bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aquifer Influx Versus Water Injection in GoM
Authors: Fassihi Mohammad Reza , Blangy J. P. 
Published: April 2022

Abstract
When developing new deep-water fields in locations such as the Gulf of Mexico (GoM), understanding the aquifer's size and its connectivity are two important variables that dictate the presence or absence of any future water injection project. Because of the substantial scale of thelarge size of investment associated with developing fields in deep offshore environments, it is important to identify the key factorsdrivers drivingthat would help with decisions onaround optimizing the development optimization, and thus, preventing the operators from incurring unnecessary expenses. The first such factordriver is the assessment of the aquifer's potential size and connectivity of the aquifer. The second factordriver is the understanding of the aquifer's strength. TWe do not feel that this second parameter has not been sufficientadequately assessquantified in the literature, so we propose a new aAquifer iInflux iIndex (AII) in order to address this gapfor that purpose.
Prior to any petroleum field startup of any petroleum field, it is important to plan for waterflooding, especially if there is uncertainty around the aquifer's strength is uncertain. We use data from several GoM fields in GoM as examples, as well as their corresponding AII, so as to provide guidance on designing an effective conceptual water injection project prior to startup.
Evaluation of Environmentally Friendly Green Solvents for the Recovery of Heavy Oils
Authors: Mathews Tanya Ann , Cortes Jairo , Hascakir Berna 
Published: April 2022

Abstract
Solvent injection recovery processes were introduced as a more energy-efficient and environmentally friendly alternative to Steam injection processes. However, BTX chemicals (Benzene, Toluene, and Xylene), commonly used for crude oil recovery due to their strong solvency and low asphaltene precipitation, are acutely toxic and harmful to the environment. These chemicals are easily soluble in water causing groundwater contamination. This paper evaluates the recovery efficiency of two green solvents, Limonene, and beta-pinene, on two samples of Californian heavy oil (C1 has an 874.8 cP viscosity and C2 has 178500 cP viscosity).
On both C1 and C2, 5 core flood experiments were conducted, in total 10 experiments were run. CO2, limonene, and Beta-pinene were tested as solvents on both oils. Limonene and beta-pinene were both chosen due to their ready availability in the State of California. Both these solvents are plant-derived, non-toxic, and biodegradable. They also have much higher flash points than BTX solvents allowing for safer handling. They have been either injected as sole solvents or co-injected with CO2 during the experiments. Limonene and beta-pinene were injected at 2 mL/min while CO2 was injected at 2000 ml/min with a back pressure of 45-55 psi. Core packs were prepared by filling the pore space of Ottawa sand with 60% PV oil samples and 40% PV water by volume. Produced oil and water samples were collected every 20 min during the experiments. Thermogravimetric analyses (TGA/DSC) were conducted on these samples to identify oil, water, and solvent percentages.
Because CO2 is insoluble in these types of high viscosity crude oils, CO2 flooding resulted in immiscibility with almost no oil production. Since both limonene and beta-pinene are aromatic solvents, by sole limonene or beta-pinene injection miscible flooding was achieved. Limonene achieved 35 and 23 vol. % oil recovery from a total of 60% oil for C1 and C2 respectively while Pinene achieved 31 and 27 vol. %. Co-injections of green solvents with CO2 are expected to yield higher recovery due to the presence of two active drive mechanisms namely miscible and immiscible. Co-injection of limonene and CO2 provided the greatest recovery with 45 vol. %, however, recovery efficiencies of pinene and CO2 had comparable recoveries with that of pinene possibly due to phase trapping. Produced samples analysis showed that oil percentages in produced samples were higher for Limonene than Pinene.
Our results indicated that limonene and beta-pinene are very promising solvents for heavy oil recovery. Because these solvents are citrus-based, they are both easy to handle and non-toxic. Hence, we believe that our study can be a breakthrough for many heavy oil and bitumen reservoirs all around the world.
Optimizing Waterflooding EOR Through Cyclic Injection: A Case Study on the Hoople Field, Midland Basin, West Texas
Authors: Farias Mario Jose , Liu Xijin CJ 
Published: April 2022

