bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probabilistic Well Production Forecasting in Volve Field Using Temporal Fusion Transformer Deep Learning Models
Authors: Al-Ali Zainab Al-Ali Hussain , Horne Roland 
Published: March 2023

AbstractAccurate well rate forecasting is critical for field development. In the oil industry, recurrent-based deep learning models have been used for production forecasting. Modern research is shifting towards using the novel transformer architecture in natural language and time series applications to better handle long-term temporal dependencies using attention layers. In this paper, we present a novel approach of applying a transformer-based deep learning model for probabilistic production forecasting.The Temporal Fusion Transformer (TFT) model, a modern transformer-based model for time series forecasting, was used to provide a better oil rate prediction in the Norwegian Volve field. The historical bottomhole pressure, wellhead pressure, wellhead temperature and choke size opening real time series data were used as past input features in the TFT model to forecast ahead the oil rate of two wells. The model was trained with a quantile loss function to produce a probabilistic prediction with both upper and lower bounds of uncertainties. After optimization the TFT model was blindly tested on the last 20% of the data to evaluate its prediction performance compared Block Recurrent Neural Network architectures (BlockRNN).The real-time production data used in this multivariate forecasting problem was found to be complex with no clear trend or seasonality. The BlockRNN model failed to produce a good prediction of oil rate compared to the TFT model. The TFT model was better at encoding the input features including, the choke size, wellhead pressure, and temperature, and understanding their long-range dependencies with the oil rate.The model was able to minimize the testing Mean Squared Error (MSE) for the two wells F-11H and F-12H reaching values of 0.08 and 0.03, respectively. In addition, the model was able to forecast a prediction bandwidth in between the 10th and 90th quantiles to account for uncertainty ranges which laid in-between the blind test intervals. Overall, the TFT model was proven successful in accurately forecasting complex trends of oil rates overcoming the limitations of conventional, BlockRNN uses a memory to understand and make predictions about new data models of information loss over long-term multivariate time series prediction.Our work presents a novel approach of using the TFT probabilistic deep learning model for multivariate oil rate forecasting in the oil and gas industry. The model showed very promising results outperforming conventional BlockRNN-based models in addition to providing a range of the forecasting uncertainty using quantile regression. Knowing the uncertainty range helps in making critical decision particularly in the well intervention and field development.
Integrated Subtle Fault Prediction Technique Based on Seismic Conditioning and Deep Learning
Authors: Xin Chen , Jianlin Li , Min Zhao , Qunli Qi , Dengyi Xiao , Qiang Li , Li Wang , Fuli An , Weixiang Zhong , Bo Wang , Pengpeng Ye , Ziquan Su , Wenwen Yu 
Published: March 2023

AbstractWith the development of oilfield, the role of subtle faults becomes more and more important. Due to the limitation resolution of seismic data, it is hard for conventional methods to identify and predict subtle faults to meet the needs of reservoir development. In order to improve the accuracy of subtle fault prediction, a new fault prediction technique based on seismic conditioning and deep learning was proposed in this study.The workflow mainly includes the following 6 steps: 1) Seismic conditioning based on regional stress and well data; 2) Forward modeling of fault models using different frequencies of wavelet, and get the seismic response sample for different throw fault; 3) Seismic attributes optimization based on the frequency and azimuth optimization for different throw of fault; 4) Fast fault identification and prediction for all different frequency and azimuth seismic data by using deep learning method; 5) Integrated the FMI and well data to optimize the different scales faults prediction results, and fusion of multi-scale faults. 6) Output subtle faults predict results after the subtle faults modeling and 3D QC.The application of this new method in M oilfield in the Middle East shows that, the seismic data with higher frequency and NE-SW azimuth can better identify the NW-SE subtle faults. When the main frequency of seismic data is 30Hz, faults with a fault displacement &gt;10m can be clearly identified, and when the main frequency of seismic data is 45Hz, faults with a fault displacement &gt;5m can be clearly identified. Deep learning technology can quickly and effectively extract faults from seismic data. Fault optimization and fusion based on different frequency and azimuth seismic data can predict multi-scale fault system more reasonably. A series of small NW-SW faults are identified in the western part of the long axis anticline in the study area. These subtle faults cut the long axis anticline and formed a fault block traps with lower OWC in the southwest slope, which explains why the OWC and formation pressure in the west are different from east. 7 new wells drilled through the fault, also confirms the presence of NW-SE subtle fault.The subtle fault prediction techniques based on deep learning and model forward modeling can better integrate the geological faults information into the deep learning model samples to improve the identification ability and prediction accuracy of multi-scale faults. The optimization of seismic frequency and azimuth can fundamentally improve the effect of deep learning and prediction of faults. High accuracy subtle fault prediction results can deepen reservoir understanding and improve for efficient oilfield development.
Carbonate Permeable Zone Cementing Practices and Challenges
Authors: Kareem Ali Ahmed , Ali Muhammad 
Published: March 2023

