naharindhra Adhi Naharindhra , Misron Mohd Al Perdaus , Daly Kerry , Ibrahim Ahmed Abdelatty Abbas , Baharuddin Nurbaiti
Published: June 2021

The perforation strategy of Dynamic Underbalance (DUB) created the surging effect to remove debris from the perforation tunnels, thus reducing skin for optimal injectivity in this offshore development water injector well in Malay Basin, Offshore Sarawak. The objective was to inject up to 18,000 bwpd for pressure maintenance purposes.

In the design phase, perforation software was used to perform the simulation iterations by sensitizing on the number of empty tubing conveyed perforation (TCP) gun chambers added at the top and bottom of perforation intervals. However, due to small gun size (4-½ in.), limited rat hole length and high static underbalance (1,000 psig), the desired amount of DUB using conventional empty gun volume only was not possible to be achieved. As a result, an innovative approach using two Pressure Operated Tester Valves (POTV's) was proposed, to create additional empty space inside the tubular between the POTVs above the packer. However, this created additional challenges which had to be overcome.

Presence of empty tubulars in between the POTVs prevented the required hydraulic pressure transmission through the tubulars to activate the perforation guns via normal hydraulic TCP firing head. Therefore, a specialized firing system was required, which consisted of an acoustic communication system triggering downhole electronics to actuate a standard TCP firing head (Top-Fire Dual) - a first for this type of firing head.

The POTV was activated by applying a pre-set annular pressure. Opening lower POTV, after the perforation fired, will create the required DUB surge, around 1,000 psi, which help cleaning up the perforation tunnels. Downhole fast gauges (recording in microseconds range) were run as part of the assembly to measure and to confirm the created DUB effect.

Both fast gauges as well as acoustic gauges confirmed that 300 psi DUB was created upon gun firing and around 1,000 psi surging was achieved after the two POTVs were opened. Maximum losses recorded at 525 gallons per minute were observed following perforation. The well's injectivity performance was evaluated by performing step rate test and the result confirmed the well was able to meet higher injection rate than the plan.
A Novel Approach to Drilling Engineering Sensitivity Analysis and Visualization
Authors: Suryadi Hendrik
Published: June 2021

Well design is a process to integrate multiple designs objects, such as trajectory, wellbore geometry, BHA and drillstring, fluid, and rig specification to work synergically to deliver a successful drilling execution. The method to validate coherency of those various design objects is by performing engineering analysis through modeling, such as torque and drag, hydraulic, vibration, and casing load analysis. Every time any design objects are changed, the engineer needs to rerun engineering analysis calculations to ensure the proposed changes are still acceptable or within equipment specification and design standards. Engineers also need to define the most optimal parameters and designs in order to get the best performance in execution. For this purpose, the engineer spends time performing engineering sensitivity analysis to understand the effect of various parameters on the design KPIs.

The challenge with the current drilling engineering application is that engineers need to perform multiple scenarios manually, which is very cumbersome and time-consuming. Time requirements will limit the engineer to perform different kinds of scenarios. Comparing and visualizing the analysis results of multiple scenarios also can be difficult, especially where they involve multiple dimensions. Novel ideas or solutions were introduced in the cloud-based new digital well construction planning applications. The system will automatically create multiple scenarios based on the number of sensitivity parameters. For example, calculating the sensitivity of hydraulic calculation for 5 different flowrates, 5 RPMs, 5 fluid densities, and 5 ROPs will produce 625 scenarios. And each scenario will be calculated for every 100 ft from run start depth to run end depth. All those will be calculated with the power of cloud computation to speed up simulation time and the results stored in the data cube, which is available for business intelligence tools to visualize it. Leveraging the latest development of data visualization technology also brings a new way for an engineer to view multidimensions of plots to quickly get the insight for decisions.

This new method of sensitivity analysis and visualization will improve drilling engineer working efficiency to identify potential risks and formulate the optimal parameters for the drilling program. The engineer can easily interact with the plots and understand the effect of multiple parameters on the engineering simulation results.

This will give a new user experience for drilling engineers on evaluating drilling engineering sensitivity analysis results and plots in the new digital way of working.
Advanced Computational Modeling for Estimating Safe Cuttings Load Through MPD Surface Equipment
Authors: Deshpande Kedar , Naphade Pravin , Wuest Chad
Published: June 2021

The critical components of Managed Pressure Drilling (MPD) operations include surface manifold, surface chokes and the pipes connected to Mud Gas separators. The MPD surface equipment needs to safely handle a multiphase mixture of drilling mud, cuttings load and reservoir fluid influx during operations. The focus of this work is to establish safe cuttings load limit that can be handled by MPD system using advanced computational fluid dynamics (CFD) modeling approach.

