bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unconventional Reservoir Modeling with Complex Hydraulic-Natural Fracture Networks Using a Parallel Reservoir Simulator Coupled with Embedded Discrete Fracture Model
Authors: Zheng Shuang , Ates Harun , Gupta Anuj , Crumpton Paul 
Published: March 2023

Abstract
Fracture diagnostic data for shale wells show that the fracture system after hydraulic fracturing is quite complex. Accurate and efficient simulation modeling of complex hydraulic and natural fracture networks is critical for evaluation of well performance and stimulation effectiveness in unconventional oil and gas reservoirs. The traditional method based on local grid refinement (LGR) has limitations in handling 3D hydraulic and natural fracture geometry. In addition, its computational efficiency is low, especially for dealing with a large number of hydraulic fractures and multiple horizontal wells.
In this study, we develop a new workflow which, for the first time, utilizes embedded discrete fracture model (EDFM) method coupled with a parallel reservoir simulator (PRS) to simulate all types of 3D hydraulic and natural fractures. EDFM can easily avoid re-gridding matrix cells containing hydraulic and natural fractures. More realistic 3D fracture geometry from either fracture propagation simulation or user definition and geological model with corner point can be accurately honored. The input fractures can be smoothly embedded into the model grid through EDFM processing
We validated the parallel reservoir simulator with EDFM by comparing the simulation results using dual porosity dual permeability (DPDP) model. After benchmarking, we applied this new workflow to simulate three synthetic field cases. The simulation results are also compared with a commercial reservoir simulator (CRS) with the EDFM method. Well performance for the real case with and without natural fractures can be efficiently simulated.
The new EDFM workflow enables to model 3D hydraulic and natural fractures with any strike and dip angels efficiently and accurately in the parallel reservoir simulator. Modifications of fracture properties can be easily done. This new workflow enables a much faster and more robust fracture modeling process, which is highly effective for the fracture model calibration and development optimization in unconventional oil and gas reservoirs.
Comparison of Analytical Model Versus Numerical Model in Estimating EUR of Well Drilled and Completed in Unconventional Source Rock
Authors: Mesdour Rabah , Almalki, Faisal , Mohammed Qarni , Mohammed Dossary , Mohamed Albassam 
Published: March 2023

Abstract
For the last decade shale gas has made a significant contribution to the oil and gas market by introducing multi-fractured horizontal wells. Forecasting the production for these wells is a challenging task due to reservoir properties and fracture network complexity created by hydraulic fracturing. Two methods ‘Analytical and simulation’ proposed in this paper to forecast the well performance, and quantify the differences one might expect to encounter in a well’s Estimated Ultimate Recovery "EUR". Analytical models are widely used as tools for history matching and forecasting production in unconventional resources due to the advantages of simplicity and efficiency. On the other hand there is an increasing interest in the use of numerical simulation for unconventional reservoirs to predict well performance and Estimated Ultimate Recovery "EUR". The two Methods used to match and predict the production of hydraulically fractured unconventional horizontal wells, and the results comparison was made to check on the efficiency and quality of these two methods.
This study will help to quantify the differences one might expect to encounter in a well’s Estimated Ultimate Recovery "EUR" when using analytical model-based Rate Transient Analysis "RTA" versus numerical simulation-based workflows in unconventional reservoirs. This workflow provides multiple history-matched models that are constrained by historical production data. The probabilistic forecast method employed in this work provides P90 (conservative), P50 (most likely), and P10 (optimistic) values for EUR. All the results obtained with the numerical method were compared to the analytical, the findings between these two methods will help to know which most reliable method to be used in predicting the future wells performance to Estimated "EUR". The operators looking for fast and reliable answer to predict the well performance for increasing the success of the models used in the completion, and help for better business planning. This study will help us to know what the most consistent method to use along with hydraulic fractures properties.
Analyzing Discrepancies in PTA and RTA for Accurate Flow Regime Identification and Fracture Geometry Estimation – An Example from a Highly Heterogeneous Unconventional Sandstone Reservoir
Authors: Altayyar Tayyar , Alowaid Abdulrahman 
Published: March 2023

