bluuebunny/crossref_metadata_2025 huggingface dataset:
Seaweed nori (Kappapycus alvarezi) physicochemical and organoleptic characteristics with moringa leaf fortification (Moringa oleifera LAM)
Authors: Limonu Marleni , Bait Yoyanda , Engelen Adnan , Muhsin Nurhayati
Published: October 2024

Nori was a product made from seaweed which contained fiber and bioactive substances even though it had low antioxidants. The solution was needed to increase antioxidants from Nori products was food diversification with the addition of Moringa leaves which contained high antioxidant activity. Identifying the physicochemical and organoleptic properties of the nori seaweed (Kappapycus alvarezi) with the fortification of Moringa (Moringa oleifera Lam) leaves was the aim of this research. The addition of Kappapycus alvarezi seaweed pulp and Moringa leaf pulp was compared in this study's single-factor randomized design (CRD) four treatments: (K0=100%:0% kontrol), (K1=90%:10%), (K2=80%:20), (K3=70%:30%). The data were evaluated using statistical analysis of variance (ANOVA), and the Duncan Multiple Range Test was used if there was a significant result (p0.05) for each treatment (DMRT). The results showed that Kappapycus alvarezi nori seaweed with fortified Moringa leaves (Moringa oleifera Lam) had an effect on physicochemical and organoleptic characteristics, and could increase the nutritional value of nori, which had an antioxidant activity value of 59.921ppm, total phenol of 252.527%, the water content of 18.030%, Fiber content of 18.637%, thickness test of 0.20 mm, tensile strength/tear strength of 0.541MPa, hydration test of 24.446%. The organoleptic values consist of color at 5.83, aroma at 4.87, taste at 5.03, and texture at 5.53. The impact of this research was to produce products that contained good bioactive substances and antioxidants.
Product inventory control at a local brand forum outlet using ABC analysis
Authors: Pradita Sintia Putri , Widodo Kuncoro Harto
Published: October 2024

A local brand forum outlet sells Micro, Small, and Medium Enterprises (MSMEs) products with inventory management still carried out manually based on employee experience. The research objectives are to analyze problems related to the inventory system and provide recommendations for planning and controlling inventory systems at a Local Brand Forum (FBL) outlet. Primary data was collected through observation, in-depth interviews, and Focus Group Discussion (FGD). The method used is ABC analysis to obtain the product classification. The results showed that 16 items (19.05%) are included in class A, with a total sales value of 69.55% of the total value for money. Class B has 25 product items (29.76%) with a total sales value of 20.29% of the total value for money. Products in class C are 43 items (51.19%) with a total sales value of 10.16% of the total value for money. As much as 43.75% of products in class A are nine basic commodities which are the basic needs of the Indonesian people, so they have a high priority in inventory control. These results are expected to provide planning and inventory control systems using the ABC class of products to avoid shortages and overstock inventory.
Evaluasi karakteristik gula kelapa cair dengan variasi penggunaan laru dan penambahan ekstrak rosela
Authors: Purbowati Ike Sitoresmi Mulyo , Wijonarko Gunawan , Maksum Ali
Published: October 2024

Coconut sugar is a food ingredient made from coconut juice. Nira is easily damaged due to microbial contamination. The destruction of sap can be prevented by the use of laru and variations of rosella constituencies.  This study aims to examine the effect of the use of laru on the quality of sap and liquid coconut sugar, the effect of variations in the addition of rosella extract on the quality of liquid coconut sugar, and the influence of the combination of variations in the use of laru and the addition of rosella extract on the quality of liquid coconut sugar. This study used experimental methods with a Complete Randomized Design (RAL). The factor studied was the use of nira preservatives: Non Laru and Laru.  The second factor is the variation in the concentration of added rosella extract which is 0; 5; 10; 15 %.   The variables observed were pH, Brix, reduction sugar, moisture content, viscosity, colour, aroma, taste, preferences, texture and flavour. The use of laru affects the pH, reduction of sugar, colour, aroma, taste, preferences, texture and flavour of liquid coconut sugar. The higher the concentration of rosella extract administered will lead to a decrease in pH, ̊Brix, viscosity and an increase in moisture content. The higher the concentration of rosella added to liquid coconut sugar, the browner the colour of liquid coconut sugar will be, the distinctive aroma will be mushier, the sweetness is slightly reduced, the level of liking decreases, and the texture is as good as diluted and the flavour of liquid coconut sugar also decreases.
Pangan fungsional dari bahan pangan tradisional: tinjauan pustaka
Authors: Setiawan Sia Clarissa Eleora , Yuliantara Arri , Murti Paulus Damar Bayu
Published: October 2024

