bluuebunny/crossref_metadata_2025 huggingface dataset:
Unlocking Carbon Capture & Sequestration in Ultra Deep Saline Aquifers in the Western Desert of Egypt
Authors: Eleoni M. , Dredge J. , De Boer Y. , Mansour K. , Ismail A. , ElSayed R. , Merghany I. , Ellamey C. , Agam A. , Taqey A. , Gomes R. , Stojic S. , Nasiri A. , Bouchet F. , Nasreldin G.
Published: May 2024

Conventional subsurface reservoir candidates for CO2 Sequestration are usually just deeper than 800 m to ensure CO2 is injected at supercritical state, typically these are shallow, gently dipped, low pressure saline aquifer or completely depleted and abandoned hydrocarbon reservoirs. However, in this study within the western desert of Egypt, none of the reservoirs are abandoned and the saline aquifers below 800 m are too tight with no injectivity. So, the only way was to target ultra deep saline aquifer deeper than 3 km with virgin pressure of more than 5000 psi. These ultra deep aquifers are usually highly titled, surrounded by major faults, and highly saline and those factors act against the typical trapping mechanisms for CO2 sequestration such as structural trapping, residual trapping and CO2 solubility. In this case study, we present a novel approach that relies on innovative technology to solve this unconventional challenge to sequester 0.5 Mton CO2 per annum in ultra deep saline aquifers and open the pathway for carbon storage in unconventional storage sites.

The applied approach is divided into three phases. Phase one is site screening to automatically identify the best possible sites for CO2 storage based on a scientific scorecard. Then in Phase two, dynamic simulation of the injected supercritical CO2 plume movement within the formations while honoring advanced trapping mechanisms such as CO2 trapping due to residual trapping and dissolution in saline water. Then the dynamic reservoir simulation models are fully coupled to 3D geomechanics models to study the impact of the injection on the well integrity, cap rock integrity as well as fault reactivation and integrity. Finally in Phase 3, an economical surface facility configuration and pipelining scenarios that fit the subsurface sites’ requirements.

It was concluded through an ensemble of geological scenarios that safe CO2 trapping mechanism can be increased by 30% using a time and rate managed sequential injection scheme starting from the bottom of the formation and upwards. the dynamic simulation results show that this technique helps increasing the contact area with the saline water while leveraging high pressure to overcome low solubility in highly saline water and creating convective water density currents, hence increasing CO2 solubility in water as well as residual trapping of CO2 even in structurally marginal sites.

The followed scientific approach unlocked the potential for CO2 sequestration in ultra deep saline aquifers within the western desert to be deployed for a long-term and safe sequestration of CO2 while accounting for the complex subsurface structure to pave the way for future successful CCS projects in similar environments.
Enhancing Rigless Intervention Efficiency in Bi-Lateral Oil Producer Through Coiled Tubing Optical Telemetry, Multilateral Tool, and Single-Phase Retarded Inorganic Acid: A Case Study
Authors: Al-Mutairi F. , Slama H. , Al-Dhafiri S. J. , Al-Dwaish M. , Al-Mutawa M. , Sanyal S. , Al-Ayyaf E. , Al-Bader A. , Alajmi A. , Al-Otaibi A. , Al-Najim A. , Badrawy K. , Molero N. , Sunagatov R. , Ujagar U. , Sebaih M. Adel , Ayyad H.
Published: May 2024

Developments in horizontal drilling and completion techniques have enabled drilling an increasing number of wells. In the pursuit of cost optimization and enhanced recovery through maximized reservoir contact, operators are placing special interest on multilateral completions. However, multilateral wells add complexity to Rigless intervention and production enhancement work as those activities are heavily dependent on lateral accessibility.

An advanced Rigless intervention in a multilateral well relied on coiled tubing (CT) equipped with optical fiber and real-time downhole measurements and a multilateral entry tool (MLT). Downhole readings included casing collar locator (CCL), gamma ray, CT internal pressure, annulus pressure, annulus temperature, and axial force. Optical telemetry was used for lateral identification and for optimal actuation of the orienting and bent sub-components of the MLT while profiling and accessing the lateral. Throughout the stimulation treatment, optical telemetry was instrumental to understanding changing downhole conditions and keeping injection rates below fracturing pressure.

The candidate well was a carbonate bi-lateral oil producer completed through 6 1/8-in. uncased horizontal sections with both laterals having an average length of 2,400 ft. Because of real-time optical telemetry, profiling of the lateral was completed in less than 3 hours, which represents 50% reduction of the average profiling time in similar wells. Both laterals were stimulated via CT with a total of 4,000 bbl of single-phase retarded inorganic acid system (SPRIAS), which enables carbonate stimulation with better worm holing performance than emulsified acid while eliminating its drawbacks, such as high CT friction pressure and potential emulsion issues. In comparison with emulsified acid, the pumping time with SPRIAS was 35% lower, bringing additional efficiency to the intervention. The ability to make fast, informed decisions based on optical telemetry was the cornerstone of this intervention approach.

