bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrating Geochemical Fingerprinting Technology with Reservoir Surveillance Data – A Montney Case Study to Optimize Pad Design in Multi-Bench Development
Authors: Liang Peter , Liu Yuchen , Unick Kate , Curzon Troy , Jin Muqing , Wu Jiang , Liu Faye
Published: March 2023

An integrated approach was taken to utilize geochemistry information extracted from cuttings and produced oil samples to monitor vertical drainage between stacked reservoirs as well as to optimize well density in multi-bench cube development in the Montney play.

Oil extracts from cuttings were profiled using high-resolution multi-dimensional gas chromatography (GCXGC) identifying 2,000+ compounds. Key reservoir properties such as indicators of oil saturation and matrix permeability were calculated using oil signatures extracted from cuttings. Subsequently produced oil were profiled using the same GCXGC method. Drainage frac height (DFH) and quantitative vertical production allocation by zone was conducted by building a geochemistry-based model and correlating the produced oils back to their contributing intervals represented by the cuttings.

In this Montney case study, two neighboring pads with different cube designs were investigated. Pad 1 is a 12-well pad with 4 target benches and a stacked wellbore placement pattern, whereas Pad 2 is a 6-well pad with 3 target benches and a staggered wellbore placement pattern. Cuttings and produced oil samples were collected from both pads at every development bench, and geochemical DFHs and production allocations were estimated. The geochemical index from cuttings were in-line with the porosity log and wetness balance log collected while drilling. Based on the geochemical production allocation, both Pad 1 and Pad 2 showed vertical fracture growth was not constrained within the target bench. As a result, more vertical overlaps were detected which leads to a more severe vertical communication problem observed on Pad 1 where wellbores were vertically stacked above or below each other.

In this study, the geochemical fingerprinting result was used to calibrate microseismic events. The quantitative production allocation allowed us to filter out any non-effective events and realistically capture the productive stimulated rock volume for optimizing well spacing and landing depth. Last but not least, the geochemical production allocation was successfully integrated with other reservoir surveillance data such as interference well testing.
Diverting Fracturing Stimulation Technique Using a Novel Temporary Plugging Agent with Multiphase Transition Properties at Different Temperatures
Authors: Chen Xiang , Liu Pingli , Zhao Liqiang , Du Juan , Zheng Jiangang , Chen Zhangxing , Yang Jian , Zhao Wanwei , Liu Fei , Lou Fengcheng , Wang Guan , Liu Jinming , Huang Chengxi
Published: March 2023

Given the fact that diverting fracturing technique can improve the effective stimulation reservoir volume, and the currently-used temporary plugging materials of chemical particles and fibers are difficult to pass through sand-control completion tools and enter into fractures due to their solid nature, this work thus developed a novel temporary plugging agent (TPA) with multiphase transition properties at different temperatures. Laboratory and field experiments were both conducted to study its feasibility on industrial field applications.

Laboratory experiments were first carried out to investigate the properties of this TPA, including multiphase transition temperature and time, plugging strength, compatibility with other fluids, and core permeability damage, in order to guide the design of plugging agent dosage, fracturing construction parameters, and wellbore-fracture temperature. Then, field experiments were conducted to demonstrate its feasibility on actual field applications. Well A and Well R with almost the same geological and engineering conditions were chosen in this experiment where Well A adopted the developed novel technique and Well R, as a comparison well, adopted a conventional fracturing technique.

The results from the laboratory experiments indicated that the performance of this TPA met the requirements of industrial standards. With an increase in temperature, this TPA underwent a solution (liquid state) - gel (semi-solid state) - solution (liquid state) transition to meet the needs of different stages in a fracturing treatment, and its multiphase transition speed was controllable. Its plugging strength was positively correlated with its plugging length, with a gradient of 8.9MPa/m. This TPA had good compatibility with other fluids and little damage to rock permeability, only 2%, much less than 25% specified in the standard.

The results from the field experiments demonstrated that this innovative technique was feasible and effective. The construction curve of Well A indicated that the construction pressure increased by 3.1MPa and the formation broke again after injecting this TPA. The micro-seismic monitoring also supported this finding and showed that new fractures propagated to the north-by-east direction instead of the due west direction. Under the same production system, the initial daily gas production of Well A was 1.3 times that of Well R. After 100 days of production, the daily gas production of Well A was 1.5 times that of Well R.
Effective Thermal Conductivity of Tight Porous Media
Authors: Ghasemi Shahab , Chourio Arocha Geragg , Fayazi Amir , Kantzas Apostolos
Published: March 2023