Abstract
This paper analyses a clear example of how results from Pressure Transient Analysis (PTA) and Rate Transient Analysis (RTA) in heterogenous reservoirs can yield different results, and proposes a methodology that capitalizes on these discrepancies to provide a logical and accurate identification of flow regimes periods, and estimation of key fracture geometry parameters. Due to formation heterogeneity, natural fractures and multi-frac stimulation along the lateral, it was clearly observed that early responses of studied wells were masked by a type of complicated flow which was a by-product of different flow regimes. This was first identified when PTA was completed, necessitating the need for additional tools to be integrated to unlock the mystery of that complicated flow. Next, RTA was analyzed by focusing on the log-log plot of pressure derivative with time. It was noticed that the log-log plot in some instances was able to clarify the uncertainties in early pressure response, and in other instances, it wasn't as clear. In the latter, the normal pressure derivative plot was utilized to identify flow regimes, confirming the feasibility of the adapted integrated workflow. the integration of PTA and RTA in cases where initial fracture signatures are uncertain, provides a practical tool that accurately and precisely estimates fracture geometry parameters that are key in the overall performance evaluation of the well. This paper illustrates the results of adapting this integrated novel workflow on an example from a highly heterogeneous unconventional horizontal well within a sandstone reservoir.
Integrated Fracture and Reservoir Model for Well Spacing Optimization in Unconventional Reservoirs With 3D Natural Fractures
Authors: Yu Wei , Ates Harun , Gupta Anuj , Zheng Shuang , Liu Chuxi , Wu Kan , Leines-Artieda Joseph , Miao Jijun , Sepehrnoori Kamy 
Published: March 2023

Abstract
This study presents a new workflow by integrating a robust 3D hydraulic fracture propagation model in conjunction with reservoir simulation through the embedded discrete fracture model (EDFM). Specifically, the hydraulic fracture model is applied to simulate more realistic fracture geometry considering 3D geomodel with rescue format and 3D natural fractures. Multiple wells with varying well spacing are considered. After fracture simulation, the predicted hydraulic fractures, activated natural fractures, and non-activated natural fractures are easily transferred to the reservoir simulator. The EDFM method can accurately and efficiently deal with the 3D complex fractures. It can avoid the complex gridding process and low computational efficiency of the traditional local grid refinement method. Based on long-term performance of different scenarios with varying well spacing, the optimal well spacing is determined. The new workflow was applied to optimize well spacing in a real shale gas case with 3D geomodel and natural fractures. The geomodel with rescue format, 3D natural fracture, 3D non-uniform distribution of stress and rock properties are all honored in the fracture model. Two horizontal wells with varying well spacing of 200 m, 300 m, and 400 m with actual completion data were considered and simulated. Subsequently, the same reservoir and fracture model was used to perform production simulation for 20 years. The distribution of heterogenous properties in matrix was considered. By comparing the estimated ultimate recovery of different well spacing scenarios, the optimal well spacing was identified. This work, for the first time, performs well spacing optimization by coupling fracture model and reservoir model considering more realistic geomodel and fracture system. This new workflow significantly improves the accuracy and efficiency of well spacing optimization process in unconventional oil and gas reservoirs compared to the traditional workflow presented in the literature.
Downhole Characterization of Clays and Formation Water Salinity Using Low Frequency Permittivity Dispersion
Authors: Abdallah Wael , Zhang Ping , Wang Gong Li , Ma Shouxiang Mark 
Published: March 2023