Abstract
Successful primary cementing operations are critical to long-term well integrity and well completion. The operator's Block-9 contract area is situated in the Southeast portion of Iraq. Wells drilled in Block-9 are primarily within the Yamama limestone reservoir. The Yamama formation is composed of four compartments (YA, YB, YC, and YD). The main production reservoir area is the YA; high-permeability characteristics and pressure depletion effects in certain layers are prominent in this compartment. In some wells, the cement quality across permeable and depleted layers of the YA presents challenges attributed to high pressure differential, early cement hydration, and microdebonding at the casing-cement interface. To achieve acceptable zonal isolation across these high-permeability and depleted layers, a thorough understanding of the issues is necessary. The operator's philosophy and procedures for cementing production casing to better understand the proposed solutions are discussed.
Cementing practices adopted in Block-9 in the past are discussed in addition to their impact on cement quality, current practices, and plans to address future challenges. To overcome this critical well integrity related challenge, a multifaceted approach was adopted. Offset well records, cement recipes, job execution, cement evaluation logs, and challenges faced during testing and production were reviewed in detail and are highlighted. Understanding these technical challenges and the formation response to cement slurry and hydration processes were key to designing cement slurries and job execution in such deep wells. Primarily, the operator focused on attempting to control/manage the cement hydration process and fluid-loss control across the permeable zones.
The proposed suggestions included understanding the permeable carbonate zones, high differential pressures, cement recipe design, cement additive impact, spacer and mud properties, pumping rates, casing centralization, casing rotation during cementing, the cement setting process, and cement evaluation log interpretation.
Lessons learned from this review can assist other operators globally with addressing similar issues with permeable depleted carbonate reservoirs and compromised cement bonding.
Multi stage Frac & Testing of High Angle HPHT Ultra Sour Exploratory Well: Challenges Encountered & Mitigated
Authors: Al-Dosari Saad Abdullah , Al-Ateeq Abdullah Fahad , Ranjan Akash , Salem Abrar , Asthana Saurabh , Peiwu Liu 
Published: March 2023

AbstractReservoir production challenges are always escalated when the concentration of H2S and CO2 are extremely high. This paper highlights the challenges encountered, mitigation techniques used to overcome hurdles, and remaining tasks in testing the first deep high angle High Pressure High Temperature (HPHT) exploratory well completed with Multi-Stage Completion (MSC) in the presence of ultra-sour fluid (H2S-31% and CO2-38%) in Kuwait.The subject Jurassic well is drilled at a highly deviated angle up to 19,000 ft in measured depth (MD). The completion installed is composed of an open-hole MSC and three stages of frac ports tied back with a Liner Hanger to the upper 4.5 inch tubing. After setting the completion, the 15.8 ppg oil base mud (OBM) completion fluid was displaced with 11.6 ppg brine. DataFrac treatment and analyses were followed by acid fracturing treatment in all three stages. Post-fracturing well clean-up is achieved by continuously pumping Hydrogen Sulfide (H2S) scavenger to protect the entire surface test equipment set up. Employing self-containing breathing apparatus for personnel safety and having two flare pits permitted uninterrupted well testing for 13 days.During the well clean-up, the very high H2S and Carbon Dioxide (CO2)concentrations in knocked out fluid were 31% and 38%, respectively. However, due to the extremely high sour nature of reservoir fluid and limitation of separator metallurgy, the flow rate measurement is limited to only 2 hours. Various technical and operational safety challenges were safely handled during the well preparation, acid fracturing, testing, and flaring operation without any HSE incident. Moreover, continuous flow rate measurements are not achieved due to equipment limitations. Currently, a multi-phase flow meter (MPFM) which can handle high H2S and CO2 is under evaluation to conduct long term well testing to ascertain the production potential.The completion of three stage acid fracturing treatments and safely testing the high sour deviated well in HPHT conditions of an exploration well for the first time in the State of Kuwait is a remarkable success, paving the way for future field development in similar well conditions. However, production and processing of this highly sour fluid will be challenging for field development.
Detailed Core Studies and Facies Characterization of Tight Cambro-Ordovician and Devonian Reservoirs (Tinrhert Nord Block, Illizi Basin, Algeria).
Authors: Guney Hasan , Ellen Helby , Ajayi Ayodeji Temitope , AlAli Abdulla Ali , Bezziane Mohamed Lamine 
Published: March 2023