This paper documents a value case study for CT Rigless intervention for a field in the region divided between Kingdom of Saudi Arabia and Kuwait, where the combination of an array of technologies, such as CT optical telemetry, MLT, and SPRIAS, enhanced Rigless intervention efficiency, reducing total operation time by 30%, when compared to conventional CT stimulation approach in multilateral wells.
Enhancing Well Integrity and Efficiency: Deploying the 7-Inch Annulus Casing Packer (ACP) Tieback System for 9-5/8" Casing Remedial & Gas Lifting Completion Purpose in Field a, UAE
Authors: Busaeedi A. Al , Sinaga A. , El-Mahdy M. , Husein M. , El-Sayed I. , Fatima B. , Hossam H. , Amr F.
Published: May 2024

The deployment of the 7-inch Annulus Casing Packer (ACP) Tieback system in Field A's 9-5/8-inch casing remedial and gas lifting completion operations yields significant advantages. With its ISO 149998 V0 qualification, the ACP surpasses conventional Tieback methods, reducing the operation timeline by 5-7 days. This is achieved by incorporating design features such as cement passage ports, a V0 rated packer, and a Landing Collar with a non-shearable ball seat. The inclusion of a non-shearable ball seat obviates the need for a Bridge Plug or Acid Soluble Cement to isolate the open hole or perforation below the top of the liner, thereby eliminating the risk of cement slumping or falling into the reservoir instead of filling the annulus between the 9-5/8-inch casing and 7-inch Tieback. This enhancement not only strengthens well integrity but also leads to significant time and cost savings, representing a promising advancement in wellbore completion techniques.

Our approach revolves around the implementation of the 7-inch Annulus Casing Packer (ACP) Tieback system with a cost-effective slurry design. The assessment of long-term well integrity necessitates the use of a stress simulation tool. Tieback casing and cementing represent remedial techniques designed to cover damaged intermediate casing above the top of an existing production liner or open hole. Furthermore, they adhere to company standards, especially when the Gas Lift Mandrel is required. Tieback installation and cementing under such conditions involve important distinctions and additional risks. The use of washes and spacers ahead of cement slurries is crucial to prevent cement contamination and mixing with the fluid in the wellbore, a critical consideration due to the potential incompatibility with the completion fluid or brine. Proper evaluation of the outer casing's condition is imperative. Applying safety factors to determine the outer casing burst pressure, selecting TOC, displacing fluid, cement density and rheology, accordingly, are essential steps to lower the maximum surface pressure.

Drawing from the success of implementing this approach in 8 wells in Field A, it has significantly reduced operation timelines by 5-7 days, obviating the need for acid-soluble plugs or bridge plugs. The cost-effective slurry design, combined with stress simulation that optimizes well longevity by simulating pressure and temperature cycling during the well's lifespan, enhances wellbore integrity.

This paper represents a novel solution for enhancing wellbore completion efficiency and integrity. As well as contribution in suitability initiative by reducing operation time 5-7 days. Practicing engineers can benefit from this advancement by streamlining their operations and achieving improved outcomes while reducing costs.
Application of Machine Learning and Deep Learning to Predict Production Rate of Sucker Rod Pump Wells
Authors: Thabet S. A. , Zidan H. A. , Elhadidy A. A. , Helmy A. G. , Yehia T. A. , Elnaggar H. , Elshiekh M.
Published: May 2024

Sucker rod pump (SRP) systems must be designed, optimized, and operated with the aid of production data. This work seeks to create machine learning-driven models that can forecast fluid flow rate at the surface of SRP artificially lifted wells because traditional separators and multiphase flowmeters (MPFMs) may not be available in all wells. Nine machine learning models were developed using real data from 598 wells over three years, with 8,372 data points randomly split into 80% (6,697 data points) for training and 20% (1,675 data points) for testing. These models include Gradient Boosting, AdaBoost, Random Forest, Support Vector Machines (SVMs), Tree, K-Nearest Neighbor (KNN), Linear Regression, Neural Network, and Stochastic Gradient Descent (SGD). Each data set contained readings for the parameters that are easily accessible during any SRP well lifting process, including wellhead flowing pressure, casing pressure, inferred bottom hole fluid production rate, inferred bottom hole oil production rate, net liquid above pump, pump size, stroke length, pump running speed (SPM), pump depth, temperature at pump depth, oil gravity, water viscosity, and pump clearance. The performance of machine learning models is evaluated using two methods (K-fold cross-validation and repeated random sampling), and the results of the top five models (Gradient Boosting, Random Forest, AdaBoost, Linear Regression, Random Forest, and stochastic gradient descent) show that the mean absolute percent error (MAPE) between the predicted fluid rate at the surface and the actual measurements is 3.6, 3.4, 3.4, 4, and 4.4%, respectively. The correlation coefficients (R2) are also 0.937, 0.935, 0.934, 0.921, and 0.915, respectively. Additionally, an oil well in Egypt's Western Desert had its fluid flow rate at the surface predicted using machine learning models. The outcomes were contrasted with the data from the separator test itself. The actual fluid rate and the model's predictions were in perfect accord. Within a wide range of pumping circumstances and completion configurations, the machine learning models are helpful for forecasting the production rates of particular wells. This should make it possible to continuously monitor, optimize, and analyze the performance of SRP wells and to respond more quickly to operational problems. The application of the proposed machine learning models is easy, quick, and affordable when compared to conventional separators and multiphase flowmeters (MPFMs).
Experimental Investigation and Molecular Dynamics of the Fluid-Fluid Interactions Between Binary Surfactant Systems for EOR
Authors: Bello Ayomikun , Rodionov Alexander , Ivanova Anastasia , Cheremisin Alexey
Published: May 2024