Abstract
Clays in reservoir rocks have a significant impact on formation evaluation. An important property of clay minerals is their ability to adsorb ions on their exposed surface, which is measured by its cation exchange capacity (CEC). This property can affect saturation calculation if not properly accounted for. Many techniques have been developed for clay characterization, but it remains a focus of frontline research to find an accurate method for quantifying clays in situ and is the main objective of this study. Extensive numerical studies have been conducted and the results have indicated that for a shaly sand formation, strong dielectric dispersions were observed for all the simulated models at frequencies below 1MHz, which allowed an equation to be established that can be used to calculate clay volume through derivatives of the permittivity dispersive curves. In deriving this equation, parameters used for the studies include water-filled porosity, formation water salinity, grain size, clay type and volume, and Archie cementation exponent.
The developed model contains two calibration constants, a and b, which need to be predefined. Results indicate that, for the simulated models, b is a constant while a depends on water-filled porosity, formation water salinity, grain size, clay content, and Archie cementation exponent. Data shows that there is no simple way to define constant a, due to its complex relationship with the various parameters. When focusing on relationships between constant a and clay volume and formation water salinity, by assuming other parameters can be estimated either by conventional petrophysical interpretations or laboratory measurements, then the current developed workflows can be used to estimate either clay volume or formation water salinity: Workflow 1: knowing formation water salinity, computing constant a, then estimating clay volume and Workflow 2: knowing clay volume, computing constant a, then estimating formation water salinity. To our knowledge, such an equation is the first model that has never been published before. The correlation works well in the synthetic data. It has a potential to provide a new method for characterizing formation clays and water salinity from low frequency resistivity measurements such as induction logs that is routinely run in almost every well drilled. Thus, it provides a powerful economical tool for enhanced reservoir characterization. Field testing is being conducted.
Chemical Reaction Equilibrium Theory - A Novel Approach to Estimate Shale Reservoir Fluid Compositions
Authors: Risum Boesen Rasmus , Leekumjorn Sukit , Agger Christian , Sørensen Henrik 
Published: March 2023

Abstract
Shale reservoirs are characterized by having low permeability which prevents the fluid components from moving freely in the reservoir. Shale producers therefore often face challenges getting representative fluid samples. This paper shows the composition of fluids in a low permeability reservoir can be estimated using the theory of chemical reaction equilibria, and in some cases can replace the need for a physical sample.
It is assumed that chemical equilibrium determines the relative stability of carbon number (CN) fractions in a shale fluid and that the distribution of components can be calculated by solving a reaction equilibrium. Known fluid compositions are used to establish Gibbs’ energy of formation as a function of temperature for each CN fraction across the fluids. Given this trained Composition Estimation Model, only temperature, pressure and GOR (gas-oil ratio) are required to estimate a fluid composition.
The method has been tested on US shale fluids. Fluids from the Eagle Ford and Permian Basin fields have been used to train the model, making it possible to predict other Eagle Ford and the Permian Basin shale fluid compositions. The model was also evaluated on a fluid from another tight formation in the Texas area. The fluid samples cover reservoir temperatures between 160-320°F, and the fluid GORs range from 2,400 to 8,200 Scf/Stb and saturation pressures from 3,700 to 5,600 psia.
A Novel Well Log Data Quality Prescriptive Framework for Enhancing Well Log Data Quality Interpretation
Authors: Katterbauer Klemens , Al Shehri Abdallah 
Published: March 2023

Abstract
Reservoir formation evaluation in real time has become essential with the rise of logging while drilling solutions, and the strive to achieve greater precision measurements, while reducing the time from drilling to production. Well log data quality represents a crucial part of ensuring that the interpretations are precise, and avoiding erroneous data that may lead to misinterpretations. Prescriptive artificial intelligence focuses on developing trained predictive models to recommend actions, while optimizing looked after outcomes.
We present an innovative prescriptive artificial intelligence framework for determining well log data quality to assist in interpretation and decision making. The framework incorporates a decision tree approach to ensure that the various collected well logs are aligned with each other, and then determines which well logs are of sufficient quality, and which have to be adapted in the interpretation framework. The well logs are then adapted in order to ensure that they provide consistent interpretations.
The framework was examined on a synthetic reservoir with various well logs. The framework evalues the quality of the well logs, and filters them in order to ensure proper correlation with each other. A sensitivity analysis and adaptation of the well logs ensures proper interpretation.
This work represents an innovative approach to autonomous well log data quality determination, and provides a new approach to assist well log interpretation.
Unleashing the Full Geothermal Potential of Türkiye Through Collaboration and Learning from the Oil & Gas Industry
Authors: Pedrosa Selin , Ochoa Oscar Nicolas , Erdurmus Sila , Oueslati Hatem , Siyako Muzaffer , Damci Emre 
Published: March 2023