Fluid and heat flow in complex porous media is widely used in various sciences such as medicine, environmental engineering, geoscience, and petroleum engineering. Understanding flow and heat transfer is may be difficult unless the pore geometry is well understood. The focus of this study is the determination of effective thermal dispersivity by both conduction and forced convection. For this purpose, experimental measurements and simulation results of heat and momentum transfer are presented. Experiments are conducted in a sand pack with various surrounding temperatures and injection rates. A 3-D heat transfer model was developed with and without fluid flow with three components. First component is mobile or stagnant fluid in the pore space, second component is the sandstone continuous matrix, and the third component is another solid that has a separate thermal conductivity and will mimic the constant temperature boundary. The transfer of the heat through the solid and fluid and also from the solid to the fluid is related to the composition and connectivity of the solid in the geometry. However, when there is forced convection, the key factor is the Peclet number. The velocity of the fluid can change the effective thermal conductivity up to four orders of magnitude. For the experiments, a sand pack 48cm long was used at temperatures of 40 - 60 °C and water injection rates of 1 - 100 cc/min. The model is augmented by numerical calculations of heat transfer parameters such as effective thermal conductivity and effective thermal advection by monitoring the Peclet number of the process. The variability of thermal dispersion of tight systems under specific composition and pore topology was presented.
Using Thermoelectric Generators (TEGs) for Electric Power Generation from Waste Heat in Geothermal Plants
Authors: Nourdanesh Nader , Kantzas Apostolos
Published: March 2023

The application of Thermoelectric Generators for converting geothermal energy to electricity is investigated in this paper, considering the effects of various parameters on their efficiency. Using renewable energy is one of the latest solutions to tackle climate change, global warming, air pollution, the ozone layer hole, etc. In this regard, a thermoelectric generator (TEG), which is a device for converting heat energy to power, could be used in different renewable energy systems like solar or geothermal. Although their initial cost is lower than the other methods of converting thermal energy to electricity, their efficiency is lower than the most common techniques. Therefore, finding the optimum situation to increase the efficiency of combined devices with TEGs can increase the likelihood of using them in different industries. The parameters investigated in this paper were the temperature of the operating fluid in channels, the optimum mass flow rate, and the channel slope. The results have shown that with increasing temperature differences of the fluid in the channel, the efficiency of the designed system increased significantly. In addition, by increasing the mass flow rate of the operating fluid in the channel, power generation and the whole system efficiency increase up to a certain plateau value. Furthermore, the experimental results have proven that increasing the slope of the channel increased the amount of power generation but has not caused a noticeable change in their efficiency.
Dynamic Surrogate Model for Oil Production Rates Prediction in SAGD Processes
Authors: Guevara Jose L. , Trivedi Japan
Published: March 2023

In this paper we propose a novel framework for the identification of a dynamic surrogate model (DSM) that can offer a fast and effective prediction of time-varying outputs (e.g., oil rates) of a Steam Assisted Gravity Drainage process. In the framework, the prediction at any given time consists of the addition of two components: a base model plus a correction term. The former is represented by a conventional one-step forecast nonlinear model(s) used recursively to make n-steps ahead forecast. The latter is modeled error term, rationalized under the assumption that the forecast error given by the base model is correlated with time due to the recursive strategy used. Since at every time step the input to the one-step forecast model is the prediction made by the same model in the previous time step, so an error accumulation is expected as the prediction time increases. This is analogous to the well-known geostatistical Kriging method, in which the basic assumption is that prediction errors are not constant, rather they are correlated with distance, and as a result, they can be modeled separately using covariance models. The identification of the base and correction model follows the typical surrogate model framework, i.e., design of experiments, evaluation of the samples, and construction of the models. In the context of DSM, the design of experiments represents the random selection of a set of steam injection policies in the preestablished production horizon. For each of these samples, a corresponding oil production rate time series is obtained using a reservoir simulation model; this model was built using publicly available data from Norther Alberta SAGD implementations. Afterwards, the base model and correction term are identified using Long-Short Term Memory neural networks. Results show that DSM significantly outperforms the conventional one-step forecast nonlinear models used recursively. In particular DSM offers, a significant increase of median R2 value of over 0.88 and a reduction of the median and standard deviation of Mean Absolute Percentage Error of over 67.0% and 80.1%, respectively. These results suggest that DSM is able to offer effective (low error and high R2) and efficient (relatively low number of samples) to identifying computationally inexpensive surrogate models for the prediction of time-varying outputs. Furthermore, the framework holds promise to be useful in SAGD optimization efforts, such as, finding the optimal steam injection policy.
Optimal Degree of Upgrading from Solvent Processes
Authors: Azom Prince , Ben-Zvi Amos
Published: March 2023

Injection or co-injection of solvents has been proposed as an in-situ recovery mechanism for bitumen (Gupta et al., 2002). Solvent-based recovery schemes have several potential advantages over steam-based schemes such as SAGD. These benefits include lower GHG emissions and water requirements, lower capital intensity, and lower operating costs. Additionally, solvent-based recovery schemes have been proposed to improve the quality of produced bitumen (Jossy et al., 2008).

The primary mechanism for in-situ upgrading during a solvent injection process is solvent de-asphalting. Solvent de-asphalting is a proven commercial process for processing and upgrading oil in surface facilities such as refineries and upgraders. Several laboratory studies have shown that solvent de-asphalting can also occur in situ, resulting in API improvement in the produced bitumen (AITF report, 2017 and 2018, Brons and Yu, 1995).

