bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluid Circulation Effects on Torque and Drag Results, a New Take on an Old Subject
Authors: Mahjoub Mohamed , Dao Ngoc-Ha , Summersgill Matthew , Menand Stéphane
Published: March 2023

The hydraulic effects on torque and drag modelling have been thoroughly studied in the past, yet their interpretation still causes a lot of misunderstandings and confusions. Historical models disregard the circulation effects and focus on the fluid mass by employing buoyancy forces based on Archimedes principle. On the other hand, the reference model including the fluid circulation effects, introduced by R. F. Mitchell in the 1990s, consists in computing the forces due to internal and external fluids along the drill-string. The first type of models called Archimedes method directly produces an effective tension, while the second one generally called pressure area method produces a true tension that must be further transformed to get the effective tension. These different forms of tensions add even more confusion.

By returning to the basic equations of the fluid effects on the drill string, an equivalency between Archimedes and pressure area models has been found for the case with no circulation. Furthermore, with the same principle, an Archimedes-like model is deduced for the case of fluid circulation, where the effects of fluid pressures, frictions, and flows could be more easily interpreted. These two hydraulic models, after implementation in a true stiff-string 3D model enable then to fairly compare the two approaches in terms of forces applied on the structure.

The comparison of this Archimedes formulation with pressure area model gave sensibly the same results for various scenarios, proving the equivalency of the two approaches even with the case of circulating fluid. In addition to the model-to-model comparisons, torque and drag results are compared to field experiments at different depths. Flow rate was varied while reciprocating the drill string up and down, and the hook load was recorded for each flow rate and each tripping direction. The model-to-data comparisons showed a good agreement between the theoretical results and experimental data.

An advanced Archimedes method with all fluid circulation effect has been developed. By tackling the problem of circulating fluid in the drill string using two different approaches and proving their equivalency, a better understanding of the hydraulic effects can be achieved, which in terms can help settle the possible debates and confusions that might arise by drilling engineers.
Performance Analysis of a Downhole Regulator on Rate-Of-Penetration and Drilling Efficiency: An Autonomous Load Management at Bit
Authors: Aribowo Arviandy G. , Aarsnes Ulf Jakob F. , Detournay Emmanuel , Van de Wouw Nathan , Reimers Nils
Published: March 2023

Over the last years, the use of autonomous solutions for balancing the loading on the drill-bit has increased annually. By 2021, downhole tools for this purpose have been used for more than 1,500 wells and these become possibly the fastest growing trend in drilling. Polycrystaline Diamond Compact (PDC) drill-bits represent a great potential for drilling economics when steady cutting is attainable. Deep drilling, however, typically involves long drillstring causing an array of dynamic instabilities preventing steady cutting conditions at the bit. Such behavior affects drilling performance in terms of the rate-of-penetration (ROP) and system damage and failure. This leaves a big potential for improvement of drilling performance. The first experiments with an autonomous downhole regulator constructed were completed at Ulrigg in Stavanger almost twenty years ago to tap into this potential. Several versions of similar tools have since developed using a variety of mechanical and hydraulic functions to modify and shift the forces acting on the drill-bit in order to improve drilling performance.

The Norwegian operator Equinor has participated from the very start of this new automation trend. By 2020 they had deployed downhole regulators to a total of 93 well sections on the Norwegian Continental Shelf alone. In this paper, Equinor shares statistic plots from comparing these first 93 sections to well section with conventional BHA's. The data show how the continuous improvement of the regulator eventually led to gradual improvement of both ROP and footage - in addition to its initial task of reducing vibrations. By utilizing a variety of dynamic models, predictions and sensitivity analysis, it has been revealed that the downhole regulator could change the dynamic response of the bit such that the friction losses at the bit are reduced and the rock cutting efficiency is improved. In this paper, it is shown that such benefits can also be expected in real-life scenarios in which two key aspects play a role: 1) a PDC bit penetrating heterogeneous layers of rock formations, and 2) involving two frictional losses due to borehole - drillstring contact in deviated wells.