Abstract
Developing of enhanced geothermal systems will be critical for future energy markets and successful energy decarbonization. New technologies and holistic drilling approaches will allow access to previously untapped sources and ensure projects are economically viable. Türkiye is the world's fourth largest geothermal energy producer with 1700 MWe of installed power capacity after the USA, Indonesia, and the Philippines. The Anatolian plate, which Türkiye is situated on, is located on the Alpine-Himalayan orogenic belt making the region one of the most seismically active places in the world. Due to these and other conditions, the country has a significant potential for geothermal energy production.
Since 2010, there has been a strong collaboration between service companies and geothermal operators to provide advanced directional drilling services in the geothermal market. This successful collaboration enabled operators to drill deeper, higher temperature geothermal wells for electricity production and provided significant environmental and economic development for different fields. Typical drilling conditions for these applications are harsh and the static temperature ranges between 220°C to 295 °C. The depth of the wells varies between 2500 m-4800 m depending on the reservoir, within high temperatures and harsh drilling conditions.
In this paper, the authors discuss the challenges of directional drilling in Türkiye's geothermal fields, and how the best practices and innovations established from the Oil & Gas industry were successfully adopted into this specific energy market, including the deployment of sophisticated Rotary Steerable Systems (RSS).
Advancement and Prospective of Hydrogen Generation from Hydrogen Sulfide Via Electrolysis Decomposition Approaches
Authors: Han Ming , Zhang Xuan , Hassan Saleh , Al-Yousef Ali 
Published: March 2023

Abstract
Hydrogen sulfide (H2S) is known as a poisonous gas associated with oil production. It is vital for sustainable oilfield development to handle H2S effectively and convert it into highly-valued products and remove simultaneously the environmental pollutant. Electrolysis decomposition of H2S is one of promising and key technologies in this field as it can utilize water as a media to convert H2S to hydrogen (H2) and elemental sulfur (S). In this review, it summarizes the technology development in electrolysis decomposition of H2S by means of direct and indirect electrolysis approaches since 1980s. The emphasis is on the research attempts in the electrolysis to overcome the main hindrances and to reduce power consumptions. It includes the technical schemes, setups, conditions, and voltage consumptions. By critical reviews of the technologies, it presents the prospective in technology development from laboratory research to small scale application. It has been long realized that the energy consumption of direct electrolysis decomposition of H2S is much lower than that of water electrolysis decomposition. H2S in aqueous solution can be directly decomposed to produce H2 at the cathode by reduction reaction and S at the anode by oxidation reaction. Although high-quality H2 can be produced at the cathode, the accumulative aggregation of S on the anode surface results in serious passivation that ceases the overall electrolysis process. Many efforts were made to modify the electrolysis conditions to improve the electrolysis efficiency. On the other hand, indirect electrolysis schemes have been developed by 2 oxidation-reduction electrolysis reactions using specific redox couples. This scheme is more operationally feasible since it avoids anode passivation and S is produced by the oxidation step and separated before the electrolysis step. Some small-scale pilots presented efficient production of H2 and S at low power consumption of 2.0 kWh/Nm3-H2 compared to the power consumption of 4.5 kWh/Nm3-H2 for water electrolysis. In addition, other route using metal as cathode has been developed which produces H2 and metal sulfide (MS) by electrochemical resolution-precipitation. This is very promising because of its low power consumption (0.8 kWh/Nm3-H2) and value-added product MS. This paper provides a state-of-the-art review of the technologies of electrolysis decomposition of H2S. It presents the prospective of hydrogen sulfide conversion from electrochemistry point of view.
Promoting a Culture of Behavior-Based Safety (BBS)
Authors: Altawal Ali , Arakzeh Mohammed , El-Ashi Rami 
Published: March 2023