This work aims to explore the properties and interactions between binary surfactant systems. We employed a methodology comprising experimental analysis, mathematical modeling, and molecular dynamics simulations. In the experimental study, we examined eight individual surfactants and six binary surfactant systems at various ratios to determine their critical micelle concentrations (CMCs), using reservoir oil and performing experiments at reservoir conditions. Then, Rubingh's Regular Solution Theory (RST) was applied to evaluate interactions within the binary surfactant mixtures. Finally, using molecular dynamics simulations, we characterized the microscopic interactions to comprehend how hydrophilic and hydrophobic parts of the surfactants interact with surrounding media, and how they self-assemble into aggregates such as micelles or bilayers. The key findings of our work showed that the occurrence of synergism or antagonism in lowering the CMC of binary surfactant mixtures depend on both the concentration of the individual surfactant and the type of surfactant used. Nevertheless, we noted a prevalent synergistic phenomenon in all binary surfactant systems, notably influenced by the concentration of the non-ionic surfactant. Increased concentrations of non-ionic surfactants notably enhanced synergistic interactions, fostering lowered CMC values when combined with anionic, cationic, and zwitterionic surfactants. On the other hand, an excessive concentration of cationic surfactants demonstrated relatively ‘weak’ synergistic effects, attributed to their comparatively smaller hydrophobic tail. Moreover, the formation of mixed micelles in binary surfactant systems led to a more negative free energy of micellization, thereby achieving synergistic effects between surfactants and resulting in lower CMC values. This emphasizes the crucial role of surfactant concentration in achieving synergistic outcomes within mixed systems. Generally, binary surfactant systems demonstrated lower CMC values compared to single surfactants, suggesting the potential for their use at lower concentrations to achieve desired interfacial and recovery outcomes, thereby reducing operational costs.
Optimization of Safety Height of Casing Shoe in Salt Cavern Gas Storage: A Case Study of Pingdingshan, China
Authors: Li Xiaolan , Feng Yongcun , Gu Chenwang , Li Xiaorong , Wang Guangyu
Published: May 2024

Salt cavern gas storage typically involves frequent multi-cycle injection and production, resulting in cyclic loading of the salt cavern system. The casing shoe, as one of the most vulnerable components, exhibits fatigue failure under cyclic loading, posing the risk of engineering accidents, including bond failure between the cement sheath and the formation, salt cavern collapse, and gas leakage. However, there has been limited research on the design of casing shoe heights for salt cavern gas storage. Therefore, in this paper, the casing-cement sheath-strata assembly was determined based on the Drucker-Prager criterion. The stability analysis of salt caverns under different interlayer distributions was conducted, and the distribution characteristics of plastic damage zones in salt caverns under different interlayer position distributions were compared. Considering the feasibility and stability of the salt cavern, the optimal range of the height of the casing shoe that meets the safety sealing requirements, the plastic zones and other indicators is proposed. The results of this paper are as follows (1) (1) Under unclamped conditions, the degree of influence of the stress concentration zone decreases as the height of the casing shoe increases. (2) When the interlayer is located above the casing shoe, the reservoir Von Mises stress becomes obviously smaller as the distance between the interlayer and the casing shoe increases. At the same time, the high strain region at the contact between the wellbore and the top of the cavity also decreases significantly, and the surrounding rock displacement at the casing shoe decreases most obviously. (3) When the interlayer is located below the casing shoe, the average value of surrounding rock displacement at the casing shoe is small, and the stress concentration area of the gas reservoir is insensitive to changes in the distribution of the interlayer. Therefore, in engineering practice, it is recommended to establish the casing shoe above the interlayer, which is more conducive to the stability of the gas storage reservoir. However, it should be noted that when the number of interlayers below the casing shoe increases, the surrounding rock displacement at the casing shoe will increase substantially, so it is recommended to have only a single interlayer below the casing shoe as much as possible. (4) No matter where the interlayer is distributed, the point of contact between the open well section and the cavity is the point of maximum equivalent stress, and there is a layer of 0.18~0.25m thick stress concentration zone on the inner side wall of the open well section. In order to avoid the local damage of the open well section leading to tensile damage at the casing shoe, the casing shoe height should be kept high enough to form a safety buffer zone. It is recommended that the casing shoe height be greater than 10m.
A New Approach to Investigate Rock Salt Creep Behavior Under Triaxial Stress
Authors: Ju Yingtong , Chen Mian , Lu Yunhu
Published: May 2024