With the development of the times, most people often consume fast food or what is commonly referred to as junk food.  The long-term effect causes many people to experience degenerative diseases like heart disease, diabetes, hypertension, cancer, and osteoporosis.  Therefore, there is a need for solutions so that people can maintain a lifestyle to support their health. The solution is in the form of functional food derived from traditional ingredients, such as tempeh, tape, and also several types of spices.  Functional foods are food ingredients that can provide many additional benefits to the body, apart from the basic nutritional functions of these foods.  For example, such as consuming antioxidants derived from phytochemical compounds contained in some of these traditional ingredients.  Phytochemical compounds that can act as antioxidants are used to counteract free radicals that occur in the body.  These antioxidants can be obtained from tempeh, tape, and several spices.  The spices include ginger, kencur, turmeric, temulawak, galangal, and cinnamon. Processed functional food products from several spices are used as health drinks, herbs, teas, juices, syrups, and sweets. Functional food from traditional ingredients has the potential to be developed.  This is due to the sufficient production of raw materials and the community's need for functional food from these traditional ingredients.  Regulations regarding functional food from traditional ingredients are considered insufficient, even though the government has made regulations regarding foods that have special nutrition.  The aim of this study is to elaborate several traditional food ingredients and its function to help in maintaining the health in the body. As a results, this paper presents some research data that has been done previously related to some of the advantages of traditional food ingredients
On the Methodology for Calculating the Economic Efficiency of Energy Storage Systems
Authors: Dobrego K. V. , Fursov S. A. , Dubnovitski S. S. , Charvinski V. L.
Published: October 2024

Due to the growth of “green” energy, the need to regulate the load on large power systems, and the development of electric transport, electricity storage systems (ESS) are increasingly, being used in the world. Conceptual documents have been developed in the Republic of Belarus and the Russian Federation stating the need to modernize the regulatory framework for the use of ESS, create scientific support for the development of ESS technologies, centers of competence and of the implementation of pilot projects. This article provides an example of calculating the economic effect of using ESS at an industrial enterprise. A methodology is proposed that can be used to develop standardized methods for calculating the economic effect of using ESS at enterprises and in local energy systems of consumers of various types. The main functions performed by the ESS at the enterprise are characterized. The features of calculating the economic effect of performing these functions under the conditions of the statistical nature of the load regime of the enterprise are considered. Calculations of the simple payback period for investments in the installation of an ESS for an enterprise with several options for payment terms for electricity are given. It is shown that the economic result of using ESS significantly depends on both the pricing conditions and load schedules of the enterprise, as well as on specific requirements for the quality and reliability of power supply and should be evaluated individually in each case.
Supervisi Pendidikan Berbasis Profetik Perspektif Al-Qur’an
Authors: Roni Harsoyo
Published: October 2024

Educational supervision as one form of effort in one of the functions of educational management plays a very strategic role in placing each educational program so that it remains on track in its implementation. However, the facts show that the implementation of educational supervision has not been maximized, there are still many obstacles faced so that it is ineffective and does not have a significant impact on improving the quality of education. So that a new breakthrough is needed in educational supervision that does not only focus on academic achievement, but also on the formation of a whole, characterful, and highly moral human being. Namely by implementing prophetic-based educational supervision. Through a qualitative descriptive approach in the form of a library research, this article aims to describe the prophetic values ??contained in the Qur'an that can be implemented in the educational supervision process. The results of the search found that; The prophetic values ??that can be developed in educational supervision are: 1) Supervisors in carrying out supervision must be based on monotheism, honesty, justice, wisdom and trustworthiness, provide examples, advise ma'ruf, deliberation and politeness, cooperative/cooperation, and constructive and creative; 2) The target/object of supervision must have the intention to improve themselves, be honest and not manipulate, and accept it as a form of practice.
Study on an Intermittent Power Generation Technology for Water Injection Wells
Authors: Tao Fu , Qinghai Yang , Chenxu Zhao , Yufei Sun , Fuchao Sun , Chenglong Liao
Published: October 2024

Currently, smart layered water injection technology is mostly powered by batteries or cables. Batteries have limited power and cables are complicated to install and easily damaged, neither of which can meet the power needs of downhole tools. This paper proposes a downhole power generation technology for water injection wells, using the kinetic energy of the injected water as the energy source and a small-diameter turbine generator to generate electricity. The device adopts an eccentric design, which does not take up the center channel and does not affect the normal production process of the intelligent layered water injection process. In the process of water injection, the water nozzle can be used to select the flow channel according to the demand for electricity so as to control the start and stop of the generator, realizing intermittent controllable power generation and improving the service life of the generator. A prototype was manufactured and a hydro generator test platform was constructed. The prototype was connected to the test process, and the circulating flow was pumped in by a variable frequency pump to simulate the downhole water injection environment, and the power generation performance of the prototype was tested under different flow rates. The test results show that the prototype works stably under the flow rate of 20-40m3/d, the output power increases with the flow rate, and the maximum output power is 12.4W, which meets the downhole power supply demand of intelligent water injection wells. In addition, the prototype has completed 720 hours of continuous experiment under 24m3/d flow rate with stable output voltage and current. This technology is expected to provide a new idea for solving the problem of long-term power supply for downhole electric control tools of water injection wells, effectively reduce the circuit maintenance cost of downhole electric control tools, and improve the long-term monitoring and automatic control level of water injection wells.
Dual Layer Cement Evaluation: Case Study on Casing Collapse Environment
Authors: Ibrahim Mohd Zulfadli , Zain Mohd Nazree Mohd , Fadzalisham Irfan Zulfadhli , Khairudin Muhammad Uthman Danial , Zulkefli Siti Nor Dahliawati , Awal Adli Zaim , Nordin Mohd Helmi
Published: October 2024