This paper brings a unique insight to the fundamentals, advanced mathematical models, and statistical results from a new line of drilling technology. The autonomous regulators bring a combination of reduction in risk and time to drill that makes a significant impact on cost.
Field Validation of Scalable Condition-Based Maintenance (CBM) of Mud Pumps
Authors: Yoon Dongyoung , Ashok Pradeepkumar , van Oort Eric , Annaiyappa Pradeep , Abe Shungo
Published: March 2023

Although mud pumps are critical rig equipment, their health monitoring currently still relies on human observation. This approach often fails to detect pump damage at an early stage, resulting in non-productive time (NPT) and increased well construction cost when pumps go down unexpectedly and catastrophically. Automated approaches to condition-based maintenance (CBM) of mud pumps to date have failed due to the lack of a generalized solution applicable to any pump type and/or operating conditions. This paper presents a field-validated generally applicable solution to mud pump CBM.

Field tests were conducted during drilling of an unconventional shale well in West Texas and a geothermal well in Japan, i.e., two very different drilling operations, to verify the feasibility and general applicability of the developed pump CBM solution. An accelerometer and an acoustic emission (AE) sensor were attached to pump modules, and data was collected during drilling operations. Anomaly detection deep-learning (DL) models were trained during pump run-time to pinpoint any abnormal behavior by the pump and its elements. The models were trained only with normal state data, and a damage score characterizing the extent of damage to the mud pump was calculated to identify the earliest signs of damage.

The system correctly identifies the degradation of the pump and produces alerts to notify the rig crew of the damage level of key mud pump components. During the field tests, different hyper-parameters and features were compared to identify the most effective ones for identifying damage, while at the same time delivering low false positive rates (i.e., false alarms during normal state pump operation). The developed CBM system provides a generalized solution for pump monitoring, capable of working for different pumps and different operating conditions, and only requires several hours of normal state data with no prior pump information. This system eliminates the environmental, health and safety (EHS) concerns that can occur during human-based observations of mud pump health, and avoids unnecessary NPT associated with catastrophic pump failures. The final version of this system is expected to be a fully self-contained magnetically attachable box containing sensors and processor, generating simple indicators for recommending pro-active pump maintenance tasks when needed.

This is the first successful attempt to validate a universally applicable DL-based CBM system for mud pumps in the field. The system allows more reliable continuous and automated pump monitoring by detecting damage in real-time, thereby enabling pro-active mud pump maintenance and NPT avoidance.
Gas Tight Mechanical Casing Anulus Packer Enables Compliance with Well Design and Barrier Requirements for Re-Entry Multilateral Application in 20+ Year Old Well on Norwegian Continental Shelf
Authors: Hrabovsky Brett , Koberg Ulrich , Roxman Keino , Fagna Jan Ove
Published: March 2023

With continually increasing drilling costs, the importance of utilizing existing slots in offshore platforms has never been higher in increasing average rate of recovery from the Norwegian Continental Shelf. Utilizing existing slots for new targets that were once inaccessible due to a multitude of reasons including technology limitations, value justification, among others pose many challenges for the operator.

One of these challenges specifically relates to compliance with current well design criteria and barrier requirements. As our industry has evolved, more stringent design criteria and additional well barrier requirements ensuring well integrity have become commonplace. In addition, integrity reduction of previously installed downhole components must be accounted for. Utilizing casing strings and polished bore receptacles (PBR's) that have been installed and exposed to harsh downhole environments for 20 + years create a need for innovative solutions

Through this paper we will demonstrate how through proper planning and equipment selection the operator was able to successfully install a gas tight mechanical casing annulus packer in a tieback string. This provided mechanical isolation of the previous casing string that had been exposed to years of wear. Traditional solutions of a tieback seal stem stung into a PBR were not possible due to expected condition of the seal surface in the PBR from years of down hole exposure. The rigorous qualification and validation program of the packer led to its selection in this application. Acceptance criteria of ISO 14310: V0 was used as the basis for testing. This included testing in a casing joint that had been previously installed in a well for 25+ years, mimicking downhole environments for this application.