Generally speaking, the rock formation with creep capability, where rocks undergo continuous deformation under constant stress, are commonly encountered especially in geomechanics, petroleum engineering, and mining science. This phenomenon significantly impacts the stability of underground engineering structures, such as petroleum/geothermal wellbores or the safety of coal mine tunnels. Therefore, investigating formation with viscous property, characterizing its creep behavior, and determining creep parameters are crucial for ensuring safe construction and production. Currently, the study of creep properties primarily relies on laboratory tests. However, rock samples obtained from underground may undergo changes in their physical and chemical properties during coring operation, transportation, and storage processes, potentially introducing discrepancies between the parameters acquired in lab and the actual value. Nowadays, apparatus capable of conducting creep or rock mechanic experiments are typically characterized by large overall dimensions, causing multiple challenges including disassembly, relocation, and poor environmental adaptability. As a result, they are typically restrained to usage in specialized laboratories. To address these limitations, this study employed a self-designed and fabricated true triaxial visualization rock mechanics test apparatus, characterized by rapid assembly, simple operation, compacting structure, etc. This apparatus allows for creep tests under true triaxial stress with only a single hydraulic power source. Moreover, even in unfavorable conditions, image acquisition can be accomplished using a phone camera, whose application has been verified through tests. Therefore, it is highly suitable for field applications in oilfields. Using this apparatus, a variety of creep experiments under different stress levels were conducted. The true triaxial visualization approach proved to be more direct in observing the influence of rock anisotropy/heterogeneity on rock creep. Through a single experiment, we were able to directly obtain creep patterns for different components, significantly enhancing experimental efficiency.
Pre-Drilling Pore Pressure Prediction Technique Based on High-Quality OBN Seismic Velocity and its Application in K Oilfield
Authors: Xin Chen , Khdhaouria Mourad , Rouis Lamia , Huang Qingfeng , Xiaolin Lv , Min Zhao , Xiaoliang Li , Dengyi Xiao , Qunli Qi , Wenwen Yu , Qiang Liu , Xin Hu , Kongzhi Huang
Published: May 2024

Pre-drilling pore pressure prediction based on seismic velocity is a critical step in the oil and gas industry to ensure drilling safety and optimize well construction. However, due to the limit resolution of the seismic data, the pore pressure prediction result is not good enough for well drilling. With the increasing quality of new seismic data, this study proposed a new pre-drilling pore pressure prediction technique based on the high quality OBN seismic velocity.

This new technique consists 6 steps: ①Abnormal high pore pressure identification based on the pore pressure test, mud weight, well logging velocity and seismic velocity. ②Mechanism analysis based on the lithology, sequence stratigraphic and tectonic movement. ③Feasibility analysis based on the comparing the OBN seismic velocity with abnormal high-pressure interval. ④Geological consistency OBN seismic velocity optimization, based on high-quality logging velocity. ⑤Pore pressure prediction based on the petrophysical analysis and pressure prediction parameters optimization.

This new technique has been successfully applied in the K oilfield in Central Asia. Integrated pressure testing data, mud weight, and seismic velocity can clearly identify high pore pressure in middle to deep formation of the study area. The abnormal pressure is formed due to under-compaction, where the mudstone of the maximum flooding surface acts as a barrier to the outflow of pore fluids in the deep layers, resulting in abnormally high pore pressure. Abnormally high pressure can be clearly identified by the OBN seismic velocity spectrum, with different pressure gradient intervals having different OBN seismic velocity gradients. Geological consistency velocity optimization methods can enhance the accuracy of OBN seismic velocity interpretation and more matched with well log velocity, thereby improving pressure prediction accuracy. Modified Fillippone method was used for pore pressure prediction, and more accurate Vmax and Vmin can be obtained through rock physics analysis, further enhancing pressure prediction accuracy. From the initial seismic velocity spectrum and pressure test results from nearby drilled wells QC, the results were matched with pore pressure prediction results, with a high correlation (up to 92%).

The new pre-drilling pore pressure technique integrated the advantages of pore pressure testing, high resolution of well log velocity, and high-quality of OBN seismic velocity. It enhances the accuracy of OBN seismic velocities through geological consistency seismic velocity optimization and improves the accuracy of pressure prediction parameters (Vmax and Vmin) through rock physics analysis, and ultimately improving the accuracy of pore pressure prediction. This method is applicable to both clastic layers and carbonate layers.
Direct Hydrocarbon Saturation So from Core Plug and Well Cuttings Using Geochemistry Based Method of Extraction-A Cost Optimized Alternative Method for Optimal Test Zone Selection and STOIIP Calculation
Authors: Koksalan T. , Alwahedi M. A. A. , Ghosh D. , Ahsan S. A.
Published: May 2024

We can assess reservoir saturation with high confidence and make timely and cost effective decisions about testing and perforation by measuring hydrocarbon directly on core and cuttings extracts and doing SARA (Saturate, Aromatic, Resin and Asphaltene) compositional analysis integrated with mud log and petrophysical data. Conventional reservoirs usually measure hydrocarbon saturation with petrophysical interpretations based on well log data. But petrophysical methods are often based on resistivity, which is indirect, interpretive and can give unreliable water saturation (Sw) in carbonate reservoirs with complex porosity and different fluid distribution. We have seen that, in many cases, Sw is underestimated, and this causes significant variation in the amount of hydrocarbon in place. Also, the Sw is calibrated by lab measurement of water extracted from core plugs with Dean Stark method. But Dean Stark method can also give misleading Sw, especially when water bound water exists. The aim of this study was to measure oil saturation directly by extracting oil from core plugs. This method has been shown to agree very well with the test results and has potential to provide a more reliable STOIIP and choice of best testing intervals.