In this work the economic benefits of upgrading bitumen in-situ will be studied. It will be shown that, at a given price environment, there exists an optimum level of upgrading (as measured by °API). Generally, too little upgrading reduces the value of bitumen due to blending and transportation costs, while too much upgrading reduces bitumen yield and ultimate recovery.
Dielectric Measurement Method for Dynamic Monitoring of Water-Saturated Sand Pack with and without Evaporation
Authors: Arabloo Milad , Kuznetcov Ilia , Fayazi Amir , Kantzas Apostolos
Published: March 2023

Thermal-based recovery techniques will continue to be used in bitumen and heavy oil recovery. Among them, electromagnetic (EM) heating is promising, especially in situations in which there are technical and environmental issues with steam-based methods. To design the EM process, precise knowledge of the dielectric properties of the target formation is of great importance. To achieve the research goals, a new patented impedance spectroscopy setup is used. An alternating electric field is applied to the sample using an impedance analyzer. The impedance measurements of the clean sand sample, which is pre-saturated with deionized water or brine, are measured at an elevated temperature and pressure to mimic reservoir conditions. There are two successive cycles of heating up to 170 °C. The first heating cycle is followed by a cool-off period, while the second heating cycle culminates with evaporation. The impedance was dynamically measured during each heating cycle. In addition, the dielectric properties of fresh water-gas and brine saturated sands were demonstrated. Results show that the electrical conductivity and dielectric constant of the samples are significantly influenced when the NaCl solution is the saturating fluid. Downward trends in both the electrical conductivity and relative dielectric constant were observed as the steam quality improved, which indicates the creation of a desiccated zone.
Experimental and Numerical Study of Asphaltene Deposition and Precipitation in the Vapor Extraction Process
Authors: Esmaeili Sajjad , Siadatifar Seyed Emad , Mesbah Mohammad , Maini Brij , Kantzas Apostolos
Published: March 2023

Vapor Extraction (VAPEX) is one of the most promising solvent-based methods to tackle the issues associated with SAGD. Asphaltene precipitation due to solvent injection and its in-situ upgrading plays an essential role in VAPEX. As the VAPEX chamber expands laterally and vertically, the speed of the front movement and the angle of the chamber boundary varies. This research investigates the rate of asphaltene precipitation and deposition in VAPEX using different solvents.

In this research, three VAPEX experiments are carried out in a physical model using bitumen and three solvents (propane, butane, and pentane), where VAPEX chamber movement, expansion rate, and the amount of precipitated asphaltenes are monitored. In addition, an Eulerian-Lagrangian model, including the Eulerian approach for the continuous phase (solvent-rich area of the chamber) and the Lagrangian approach for the extracted asphaltene solid particles by bitumen dilution, is generated for numerical modelling. The movement and the deposition of the asphaltene particles at the front are calculated and then validated with the physical model experiments.

A significant amount of precipitated asphaltenes was observed when pentane was used, as it creates a pattern on the wall of the physical model, especially near the wellbore area. However, no specific pattern was observed for other experiments. In terms of chamber expansion and movement, the chamber expanded laterally and then vertically in the pentane and propane systems, while the butane system revealed vertical movement at the beginning, followed by lateral movement. In all cases, the amount of precipitated asphaltenes was always higher near the wellbore compared with areas far from the production well. A numerical model has been implemented to capture the transport phenomena, simulate the asphaltene deposition mechanisms, and reveal the variations in the behavior of different solvents.

This study can assist the oil sands industry in optimizing the VAPEX process to have an effective in-situ upgrading and the highest production rate with better oil API gravity, as the literature suffers from a lack of understanding of the mass transfer physics involved in VAPEX. Also, this study sheds light on the physics behind the asphaltene deposition and precipitation process in VAPEX, as it is impossible to be understood without molecular dynamic simulation besides laboratory experiments.
Determination of Optimal Distance Between Wells in SAGD and VAPEX Methods Using Reservoir Simulation
Authors: Bataee Mahmood , Abduljabbar Hebah Mahmood , Shabib-Asl Mohsen , Hamdi Zakaria , Moradi Babak , Ridha Syahrir
Published: March 2023

Energy resource extraction is getting more difficult and using the enhanced and advanced level of technology for oil production is getting more common. Steam-assisted gravity drainage (SAGD) and Vapor extraction (VAPEX) are two favorable methods of EOR in heavy oil reservoirs. However, there are some obscure points about these methods, like optimum distances between wells and the overall cost of each method. The main objectives of this project were to find the best distance of wells in these types of EOR methods and to enhance the production of heavy oil reservoirs by SAGD and VAPEX methods, taking into consideration of the economic aspects of this project. In this project, SAGD and VAPEX methods were modeled to increase the production rate. Each stage of the Enhance Oil Recovery (EOR) was simulated and modified through many scenarios in terms of the injection patterns, production & injection wells’ locations as well as the adjustment of different injection steam injection and solvent injection. This project analyzed the SAGD method in the shallow reservoir (RF of 69.8%), and in the deep reservoir (RF of 38%). In addition, the maximum allowable depth to apply the SAGD method was found in this study (3500ft). Based on the calculation from the software, it was observed that the heat loss for this reservoir was around 350°F. The cumulative oil production of the SAGD method in the shallow reservoir was 3.87×10^6 bbl and the deep reservoir was2.1×10^6 bbl, and it for the VAPEX method at the shallow reservoir was 2.74×10^6 bbl, and at deep reservoir around 2.64×10^6 bbl, based on the results of each method the VAPEX method remain with the same quality at both reservoirs, however, the SAGD has the lower production in the deep reservoir which means this method is not suitable for the deep reservoir. Furthermore, the profit of each method was calculated; the profit of SAGD and VAPEX were (190.97 MM$ & 168.97 MM$) at the shallow reservoir, and (72.97 MM$ 162.32 MM$) at the deep reservoir for each process. Finally, the spacing between injection and production wells was obtained at different distances and the best distance was 30 m.
The Impact of Autonomous Inflow Control Valve on Enhanced Bitumen Recovery in a SAGD Late Life Reservoir: Lab Experiment and Simulation
Authors: Taghavi Soheila , Aakre Haavard , Moldestad Britt M.E.
Published: March 2023