Abstract
This paper presents a case study of implementation and results of cyclic injection EOR technique in Hoople field. It is located in Crosby and Lubbock Counties, west Texas and sits on the Eastern Shelf of the Midland Basin. The Hoople oil field, discovered in 1970's, is in its depletion stage with water cut greater than 95%. The reservoir rock consists of tidal flat dolomite and limestone interbedded with shale in Lower Permian Clear Fork Formation. Severe reservoir heterogeneity with low porosity and permeability are observed through core examination. This type of reservoir is suitable for cyclic injection.
Cyclic injection consists of two stages for water injection: pressurization (or injection) and depressurization (injection shut-in). Cyclic injection was initiated in part of the Hoople field in 2020. We selected two sections in the field for pilot testing and completed a full cycle in each section. After encouraging results, the cyclic injection technique was deployed over the whole field. The large-scale operation consists dividing the field in four sectors to maximize water handling and optimize cyclic injection operations.
Cyclic water injection has generated positive results. During depressurizing (or shut-in) half cycle, water production decreased dramatically with increasing oil-cut. Water production decreased 10% in each area while oil-cut improvement ranges from 13% to 33%. During the pressurizing (or injection) half cycle, oil production increases with total fluid production. The observed increase in total production ranges between 10% to 19%. The most significant finding is the consistent reservoir oil production and oil-cut response. Overall oil production has been kept at a stable level, countering the expected natural decline, suggesting that the cyclic injection led to enhanced oil recovery. Overall water production dropped significantly, reducing the cost associated with lifting from and injecting back to the reservoir. Cyclic injection has a very positive impact on the financial performance of the field development.
The cyclic injection methodology, an alternative EOR technique, can be applied to other mature fields with similar reservoir properties.
Nanoparticle Stabilized Strong Foam for EOR in High Salinity Fractured Carbonate Reservoirs
Authors: Xuezhen Wang , Kishore Mohanty K 
Published: April 2022

Abstract
Foam flooding can minimize bypassing in gas floods in fractured reservoirs. Finding a good foam formulation to apply in high salinity reservoirs is challenging, especially with divalent cations, e.g., API brine (8% NaCl with 2% CaCl2). When formulating with nanoparticles, the colloidal dispersion stability is difficult due to the dramatic reduction of the Debye length at high salinity. The aim of this work was to develop a strong foam in API brine, using nonionic surfactant (SF) and ethyl cellulose nanoparticles (ECNP), for gas flooding in fractured carbonate reservoirs. ECNP particles were synthesized and dispersed in API brine using a nonionic surfactant (SF). SF and SF/ECNP foams were created and their stability was studied at atmospheric pressure and 950 psi. Foam mobility was measured in a sand pack at the high pressure. Foam flood experiments were conducted in oil saturated fractured carbonate cores. The nonionic surfactant was proven to be a good dispersion agent for ECNP in API brine. Moreover, the SF-ECNP stabilized foam in API brine, even in the presence of oil. The foam was found to be shear-thinning during flow through sand packs. Core floods showed that SF/ECNP foam recovered 81.6% of the oil from the matrix, 13.8% more oil than the surfactant only foam, indicating the synergy between ECNP and surfactant. ECNP accumulates in the foam lamella and induces larger pressure gradients in the fracture to divert more gas into the matrix for oil displacement.
Discussion of the Effect of Shut-In After Fracturing on Oil Recovery
Authors: Sheng James J , Zeng Fanhua 
Published: April 2022