AbstractThe Tinrhert Nord Block is located in the Illizi/Berkine-Ghadames Basin where in the central-eastern part of Algeria, near the border with Libya. The sedimentary infill of these basins is composed of thick Palaeozoic sedimentary sequences which constitute a world-class petroleum system, confirmed and producing in Algeria, Tunisia and Libya. Previously drilled wells by Sonatrach in the block had shown a considerable prospectivity for the Block, and further studies were undertaken for well planning and appraisal of the Ordovician, Silurian, and Devonian reservoirs. The target of this study was to better understand the characteristics of the reservoir and quality of the productive series in the block. A comprehensive core study was therefore run for 15 wells with a total of 647 meters of sediments in the Tinrhert Nord block (Figure 3). The study showed that 7 clastic facies for the Palaeozoic sequences can be distinguished. The Ordovician facies subdivided into 3 main facies that were deposited in Glaciomarine, Tidal-Delta and Upper shoreface-shoreline environment and is composed of diamictites, titillates and fine-grained tight reservoir facies. Silurian and Devonian sequences are composed of marine shales that are confirmed as constituting the major source rock in the basin (Silurian hot shale and Frasnian hot shales), and additional fluvial-deltaic coarse-medium-fine grained sandstone facies. SEM (Scanning Electron Microscope), routine core analysis, and fracture studies were performed on selected core intervals in order to perform a more detailed reservoir characterisation. Routine core analysis show that the Ordovician reservoir has a limited porosity up to 4-8% due to the overall texture of the sediments and shows also a low permeability (&lt;1Md). Effective porosity of the Upper Silurian F6 reservoir is up to 15-20% and Devonian F2 reservoir is most likely up to 10%. Core fractures show drilling-induced vertical fractures, and natural hairline type healed fractures, and an additional natural open joint system. The open hole DST well tests that have shown moderate flow rates with can be related to the presence of a high porosity and main permeability system which is composed of interconnected small scale open fractures and larger scale sub-seismic fracture corridors. These features permit to produce also from the reservoir layers that generally show low porosity/permeability facies.These studies confirm that the Silurian F6 reservoirs are the best reservoirs in the basin and Devonian fluvial-deltaic sequences (C and F2)are secondary best reservoir in the basin. The Ordovician reservoirs are tighter with limited porosity and permeability but can be produced by stimulation of the natural fracture system.
Numerical Simulation of CO2 Mineral Trapping Potential of Carbonate Rocks
Authors: Mouallem Johny , Arif Muhammad , Mahmoud Mohamed 
Published: March 2023

AbstractDuring CO2 geo-storage, mineral dissolution is considered as the safest trapping technique however it is the longest and the most complicated trapping mechanism involving geo-chemical reactions and physical forces like diffusion and advection. Many factors also influence the mineral trapping capacity of the geological formation e.g., mineralogy, temperature, pH, CO2 fugacity, pressure of CO2, salinity and impurities.The scope of this study is to investigate the mineral trapping of CO2 in Arabian carbonates reservoirs as a function of CO2 pressure injection, presence of contaminants and well configuration. Numerical simulations were performed using the multi-phase simulator GEM-CMG. 2D and 3D models were developed to examine the mechanisms occurring during mineral trapping and how these affect its efficiency. The mineralogy of a carbonate field from an Arabian formation was used. Sensitivity analysis was performed on the above variables on CO2 mineralization tendency.The results suggest that dissolution and precipitation of minerals occurred during and post CO2 injection. Increasing pressure led to higher amount of CO2 trapped while the presence of impurities in the injected fluid reduced the potential of CO2 mineralization. Moreover, using horizontal well tends to promote the mineral activity during CO2 storage.While a score of publications investigated CO2 storage via structural, residual and dissolution trapping mechanisms, still the mineral trapping potential and its influencing factors have not been investigated much. This paper thus provides insights into CO2 sequestration by mineral trapping pertinent to Arabian carbonate rocks.
Negatively Charged Polyelectrolyte-Complex Nanoparticles Using Pei/pvs for Encapsulation of Fracturing Fluid Breakers
Authors: Alhajeri Mubarak Muhammad 
Published: March 2023