Steam assisted gravity drainage (SAGD) is an effective thermal recovery method for enhanced bitumen recovery. However, the success of SAGD operation depends on several factors. Reduction in gas and steam production is a crucial factor to achieve a successful SAGD operation. Autonomous inflow control valve (AICV) restricts the inflow of steam and/or gas in the zones where breakthrough occurs and improves recovery from SAGD operations. This can be achieved by restricting the excessive steam and/or gas production in a well that is perfectly isolated by packers. This paper presents the performance analysis of AICVs, and passive inflow control devices (ICDs) based on the results from experiments and simulations.

Experiments which illustrate the performance of an orifice type ICD and AICV is presented and compared. The results confirm the significantly better ability of the AICV to restrict the production of gas and/or steam. Simulations are performed with OLGA/ROCX which provides a dynamic wellbore- reservoir model. Simulation results show that utilizing AICV in the SAGD production wells will reduce the gas and steam production by 74% after 365 days of production. The results confirmed the significant benefit of AICV in steam and/or gas reduction and consequently increased oil production. Reduction in steam production will improve the overall SAGD operation performance. This will also result in more cost-effective oil production.

In addition, the annular flow in a well completed by inflow controllers was studied by using OLGA and NETool. Almost all the reservoir simulators calculate the multiphase flow properties in annulus with no-slip. This study was an attempt to initiate discussions and provide an insight into a fundamental problem that almost all the reservoir simulators are dealing with.
A Comprehensive Model for Life Cycle Assessment of Blue Hydrogen Production and Optimization Along with CO2 Enhanced Oil Recovery - Reservoirs in Alberta
Authors: Dhingra Simran , Gupta Saahil , Trivedi Japan
Published: March 2023

This study considers the generation of hydrogen by the conventional method of steam methane reforming using natural gas as feed. Natural gas extraction and transportation have been incorporated within the system boundaries of LCA. A base case has been assumed to account for the emissions related to the construction of necessary facilities. Calculations have been performed to determine the CO2 retention percentage based on the HCPV% of CO2 injected into the reservoir. Reservoir field segregation for CO2 sequestration and EOR have been carried out in three levels; initially with respect to location, then based on recovery potential (reserve in place), and finally narrowed down based on petrophysical parameters required for an economic EOR using CO2. The model is designed to perform sensitivity analysis for four major scenarios occurring during the process. This includes the location of the natural gas feed source, point of carbon capture, mode of CO2 transportation, and CO2 sink for sequestration and EOR.
Life Cycle Assessment of Hybrid and Green Hydrogen Generation Models for Western Canada
Authors: Gupta Saahil , Trivedi Japan
Published: March 2023

The aim of this paper is to conduct a techno-economic feasibility analysis of adopting a hybrid approach to hydrogen generation. This includes grey hydrogen sourced from natural gas using Steam Methane Reforming (SMR) and green hydrogen from renewable energy. The key focus is on assessing the environmental impacts of such a transition over the next decade in Western Canada while ensuring a clean and stable supply of hydrogen for various industrial processes. A life cycle assessment (LCA) is performed to ascertain greenhouse gas emissions per kg of hydrogen produced. The system boundaries extend from the set up and generation of renewable electricity at standalone and integrated renewable power plants (solar and wind) to the production of hydrogen using water electrolysis. The viability of a site for hydrogen generation from renewables is based on a study of the photovoltaic (PV) and wind potential of various locations in Western Canada. Additionally, an analysis considering the expected improvements in efficiency and scale of upcoming electrolyser technologies is incorporated into the model. Most of the life cycle CO2 emissions of solar and wind sourced hydrogen are from the initial setting up of the power plants. In comparison with SMR sourced hydrogen, total life cycle emissions show a reduction of approximately 90%. As electrolyser technology is improved, hydrogen produced using dedicated renewable sources will achieve price parity over the longer term with the model proposed. It also helps predict the rate at which a hybrid supply of hydrogen can be converted to a primarily green hydrogen supply. These results will serve as a reliable way to transition from grey hydrogen that is currently being produced to green hydrogen, without increasing costs exponentially and with no change in availability. The analysis provides a roadmap for a phased decarbonization of various industries, including the oil and gas industry, where hydrogen is used as a feedstock. Further, it acts as a technical guide to effectuating various hydrogen strategies and achieving emission reduction targets that have been envisaged by provinces in Western Canada.
Unsupervised PSD Clustering to Assess Reservoir Quality Along the Horizontal Wells: An Efficient Inflow Control Devices Design
Authors: Izadi Hossein , Roostaei Morteza , Mahmoudi Mahdi , Rosi Giuseppe , Stevenson Jesse , Tuttle Aubrey , Sutton Colby , Mirzavand Rashid , Leung Juliana Y. , Fattahpour Vahidoddin
Published: March 2023