Maintaining the integrity of the well is very crucial to extend the well's life. One of the operational nightmares is having the casing failure such as collapse in the middle of the well life. Casing collapse happened when excessive stress applied to the body of the casing from surrounding environment and it could occur due to various reasons, such as corrosion and corrosive environment, excessive pressure, geological shifts, cement issues or mechanical damage. The focus of this paper will be addressing the cementing issue that contributes to the casing collapse. While investigating the casing integrity problem, it was discovered that the only cement data available is from the drilling report. To reduce uncertainty and better assess the integrity of the well, the approach taken was to acquire the cement data to evaluate cement behind 13-3/8-inch casing and 9-5/8-inch liner. Acquiring this data is no longer a simple task as the casing has been damaged and the well is no longer in the best condition to acquire the data. Due to the urgency of this operation and the complexity of the well, the options have become very limited. Through Tubing Cement Evaluation technology (TTCE) was implemented to aid in investigating 2 layers of cement behind 13-3/8-inch and 9-5/8-inch liner simultaneously.

Due to the absence of cement data, previously the top of cement (TOC) was referred to the estimated TOC in the drilling report. Therefore, the casing collapsed issue may be inter-related with the absence of cement data. TTCE uses a combination of nuclear and acoustic data technique to evaluate two layers of cement while investigating fluid movement behind the casing. The outcome of TTCE data reveals that the TOC behind the surface casing was deeper than estimated in the drilling report with indication of fluid movement from the collapse interval down to near perforated zone. By integrating Acoustic and nuclear data cement behind 13-3/8-inch casing can be evaluated even across the 9-5/8-liner interval. The absence of cement across the interval could be one of the factors that lead to casing failure. Casing collapse could have been avoided if the cement data (CBL Legacy) was available at the earlier phase by providing a crucial insight during the brainstorming process. In well operation, preserving the well integrity cannot be understated. One of the ways to maintain the well integrity is by obtaining data as much as possible. To conclude, gathering cement data aids the decision-making process in creating a mitigation plan to overcome the casing collapse issue. With more data available, the condition of the well can be easily understood in the future.
Reservoir Simulation-Informed Cost-Benefit Analysis for Structural Assessment: A Case Study of Hydrogen Geostorage in the Ahuroa Gas Field, Aotearoa New Zealand
Authors: Dempsey David , Parker Matt , Liu Jinjiang , Chang Qiuhao , Nicol Andy , Passmore John
Published: October 2024

As hydrogen production increases around the world, subsurface porous media such as depleted gas reservoirs are being considered for buffer storage of large volumes of renewable gas. In Aotearoa New Zealand, Ahuroa gas storage reservoir in the Taranaki region is a possible site to be converted into underground hydrogen storage (UHS). However, from a structural perspective, this site is incompletely characterized, with differing model interpretations arising because only 2D seismic data and well intercepts are available. In this study, based on the exiting data, two geological models (curved fault model and tear fault model) were built. The same hydrogen storage scenario was evaluated on both models to study the impact of geometric uncertainty on UHS performance. To model hydrogen migration scenarios in the reservoir-fault system, we use a workflow that integrates Leapfrog Energy for geological modeling and PFLOTRAN-OGS for reservoir simulation. Our model describes cyclic injection and production of hydrogen/methane gas mixtures from the water-wet reservoirs, quantifying the operational performance of the site with respect to the undetermined fault geometry and transmissibility. Simulation results indicate that in the tear fault model less cushion gas is required but more hydrogen was ultimately unrecoverable from a distant region beyond a spill point. Economically, the cost of additional cushion gas trades off against the cost of hydrogen loss, both of which are on the order of several tens of millions of dollars. Our findings highlight the value of robust geological modelling and seek to build an economic case for further data acquisition to reduce uncertainty.
Densest Arrangement of Friction Lcm Particles Packing with a Power-Law Grain Size Distribution Via Dem Method
Authors: Zhang J. , Kang B. , Mi Z. , Jiang L. , Qu J. , Cheng Y. , Cao X.
Published: October 2024

Lost circulation pose a primary challenge in the exploration and development process. For the problem of Lost circulation in fractured formations, the addition of plugging materials with different functions and in specific proportions into the drilling fluid to seal the fractures is the most commonly employed method for lost circulation control in engineering. This paper compares and selects the densest packing model, determining the optimal model for research on lost circulation control. Furthermore, simulations of the densest packing of plugging material particles within fractures were conducted using the CFD-DEM method. A simulation method for the formation and pressure-bearing process of the fracture plugging zone was established. The particle size distribution capable of forming the densest packing was determined. Based on the Fuller curve for designing grain size distribution, the wider the range of particle sizes, the greater the packing density, there exists an optimal gradation distribution index for the densest packing, which is between 0.5 and 0.7. This paper identifies the densest particle size distribution, providing a basis for the design of on-site plugging formulas and enhancing their scientific foundation.
A Novel Approach to Accelerate CO2 Mineralization Storage through CO2 Nanobubbles
Authors: Mao Zhiqiang , Liu Yueliang , Rui Zhenhua , Peng Zesen , Zhao Dan , Tang Yiyang , Jiang Hongzhi
Published: October 2024

