bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrated Multiphase Flow Modeling for Downhole Pressure Predictions
Authors: Alkhezzi A. , Fan Y. 
Published: October 2023

Abstract
This work presents a new integrated multiphase flow model for downhole pressure predictions. The aim of the model is to produce relatively more accurate downhole pressure predictions under wide flowing conditions while maintaining a simple form. As a component of the integrated model, an improved two-fluid model for segregated flow is proposed. Results of the two-fluid segregated model are compared with five state-of-the-art existing models, while results of the integrated model are compared with three.
The proposed integrated model incorporates the state-of-the-art onset of liquid loading predictive model. It classifies the flow into two major categories based on the onset of liquid loading, that are modeled by two different approaches respectively. If liquid loading occurs, the model uses a sophisticated drift-flux model which proved to be simple and relatively accurate when dealing with high liquid holdup. On the other hand, if liquid loading does not occur, an improved two-fluid segregated flow model will be used. The proposed two-fluid model was developed by improving the modeling of wetted perimeters and the liquid wall shear stress.
The proposed new two-fluid model for segregated flow outperformed five other existing state-of-the-art models in predicting the liquid holdup and pressure gradient of 11 experimental datasets from the literature. The datasets range widely in pipe diameter, inclination angle, gas density, and flowing conditions. The model succeeds in capturing the effects of inclination angle, pressure or gas density, and liquid and gas superficial velocities on liquid holdup and pressure gradient. The new model eliminates the need of changing interfacial friction factor correlations when the flowing condition variates, significantly reducing the uncertainties and complexities associated with closure relationship selection and alteration. Moreover, the new integrated model outperformed the other multiphase flow models in predicting the downhole pressure of 313 field data points. When dealing with wells that have both segregated and intermittent flows, the new model produces outstanding results compared to other existing state-of-the-art models. In addition, it is capable of predicting the location and amount of liquid loading in a well, which will benefit the design and optimization of artificial lift processes.
Diammonium Hydrogen Phosphate Treatment for Sustaining Long-Term Acid Fracture Conductivity of Chalk Formations
Authors: Samarkin Yevgeniy , Aljawad Murtada Saleh , Solling Theis Ivan , Amao Abduljamiu Olalekan , AlTammar Murtadha J. , Alruwaili Khalid M. 
Published: October 2023

Abstract
The reactive acid, injected into the formation during acid fracturing operations, etches the surfaces of the fracture, generating asperities that keep the fracture conductive. However, the stresses acting on the fracture tend to close it, destroying the asperities. Asperities' destruction is especially severe in soft carbonate formations such as chalk. This work focuses on improving the long-term acid fracture conductivity sustenance by hardening the chalk rocks through chemical treatment.
Diammonium Hydrogen Phosphate (DAP) is applied to harden chalk slabs treated with 10% HCl acid in this work. Treated slabs are inserted in the API conductivity device that allows for measuring the conductivity of the fracture. The conductivity of the fracture treated by DAP after acid injection is measured at different stresses and compared with the conductivity of the acidized fracture with no DAP treatment. Furthermore, the additional analysis is conducted to observe the changes in the roughness and hardness of the samples before and after treatments.
The results demonstrated that the hardness of the chalk samples was decreased by 30 - 40% after acidizing. However, the subsequent treatment of the acidized samples with the DAP solution restored their original hardness. Moreover, the hardened samples were more deformation-resistant to the applied stresses based on Linear Variable Differential Transformers'(LVDT) measurements. The conductivity of the DAP-treated fracture decreased less abruptly with applied stresses (up to 2,500 psi) compared to the acidized but untreated fracture. As a result, the ultimate conductivity of a DAP-treated fracture was 60 md-ft, which was significantly higher than the conductivity of the untreated fracture that constituted 8 mdft. Additional long-term conductivity experiments were conducted over time (6 days) while applying the fixed stress. These experiments have shown that the decline in the conductivity of treated fracture is less severe compared to untreated fracture. It was noted that the plateau value of long-term fracture conductivity for the treated samples was significantly higher than for the untreated case.
This work presents a novel approach to sustaining acid fracture conductivity in soft chalk formations through chemical treatment with a DAP solution. This approach is validated through the API conductivity experiments that mimic the behavior of a fracture at reservoir conditions. The positive results obtained from this research allow suggesting that the technique will have great potential if deployed in the actual field operations.
Barcoded NanoTags for Real-Time Tracing Cuttings in Mud Logging
Authors: Wang Wei , Chang Sehoon 
Published: October 2023