A suite of more than two hundred (200) core plug samples from different wells were analyzed. Total Extract Yield was determined on extracted samples to assess hydrocarbon saturation through the reservoir of interest. Our method is based on extraction of pulverized core plugs and well cuttings samples. The extracted oil is collected in glass vials, measured in milligrams and is reported per gram of the rock weight extracted. The weight of the oil extracted is then converted, using a mathematical expression, into water saturation (Sw).

The approach presented here utilizing extract yield normalized to rock weight has been adopted to assess hydrocarbon saturation. Furthermore, the use of Sw obtained and calculated from extract yield of cores, coupled with conventional open hole logs and mud log, core samples can assist in making time-sensitive drilling and completion decisions, such as selecting optimal perforation zones and identifying high water saturation zones for plugging. Additionally, it can help in keeping horizontal wells within sweet spots and in estimating in-place hydrocarbon volumes in both conventional and unconventional reservoirs. Perforation interval selection or isolation of high-water zone in a horizontal well scenario is particularly very critical in thin and tight reservoirs where improper well completion may severely impact reservoir performance and project’s economics.
Next Chapter of Drilling is Opened by Using New Technologies to Reduce Shocks and Vibrations and Improve Drilling Performance
Authors: Al-Meer Ali , Fakhrylgayanov Ayrat , Gari Abdulrahman , Alqahtani Khalid , Osman Ahmed , Alabdallah Mansour , Santoso Gagok , Franco Nata , Almomen Mohammed , Aswal Uttam
Published: May 2024

In the oil and gas industry, one of the biggest challenges in drilling deep gas wells is to maintain the drilling tools in good working condition despite the harsh drilling environment, which can cause shocks and vibrations. This is especially true in long horizontal sections with reservoirs that have heterogeneous formations such as tight and interbedded porous limestone formations between anhydrite layers. During drilling operations, severe stick-slip, shocks, and vibration can occur. Furthermore, high-frequency torsional oscillations (HFTO) can be generated, reducing the rate of penetration and damaging drilling tools or bits. This affects the drilling performance and efficiency.

A new technology of HFTO dampener tools was used in a Lump SumTurnkey (LSTK) gas project in the Middle East. By applying certain optimized drilling parameters, significant improvements were made in drilling performance. The longest footage was drilled with more than 4,450 ft in a single run, achieving a total measured depth of 19,800 ft. The new technology reduced vibrations amplitude by 50% and enabled drilling in highly challenging long-lateral sections more efficiently. These results played a crucial role in achieving the well objectives with a huge increase in drilling performance and efficiency. The technology also allowed for proper identification of optimum drilling parameters in the reservoir.

This paper describes the field deployment of the HFTO dampener tool and the application of optimized drilling parameters, which were used for the first time to drill the challenging horizontal lateral section in the LSTK gas project. The results can be implemented in any project worldwide.
A Gupco Drilling Case Study Illustrates How Shifting an Organization’s Culture Can Shape How it Approaches Innovation
Authors: Saloma Mohamed Farouk , Salama Ayman , Ibrahim Lotfi , Elsayed Mohamed Farouk
Published: May 2024

Change the collective organizational culture from risk avoidance to risk taking because of the realization that taking calculated risks can lead to innovation and progress. This approach enabled a more agile and adaptable response to enhance performance while also cultivating a culture of continuous improvement.

To achieve the required change, a communication and engagement strategy was selected through the following.

To help GUPCO drilling organization understand the need for change, a high-value learning study was carried out. The study involved analyzing current practices, identifying areas of inefficiency, and exploring innovative approaches to enhance productivity and performance. To help GUPCO drilling organization start making the necessary adjustments, a workshop on drilling performance improvement was held. The workshop aimed to identify areas of improvement and develop strategies to enhance drilling performance. It provided a platform for employees to share their insights and collaborate on implementing effective solutions.

By adopting this mindset, the GUPCO drilling team was able to approach challenges with a fresh perspective, encouraging innovative solutions and fostering a culture of continuous improvement. Consequently, the drilling team unlocked previously inaccessible opportunities. This new working philosophy was implemented in the EDFU field 2021 campaign by combining two sections that had never been drilled together. This resulted in time and cost savings and the unlocking of opportunities that had been blocked since 2017. Same approach of combining two sections was utilized in Saqqara, July, and October fields with outstanding results. The successful implementation of this new working philosophy not only allowed the drilling team to tap into previously untapped opportunities but also led to a significant increase in productivity and overall success, solidifying the effectiveness of this strategy and paving the way for future attempts.