Carbon capture and storage (CCS) technology is a crucial means to address global climate change and reduce atmospheric CO2. CO2 mineralization storage can store CO2 in underground rock formations in a long-term and safe manner, which is the most stable storage method. However, this process may take several decades or even longer, severely constraining the application of CO2 mineralization storage in mining fields. In this work, we propose an innovative approach utilizing CO2 nanobubbles to achieve efficient CO2 mineralization. Chlorite was selected as the experimental sample to compare the effects of carbonated water and CO2 nanobubbles on CO2 storage. Analytical instruments were employed to analyze the rock surface morphology, mineral composition, and ion concentration in the reaction solution post-experiment, revealing the mechanism by which CO2 nanobubbles accelerate the CO2 mineralization rate. Results reveal that CO2 nanobubbles have an average size of 167.6 nm, a Zeta potential of −18.98 mV, and a concentration of 9.4×107 particles/mL. The solution's pH is lower than that of carbonated water, suggesting that the CO2 nanobubble solution enhances the supersaturation level of CO2 in the solution, which facilitates the dissolution of rock minerals. After the reaction of chlorite minerals with CO2, the concentrations of Mg2+, Fe2+, and Al3+ ions initially increased and then decreased, while the concentration of Si4+ ions increased and then stabilized. The ion content in the solution followed the order of Mg2+ > Fe2+ > Si4+ > Al3+. Dissolution processes dominate within the first 1 to 6 days, after which the precipitation rate surpasses the dissolution rate. The surface of chlorite exhibits corrosion features and a new element peak of carbon (C), indicating the formation of inorganic carbonate minerals after the reaction. Thermogravimetric analysis shows that the thermal decomposition of chlorite occurs in two stages: primarily MgCO3 decomposes between 350°C and 650°C, while FeCO3 decomposes between 700°C and 850°C, with a higher content of MgCO3 compared to FeCO3. Compared to carbonated water, the CO2 mineralization rate increased by 17.07% when the reaction solution contained CO2 nanobubbles. This approach can shorten the time required for CO2 mineralization storage, facilitating large-scale CO2 storage. Furthermore, the mechanism of CO2-water-rock interaction is also deeply revealed, which is of great value for understanding the underground CO2 storage process and optimizing the conditions for storage.
Thermal Decarbonization Abatement Plan to Improve Energy Efficiency in Oil and Gas Thermal Operations Asset
Authors: Al Fazari M.
Published: October 2024

Petroleum Development Oman LLC (PDO) is Oman's premier oil producer and operates several fields. Thermal Development is one of key enablers in Oman for significant Oil Recovery.

External landscape around Green House Gas (GHG) Emissions is changing, which is evident from various international and national commitments. Oman commitment to Paris agreement is to control 2% of its GHG emissions growth by 2030. PDO, as one of significant contributor of total national GHG emissions, will play a significant role towards achieving this commitment. One of the key elements in PDO's Environment Strategy is GHG reduction. As per PDO Specification for Environmental Management, each asset shall establish and maintain its GHG and Energy Management Plan (GHGEMP). The aim of this GHGEMP is following:

To provide a consistent asset baseline description of its historic energy efficiency and GHG emissions. To identify and review the inventory of GHG/energy suppliers and users. To provide a forecast of energy use and GHG emissions aligned with Program Build (PB). To describe confirmed opportunities/projects for energy efficiency improvement and GHG reduction, selected for implementation as per program build. To assess the gap to potential for GHG and energy efficiency improvement of the cluster by benchmarking To brainstorm aspired projects to bridge gap to potential in terms of reducing emissions and/or energy use and set targets.

Thermal Cluster Is known for being non-resilient in terms of energy efficiency. This is due to the mode of operation as enhanced oil recovery (EOR) by means of steam flooding. This development tends to be required high intensity of energy to produce the steam and for processing the hot fluid coming into processing facility. The thermal Cluster Strategy is devised into three main pillars which are Decarbonatization, Renewable and Renewable energy carbon credits.

Below are some of the initiatives used for this journey which will be part of this paper as follow:

Utilization of the sour flared gas for Once Through Steam Generator (OTSG) as fuel Facility Improvements Initiatives including OTSGs efficiency. (SPE- 222571-MS) Low Operating Pressure Study / OTSGs retirements Steam Integration System (SPE- 209674-MS) Hydrocarbon Facility & Heat Recovery Steam Generators (HRSGs) Heat Integration HRSGs Efficiency and reliability Improvements

The main objective of this paper is to demonstrate the Energy Management & GHG Abatement Plan using different tools and methods to improve in the thermal Asset overall efficiency.
Unlocking Potential of CO2-Enhanced Recovery and Sequestration in a Waxy Oil Reservoir: A Phase Behavior Investigation
Authors: Hendraningrat L.
Published: October 2024

It is evident that the use of carbon dioxide (CO2) for enhanced oil recovery (CO2-EOR) and sequestration into reservoirs has the potential to not only enhance oil recovery but also contribute to reducing greenhouse gas emissions. This paper comprehensively evaluates the potential of CO2 to enhance recovery and sequestration in a waxy reservoir and focuses on phase behavior.