Abstract
To increase the frequency of safe behavior and decrease the occurrence of at-risk behavior, behavior- based safety (BBS) focuses on identifying and providing interpersonal feedback for the critical behaviors that may cause or prevent injury. It also examines the factors that contribute to critical safety-related behaviors. Line-level employees have typically participated in BBS with assistance from the leadership. The identification, analysis, and improvement of essential safety-related behaviors among staff members at all organizational levels, from wage workers to supervisors and executives, constitutes a more comprehensive understanding of BBS. Moreover, unsafe acts and different types of factors that affect personality and could impact an employee's behavior and colleagues can influence an individual's personality, attitudes, and values.
The scope of this study is limited to the personality construct of extroversion. Extroverts have been shown to exhibit more positive attitudes toward safety, which may contribute to their increased risk-taking behavior. This study aims to analyze the relationship between extroversion, safety behaviors, and leadership levels as moderators of the relationship between context, performance, and safety behaviors among line employees.
Geothermal Pre-Drilling Decision Optimization: Methodologies and Case Histories
Authors: ElSherbeny Wael , McCarthy Kevin , Mattie Taylor , Al-Murshed Rakan , Alshamry Mohammad 
Published: March 2023

Abstract
Geothermal formations are hot, often hard, highly fractured and under-pressured. They often contain corrosive fluids and some formation fluids that have very high solids content. These harsh environments mean that drilling is usually difficult. Challenges include degradation of drilling fluids with associated variances in fluids properties, difficulty in managing mud systems, slow rate of penetration, short bit life and lost circulation. The potential for fines migration and induced formation damage in geothermal wells is significantly high due to weakening of attaching electrostatic forces under high temperatures and as a result of thermal contraction. Through case histories, this paper presents drilling challenges and the mechanisms of reservoir damages. The paper will also show the workflow and methodology of using the integrated geosciences analysis in pre-planning to mitigate the challenges related to geothermal activities.
Understanding geothermal reservoirs challenges requires a systematic workflow including but not limited to the following: structural geology, mineralogy, geochemistry, drilling fluid chemistry, high-temperature rock-water-fluids interactions, drill bit selection, and geomechanics modeling. ThermoChemo-Poroelasticity stability analysis is also an important consideration. Lab work to properly select the drilling fluids chemicals is required to optimize the drilling fluids parameters and simulating bottom hole temperature.
The outcomes from geology, mineralogy, geochemistry and geomechanics will be considered for optimum drilling fluids selection and fluids formulation optimization. The ultimate outcomes include but are not limited to MWT limits (Window), Breakout width, Pmud to trigger slip, drilling fluids formulation effects, drilling bits selection and surface parameters optimization.
For reliable performance in high-temperature environments, we need to consider the following: Know your geothermal reservoir; rock type, mineralogy, geochemistry, structural controls, geomechanics and Thermo/Chemo-Poro-elasticity conditions.Matching your injected water chemistry to formation water chemistry is very important, especially in high TDS geothermal brines. Incompatible total dissolved solids (TDS) concentrations will alter the ion carrying capacity, disturb the natural reservoir equilibrium and can lead to formation damage.Optimizing drilling fluid selection.Hydraulics, gel breaking, swab and surge including thermal effects.High-performance drill bits to keep you in the hole longer, reducing trips and saving you moneyAdvanced drilling technologies to deliver fast, efficient wellbore construction, including specially engineered motors for extreme operating environments, automated drilling systems, and high-temperature MWD technologies.