In steam-assisted gravity drainage (SAGD) operations, inflow control devices (ICDs) might provide an extra pressure drop (ΔP) on top of the liquid pool's ΔP. To avoid hot-spot zones, this ΔP design heavily relies on reservoir quality. Flow-loop experiments can provide flow قate measurements versus ΔP for various nozzle designs. Therefore, an efficient ICD design should be investigated in a numerical flow simulation that represents reservoir quality and heterogeneity by employing flow-loop data.

In this study, core analysis and 40 PSD data drilled in the same location are collected, and permeability for each PSD is estimated using a correlation developed in our previous study. Given PSD offers a measure of hydraulic properties and heterogeneity, it can provide an indirect indicator of potential hot-spot zones. Moreover, representative PSDs are determined by using a clustering algorithm to tie the best-designed ICD to the relevant geology. The reservoir model for the database's location is generated using real data, three tabular data from flow-loop experiments are assigned to the reservoir simulation, and the ICDs' performances are compared.

The clustering algorithm generated five groups with a weighted average permeability of 4,013 mD. The first and second largest clusters with 6.55% and 35.05% fines content cover 55% and 23% of the database, respectively. By employing a relatively conservative production with subcooling between 10°C and 15°C, the cases with liner deployed (LD) ICDs offered a greater oil production rate, better steam conformance, and lower cumulative steam oil ratio (cSOR) than the cases without ICDs. However, in a rather risky production scenario with subcool between 1°C and 5°C, the case without ICDs could not be simulated in the desired the subcool temperature. Because of its enhanced steam conformance and slightly higher oil production rate, LDICD#1 was picked as the best case for the two scenarios. Compared to the case without ICDs, the oil production rate and cSOR for the case with LDICD#1 at higher subcool temperature rose by 17% and reduced by 8%, respectively. Compared to the case without ICDs, the oil production rate and cSOR for the case at lower subcool temperature with LDICD#1 raised by 21% and reduced by 12%, respectively.

The findings demonstrate the effectiveness of ICDs at various subcool levels. The results could be applied in SAGD projects to reduce greenhouse gas emissions by reducing the water and natural gas usage to generate steam. Completion and production engineers would benefit from a better understanding of production relative performance to develop more effective operations design.
Carbon Sequestration: The Ignored Promise of the Non-Utilization of Carbon Route
Authors: Gupta Subodh
Published: March 2023

Despite the mature nature of carbon capture and storage (CCS) technology and its combination with various ways of carbon utilization (CCUS), the extent of its global application has been less than 0.1% in addressing the emissions challenge. The reason is the high cost of CCS compared to the prevailing price on carbon in most jurisdictions. The objective of this paper is to present potentially low-cost alternatives to CCS/CCUS.

Petroleum is the most suitable fuel for the transport needs of the society due to its unparalleled energy density and affordability. The goal of limiting atmospheric CO2 can be met equivalently either by addressing emissions from petroleum (e.g., with CCS) at a cost, or with use of low carbon fuels such as renewables. So far, alternatives to petroleum, despite some advances, have faced an even higher cost hurdle. Therefore petroleum-based fuels with carbon mitigation, deserve a fresh look. CCS has a cost range of $70 - 150/t CO2. While at this cost, oil may still have an advantage over some alternatives, it is an edge that can be further enhanced with new developing technologies such as Lower-oxidation (L-ox) among others (SPE-196109). In L-Ox, energy is derived from carbonaceous fuels in a manner that does not produce a gaseous waste product - CO2.

The current work first starts with highlighting the limitations of various now-familiar options such as hydrogen, direct air capture, or renewables etc., then it discusses the technical feasibility of electro-thermo-chemical (ETC) routes that show promise and require relatively limited further development of technology, utilizing insights and support from recent advances in unrelated fields. ETC-based approaches can be used both for deriving energy without CO2 production (as in L-Ox), as well as for chemical reduction of the CO2 (produced in the combustion process of energy generation) into ‘useless’ liquids or solids. This latter approach – ‘non-utilization and sequestration’, quite opposite to CCUS, along with L-Ox presents a more economically sustainable option for carbon abatement. This paper lends substance to support the expected feasibility of each.

Aside from providing a critique of various alternatives, this work offers new insights into developing novel electro-thermo-chemical methods for a low-cost carbon abatement. The significance of this is in helping sustain and preserve global living standards, through affordable, energy-dense, and carbon-neutralized petroleum.
Geomechanical Investigation of Caprock Integrity of Potential CO2 Storage Reservoirs in Lloydminster Area
Authors: Shen Chen , Wang Bo , Azadbakht Saman , Hawkes Christopher , Zhang Zhi , Zeng Fanhua
Published: March 2023

Carbon Capture Utilization and Storage (CCUS) has been widely accepted to be an effective technology to control anthropogenic greenhouse gas emissions globally. For CO2 geo-sequestration, the key is to understand the caprock integrity to assure the safety of the long term sealing effect. However, many caprock integrity studies do not consider the effects of geochemical reactions among CO2, formation brine and caprock.