The thermodynamics of CO2-hydrocarbon systems play a crucial role in determining the phase behavior of CO2 in the reservoir. Comprehensive fluid analysis laboratory experiments have been conducted such as compositional analysis, constant composition expansion (CCE), differential liberation (DLE), viscosity, and wax experiments, and swelling tests due to various CO2 injections. The dewaxing of crude oil was done as reference to investigate the influence of wax component to the phase behaviour. A PVT software was used to validate the laboratory data through PVT fluid characterization.

Phase behavior of waxy crude oil the presence of various compositions of CO2 enrichment was studied. A thermodynamic EOS model was developed and characterized using PVT Software and fine-tuned to match the PVT experiments, including expansion and depletion studies, viscosity, solid content, and wax apparent temperature, including swelling tests over different enriched CO2 compositions. The swelling factor measurements indicate that the oil volume increases with pressure up to a certain point before decreasing. The comparison between laboratory measurements and model prediction of wax content also satisfactorily matches. The CO2 was found to change fluid properties which consequently increased bubble point pressure and other critical parameters. The presence of wax in crude oil has been identified to increase bubble point pressures can lead to require higher minimum miscibility pressure (MMP) because the oil is already closer to its gas liberation point, requiring more pressure to achieve miscibility with CO2. Higher MMP in CO2-EOR project can pose a challenge in CO2-EOR in waxy crude oil such as operational costs, safety risks, and technical challenges. It requires careful consideration of reservoir conditions, economic factors, and engineering solutions to ensure successful and efficient CO2-EOR method.

This study demonstrates the importance of conducting extensive PVT experiments and analyses before deciding a CO2-EOR project, as this is crucial to understand the phase flow behaviour of fluids. Thermodynamic modeling is an effective approach for analysing advanced fluid behaviour.
Optimization of Interval Pumping System for Oil Wells Under New Energy Self-Consumption Scenarios
Authors: Xu Jianguo , Fan Chuanlei , Song Kecong , Yang Qinghai , Zhang Hao
Published: October 2024

Intermittent production can significantly enhance system efficiency and reduce lifting power consumption in low-production oil wells located in low-permeability reservoirs. The original determination of pumping shut-in duration of intermittent pumping oil well was mainly based on experience, which led to the inappropriate setting of shut-in time, affecting the economic benefits of oil wells. The determination of intermittent pumping well shut-in period is based on the principle of peak cutting and valley filling. The participation of photovoltaic(PV) power generation in energy supply changes the peak and valley of electricity price. If the oil well runs according to the original system, the photovoltaic power output will exceed and the power will be abandoned during the peak period. This study proposes an optimization methodology tailored for interval pumping systems under new energy self-consumption scenarios, integrating PV power generation. Liquid level recovery tests during shutdown periods were conducted to analyze recovery patterns and identify optimal shutdown durations based on the recovery speed "inflection point". Real-time electricity price curves, incorporating both PV generation and grid consumption, facilitated the determination of rational shutdown periods aligned with electricity pricing dynamics. Implemented in Block X of the Jilin Oilfield, the study found that traditional shutdown periods of 8 to 10 hours were suboptimal. Following on-site fluid level recovery tests, shut-in periods of 4 to 6 hours were identified, corresponding to a recovery rate showing an "inflection point," thus determining a reasonable shut-in duration. Previously scheduled shutdown periods were from 9:00 to 11:30 and 15:30 to 19:00. Considering PV generation, the peak electricity pricing period from 16:00 to 21:00 was identified as the optimal shut-in period. Comparative analysis pre- and post-optimization demonstrated a reduction in abandonment rates from 7.2% to 0% and a 12% decrease in lifting electricity costs. The study highlights the effectiveness of optimizing shutdown durations based on liquid level recovery characteristics and aligning them with PV power generation, effectively mitigating surplus electricity and abandonment issues. This approach underscores its adaptability for low-yield interval pumping wells in evolving energy consumption landscapes.
Rapid Screening and Optimization of CO2 Enhanced Oil Recovery Process in Unconventional Reservoirs Using Interpretable Random Forests
Authors: Wei Bing , Wen Shuqin , You Junyu , He Yujiao , Wu Runnan , Chen Yongqiang , Lu Jun
Published: October 2024