Abstract
Water is accumulated near the fracture surface after fracturing, which will block oil flow out. The water blockage can be mitigated through the immediate well flow back or through shutting in the well before flow back. Which method is more effective? There are mixed results in the literature from field reports and experimental or simulation studies.
This paper discussed the literature results and simulation data obtained from this study. It is found that the oil recovery mainly depends on the magnitude of pressure drawdown and the strength of imbibition. When the pressure drawdown is high, immediate flow back may lead to higher oil recovery than shutting in a well before flow back. When imbibition is strong, shutting in may be beneficial to enhance oil recovery through counter-current flow. Although many parameters of reservoir properties and operations may affect the shut-in effect, those parameters may be grouped into the pressure drawdown and imbibition strength. The parameters of matrix permeability, wettability, initial water saturation, and formation compressibility are discussed. Analysis and discussion of simulation data also suggest that the oil recovery is a linear function of pressure drawdown, but the relationship between oil recovery and capillary pressure is non-linear and more complex.
The results and discussion from this study suggest that the immediate flow back may outperform the shut-in if a large pressure drawdown is applied. If a reservoir provides a strong imbibition condition, the shut-in may be beneficial. Surfactants may be chosen to enhance imbibition. The surfactants which alter the reservoir from oil-wet to water-wet may be preferred.
Conformance Improvement in Fractured Tight Reservoirs Using a Mechanically Robust and Eco-Friendly Particle Gel PG
Authors: Wei Bing , Mao Runxue , Tian Qingtao , Xu Xingguang , Wang Lele , Tang Jinyu , Lu Jun 
Published: April 2022

Abstract
Conformance control in tight reservoirs remains challenging largely because of the drastic permeability contrast between fracture and matrix. Thus, reliable, durable and effective conformance improvement methods are urgently needed to increase the success of EOR plays in tight reservoirs. In this work, we rationally designed and prepared a mechanically robust and eco-friendly nanocellulose-engineered particle gel (referred to NPG) toward this application due to the superior stability. The impacts of superficial velocity, NPG concentration and particle/fracture ratio on the transport behavior in fracture were thoroughly investigated. We demonstrated that the mechanical properties of NPG such as strength, elasticity, toughness and tensile strain were substantially promoted as a result of the interpenetrated nanocellulose. During NPG passing through fracture model, it produced a noticeably greater flow resistance in comparison with the control sample (nanocellulose-free), suggesting the better capacity in improving the conformance of fractured core. It was found that the generated pressure drop (ΔP) was more dependent on the particle/fracture ratio and NPG concentration.
CCUS in China: Challenges and Opportunities
Authors: Guo Hu , Lyu Xiuqin , Meng En , Xu Yang , Zhang Menghao , Fu Hongtao , Zhang Yuxuan , Song Kaoping 
Published: April 2022

Abstract
CO2 emission was the major cause that accounted for the global warming and climate chance. How to reduce CO2 footprint to stop or slow down the global warming has been hot topic. As a developing country, China has become the largest CO2 emission nation in the world during the industrialization process to develop economy, although the CO2 emission intensity has been reduced significantly compared to previous stage. China has promised and succeeded to keep the promise reduce carbon intensity to meet the requirement of Paris Agreement. To meet the promise to attain carbon peak emission in 2030 and carbon neutrality in 2060 (CPCN), carbon capture, utilization and storage (CCUS) is an important and necessary step. Considering the high cost, high energy intensity and complex technology integrated optimization add uncertainties of CCS, utilization of captured CO2 can be of vital importance. One of the most attractive CCUS in China is CO2 enhanced oil recovery with captured CO2 (CCS EOR). CO2 EOR with captured CO2 may be one the best CCUS ways for China for the following three reasons. First, it can meet the increasing oil demand while reducing the carbon intensive coal. Second, around 66 CO2 EOR field tests have been conducted in China and experiences have ben gained. Finally, CO2 EOR in the USA was a proven technology which can increase oil production significantly and stably. Latest CCUS technology progress in China was reviewed. As of July 2021, 49 projects were carried out or under construction. Net CO2 avoided costs from 39 projects varied from 120 to 730 CNY/ ton CO2 (18.5-112.3 USD/ ton CO2). Although CCUS technology development in China was significant, the gap between global leading levels are obvious. Current challenges of CCS EOR include high CO2 capture cost, small scale, low incremental oil recovery, long-time huge capital input. The costs can be significantly reduced when the scale was enlarged to a commercial scale and transportation costs were further reduced by either pipelines or trains. CO2 transportation with well-distributed high-speed rail in China may be a feasible choice in future. If the CO2 EOR in China develops with the same speed as the USA, CO2 used for EOR in 2050 can be as high as 87.27 million tons. CO2 used for CO2 EOR in 2050 can account for 17% to 44% of the CO2 emission. CCS EOR in China will provid both domestic and international companies with good opportunities.
Full Cycle of Unconventional EOR with Microbial Technology – From Lab to Field
Authors: Lu Bo , Liu Songyuan , Li Yifan , Price Brian 
Published: April 2022