Abstract
Rock cuttings are often collected for lithology and petrophysical characterization during a drilling operation. The depth origin of the sampled cuttings could be determined by calculating the lag time required for the cuttings to travel from the bit to the surface, but traditional mud logging methods may give inaccuracies of ±10-20 feet in the depth correlation due to the shuffling and settling of cuttings as they travel with drilling fluid to the surface, especially for horizontal wells. Aramco researchers have developed a technology that pulse pumps a series of barcoded tags sequentially to label drill-cuttings when they are formed during drilling without adverse impact on the drilling operation in field, and field tests demonstrated that the depth-correlation uncertainty could significantly improve to about ±2 feet. However, this technology critically relies on the efficiencies of mud tracer materials and technology of rapid detection for real-time monitoring in mud logging. To enable the determination of cuttings at various depths and times, a number of mud tags are essentially needed. Towards achieving this goal, we have developed 6 series of novel tracer materials as mud tags and analytical methods for rapid, trace level detection of these tags. The new series of nano tracer materials (NanoTags) include CompTags, MagTags, PolyTags, FluorTags, CarbTags and FiberTags, in which unique compositions or optical properties as barcoded information are incorporated. The synthesized tracer materials have controllable compatibility with either water-based mud (WBM) or oil-based mud (OBM) and have been tested in simulated mud formulation and cutting samples. Stability tests demonstrated that the tracers are stable in simulated reservoir condition with high-salinity water and crude oil at elevated temperature (~95°C). These NanoTags in drilling muds can embedded into cuttings at a drilling bit and travel with the cuttings to surface, and then be identified by optical detection and other orthogonal analyses using various detection methods at nano-gram level in the cutting samples.
Prevent the Scale Deposition Inside Wellbore by Applying the Physics Without Using Chemicals
Authors: Ahmed Mohamed Ghareeb M. 
Published: October 2023

Abstract
The build-up of scale deposits inside well bores can have a significant impact on the efficiency of oil and gas well production and operations especially the artificially lifted oil wells. In this paper, we aimed to present very simple technique operator can apply to avoid scale deposition inside wellbore without using chemicals by applying only physical methods. This can be done by controlling wellhead parameters. Methods, Procedures,
Our methodology involved analyzing the flow dynamics, pressure and temperature conditions inside the wellbore, and by calculating the scale tendency of produced water formation, operator from wellhead implementing measures can control the formation of scale deposits. This can be achieved by changing the flow dynamic inside the wellbore at the depth where scale start to deposit.
The results showed a significant prevention in the accumulation of scale deposits, leading to improved well production, operation and reduced maintenance costs without using any type of chemical treatment. Different real cases applications from the Egyptian oil fields will present.
The novelty of this paper lays in the application of physical methods to address the issue of scale deposition, which is a common challenge in some of the oil and gas industry. This approach offers a cost-effective, operation efficiency and environmentally friendly solution for mitigating the impact of scale deposition in well bores.
Open Hole Whipstock Technology Combines Cement Abandonment and Kick-Off in Single Trip
Authors: Emelander T. 
Published: October 2023

Abstract
In every basin around the world, planned or contingency open hole sidetrack operations are commonplace in drilling operations. In the recent year, there has been an evolution of the open hole whipstock systems to reduce sidetrack time/cost associated with kicking off from cement plugs. The most recent advancement for these systems combines kick-off operations in the same trip as setting whipstock and cementing the open hole below.
The whipstock systems that came to market in the recent unconventional shale era provided the industry a much-needed low risk/efficient option in wells where cement abandonment was required or desired, but kick-off from the whipstock was completed on the following trip. The most recent advancement in open hole whipstock technology utilizes the same concave, anchors, and abandonment methods but is deployed on a cutting structure rather than a running tool. The added ability to kick off in the same trip now further reduces sidetrack times when compared to cement plug or conventional whipstock kick-off operations.
This new open hole system has been installed in 18 wells in the United States (US), three different hole sizes, with 10 of these applications including cement operations to abandon and isolate the open hole below the whipstock. The original version of this technology was run on a crushed/insert carbide milling bottomhole assembly (BHA). The most recent cutting structure has been changed to polycrystalline diamond compact (PDC) cutters to decrease average kick-off times by around 50% and reduce the risk of a second trip in hard/abrasive formations. Two recent installs, including cement abandonment and PDC technology, highlight the success and benefits of this system. The first install was required because a radioactive source was left in the hole and the required deflection device (whipstock) could be used to sidetrack/continue well construction while pumping the required red cement and kicking off efficiently in one trip. Total well possession time for the operation including the wellbore preparation run was 64.5 hours. The second install was a planned pilot hole application with the kick-off being in the hard/abrasive shale. The local regulatory agency required the cement abandonment of lower exposed zones. Total well possession time for the operation including two wellbore preparation runs was 102 hours.
This paper shows that advancements in open hole whipstocks provide the industry with a reliable/efficient option for planned or contingency sidetracks. This sidetracking solution can be used in various applications worldwide to lower total time spent on the well construction process.
The Role of Fiber Properties s in LCM Design – A Numerical Approach
Authors: Henriques Cassian , Taleghani Arash Dahi 
Published: October 2023