The annulus packer was installed integral to the tieback casing and activation was combined with subsequent installation of multi-lateral junction equipment. Requiring no dedicated runs for installation or activation provided additional value for the operator. The packer was tested as per well design criteria which allowed the operator to proceed with well construction and continue to new target with upmost confidence in barrier compliance and well integrity.
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

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

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

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

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

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

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

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

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

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

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

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.
Upskilling the Next Generation of Petrophysicists
Authors: Dutta Masa , Choudhary Nikhil , Edem Cyril , Almuslim Sarah Mohammed
Published: March 2023

National and international oil and gas companies have pledged to reduce emissions from their upstream operations—a vision that calls for a highly competent workforce that is multiskilled and aware of the current transitions in the energy industry. The learning path of the petrophysics population has always been less clear than sister domains because of the lack of a university degree program. Superior quality training comprising classical petrophysics, sustainability understanding, and astute digital insight are essential to combat challenges in the modern realms of petrophysics.

To avoid a talent and skill shortfall during this critical period of transition in the energy sector, this study aims to highlight the major adjustments that may be made in workforce training and development—1) multidisciplinary petrophysics to understand the domain in light of geology, petroleum engineering, and drilling operations, and 2) digital awareness to predict formation properties using data analytics; e.g., multilinear regression and machine learning algorithms. Knowledge of programming language is also necessary to help with automation in analytics, and sustainability understanding to extend experience in the petrophysics domain to carbon management and geothermal projects (e.g., in relation to permeability, net thickness, and porosity).

Digital adoption, new energy focus, and core technical petrophysics with a multidisciplinary approach will T-shape (see illustration in Fig. 2) the profile of a future petrophysicist. The addition of digital literacy and sustainability awareness will help to diversify the learning portfolio of professionals irrespective of their career stage. A training program tailor-made to deliver the discussed components will create a flexible career path for both technical and managerial roles of operations and reservoir petrophysicists. Holistic petrotechnical training will ease the process of transition. An all-encompassing training will increase employee engagement and positively influence employee retention. The training program will ensure its relevance with current business trends and will reflect any changes to further avoid competency gaps. It will motivate senior petrophysicists to leverage expertise in new energy sectors such as geothermal and carbon management. With a clear understanding of its limitations, a revamped program for petrophysicists will strategically reduce the development cost.

The key innovative aspect of this paper is to guide petrophysicists in industry as well as in academia to train themselves with skills and competencies relevant to this highly volatile energy market. This paper catalogues the technical-digital skills in detail and also identifies free resources available on open-source platforms. This paper can be used by the petrophysics trainee, and organizations developing training or mentoring programs for their petrophysics population.
Frac Plug Evaluation to Improve Operations Efficiency
Authors: Baki Sohrat , Alzamil Abdullah , Habiballah Zeyad , Shariff Emad , Alowaid Abdulrahman , Alnakhli Wafaa , Alshammari Hamoud , Mahfouz Mohannad
Published: March 2023

Success of the unconventional resources (UR) operations is improving the efficiency by minimizing cost without compromising production. Plug and perforation (PnP) method is widely applied practice for unconventional wells completion due to flexibility of stimulating targeted intervals. One of the key parameters for operations efficiency of stimulation activities is utilization of fit for purpose frac plug to run with wireline PnP, proper frac isolation, and increasing efficiency of coil tubing mill-out. This paper provides comprehensive evaluation and comparison of various frac plug selection, execution and evaluation as well as optimization considering improving efficiency at multi-stage frac operations.

To improve contact area with targeted formations, longer laterals are drilled and during milling operations, it can generate additional challenges to the milling efficiency due to decreasing weight on bit and potential lockups due extended laterals. There are various types of plugs in the market depending on the technical requirements of the operation such as composite, semi-dissolvable and fully dissolvable fracturing plugs. Therefore, the search to obtain the most optimum fit for purpose frac plug selection is critical with the objective of being milled with minimal weight on bit and low to no debris produced from milling activities. The application of a rigorous system for choosing frac plugs to be tested and implemented considers various well completion, formation, operational and technical parameters, while cross-referencing case studies and historical usage at different fields worldwide.