In this work, we used the Lloydminster heavy oil region as the target area and studied the effects of geochemical reactions on the caprock integrity. We collected caprock core samples from both Waseca heavy oil layer and the Deadwood saline aquifer in this area. Then, static tests (Caprock submerged into formation brine over-saturated with CO2 for 40 days) were conducted in the autoclave system under the reservoir pressure (Waseca: 5.4MPa, Deadwood: 11.5MPa) and temperature (Waseca: 25⁰C Deadwood: 35⁰C) to mimic the process of CO2 storage in two candidate formations. Finally, triaxial tests were conducted to compare the change in rock strength between core samples before and after CO2 treatment. Meanwhile, XRD analysis has also been conducted to provide the information of mineral composition change on caprock samples before and after CO2 treatment.

Triaxial test results showed that caprock strength has increased (higher axial stress and lateral stress) and fracture pressure increased by 15.84% and 5.45% on average in Waseca and Deadwood formation respectively. Mineralogy analysis indicated that a large amount of carbonate minerals reacted with CO2-saturated brine and stable minerals were generated which help tighten the caprock structure, triggering the self-sealing effect thus caprock strength was enhanced. The research outcomes indicate that in the future site selection for CCS projects, reservoirs with caprocks containing carbonated minerals can be competitive candidates.
CCUS and Comparison of Oil Recovery by Huff n Puff Gas Injection Using Methane, Carbon Dioxide, Hydrogen and Rich Gas in Shale Oil Reservoirs
Authors: Bao Xiaolin , Fragoso Alfonso , Aguilera Roberto
Published: March 2023

The objective of this paper is to compare oil recoveries by huff ‘n’ puff gas injection using methane (CH4), carbon dioxide (CO2), hydrogen (H2) and rich gas (70% CH4, 20% C3H8, plus 10% C6H14), and to advance some ideas regarding carbon capture, utilization and storage (CCUS) of CO2, and storage of hydrogen when these gases are used in huff ‘n’ puff operations.

The procedure considers a real huff ‘n’ puff pilot well in the Eagle Ford shale of Texas with methane injection. Following history match of the pilot well, the injected gas is switched in the reservoir simulator to CO2, H2 and rich gas. Key to success in this process, is geologic containment, which occurs when large volumes of hydrocarbons remain over geologic time in the windows where they were generated. This is the case of the Eagle Ford shale, where hydrocarbons display an upside-down distribution, with oil on the top, condensate in the middle and dry gas at the bottom. Geologic containment permits the implementation of simultaneous huff ‘n’ puff, utilization and storage of CO2 with nil probabilities of leakage.

Results show that huff ‘n’ puff gas injection can significantly increase oil recoveries to be 25-35% of the OOIP (depending on the specific injected gas), compared to about 10% by primary means during the simulation time. The benefits of huff ‘n’ puff gas injection are also applicable in other shale reservoirs where oil, condensate and dry gas present an upside down distribution. One example in Canada is the Duvernay shale. Geologic containment allows adequate and safe storage of CO2 and hydrogen without leaks at the end of the huff ‘n’ puff project. This paper also assesses and corroborates the conclusion that "significant improvements in oil recovery can be obtained by injecting gas at larger rates during shorter periods of time (as opposed to injecting gas at smaller rates during longer periods of time)." The same conclusion holds true for methane, CO2, hydrogen and rich gas injection.

The novelty of this work is demonstrating the efficiency of CCUS and huff ‘n’ puff gas injection when geologic containment exists in the shale reservoir. It is a solution where everyone benefits and allows to significantly increase oil recoveries, while providing safe storage of CO2 and H2 without any leaks.
Perforating for Stimulation: Techniques, Challenges, Considerations, and Efficient Workflows
Authors: Khan Abdul Muqtadir , Binziad Abdullah , Alsubaii Abdullah , Ahmed Danish , Alotaibi Abdulmajeed
Published: March 2023

Connecting the wellbore and reservoir rock systems through perforating is the primary mechanism to provide a flow path for hydrocarbons. In stimulation, this pathway becomes two dimensional (in functionality) because it is required to facilitate injection of fracturing fluids and production of reservoir fluids. Ineffective perforation can add of near-wellbore complexities. In this study, we looked at different perforation techniques from classical to recent contemporary. We investigated both stimulation and intervention aspects to provide pros and cons for these techniques and evaluate their effectiveness. Six challenging scenarios in stimulation were detailed with lessons learnt, best practices, and guidelines. These included deviated wells, soft rock formations, double pipe completions, fracture diversion requirement, horizontal wells with plug-and-perforate completions, and a mature asset. The workflows included perspectives such as perforating, fracture pressure analysis, and diagnostic injections. Efficient workflows for the well engineering cycle were also developed for the case when the injection rate cannot be established due to the inefficient wellbore−rock connection. Contingency interventions and bottomhole assembly (BHA) configurations were investigated with the goal of enabling a flexible strategy in a single intervention run to enhance injectivity.

