bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.