In MPD operations the surface choke is the key surface manifold component through which the fluid and cuttings flow before entering the Coriolis meter. Based on choke position only a certain volume and size of cuttings (cuttings load) can pass through chokes without causing unintentional pressure surges. In this work, Non-Newtonian fluid flow using Eulerian-Granular modeling approach is presented to understand the effects of cuttings load and different choke positions on the overall pressure drop through MPD surface manifold. Several CFD studies were conducted for different choke sizes, cuttings load and fluid properties to understand velocity profiles, cuttings accumulation and pressure drop across the MPD surface manifold.

CFD results were first validated with available test data to generate confidence in CFD simulation model settings, good match was observed in pressure values between test and numerical results. Based on CFD simulations, charts were developed showing effect of operational parameters that help field personnel design the best surface equipment configuration, determine associated pressure drop and guard against the possibility of Non-Productive Time (NPT). CFD studies provided insights into cuttings accumulation and associated pressure drop change across choke for given operating conditions.

Usage of advanced computational methods helped model the multi-phase flow with cuttings accurately and provided safe cuttings load estimation for given range of operational parameters.
Predictive Modelling and Technical Design Application into Effective Casing Wear Operational Management Plan
Authors: Cahill Q. , Marsh R. , Calogero D. , Dutta B.
Published: June 2021

Predicting casing wear has often been regarded as an empirical art as there are many influencing factors, including but not limited to the sizes and grades of the drill pipe and casing, type of hardbanding, drilling fluid properties, rate of penetration, trajectory and formation properties. Formations present in offshore Western Australia often contain loose and friable sands which produce highly abrasive cuttings which, when suspended and circulated in drilling fluid, are known to exacerbate casing wear.

Casing wear is considerably worse in deviated and multilateral (ML) wells; Woodside's experience drilling ML wells has involved costly non-productive time (NPT) due to the subsequent requirement for remedial tieback systems to maintain well integrity.

In 2018 and 2019 three tri-lateral wells were drilled as part of the larger Greater Enfield Project drilling campaign. Each of the multilateral wells were progressively longer and more challenging with regard to casing wear. Previous experience on nearby wells in analogous fields identified casing wear as a significant risk for the project.

Further to this, an opportunity was identified to design the longest tri-lateral well as a quad-lateral well, which would allow increased recovery if reservoir quality was poorer than expected. The Drilling and Completion Engineering team were challenged with proving that casing wear could be effectively evaluated and managed during operations to allow a quad-lateral well design if required.

Several key areas were investigated in order to effectively manage casing wear. These included: Assessment and measurement of casing manufacturing tolerances;Predictive casing wear modelling using well offsets in conjunction with casing wear software;Casing connection finite element analysis and mechanical hardbanding testing;Full length ultra-sonic testing of casing for wall thickness benchmarking;Hardbanding management plan (which formed part of the overall drill pipe fatigue management plan);Casing wear management plan based on well offsets and casing wear software modelling results, including additional controls such as 'krev' and swarf monitoring;Planning and execution of casing wear logging;Post well evaluation.

The casing wear operational plan was effective in monitoring and limiting the amount of wear. It provided confidence to the management team that successful execution of a quad-lateral well was feasible.

This paper will describe the steps taken to minimise casing wear, discuss comparisons between the predicted wear and the actual measured casing wear, and provide a recommended workflow for predicting casing wear in future wells where casing wear is a critical factor.
Lesson Learned from Low-Cost Fracking of Low Permeability Glutenite Reservoirs
Authors: Li Shuai , Cai Bo , Ding Yunhong , Wang Jia , He Chunming , Cheng Ning , Chen Jin , Gao Yuebin
Published: June 2021