For the current study, more than twenty frac plugs were systematically evaluated based on technical requirements, and were implemented across more than 2,000 stages of UR stimulation applications and coil tubing (CT) millout operations. Additionally, the paper discusses about contingency plans with solutions during wireline pump down and coil tubing millout operations challenges and opportunities.

Fracturing plug manufacturers are continuously improving their frac plug technologies to meet customers demands of ease of use, applicability and functionality. Hence, the introduction and development of semi or fully dissolvable plugs. This paper highlights a full cycle of process for qualifying fracturing plugs for fit-for-purpose applications.
Preparation and Characterization of Rapid Gelling Agent for Light Hydrocarbons-Based Gelled Fracturing Fluid
Authors: Du Tao , Chen Chen , Feng Jiangpeng , Yao Yiming
Published: March 2023

Light hydrocarbon-based gelled fracturing fluid is prepared by light oil, and oil-base fracturing fluid is prepared by heavy oil. The gelling agents for them contains different components. There are two kinds of the alkyl chains in gelling agents. They are the high carbon number alkyl chains and the low carbon number alkyl chains. High carbon number alkyl chains interact with each other and creat physical cross-linking. The existence of low carbon number alkyl chains helps to raise the compatibility between gelling agent and solvents. A L18(37) orthogonal tests are carried out and a series of gelling agent samples are synthesized. Range analysis, acidity value analysis and the gelling time are carried out to do experiments. The best concentration of gelling agents is tested by gelling kinetics. The results shows that the viscosity of the fracturing fluid is 75 mPa·s at the condition of 170 s−1 shear rate and 80°C. A new gelling agent sample is synthesized adding a small amount of polyol. This new gelling agent has high viscosity and less gelling time compared to traditional gelling agents. This polyol-included gelling agent is rapid cross-linking gelling agent.
The Niger Delta Process Safety Dilemma: Restoring & Maintaining Well Integrity in the Face of Perennial Asset Vandalization
Authors: Bougha Arthur , Alalade Temitope , Oluwatobi Ugoh , Eze Nnadozie
Published: March 2023

Safely operating Oil and Gas wells in the Niger Delta region of Nigeria has become quite challenging to achieve owing to the prevalent vandalization of assets in the operating environment. The asset vandalization ranges from minor theft of Christmas tree accessories, flowlines vandalization, to major wellhead damages and in some cases, wells get blown up with explosives by criminal elements. The major dilemma for the operations teams in this environment lies around how to (not only) restore integrity on wells with a complex state of vandalism, but also how to produce these wells safely.

Restoring integrity on vandalized wells depends on nature of damage. For subject wells, the complete wellhead systems were severed and carted away with only Down Hole Safety Valve and production packer preventing the release of hydrocarbon. Restoration included design of a false rotary, fishing of the severed tubing stumps on drill pipes, installation of plugs above the safety valve and chemical cut of the tubing above the plug. Casing plug was installed above cut tubing depth as second barrier.

Casings were then cold cut below impacted depth and tied back to surface. NDT, heat treatment carried out on weld joints.

In this paper, the unconventional well integrity challenges faced in the Niger Delta onshore wells (Ukp- wells 1, 2, 3 and 5) and the in-house capabilities (innovative and unconventional steps) developed to address these challenges are presented. The wells in this paper had all concentric tubulars severed from below the casing head housing and carted away by vandals. These wells had a very high potential of damage to the environment and reputational impact to the company due to the HSE exposure level, apart from not conforming to the Company's well integrity policy of a minimum of two (2) tested and independent barriers. The Well Integrity restoration team showcased various innovative ways which were applied in other to secure these wells safely, bearing in mind the non-existence of barriers for standard rig up of equipment for the securing operations. Integrity was successfully restored on the wells through the unconventional novel approach. The Heat treatment and NDT ensured integrity of the weld joints for safe rig up of the planned HWU for the abandonment.