Rapid screening and optimization of CO2 enhanced oil recovery (EOR) process in unconventional reservoirs is urgently needed but challenging due to the complexity of this process and poor understanding of seepage in multiscale porous media. To address this issue, an interpretable model with high interpretability was developed to evaluate the response of CO2-EOR processes using random forest (RF) to maximize performance. The feature importance and interaction analyses were conducted to enhance the interpretability of RF model from global to local levels. The genetic algorithm (GA) was used to optimize the CO2-EOR response, and select operational parameters with a minimum CO2 injection and maximum incremental oil recovery. To validate the reliability of the method, the results of the GA-RF model were compared with numerical simulation results under the same conditions, yielding an average relative error of 5.3%. The feature importance analyses show that geological parameters such as Φ and SO have a greater impact on the oil recovery compared to operational parameters. This work represents a pioneering advancement in the rapid optimization of the CO2-EOR process in unconventional reservoirs. The developed workflow offers an efficient process for optimizing the most suitable CO2-EOR process for various types of reservoirs and provides valuable time and resource savings in the optimization.
Rock Dry-Out and Fines Migration During CO2 Storage: Laboratory and Mathematical Modelling
Authors: Nguyen C. , Loi G. , Keykhosravi A. , Russell T. , Yang Y. , Zulkifli N. N. , Amir M. I. Mahamad , Manap A. A. Abdul , Shafian S. R. Mohd , Badalyan A. , Bedrikovetsky P. , Zeinijahromi A.
Published: October 2024

The work comprises the set of lab corefloods of the displacement of water by CO2 from sandstone cores. Previous experimental studies investigated the effects of water evaporation, Rock Dry-out, viscous fingering and Fines Migration with respect to permeability damage during CO2 injection. However, the synergy of those physics mechanisms, their simultaneous occurrence and mutual interactions haven't been studied in necessary details. We performed 8 corefloods in 5 Berea cores, creating secondary and tertiary core re-saturations by brine after complete drying during CO2 flood. To study detachment of fines during different stages of rock drying, we modelled forces and torques exerting the attached clay particles by the by-passing CO2 flow. It allows formulating the mobilisation criteria for attached clays. The main phenomena observed encompass intensive viscous fingering, rock sweep by isolated fingers under high water saturation, uniform timely drying of the rock by injected CO2 during hundreds of thousands of PVI, abrupt rock permeability increase under joining the isolated viscous fingers into a united gas-conductive network, and fines production during the overall drying period. The micro-scale mechanical-equilibrium modelling of fines detachment accords to the fact of fines production during the total displacement period.
Methane Pyrolysis to Produce Hydrogen and Carbon Solids Using Thermocatalytic Pathway
Authors: Chai I. C. H. , Chan Y. H. , Nikulainen K. , Laukka J. , Ishak M. A.
Published: October 2024

Thermo-catalytic decomposition (TCD) of natural gas is a suitable technology to provide clean hydrogen (H2). This TCD process directly splits hydrocarbons, mainly methane (CH4), into H2 and carbon as illustrated in Equation 1. [Equation 1]CH4(g)→C(s)+2H2(g)ΔH∘=74 kJ/mol

In TCD process, H2 is produced as a gas while carbon is generated in solid form. Though the reaction can occur with heat energy alone, the use of a catalyst significantly reduces the required reaction temperature, making the process less energy-intensive. Various reactor designs are used for TCD to pyrolyze CH4, including fluidized/packed bed reactor, moving bed reactor, bubble column reactor (using molten metal or salt), and plug flow reactor. This paper elucidates ROTOBOOST's bubble column reactor, which utilizes a specific molten metal alloy as TCD catalyst. Although methane pyrolysis demonstration has started since the 1950s, the development and understanding of liquid catalyst in bubble column has gained more momentum since the 2000s. This stems from the benefit of lowering the reaction temperature to below 1000°C, making the process less energy-intensive, mitigating coking issues and subsequent deactivation of solid catalysts, and allowing better control and tuning of solid carbon quality Von Wald et al. (2020) reported that methane pyrolysis using the bubble column technology with liquid metal catalyst is a suitable process for reducing CO2 emissions in the short term.

In TCD process with bubble column reactor, pre-treated natural gas or methane is continuously fed to the bottom of the reactor, allowing it to travel upward through the molten catalytic alloy, which is heated to the reaction temperature. The catalytic alloy, with high heat capacity, provides a homogenous heat supply directly to each hydrocarbon gas molecule. As the bubbles burst at the upper interface of the liquid media, H2 and carbon are released. Since the density of carbon is much lower than that of the molten media, the produced carbon rises with the bubbles, floating at top of the liquid surface, and finally deposits at the surface of the liquid column. Therefore, the produced carbon does not affect the reaction zone on the inside/surface of the bubbles as they rise through the molten media, ensuring the bubble surface is a continuously renewed catalyst. The main advantage of liquid bubble column reactors is the continuous carbon removal from the liquid media due to density differences, preventing reactor blockage or contamination from carbon accumulation.
Skidding Rig and Introduction of Batch Drilling System Increased Drilling Operation Efficiency in Onshore UAE Unconventional Project Saving 70mm $
Authors: Elzeky Moataz Mohamed Fahmy , Varma Esha Narendra , Elhusseiny Mahmoud , Anwar Mohamed , Al Shamisi Eisa Daban , Hamdy Ibrahim
Published: October 2024

Batch drilling is not a new concept to Oil and Gas Industry, however thorough studies and analysis were conducted to adopt Batch vs Standard drilling methodology in unconventional wells project. The application of batch drilling resulted in huge cost saving up to 30% of total well cost. Thus, enhancing the sustainability by reducing the Footprint Impact by re-using same mud in each section for the clusters and reducing the rig flat time.