Currently, operational efficiency and business needs are paramount. This work presents integrated understanding, established practices, and resulting workflows to manage tradeoff and optimize the net present value of integrated projects.
An Improved Parameterization Procedure for NDDO-Descendant Semiempirical Methods
Authors: Ong Adrian Wee Wen , Cao Steve Yueran , Kwek Leong Chuan
Published: March 2023

Concept
MNDO-based semiempirical methods in quantum chemistry have found widespread application in the modelling of large and complex systems. A method for the analytic evaluation of first and second derivatives of molecular properties against semiempirical parameters in MNDO-based NDDO-descendant models is presented, and the resultant parameter Hessian is compared against the approximant currently used in parameterization for the PMx models.

Methods
As a proof of concept, the exact parameter Hessian is employed in a limited reparameterization of MNDO for the elements C, H, N, O and F using 1206 molecules for reference data (heats of formation, ionization energies, dipole moments and reference geometries). The correctness of our MNDO implementation was verified by comparing the calculated molecular properties with the MOPAC program.
Hybrid 18F-FDG PET/MRI can Improve the Evaluation of Adult Moyamoya Disease in a “one-stop” Measurement Model
Authors: Yuan Leilei , Li Xiaotong , Xu Yang , Cui Tao , Ai Lin , Chen Xiaolin , Chen Qian
Published: March 2023

Background
Accurate measurement of cerebral blood flow (CBF), tissue function and viability are particularly significant and important to help neurosurgeons identify MMD patients who would benefit from surgical revascularization. The present study aimed to evaluate the application value of hybrid 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI) in adult moyamoya disease (MMD) and its correlation with digital subtraction angiography (DSA) findings. Twenty-seven hospitalized adult MMD patients who underwent both hybrid 18F-FDG PET/MRI and DSA were enrolled in this study. The relative number of abnormal cerebral regional distributions of parameters derived from PET/MRI or DSA, including PET score, “ivy sign” score, ASL-CBF score, DSA irrigation score and the collateral score of each cerebral region in different Suzuki’s stages, were analyzed and compared with GraphPad Prism. The Spearman rank correlation test was performed to show the internal relationships among these parameters. The chi-square test was applied to assess the performance of MRI in the evaluation of collaterals and perfusion status using DSA as a reference method. Log-rank tests were used to identify independent indicators of regional glucose hypometabolism.
Results
The relative number of regions with a positive “ivy sign”, DSA collaterals, hypometabolism on PET, hypoperfusion on ASL-CBF or deficient DSA irrigation in hemispheres in the mid-stage and late stage were significantly different from those in the early stage (p < 0.05). The “ivy sign” score was positively related to the DSA collateral score (r = 0.6552, p < 0.05). The PET score was positively correlated with the ASL-CBF score (r = 0.685, p < 0.05) and the DSA irrigation score (r = 0.258, p < 0.05). The ASL-CBF score may be an independent indicator of brain regional glucose hypometabolism (p < 0.05).
Conclusions
Brain hybrid 18F-FDG PET/MRI can improve the evaluation of adult MMD patients in a “one-stop” measurement model. Simultaneously, the accuracy of PET and MRI findings can be validated against one another to provide more convincing objective evidence for the choice of the treatment strategy.
Effect of Empagliflozin/Linagliptin on Oxidative Stress Markers among patients with Chronic Kidney Disease and Type 2 Diabetes: a Randomized, Open-label, Controlled Trial
Authors: Satirapoj Bancha , Suebsiripong Supaporn , Runprapan Saranyapong , Nata Naowanit
Published: March 2023

Background
Combined therapies employing sodium-glucose cotransporter 2 inhibitor (SGLT2i) and dipeptidyl peptidase-4 inhibitor (DPP-4i) are expected to produce additive glycemic and reactive oxygen species (ROS) effects among patients with type 2 diabetes (T2DM). The present study evaluated whether SGLT2i and DPP-4i attenuate renal oxidative stress evoked by chronic hyperglycemia.
Methods
A clinical trial was conducted among patients with T2DM and CKD stage 3. The patients were randomized 1:1 to receive empagliflozin (10 mg/day)/linagliptin (5 mg/day) or standard treatment for 12 weeks. Renal oxidative stress and renal biomarker were measured using urine 8-hydroxy-2'-deoxyguanosine (8-OHdG) and urine albumin creatinine ratio, respectively.
Results
Forty-eight patients were analyzed. At week 12, the empagliflozin/linagliptin group significantly reduced urine 8-OHdG compared with that in the control group [-53.90 ng/mgCr; 95%CI -102.93 to -4.84, P = 0.034] and the empagliflozin/linagliptin group also significantly reduced urine albumin compared with that in the control [-159.64 mg/gCr; 95% CI -318.23 to -1.06, P = 0.049]. Additionally, reduced HbA1c with empagliflozin/linagliptin treatment was superior to those with the control treatment. No between-group differences were observed regarding body weight, blood pressure, and estimated glomerular filtration rate at the end of follow-up. The proportion of subjects with adverse events over 12 weeks was similar across treatment arms with no hypoglycemic event requiring assistance.
Conclusion
Combined SGLT2i and DPP-4i treatment for 12 weeks improved renal oxidative stress and glycemic control among patients with T2DM and CKD, which could play a key role in reducing the progression of diabetic nephropathy and appeared to be well tolerated.
Linguistic multidimensional perspective data simulation based on speech recognition technology and big data
Authors: Honggai Shi , Qian Yang
Published: March 2023