By fostering a culture that values experimentation, risk-taking, and open communication, companies can create an environment where employees feel empowered to think creatively and explore new ideas. This cultural shift can lead to increased collaboration, the breaking down of silos, and a greater emphasis on continuous learning and improvement, ultimately driving innovation forward.
Research on the Influence and Mechanism of Particle Geometry and Mechanics on the Strength of Temporary Plugging Zone
Authors: Zhao Feng , Guo Jianchun , Ren Jichuan
Published: May 2024

Temporary plugging and diversion fracturing technology is an essential approach in the development of shale oil and gas. Enhancing the shear strength of temporary plugging zone is crucial for the success of this technology, which significantly depends on the geometric and mechanical characteristics of the plugging particle. Based on the rolling resistance model, this study uses Particle Flow Code (PFC) to establish a shear model for the temporary plugging zone. It explores the evolution of the strength of the plugging zone during shear failure through stress-strain curves. The research also reveals the mechanisms of strength variation from a microscopic perspective by integrating the force chain network structure. Furthermore, it quantitatively analyzes the influence of the friction coefficient, Young's modulus, and aspect ratio of the temporary plugging particles on the strength of the plugging zone. The results indicate that the strength of the temporary plugging zone is positively correlated with the strength of the force chains, but has a weaker relationship with the number of force chains. The greater the strength of the force chains, the higher the strength of the temporary plugging zone. The friction coefficient, Young's modulus, and aspect ratio of the particles are key factors affecting the strength of the force chains. As the friction coefficient, Young's modulus, and aspect ratio of the temporary plugging particles increase, the strength of the plugging zone initially increases and then stabilizes. The critical value for the friction coefficient is 1, for Young's modulus is 6.5 GPa, and for the aspect ratio is 2.7. The friction coefficient has the greatest impact on the strength of the plugging zone, followed by Young's modulus, while the aspect ratio has the least impact. This paper establishes a predictive model for the strength of the temporary plugging zone, clarifying the quantitative relationship between particle parameters and the strength of the plugging zone. It provides a basis for the optimal selection of particle materials and the development of new materials in the process of temporary plugging and diversion fracturing technology.
Unleashing the Potential of Advanced Diversion Techniques: Integrating Simulation and Real Case Study to Enhance Productivity in Limited Entry Slotted Liner Horizontal Completions within Tight Carbonate Reservoirs
Authors: Elhadidy Ahmed Ayman , Gabry Mohamed Adel , Thabet Samuel Adel
Published: May 2024

ARX is a common carbonate reservoir located in Egypt deserts. It is described as a Dolomite reservoir with tight formation, strong lateral continuity, and naturally fractures with low connectivity. The main challenges to maintaining economically viable well productivity are the heterogeneity and tightness.

The large interest in developing such low permeability reservoirs has been a direct result of the favorable economics achieved by the advancements in horizontal well drilling and stimulation technologies hold great promise to increase production by dramatically increasing the contact area with the producing interval, maximizing the drainage volume around a well and link those natural fractures network

Acid stimulation is a common technique used in oil and gas reservoirs to enhance the productivity of reservoirs. However, when horizontal wells completed with slotted liners are involved, unique challenges can arise. Horizontal wells have gained popularity due to their ability to access a larger reservoir area and increase production. Slotted liners, which consist of perforations along the wellbore, are commonly used in these wells to prevent sand intrusion. However, obstructions such as production logs, debris, or scale buildup can hinder the successful deployment of coiled tubing and acid stimulation tools.

This study investigates the challenges faced during acid stimulation of a horizontal well completed with a slotted liner, specifically focusing on a section where coiled tubing became stuck, spanning approximately 2000 ft horizontally. The study integrates software simulation of acid stimulation operations with actual well data and post operation production data to address the utilization of chemical diverter for delivering the acid stimulation to large areas that are inaccessible by coiled tubing due to obstructions in the horizontal section.
Facies Classification of Clastic Reservoirs Using Machine Learning Technique and their implication for New Drilling Opportunities
Authors: Moeen M. , Javed T.
Published: May 2024

This paper discusses successful implementation of machine learning techniques like Neural networks for prediction of reservoir facies in a highly variable clastic depositional area with limited core & log data. These predicted facies were then populated into the static model for robust field development and future well placement in Beta field of Middle Indus Basin, Pakistan.

In the study area, only 1 well outside the field had reservoir core data. This data and poro-perm facies were combined with log data to train the neural network (1D convolutional neural net). After getting an excellent match at known points, trained network was used to predict facies at Beta-1 well (exploratory well that discovered the field) utilizing the available well logs. Predicted facies were then distributed statistically using variogram (based on geological and depositional architecture of the area) and co-kriged with seismic amplitude distribution within the Beta field area.