Unconventional Pad wells consists of 10 wells with 10m spacing in a single row,identical for unconventional reservoir.The wells were drilled in 3batches.This was achieved by spudding on well A and drilling and cementing the first section 16" Hole.The rig is then skid to well B to start drilling the first section again,meanwhile in well A is nipple down the Diverter,install wellhead section offline.This operation is repeated till well #10 in the last corner, optimizing the materials/services and applying the lessons learned from each section, improving the operations well by well. The wells were completed with 30% improvement of well performance.

Applying Batch drilling technique in Unconventional Pad wells has had great savings up to 13% of cost and 7% of duration per well that will finally save the cost of 1 complete well from the 10 wells in the cluster, more savings were achieved by recycling same mud system for each section to be used for the next well requiring treatment only, additional many operations can be shifted offline as: - Pickup and makeup drill string and BHA - Nipple up diverter - Nipple wellhead sections/ Christmas tree - Run mutli-shot gyro survey - Rigless Cementing The Batch drilling aimed to optimize time and learning curve for the drilling team at site for the same section drilled.Several Simultaneous Operation (SIMOP) between drilling and Fraccing is decided from the very beginning.Utilization of triple catwalk helped improve performance in tripping by 50% and the rig setback area was sufficient to skid with pipes on the rack, thus eliminating the tripping time. This technique has also showed a huge impact by reducing CO2 emissions due to less resources required, compared with standard rig move. This concept was transferred to all the fields resulting in savings of 70MM$ across 10 batches.

First time implemented in Onshore Abu Dhabi UNCONVENTIONAL wells, In terms of HSE, reduce crew exposure to high-risk operations such as pickup and laydown drill string, lifting heavy equipment during the moving and minimizing rig footprint impact owing to the reduction of CO2 emissions
Advanced 4D Drilling Dynamics Model Simulates Downhole Vibration and Helps to Optimize in Preventing Drill String Failure
Authors: Zhang Jiawei , Wang Qing , Du Shiliang , Zhuo Lubin , Liu Wei , Ling Bo
Published: October 2024

Downhole vibration, such as backward or chaotic whirling, is one of the primary causes for drill string failure during drilling operation. Understanding drilling dynamics is crucial for determining the mechanism of vibration and fatigue accumulation so as to mitigate risk of drill string failure. Drilling dynamics or vibration data can either be obtained from real-time measurement or simulation based on dynamics model, which plays a crucial role for drilling optimization in pre-drill planning phase.

An advanced 4D drilling dynamics model, which considers the interaction between drill bit and formation, impact and friction between drill string and wellbore, constraints exerted on drill string and drill bit, is proposed to simulate the distribution and variation of 3D displacement, velocity, acceleration as well as the stress state of entire drill string within specified time period. This time domain model allows exploration of the full range of dynamics response under different drilling scenarios, which helps to optimize the performance and reliability of BHA as well as WOB/RPM selection. Moreover, drill string fatigue life prediction can also be achieved by combing simulated stress state and fatigue accumulation theory.

Simulation shows that BHA with smaller- sized drill collar or fewer stabilizers are more susceptible to backward and even chaotic whirling while drilling. Also, inappropriate WOB/RPM combinations such as low WOB with high RPM could also cause the onset of severe lateral vibration. High frequency bending stress, mainly concentrated on BHA and caused by lateral vibration, is the main reason for rapid fatigue accumulation and continuous severe vibration could even result in drill string fatigue failure within hours. These findings helped to justify the 5 consecutive BHA failure and 1 washout while drilling the 171/2" wellbore with 7621 ft length of an ultra-deep well. Simulation also showed that downhole lateral vibration severity was significantly reduced after optimizing drill bit design, adopting BHA with larger stiffness and optimizing drilling parameters, which guaranteed the successful drilling of a new 171/2" wellbore with 4659 ft length of another offset well without downhole accident.

This 4D drilling dynamics model could be used to conduct comparative analysis of dynamics responses based on specific criteria to identify the optimum BHA design and drilling parameters, which shows great potential in drill string fatigue failure prevention and drilling optimization.
Stability of Perforation During CO2 Injection
Authors: Younessi A.
Published: October 2024

The injected CO2 in geological storage layers has lower downhole temperature compared to the storage formation. This induces cooling effects in the formation rocks surrounding the injection wells and their perforations. The stability of the perforations is affected by the cooling. Perforation stability is investigated for different reservoir pressures, bottom hole pressures and temperatures. The tendency for shear failure at the perforation wall is investigated through a series of customized finite element simulations, while the risk of tensile failure in the perforations is modelled using an analytical approach. The tensile failure analysis is done for two major time steps at the start and at the end of the CO2 injection. The tendency for shear failure is quantified by the plastic strain magnitude calculated around the perforation tunnel in the numerical simulations. The perforations oriented to the side of the well are more unstable compared to the perforations oriented to the top of the well for the selected normal-faulting stress regime. As expected from the theory of thermo-elasticity, the perforations are more stable with greater cooling. The plastic strain increases with higher drawdown, while less plastic strain is calculated in overbalance-injection scenarios. The cooling effect reduces the fracture initiation pressure, i.e. increases the risk of tensile failure. The fracture initiation pressure is compared against the planned highest bottom hole pressure for individual cases to ensure the stability of the perforations. Overall, injecting CO2 with a temperature lower than the formation temperature does not induce excessive compressional or shear stresses, and is unlikely to cause collapse of the perforation. The risk of shear failure tends to be higher during the early stages of injection when the reservoirs are fully depleted. The cooling effect from CO2 injection may induce tensile fractures in the perforation tunnels, which requires a case-by-case detailed investigation.
Study on CO2 Potential Damage to Fracture Conductivity and Matrix Permeability in Shale Reservoirs
Authors: Tao Jiaping , Meng Siwei , Li Dongxu , Liang Lihao
Published: October 2024