AbstractHydraulic fracturing treatment is a stimulation technique in low-permeability reservoirs and tight rock formations. It involves pumping large quantities of fluids into the well at extremely high pressure. Due to hydraulics, it creates small cracks in the rock formations called fractures, allowing reservoir fluids such as natural gas, petroleum and brine to flow out of tight formations. Nanotechnology leads the research direction especially in the field of hydraulic fracturing. This paper/poster presents a novel approach for improving the fracture cleanup process, using negatively charged assembled polyelectrolyte-complex (PEC) nanoparticles as a technique for targeted and controlled release of enzyme breakers. Our previous work (Alhajeri et al. 2021) showed that positively charged PEC nanoparticles using the Polyethylenimine-Dextran Sulfate system can produce stable nanocontainers for enzyme breakers during the hydraulic fracturing process. However, negatively charged PEI/DS nanoparticles showed a significant loss of fracture clean-up efficiency due to the high pH level over the encapsulated enzyme that led to denaturing. In this study, negatively charged PEC nanoparticles were formed by the mixture of polyethyleneimine (PEI) and poly(vinlySufonic acid) (PVS) in nonstoichiometric amounts to encapsulate breakers. It is hypothesized that PEI/PVS system would provide a higher controlled release of breaking agents with high loading capacity due to lower toxicity levels. The development of negatively charged PECs nanoparticles was examined. The nanoparticles were assembled by means of alternate electrostatic adsorption of a polyanion (PVS) and a polycation (PEI). Enzyme-breaking agents were introduced into the PECs during the complexation process. A screening test of the PEI/PVS PEC loaded with enzyme was conducted based on particle size, polydispersity, and zeta potentials. The most stable PEC structure was selected for Enzyme viscometric assays to measure the entrapment efficiency (EE,%). Results from this study demonstrated a proof of concept that negatively charged PEC nanoparticles using PEI/PVS can be used to encapsulate fracturing fluid breaks, minimize premature degradation of fracturing fluids, and provide protection from inhibited surroundings at downhole conditions. In addition, the negatively charged PEC nanoparticles show higher particle stability in terms of smaller particle sizes (&gt;200 nm) and zeta potential (&gt; - 40 mV) for more than 94 hours, thus; improving fracturing clean-up efficiency. The general goal of this study is to develop nano-sized particles loaded with enzyme breakers capable of functioning within fracturing fluids during fluid leak-off into the reservoir matrix, filter cake development, and hydraulic fractured area.
Organizational Safety Culture Transformation Through Coaching
Authors: Okeudo Ameze , Odiase Kevin 
Published: March 2023

AbstractOrganizational culture is simply known as ‘the way we do things around here’. Culture is developed over the time and evolves as people transit through the organization. It is an uphill task to transform organizational culture when this is not desirable, with regards to safety, it becomes even more important that the right mindset and behaviours are modelled across the organizational strata as these are fundamental to keeping people, asset and the environment safe. When focus is placed on keeping safety track records, personnel become wary of reporting incidents for fear of toppling the safety performance. Another factor that contributes to under reporting is the attitude of the leaders when receiving ‘bad news’ of an incident, excessive questioning, blame culture and consequence management for failures creates an environment of fear and inability to intervene in unsafe conditions.
Experimental Study on the Effects if Ift Reduction on Water Blockage after Hydraulic Fracturing in Tight Sandstone Reservoirs Based on The NMR Method
Authors: Hou Xiaoyu , Sheng James J. , Dai Jiacheng 
Published: March 2023

AbstractThe current studies regarding the effect of interfacial tension (IFT) reduction on removing the water blockage of tight sandstones are significant, but the migration characteristics of trapped water in the stimulation process have not been researched. These issues lead to the stimulation mechanism of IFT reduction after hydraulic fracturing is unclear. In this work, a new coreflood platform was designed to simulate the water invasion, shut-in, and flowback process, and how the IFT affects the water blockage was further studied from pore levels. The oil production rates before and after shut-in were measured, which were used to detect the regained permeability of tight sandstones. The T2 spectrum signals, 1D frequency, and magnetic resonance imaging (MRI) based on the nuclear magnetic resonance (NMR) experiments were used to explore the migration characteristics of trapped water under different conditions. The results indicate that the core damage induced by water invasion is severe. The regained permeability is decreased to less than 25% after shut-in. IFT reduction is an effective way to improve the regained permeability, but the emulsification effect of fracturing fluid needs to be avoided, which will reduce the permeability of tight sandstones by the Jiamin effect. The NMR signals of the 1D profile show the water saturation of cores gradually decreases from the fracture face to the exit end, which demonstrates that the water blockage occurs mainly in the area near the fracture face. The T2 spectrum signals show that the residual water saturation of mesopores and macropores after flowback can be reduced by decreasing the IFT values, but the reduction of residual water saturation in micropores is insignificant. This result demonstrates that the core damage caused by water blockage may mainly come from mesopores and micropores. Our study reveals a deeper mechanism of removing water blockage during the IFT reduction process, which can guide the application of surfactants in the oil field.