This innovative approach prevented the potential process safety incident which could have led to asset, environmental and reputational damage. This paper would detail the history of the wells, planning, design and execution of the innovative in-house integrity restoration operation. The operation led to a total cost saving of US$1.8mln versus plan for the four vandalized wells that were restored.
First Microseismic Monitoring of Hydraulic Stimulation in Bahrah and Sabriyah Fields, Northeastern Kuwait
Authors: Rajeul Sebastien , Fortier Eric , Barbieri Ernesto , Abd El-Aziz Sabry , Vemparala Chintamani
Published: March 2023

The first microseismic monitoring operations of hydraulically stimulated wells were run in Bahrah and Sabriyah oilfields, Northeastern Kuwait. The main objective was to evaluate the capacity of the microseismic in optimising the fracturing process and consequently improving the production of these reservoirs.

The major phases of such monitoring projects are sensors network design, deployment, acquisition, data processing, results delivery, and interpretation. Fit-for-purpose monitoring networks were designed by modelling the expected sensitivity and location accuracy of various sensors geometry scenarios, considering local reservoir properties. Geophones were deployed in observation wells nearby treatment wells to record the seismic waves emitted by the microearthquakes induced by the rock fracturing process. This seismicity was located and characterised to image the fracture networks growth under the effect of pumping. From this, fracture geometry parameters were assessed, stress and hazard characterised, unexpected behaviours were monitored and analysed.

By providing information in real-time during rock stimulation operations, microseismic monitoring successfully helped improving production while maintaining a focus on the risk assessment indicators. In Bahrah, seismic response to the treatment was assessed for the target carbonate formation Mauddud, evaluating stimulation effectiveness while characterising unexpected and unwanted behaviours. In Sabriyah, fracture geometry estimates helped calibrating injection models and fine-tuning stimulation plans. Furthermore, a strong focus was also placed on monitoring hazard and anomalies in the Tuba carbonate formation being stimulated near a natural fault. Monitoring procedure, results and lessons learned from these projects can be transferred to other existing or upcoming wells to be drilled in the same formations, adding value to these reservoirs by optimising the fracture design, and making hydrocarbon recovery safer and more efficient.

This paper reports on the first usage of microseismic monitoring in Bahrah and Sabriyah oilfields in Kuwait. Monitoring met the initial objectives and both the approach as well as results are now a baseline for the effective development of hydraulic stimulation in these reservoirs and others with similar characteristics.
RTPD Safety Management System Toward Safety Excellence
Authors: Al Hakami Muatasem , Al Hamzah Majed
Published: March 2023

Event: Middle East Oil, Gas and Geosciences Show

Title: RTPD Safety Management System Toward Safety Excellence

Objectives/Scope: The objective of this abstract is to explain how Ras Tanura Producing Department have achieved the President's Award for Safety Excellence for the most improved department among all Saudi Aramco departments.

Ras Tanura Producing Department had shown a high level of collaboration and engagement with Loss Prevention Department that led to improve the safety performance and culture among Ras Tanura Producing Department employees. As a result, Ras Tanura Producing Department has achieved an overall score of seventy six (76) percentage during the assessment of safety Compliance Review management system carried by Los Prevention Department in the year of 2021, which demonstrates a commendable improvement from the year of 2018 review score of fifty seven (57) percentage which is recognized as the highest in Saudi Aramco Company.

The Ras Tanura Producing Department safety program effectiveness was assessed utilizing a risk based approach which focuses on the most prevalent areas for improvement identified in an analysis of Saudi Aramco safety performance and a thorough review of Ras Tanura Producing Department's documentation. The review also assessed the implementation of the Eight Lifesaving Rules. Evidently, Ras Tanura Producing Department has an opulent and mature Safety Management System that reveals comprehensive and logically written processes. These processes have gone through several reviews and revisions. Also, Ras Tanura Producing Department piloted management monthly safety audits and the verification, closure system of major incidents recommendations, which have been recognized as best practice.