The predicted facies were used as one of the inputs into the Reservoir Static model. Post modelling, favorable undrained area was identified in the Beta field and next development well was drilled. Well results showed that predicted facies matched with new well results by more than 70%. The results clearly demonstrate the effectiveness of machine learning techniques in predicting reservoir facies. This successful demonstration of facies prediction highlights the significance and power of implementation of machine learning methods when used with geological & geophysical data. This approach has allowed for better understanding of field dynamics, aided in better well placement, and ultimately improved production performance in the Beta field.
Leveraging Python in Decline Curve Analysis: Automation, Integration, and Advancements in Reservoir Management
Authors: Nukala S. T. , Kumar A. , Rajput S. , Lopes V. S.
Published: May 2024

Decline curve analysis (DCA) serves as a fundamental technique in the realm of oil and gas production, particularly for assessing the diminishing production rates of wells and projecting their future performance. This method entails fitting standard curves to historical production data, enabling the identification of trends that reflect the decline in production over time. By extrapolating these established curves, DCA facilitates the prediction of future well performance. It stands as a pivotal tool in estimating recoverable reserves, especially applicable in scenarios where the production history spans a sufficiently long duration to discern discernible decline patterns.

An integral technology employed in this process involves an automated Decline Curve Analysis (DCA) methodology, capable of autonomously executing on a machine with minimal human intervention and reduced error rates. The traditional DCA, rooted in Arp's equation, distinguishes three primary types of decline curves: exponential, hyperbolic, and harmonic.

This research endeavor encompasses the development of a Python-based framework by the authors and comparison of different methods, aimed at applying Decline Curve Analysis (DCA) methods to wells in a manner characterized by impartiality, systematic execution, and automation. Various methodologies for automating decline curve analysis were explored, and their outcomes were meticulously compared. This innovative approach stands in stark contrast to the conventional practice of manual DCA, which has historically dominated the industry. As the oil and gas sector transitions into the digital transformation era, the fusion of digital capabilities with traditional expertise in DCA becomes increasingly imperative. Embracing this synergy facilitates not only enhanced efficiency and accuracy but also fosters a deeper understanding of reservoir behavior and production dynamics.
Assessing structural connectivity and anthropogenic impacts on Ambystoma altamirani populations in Bosque de Agua, Central Mexico
Authors: Ruiz-Reyes Jessica , Heredia-Bobadilla Rosa Laura , Ávila-Akerberg Víctor , Tejocote-Perez Moises , Gómez-Ortiz Yuriana , Domínguez-Vega Hublester , Ramírez-Corona Fabiola , Alvarez-Lopeztello Jonas , Bolom-Huet Rene , Sunny Armando
Published: May 2024

Ambystoma altamirani is a microendemic amphibian limited to central Mexico, specifically the Bosque de Agua region in the Trans-Mexican Volcanic Belt, renowned for its endemic amphibian species. Anthropogenic activities such as land use change, water pollution, and the introduction of exotic species such as rainbow trout (Oncorhynchus mykiss) have substantially transformed its habitat, creating barriers that fragment it and impeding the mobility of the species and connectivity with other populations. This fragmentation poses challenges, including emerging diseases, inbreeding, limited gene flow, and a loss of genetic diversity, placing Ambystoma altamirani in national and international risk categories. The present study utilized the ENMeval and biomod2 models for environmental niche modeling (ENM) to assess the potential distribution of Ambystoma altamirani in the Bosque de Agua region. The key supporting variables include rivers, lakes, altitude, and a combination of Abies and Pinus forests, while the detrimental factors include urbanization and agriculture. Employing circuit theory (CT) and least-cost path (LCP) methodologies, this research explored structural connectivity, identifying core areas in the central region of Bosque de Agua. As migration distance decreases, the number of corridors facilitating population flow decreases. In the concluding phase, an analysis assessed the coincidence of state and federal Mexican Natural Protected Areas with core areas, revealing a lack of protection. The results of this study could lead to improved knowledge about Ambystoma altamirani, providing valuable tools for helping stakeholders formulate comprehensive strategies for species conservation.
Intravenous ketamine is ineffective compared to midazolam for treatment-resistant depression: a double-blind, randomized controlled study
Authors: Pattanaseri Keerati , Lortrakul Juthawadee , Jaisin Kankamol , Srifuengf Maytinee , Sa-nguanpanich Naratip , Viravan Natee , Pariwatcharakul Pornjira , Makarasara Wattanan , Ratta-apha Woraphat
Published: May 2024