In recent years, the multi-dimensional visualization technology continues to accelerate, resulting in a huge amount of data, higher requirements for related technologies, and more opportunities. Under the background of big data technology application, multi-dimensional visualization methods can shine in different fields, such as applying them to linguistic research. Although the technology has a wide range of applications, it can not effectively and intuitively display multi-dimensional voice feature data, which is difficult to fully meet the requirements of parameter visualization. In order to deeply study linguistic speech recognition and other issues, this paper introduces speech recognition technology to complete the creation and improvement of a multi-dimensional perspective analysis system for speech data, and uses socket mechanism to complete the server construction, including voice recognition, data enhancement, model training and other modules. This system takes the target voice data collection as the calling end, Thus, based on socket connection, data interaction with the server can meet the task requirements of the multi-dimensional perspective analysis system, and can achieve two-way data interaction. The simulation experiment results show that the system based on OpenSMILE toolbox can effectively obtain high-dimensional features, and its performance is excellent, which can meet most of the task requirements. It contains many kinds of acoustic feature data, which can solve the problem of over compression of the original signal, and mine the characteristics of voice waves to explain the relationship between frames. The system is higher than low dimensional features in recognizing multiple speakers. This paper designs an effective simulation system by applying speech recognition technology to multi-dimensional linguistic data analysis in the context of big data.
Metagenomic analysis of Hot Springs of Surajkund and the exploration of thermostable enzymes from endogenous isolates
Authors: Soy Snehi , Lakra Usha , Prakash Pragya , Suravajhala Prashanth , Nigam Vinod Kumar , Sharma S. R.
Published: March 2023

Hot springs serve as a hub for microbial diversity, the microflora of the hot springs can be a source of numerous biologically important molecules. Extremophile bacteria were isolated from different hot springs of India to investigate their potential in industrial applications. The analysis involved both culture dependent and culture independent methods. The metagenomic analysis of the microflora was carried out using next-gen sequencing. Also, thermophilic isolates were culture and primarily screened for amylase, xylanase and cellulase enzyme production. The production for amylase was optimized and partial purification was carried out. Partially purified amylase was tested and characterized using; UPLC, DLS-ZP and TGA. The retention time for the amylase was observed to be around 0.5 minutes along with a stable thermo gravimetric profile around 400oC confirming its stability at higher temperatures. One of the thermophilic isolate was able to degrade lignocellulosic waste exhibiting the potential of isolates from the kund.
Effect of a customized digital adherence tool on retention in care and adherence to antiretroviral treatment in breastfeeding women, children and adolescents living with HIV in Tanzania: a mixed-methods study followed by clinical trials
Authors: Boer I. Marion Sumari-de , Ngowi Kennedy M , Swai Iraseni U , Masika Lyidia V , Maro Rehema , Mtenga Alan E , Mtesha Benson A , Nieuwkerk Pythia , Reis Ria , de Wit Tobias Rinke , Aarnoutse Rob
Published: March 2023

Background

Adherence to antiretroviral (ARV) treatment for HIV infection is challenging because of many factors. The World Health Organization (WHO) has recommended using digital adherence technologies (DATs). However, there is limited evidence on how DATs improve adherence. Wisepill® is an internet enable medication dispenser found feasible and acceptable in several studies. However, limited evidence is available on its effectiveness in improving ART adherence, specifically among children and adolescents. Furthermore, DATs are often developed without involving the target groups. We propose a two-stage project consisting of a formative study to customize an existing Wisepill DAT intervention and a randomized clinical trial, to investigate the effectiveness of DAT combined with reminder cues and tailored feedback on adherence to ARV treatment among children and adolescents living with HIV and retention in care among breastfeeding women living with HIV in Kilimanjaro and Arusha Region, Tanzania.

Methods

We will conduct a formative study mixed-methods study and three sub-trials in Kilimanjaro and Arusha Regions among (1) children aged 0–14 years and their caregivers, (2) adolescents aged 15–19 years and (3) breastfeeding women and their HIV-negative infants. In the formative study, we will collect and analyse data on needs and contents for DATs, including the contents of short message service (SMS) texts and tailored feedback. The results will inform the customization of the DAT to be tested in the sub-trials. In the trials, participants will be randomized in the intervention arm, where the DAT will be implemented or the control arm, where standard care will be followed. Participants in the intervention arm will take their medication from the Wisepill-box and receive daily reminder texts and tailored feedback during clinic visits.

Discussion

If the intervention improves adherence to ART and the devices are acceptable, accurate and sustainable, the intervention can be scaled up within the National Aids Control Programmes.
Trial registration: PACTR202301844164954, date 27 January 2023