Abstract
To combat the problem of lost circulation during drilling, lost circulation materials (LCM) have most commonly been added to the drilling fluid to seal the fractures and recover the rate of penetration (ROP). In recent years, fibers have become an attractive addition to many lost circulation treatments specifically due to their ability to overlap, intertwine and give rise to net-like structures within the fracture, that are able to effectively cause bridge-initiation and seal fractures. However, the behavior of fibers in particle-laden flow display multi-variate complexity due to the effects of multiple mechanisms – both particle and fluid related, that influence the fibers during flow. As a consequence, evaluating fiber LCMs in the lab in a detailed manner can be very cumbersome and tedious. To overcome this limitation, we developed a validated, Computational Fluid Dynamics coupled Discrete Element Method (CFD-DEM) model to simulate the fiber-laden fluid flow process in millimeter-wide fractures. The effect of fiber concentration, fracture roughness, and fiber stiffness on plugging capability is evaluated. It is found that, although fibers are known to create net-like structures that portray better fracture bridging than conventional LCMs, the bridging mechanism is affected by the bending stiffness of the fibers. We propose two new concepts for the bridging mechanisms of fibers and their effects on the plugging time and maximum plugging pressures for the LCM plugs. This study also attempts to better understand the effect of employing mixed blends of soft and stiff fibers on fracture plugging effectiveness by simulating mixed fibers of different soft-stiff compositions.
Assessing the Value of in-Well Fiber Optics Deployment in Pre-Salt Projects for Real-Time Reservoir Monitoring
Authors: Ribeiro P. M. , Gildin E. , Emerick A. A. 
Published: October 2023

Abstract
Brazilian pre-salt faces quite a few challenges for reservoir management given their complexity and uncertainty in fluid distribution and multiphase rate allocations along the wells. Real-time surveillance strategies and fluid control using intelligent completions are key to reduce uncertainty and optimize production. A central issue, however, is to determine the best strategy for real-time downhole monitoring systems deployment. Distributed acoustics and temperature measurements can be continuously acquired by fiber optics sensing (DAS and DTS, respectively), and thus can illuminate the determination of well information almost in real-time, but its value has not been quantified yet. Particularly, wet completions pose a challenge for the fiber optics application, requiring not only the investment in acquiring the hardware but also R&D to develop key missing components. In this paper we tackle this issue by providing a methodology for determining the value of distributed information for future deployments.
In this work, we apply a stochastic approach to estimate the value of information provided by in well fiber optics sensing. The study scenario considers representative characteristics of the main pre-salt carbonate reservoirs: thick, highly productive, and very heterogeneous, where the wells contain multizone intelligent completion. We compare data assimilation and optimization workflows applied to an ensemble of model realizations considering scenarios where only surface measurements are available (standard practice) and where the fiber optics provides the continuous downhole production/injection information. The impact of timing in the fiber optics deployment is also considered.
The rate allocation, especially in wells completed with intelligent completions and in fields performing water alternating gas injection, is essential to leverage decision making process and improve reservoir management. The cost of obtaining information from permanent sensors needs to be balanced against the expected benefit from improved reservoir performance, for example. Results show that the information provided by fiber optics sensing adds value by reducing the uncertainty and leading to an optimum well control closer to the optimum obtained with the reference (true) model. This value decreases as the information arrives later in time in a field development schedule.
Although the perception of the added value by fiber optic installations in this context is unquestionable, translating this value into numbers – which is essential for decision making – is not trivial task to achieve. The methodology proposed here enables the assessment of fiber optics sensing value of information applied to pre-salt reservoirs and is useful to guide the decision of acquiring or not this monitoring technology, particularly in the later development stages of a field.
A Data Analytics and Machine Learning Study on Site Screening of CO2 Geological Storage in Depleted Oil and Gas Reservoirs in the Gulf of Mexico
Authors: Leng J. , Wang H. , Hosseini S. 
Published: October 2023