Abstract
Historical production data from unconventional oil wells show rapid decline, that leads to low ultimate recovery. With more and more production wells entering low rate period, it’s critical to conduct well stimulation to recover more from existing wells. Alternate application scenarios for production enhancement is during parent pressure up operations. Operators usually pump large volume water to parent well to prevent frac-hit while performing hydraulic fracturing. EOR application can be easily combined into this process to achieve multiple goal the same time.
Microbial EOR has been developed as an environmentally friendly EOR technology. The objective of this paper is to present the full cycle of a MEOR process, from microbiology theory, to prove concept though lab experiments, then to implementation in field. The lab laboratory experiments are to investigate the mechanism that the microbes can be stimulated and effective to clean up near wellbore fractures. The field trials are to demonstrate the effectiveness of MEOR to shale wells. Field results show that MEOR can be an economical effective approach to add reserves to shale wells at low cost. Additional value of microbial technology is that it doesn’t change oil and water quality in production, then there is no treatment cost as other stimulation methods.
Historical Window-Enhanced Transfer Gaussian Process for Production Optimization
Authors: Zhong Chao , Zhang Kai , Xue Xiaoming , Qi Ji , Zhang Liming , Yan Xia , Zhang Huaqing , Yang Yongfei 
Published: April 2022

Summary
As a crucial step of reservoir management, production optimization aims to make the optimal scheme for maximal economic benefit measured by net present value (NPV) according to reservoir states. Despite the remarkable success, more advanced methods that can get higher NPV with less time consumed are still in urgent need. One main reason for limiting the optimization performance of existing methods is that historical data cannot be fully used. For a practical reservoir, production optimization is generally implemented in multiple stages, and substantial historical data are accumulated. These hard-won data obtained with lots of time encapsulate beneficial optimization experience and in-depth knowledge of the reservoir. However, when encountered with an unsolved optimization task in new stages, most methods discard these historical data, optimize from scratch, and gradually regain the knowledge of the reservoir with massive time for “trial and error” to find the right optimization direction, which is time-consuming and affects their practical application. Motivated by this, a novel method named historical window-enhanced transfer Gaussian process (HWTGP) for production optimization is proposed in this paper. Each optimization stage is regarded as a time window, and the data in historical windows are adopted as a part of training data to construct the transfer Gaussian process (TGP), which guides the whole optimization process. To solve the high-dimensional feature of practical problems, the prescreening framework based on a dimension-reduction method named Sammon mapping is introduced. The main innovation of HWTGP is that like experienced engineers, it can extract beneficial reservoir knowledge from historical data and transfer it to the target production-optimization problem, avoiding massive time for “trial and error” and getting superior performance. Besides, HWTGP has a self-adaptive mechanism to avoid harmful and ineffective experience transfer when tasks in historical and current windows are unrelated. To verify the effectiveness of HWTGP, two reservoir models are tested 10 times independently and results are compared with those obtained by differential evolution (DE) and a surrogate-based method. Experimental results show that HWTGP can achieve the optimal well controls that can get the highest NPV, and has significantly enhanced convergence speed with excellent stability, proving the effectiveness of transferring historical data.
Visceral Adiposity Index and Sex Differences in Relation to Peripheral artery disease in Normal-Weight Adults with Hypertension
Authors: Shi Yumeng , Yu Chao , Hu Lihua , Li Minghui , Zhou Wei , Wang Tao , Zhu Lingjuan , Bao Huihui , Li Ping , Cheng Xiaoshu 
Published: April 2022