CO2 fracturing is a promising unconventional reservoir fracturing technology that can effectively increase fracture complexity and supplement formation energy, thus improving oil production. However, during the development of continental shale reservoirs, some of the CO2 fracturing field tests were not as effective as expected. Therefore, targeted analysis is needed to clarify the CO2 potential damage to shale oil production.

Based on nanoindentation experiments, the effect of CO2 treatment on the micro mechanical properties of the shale fracture surface is explored. Then, the effect of mechanical properties changes on the embedding of proppants is clarified. Based on physical simulation experiments, the damage law of fracture conductivity before and after CO2 treatment is analyzed. Finally, through the porosity and permeability analysis, the differential evolution law of shale porosity and permeability around the fractures is clarified.

The results show that there is a significant effect of CO2 on the micro mechanical properties of the shale fracture surface. After CO2 treatment, the average hardness of the shale surface is reduced by 22.54%. This leads to a significant increase in the indentation depth of the indenter on the shale surface under the same load. The CO2 treatment can increase the average indentation depth by 15.83%, which will lead to a deeper embedding of the proppants under formation pressure, and consequently lead to a significant decrease in the fracture conductivity. Analysis of porosity and permeability shows that near the fracture areas, the permeability of the shale matrix is improved. However, in the deeper area, the permeability of the shale matrix shows significant damage, with permeability loss of up to more than 70% after CO2 treatment.

Based on laboratory experiments, the effect of CO2 on the micromechanical properties of shale fracture surface is explored, the resulting damage to fracture conductivity by proppant embedment is elucidated, and the matrix permeability damage that exists around the fractures is clarified. Therefore, the possible formation damage of CO2 fracturing should be carefully considered in the development of high clay shale reservoirs.
Exploration and Understanding of Intermittent Water-Flooding in Low-Permeability Reservoirs Supported by New Energy Supply
Authors: Xu Jianguo , Liu Yazhen , Shen Qiaochu , Huang Hui , Yang Qinghai , Xu Gege , Han Yingda , Liu Kexin,
Published: October 2024

The expansion of new energy construction, characterized by its scalability and cost-effectiveness, is increasingly integrated into the oil and gas industry, albeit still in the exploratory phase. Chinese oil fields predominantly employ continuous water injection methods, which incur substantial electricity consumption and costs. Embracing new energy sources for supply promises substantial reductions in electricity costs. However, the intermittent and unpredictable nature of wind and solar power generation does not align with the consistent and stable electricity demand required for continuous water injection, necessitating the exploration of novel water injection models compatible with new energy supplies.

In pursuit of minimizing water injection electricity costs, this study proposes an intermittent water injection model grounded in the distinctive characteristics of new energy supply. During peaks of green electricity output surpassing production demand, "increased injection" is implemented, while during troughs of green electricity output falling below production demand, "reduced or halted injection" strategies are adopted. Insights derived from well test interpretations using shut-in pressure drop data guide the fine-tuning of water injection parameters. This transition shifts the water injection regime from the conventional "24-hour stable flow continuous water injection" to an "X hours injection/ 24-X hours shut-in intermittent water injection" approach. The feasibility of this model is comprehensively evaluated through real-time monitoring, engineering tests, and well test interpretations, assessing injection capacity, water absorption efficiency, reservoir characteristics, and productivity across the project lifecycle.

A 5-month intermittent water injection trial was conducted across two injection-production well pairs in the low-permeability reservoirs of the Jilin oilfield. Three distinct intermittent water injection protocols were designed: "15 hours injection/ 9 hours shut-in", "13.3 hours injection/ 10.7 hours shut-in", and "12 hours injection/ 12 hours shut-in". The injection rates, set at 1.6 times, 1.8 times, and 2.0 times the rate of continuous water injection, respectively, were determined by these protocols. Trial outcomes demonstrate reasonable high-speed injection pressures, satisfactory injection volumes, intact reservoir conditions, a 2.5 % reduction in water cut, and a delay of over 1.5 % in natural decline. Calculations based on new energy generation costs reveal a reduction of over 60% in daily electricity expenses compared to continuous water injection methods.

The successful field trial validates the feasibility of intermittent technology in low-permeability reservoirs, showcasing substantial savings in electricity costs and offering robust technical underpinning for the efficient development of such reservoirs.