The unconventional reservoir in Mahu Basin in Xinjiang Oilfield has more than one billion tons of oil and gas resources, and it is the first effectively developed glutenite reservoir in China. In the development of this basin, we faced with the following problems: complex lithology (glutenite reservoir), large reservoir depth (3750-3900m), low permeability (average porosity 9.8%, permeability 5.4mD), thickness variation (3.4-23m), multiple thin layers distribution (3-5 thin layer distribution) and high-pressure coefficient (1.6-1.8). This kind of reservoirs have no economical production without hydraulic fracturing, while the stimulation operation still faced with difficulties such as un-predicate fracture propagation, high cost and multi-layers. In order to solve the above problems, we investigated the economic stimulation of glutenite formation: (1) 30cm×30cm×5cm rock sample experiments revealed fracture initiation and expansion regulation including piercing gravel, bypass gravel and stop expansion; (2) A low concentration fracturing fluid system was developed, guar concentration reduced from 0.40% to 0.25%. Viscosity of this kind fracturing fluid can maintain 100mPa.s under condition of 90°C and 170S-1 after 120min. By using this fracturing fluid, operation cost can be reduced by 5.8$/m3, residue can be reduced by 10%. (3) Optimize the p'n'p technology of staged fracturing for horizontal wells, establish an effective fluids pump process, that is, pre-gel to initial fractures, followed slickwater to extend fractures then followed gel to carry sands. (4) A soluble plug and multi-stage cementing sleeve was formed after the investigation of fracturing completion tools. (5) Replacement of ceramsite by low-cost quartz sand, reduced 31 million US dollars in 72 horizontal wells. (6) A factory-fracturing model has formed in which operating time can be reduced by 20%. The above integrated technology has been applied in more than 135 wells, the daily oil production per well has increased from 5t/day to 26.7t/day and now the basin has a capacity of 2.32 million tons. Application of the integrated technology can be references for efficiency development of low permeability glutenite reservoirs.
First Autonomous Inflow Control Device AICD Deployment in Wassana Field
Authors: Taksaudom Pongpak , Kelly Tim , Meeteerawat Atisuda , Carter David , Swaminathan Kannappan , Lozet Aymeric , Tan Chee Seong , Watana Kulapat , Moses Nicholas , Goh Gordon , Kumar Amrendra , Krishnamoorthy Suba-Rao
Published: June 2021

Wassana oil field is located in the Gulf of Thailand with shallow water depth at approximately 60m. A major challenge is excessive water production which reduces reserves recovery and increases costs associated with produced water handling.

The target reservoir is ~20ft thick with active aquifer support. The low oil/ water mobility ratio due to high oil viscosity (≥ 30cp) risks early water coning and high watercuts. All horizontal wells drilled in the Wassana field during the initial development and the first infill campaign were completed as non-ICD openhole standalone screen. For the second infill campaign, the non-ICD simulation showed water breakthrough occurring at the start of production. Once breakthrough occurs, water production rapidly dominates production prompting premature shut-in of production, leaving much unrecovered oil behind. To overcome this problem, Autonomous Inflow Control Devices (AICDs) were introduced to control the production influx profile across the entire horizontal section to delay water coning and to significantly choke back water production when it occurs.

With intensive pre-drilled AICD modeling using 3D dynamic time lapse simulation, two wells in the second infill campaign were subsequently chosen to be completed with a configuration of zonal AICDs isolated by swell packers. This design enables isolation across horizontal reservoir section with high water production in tandem with compartmentalization across the contrasting permeability region. Once water breakthrough occurs, the unique autonomous ability of the cyclonic AICD is triggered by exploiting the physics of rotational flow of the vortex-inducing pressure drop principle through a restrictive funnel-type flow-path in a tool with no moving parts. The low viscosity of both water and gas phase promotes higher rotational velocity inducing higher pressure drop or back-pressure of inflow vortex breakdown towards the inlet into the tubing flow, thus helping to further reduce the influx contribution of the high water producing sections. Essentially, the higher watercut zones flowing through the device is restricted more rigorously compared to the oil-prone zones.

Both wells were successfully drilled and completed with AICDs in February 2019. Based on actual and early-production history-matched performance, these 2 pilot AICD wells are projecting an improved cumulative oil production gain of up to +7% over 5 years of production. The reduction or delay of water production can benefit the field both in enhancing oil recovery and water handling cost saving.
Internal Friction and Compressive Deformation in the Primary Zone during the High-Speed Cutting of SiCp/Al Composites
Authors: Lin Xiaoxuan , Yang Wenyuan , Xu Daochun , Li Wenbin , Ma Simin
Published: June 2021

The present work proposes that there is internal friction and compressive deformation in the primary zone. Mathematical model was established, in which the internal friction coefficient and some compressive characteristics of serrated chips were calculated. High-speed orthogonal cutting experiment was performed on SiCp/Al composites at cutting speeds of 10–350 m/min and feed rates of 0.07–0.12 mm/r. The internal friction and compressive deformation in the primary zone were investigated by combing results obtained in the experiments with the mathematical model. The internal friction coefficient (0.21–0.47), compressive stress (185.4 MPa–226.9 MPa), and compressive strain rate (0.013×104 /s–0.554×104 /s) increased with increasing cutting speed. However, the compression value (17.3 µm–50.0 µm) and compressive strain (0.18–0.26) decreased with the cutting speed.
Numerical Research on Multi-Particle Movements and Nozzle Wear Involved in Abrasive Waterjet Machining
Authors: Du Mingming , Wang Haijin , Dong Huiyue , Guo Yingjie , Ke Yinglin
Published: June 2021