Background: Studies have confirmed the rapid antidepressant action of ketamine in depressive episodes. Nevertheless, a standardized procedure for the delivery of ketamine infusion in individuals suffering from treatment-resistant depression, particularly in terms of infusion frequency and total dosage, remains undetermined. In addition, an efficacious ketamine regimen for persistent pain management involved a continuous 10-day infusion period with no notable adverse effects. Consequently, the primary objective of this study was to evaluate the antidepressant capacity of consecutive ketamine infusions spanning over three successive days, the duration of therapeutic response, and the overall safety profile of the treatment.
Methods: In this randomized controlled trial, participants aged 18-64 with treatment-resistant depression were randomized to receive either intravenous ketamine or midazolam (used as an active placebo) for 40 minutes daily over three consecutive days. Statistical analysis using repeated measures ANOVA was employed to assess the changes in the total score of the Montgomery–Åsberg Depression Rating Scale (MADRS) and the clinical global impression (CGI) from the initial assessment to 10 and 31 days post-infusion. Additionally, the duration of response and remission was evaluated using Kaplan–Meier survival analysis.
Results: Out of 33 randomisedparticipants, 20 underwent the treatment as planned. By day 10, the ketamine group had a mean reduction in MADRS score of 12.55 (95% CI = 6.70–18.09), whereas the midazolam group had a decrease of 17.22 (95% CI = 11.09–23.36). This pattern continued to day 31, with ketamine showing a mean score decrease of 13.73 (95% CI = 7.54–19.91) and midazolam a fall of 12.44 (95% CI = 5.61–19.28). Both treatments were well tolerated, with dissociative symptoms in the ketamine group being temporary and ceasing by the end of each infusion.
Conclusion: Intravenous ketamine given for 3 consecutive days did not show a notable antidepressant advantage when compared to the active placebo midazolam, highlighting the need for further research into effective treatments schedules for treatment-resistant depression.
Trial registration: NCT05026203, ClinicalTrials.gov, registered on 24/08/2021.
Hybrid Phase Unwrapping Approach for InSAR Interferometry: Content-Based Interpolation & Adaptive Phase Unwrapping
Authors: omar Hadj Sahraoui , faouzi berrichi , Chamakhi Djemoui , Dif Amar
Published: May 2024

In this research article, we present a novel hybrid approach for phase unwrapping in Interferometric Synthetic Aperture Radar (InSAR) interferometry. Our proposed method combines Content-Based Interpolation (CBI) techniques with Adaptive Phase Unwrapping (APU) algorithms to address the challenges associated with phase unwrapping in complex interferograms. Content-Based Interpolation utilizes the spatial and spectral characteristics of the interferogram to interpolate phase values in regions of missing or unreliable data, while Adaptive Phase Unwrapping adapts the unwrapping process to the local phase gradient, enhancing the robustness and accuracy of the unwrapped phase. We demonstrate the effectiveness of our hybrid approach through experiments conducted on synthetic and real InSAR data, showing significant improvements in phase unwrapping accuracy and reliability compared to traditional methods. Our proposed hybrid phase unwrapping approach offers a promising solution for enhancing the quality of InSAR interferograms and advancing the capabilities of remote sensing applications such as terrain deformation monitoring, surface displacement analysis, and topographic mapping [1][2][10].
By exploiting the phase of the coherent radar signal, interferometry has transformed radar remote sensing from a largely interpretive science to a quantitative tool for Environmental Monitoring[14][16], with applications in cartography, geodesy, land cover characterization, and natural hazards. Extensive testing across multiple sites has demonstrated the effectiveness of the proposed method, showcasing promising results.
The Relationship Between Parental Health Literacy and Primary School Students' Anthropometric Measurements and General Health Status
Authors: Uner Elif , Aygun Ozcan , Duman Alime , Gungor Nazli
Published: May 2024

Background Parental health literacy plays a critical role in children's health and development. This study was conducted to reveal the relationship between parents' health literacy level and anthropometric measurements and general health status of primary school students.Methods Power analysis was performed to determine the sample size of the study and 681 children and their parents in 2 primary schools were included in the study. Data were collected using the socio-demographic data form, the student follow-up form, and the short form of the European Health Literacy Scale. The data collection forms were sent to the parents together with the students, and the anthropometric measurements of the children were carried out in an office set up in the school in which they were located. Chi-square test and binary logistic regression analysis were used to analyze the data.Results Parental health literacy was found to be adequate. Statistically significant relationships were found between parental health literacy and factors such as educational level, marital status, general health status of children, and preferences for access to health services (p < .05).Conclusions Parents who were single, had completed high school or college, rated their general health as high, perceived their children's health as good or excellent, visited the hospital, and did not have oral and dental health problems in their children were found to have higher levels of health literacy. It is recommended to prepare information and education programs specifically for these groups.
Phase angle is associated with neck circumference in sleep apnea patients--a cross-sectional study
Authors: Wang Haodong , Zhang Junli , Ma Jianhong , Luo Huiping , Wei Chunsheng , Huang Jingjing
Published: May 2024

The aim of this study was to characterise the whole-body 50 kHz phase angle in patients with obstructive sleep apnoea (OSA) and to estimate it using other nutrition-related physical examination indices. We enrolled 117 patients with OSA who underwent polysomnography. Patients underwent body composition measurements, physical examinations, and nutrition-related laboratory tests, and were grouped according to neck circumference (NC) quartiles to analyse the correlation between NC and nutritional assessment index values. A significant positive correlation was observed between NC and various nutritional indicators, including height and whole-body 50 kHz phase angle. An increase in NC resulted in a corresponding increase in weight, body mass index, waist circumference, arm muscle circumference, whole-body 50 kHz phase angle, apnoea–hypopnea index, and the longest apnoea time. Further stepwise regression and multiple linear regression analyses revealed: whole-body 50 kHz phase angle =(0.126×waist circumference + 0.345×arm muscle circumference − 1.420- NC)/(-1.496). The whole-body 50 kHz phase angle in patients with OSA can be estimated using NC, arm muscle circumference, and waist circumference, helping assess the combined nutritional, inflammatory, and immune status of patients with OSA.