Abstract
Carbon capture, utilization and sequestration (CCUS) is playing an important role in mitigating greenhouse gas emissions and reversing global warming. Finding suitable sequestration sites is a key stage for CCUS, however, numerous potential sites do not hold sufficient data for evaluation based on conventional criteria. This study presents a feasible and efficient composite-scoring system using data analytics method to provide feeding data for machine learning studies to assess the potential depleted oil/gas reservoirs for carbon storage with limited data available. BOEM database in Gulf of Mexico (GoM) is used to apply the scoring system as a case study. The paper first presents a description of the reservoir properties and geological properties in GoM; then, the paper introduces the analytics method that maximize values of the available data and generate the final composite score for machine learning models; finally, the paper applies unsupervised machine learning method to cluster the reservoirs based on the location and composite scores. The findings of this study present that the scoring system quantifies and generalizes different types of geological and petroleum data to be feasibly applied in machine learning studies. Besides, with the BOEM database, the study revealed the best scored reservoirs located along the Louisiana coastline with large capacity, good injectivity potential and great performance in safety and economy. The result is consistent with the previous multi-criteria screening studies.
New High-Frequency Pressure Monitor Algorithm Guided Multistage Stimulation for Long Lateral without Mechanical Isolation
Authors: Zeng Bo , Zhou Nayun , Guo Xingwu , Wang Yiting , Fu Yunlong , Wang Guan , Korkin Roman , Fedorov Andrey , Borisenko Alexey , Luo Yin , Li Haoyan , Zhang Jie 
Published: October 2023

Abstract
Due to the reservoir complexity that includes natural fractures and weak bedding planes, over 30% of China shale gas wells in Sichuan Basin encountered casing deformation issues. Casing deformation resulted in huge challenges for wellbore accessibility and prevented setting of bridge plugs of the subsequent stages at the originally designed depth. To avoid leaving the target lateral unstimulated after casing deformation incidents, operators would have to perforate the entire remaining lateral and conduct multiple fracturing treatments with diversions; however, high uncertainty in such practice risks under-stimulation or overstimulation.
In this study, we share several field cases that utilized high-frequency pressure monitoring (HFPM) to evaluate and improve stimulation effectiveness in wells with casing deformation. The detailed operational procedure and initial findings from comparison between HFPM diagnosis and results from other monitoring techniques, such as seismic monitoring and downhole camera, are also discussed. Observations, limitations, and potential improvements from these cases demonstrate a potentially duplicatable practice for stimulation in wells with casing deformation.
Experimental Studies on Thermal Properties of Different Class G Cement Composites for Geothermal Well Applications
Authors: Abid Khizar , Tellez Miguel L Romero , Teodoriu Catalin 
Published: October 2023

Abstract
The efficiency of geothermal energy depends on the amount of heat gathered at the surface. Therefore, the heat transfer between the working fluid and the formation must be reduced. This can be done by using cement with low thermal conductivity on the upper section of the cement. While on the other hand, high thermal conductive cement should be deployed at the lower section of the well to facilitate heat transfer.
Therefore, the thermal properties of cement become important in the context of geothermal wells. For this reason, thermal conductivity tests were conducted for 305 days on different Class G cement composites. The additives used were Fly Ash, Bentonite and Gilsonite. Moreover, the samples were cured at dry and wet conditions to observe the effect of moisture on thermal conductivity. Whereas the value of thermal conductivity (k) was measured with the help of two separate apparatuses that work on different principles.
It was found that with the addition of additives, the thermal coefficient of the Class G cement was reduced, but more importantly, fresh cement data differs from long-term cured samples, which will have an impact on the overall heat transfer coefficient. It was also observed that the sample's thermal conductivity is a time-dependent property and evolves as the curing time increases and then becomes relatively constant. While the addition of an additive in the class G cement has an impact on the value of k and it was also noted that irrespective of the cement additive or curing time, the thermal conductivity of the cement cured in saturated condition always had a higher thermal conductivity than the samples cured in dry condition.
The novelty of this work is that this study deals with the long-term measurement of the thermal conductivity of different Class G cement composites. Moreover, it also compares the value of k obtained from two different measuring thermal conductivity equipment and discusses the reason for obtaining the different values of k.
Efficient Modeling of Proppant Transport in Multi-Cluster Stages
Authors: Wang J. , Olson J. E. 
Published: October 2023

Abstract
In this study, an Eulerian-Lagrangian (E-L) proppant model was coupled with the simplified three-dimensional displacement discontinuity method (S3D DDM) hydraulic fracture model to simulate proppant transport in multiple simultaneously propagating hydraulic fractures in a stage. The E-L proppant model computes slurry flow in the Eulerian regime and proppant particles in the Lagrangian regime, while the S3D DDM hydraulic fracture model efficiently simulates 3D non-planar hydraulic fracture geometries. Synthetic case studies were conducted to examine the effect of cluster spacing and the number of clusters on proppant placement in multi-cluster stages. Numerical results showed that the tip process zone of the nearby hydraulic fractures significantly reduces the hydraulic fracture width at the affected area, which obstructs the proppant transport in the affected hydraulic fractures. In addition, the non-planar hydraulic fracture plane slows down proppant movement and can potentially cause proppant bridging. The effect of multi-cluster design on proppant transport is mitigated with larger cluster spacings or fewer numbers of clusters in a stage.