Multi-particle velocities and trajectories in abrasive waterjet machining are of great value to understand the particle erosion mechanism involved in the cutting process. In this paper, the whole-stage simulation model is established from the high-pressure water and abrasive particles entering the nozzle to the mixed abrasive jet impacting the workpiece based on the SPH-DEM-FEM method. Comparing the simulation results with the experimental results under different process parameters, the capability of the proposed model is systematically validated. The model is applied to study the mixing and accelerating process of abrasive particles, and the results show that a speed difference is existed between the water and abrasive particles after being ejected from the nozzle. In addition, the nozzle wear pattern is also analyzed carefully. It is discovered that the most serious wear happened at the junction of the mixing chamber and the focusing tube. And the focusing tube wear is uneven and spreads downward.
Focusing properties and focal shift of a vortex cosine-hyperbolic Gaussian beam
Authors: Hricha Zoubir , Halba El Mostapha El , Lazrek Mohammed , Belafhal Abdelmajid
Published: June 2021

In this paper, we investigate the focusing properties of a vortex-cosh-Gaussian (vChG) beam passing through a converging thin lens. Based on the Huygens-Fresnel diffraction integral, we derived the analytical propagation equation as well as the beam width expression of a focused vChGB. It is shown that the focusing properties including the focal shift of the focused vChGB are crucially dependent on the incident beam parameters namely the decentered parameter and the topological charge in addition to the Gaussian Fresnel number\({N_F}\). From typical numerical examples, it is found that the focused vChGB is transformed into a multi-lobes structure shape at the real focus plane, and the principal maximum intensity of the beam is located away from the axis. The amount of focal shift, which is determined from the minimum spot size criterion, is strongly dependent on the Fresnel number, the decentered parameter and the vortex charge m. The obtained results may be useful for the applications of the vChGBs in beam shaping and beam focusing.
Numerical Analysis of Temperature Reduction Effect of Permeable Pavements
Authors: Liu Zhe , Tian Yuxiang , Ma Biao , Si Wei , Wang Xiaoqing
Published: June 2021

Permeable pavements can effectively reduce the urban road surface temperatures. To study the cooling effect of holding water on the road surface under the comprehensive influence of the external water and heat environment, a numerical model established by a finite element analysis software and an indoor test were used to verify the temperature change behavior of the road surface under different heating temperatures and holding water conditions. The results show that the average error between the numerical model and indoor test is 3.5%, and the model reliability is high. Under the same conditions, the change in thickness of the permeable pavement surface and base course has a negligible effect on the temperature of the road surface. For every 100 J/(kg/°C) increase in the specific heat capacity of the upper surface course and lower surface course, the maximum daily road surface temperature can be reduced by approximately 2.1°C and 0.4°C, respectively. The road surface temperature shows a similar pattern when the thermal conductivity increases. Under dry conditions, the maximum daily road surface temperature can be reduced by approximately 3.4°C and 4.3°C for surface-permeable and fully permeable pavements, respectively. This study provides reference suggestions for optimizing the selection and design of urban road pavement structures from the perspectives of permeable pavement design, material parameters, and structure type.
Heavy Metal Concentration in Neotropical Aquatic Snakes (Helicops Pastazae) and Its Potential as a Bioindicator of Water Pollution
Authors: Hurtado-Morales María Jose , Rodríguez Manuel , Amezquita Adolfo
Published: June 2021

The purpose of the present study was to test the potential role of the aquatic snake Helicops pastazae as indicators of water pollution caused by heavy metals. In particular, we tested whether the total heavy metal concentration is related to (1) the position (upstream vs downstream) of the sampling point and its distance from the point where wastewater is discharged; (2) the taxonomic group studied and its place in the trophic chain: piscivorous snakes vs characid fish that co-occur with them; and (3) the organ or tissue examined: snake liver versus muscle. We quantified cadmium (Cd), chromium (Cr) and lead (Pb) by using atomic absorption spectrophotometry with electrothermal atomization. Significant differences were found between some of the sampling points, particularly high metal concentrations were detected upstream at point 1, but no clear spatial pattern was found. There were no significant differences in the concentration of any of the metals between fish and snake muscle, suggesting potential mechanisms of metal excretion in snakes. With regard to interactions, the snake liver had the highest concentrations of cadmium and the muscle of lead and chromium, which may indicate tissue affinity differences for certain metals. Altogether, our results indicate that H. pastazae accumulates contaminants differentially, depending on the tissue and location, which render them useful bioindicators of water contamination.
AOHDL: Archimedes Optimization Based Hybrid Deep Learning Model for Soybean Plant Disease Classification
Authors: Annrose J. , Rufus N. Herald Anantha , Rex C. R. Edwin Selva , Immanuel D. Godwin
Published: June 2021

The authors have requested that this preprint be removed from Research Square.