Abstract
Background: Previous studies on the relationship between the visceral adiposity index (VAI) and peripheral arterial disease (PAD) are limited. Therefore, this study explored the relationship between VAI and PAD in normal-weight patients with hypertension.Methods: A total of 6,615 normal-weight patients with hypertension were included in the current study. The VAI, a simple index calculated using blood lipid and waist circumference (WC), can be used as a simple biomarker of body fat distribution. The outcome was PAD, which was defined as present when each side’s ankle-brachial index (ABI) was ≤ 0.90.Results: A significant positive association was observed between VAI and PAD prevalence. For per unit increment in LnVAI, the adjusted odds ratios (ORs) of PAD for the total participants and males were 1.55 (95% CI: 1.15–2.10) and 2.12 (95% CI: 1.46–3.07), respectively. However, the VAI was not associated with PAD in female patients with hypertension (OR, 1.28; 95% confidence interval [CI]: 0.85–1.95). There was no interaction between sex and VAI (P for interaction = 0.128). Accordingly, in total participants, when VAI was assessed in quartiles and compared with quartile 1 (< 0.84), the PAD prevalence was higher than that of quartiles 2 (0.84 to < 1.36: OR, 1.49; 95% CI, 0.92–2.44), 3 (1.36 to < 2.25: OR, 1.95; 95% CI, 1.14–3.32), and 4 (≥ 2.25: OR, 1.93; 95% CI, 1.04–3.57). There were no significant interactions with the other confounders.Conclusion: This study showed a positive association between VAI and PAD in normal-weight adults with hypertension among men but not among women.
Iron Abundance in the Solar Photosphere: The Role of Ions, Non-LTE, Model Atmospheres, Oscillator Strengths, and Free Parameters
Authors: Foxon Floe 
Published: April 2022

Abstract
The photospheric iron abundance is important to understanding solar system formation and evolution, but methodological designs in the literature have produced significantly different abundance estimates. 315 original photospheric iron abundances were extracted from 70 primary publications identified through SAO/NASA Astrophysics Data System and Google Scholar. Methodological characteristics corresponding to each abundance estimate were categorised, including the ion studied, local thermodynamic equilibrium (LTE) assumption, the atmospheric model and its dimensions, the source of oscillator strengths, and microturbulence velocity. A linear mixed-effects regression model was implemented to quantify the role these variables play in abundance estimates. The mean photospheric iron abundance across all sources was 7.44 ± 0.02 dex on the astronomical log scale. On the average, abundance estimates from Fe II lines were 0.106 dex higher than those from Fe I lines (main effect), after controlling for other factors. Compared to LTE estimates, NLTE estimates were higher by 0.098 dex (main effect). The role of LTE was different for neutral and ionised iron analyses. LTE abundance predictions were lower than NLTE predictions for Fe I, but higher than NLTE predictions for Fe II. Other differences are described for various model atmospheres and oscillator strengths. A subgroup analysis of 257 1D and <3D> model abundances suggests every 0.1 km s−1 increase in the microturbulence velocity parameter results in a 0.04 dex decrease in estimated abundance. These findings explain much of the differences in photospheric iron abundance estimates over time.
Corneal histopathology in Stevens-Johnson syndrome: A case report and review of literature
Authors: Gun Eylul , Ozer Erdener 
Published: April 2022

Abstract
Stevens-Johnson syndrome is a life-threatening, immune-mediated, acute inflammatory disorder of the mucocutaneous membranes. It affects people of almost any age and has a high mortality and morbidity rate. Therefore, histopathological confirmation of the diagnosis is essential. Ocular involvement occurs in more than 50% of the affected patients. Here, we report a case of Stevens-Johnson syndrome with ocular involvement in a 10-year old boy that presented with complaints of pain, burning, stinging in both eyes, and decreased vision. Histopathological findings were consistent with the changes due to the syndrome. Stevens-Johnson syndrome affects various mucous membranes along with the skin. Ocular involvement may manifest both acutely and chronically and causes morbidities. Therefore, a careful clinical and histopathologic examination is required in order to give the correct diagnosis.