bluuebunny/crossref_metadata_2025_split huggingface dataset:
Waterflood Analysis in Compartmentalised Reservoir Using Multiwell Retrospective Testing and Tracers
Authors: Shilanbayev Batyrzhan , Balimbayev Bekzhan , Aslanyan Arthur , Rushana Farakhova , Zinurov Linar , Gulyaev Danila , Krichevsky Vladimir 
Published: October 2021

Abstract
The study field consists of four oil pays and is currently going through a waterflood trial.
Due to a presence of high amplitude faulting it becomes crucially important to understand the geology of the field and reservoir connectivity prior to progressing the waterflood project.
The results of the cross-well tracers have indication (some strong and some vague) of communication between a trial water injector and all oil producers in the same and adjacent compartment.
Since the wells were equipped with permanent downhole pressure gauges it was possible to decipher the cross-well communication using the Multiwell Retrospective Testing (MRT) technique based on multiwell deconvolution algorithm (MDCV).
The results of MRT study were showing no traceable communication between trial water injector and offset wells in adjacent compartment except one producer which showed a strong response across the fault.
By correlating the MRT results with seismic profile and well completion it became possible to establish how exactly the main pay is communicating between the compartments.
It also carried few learning points on how to interpret results of cross-well tracers and MRT in terms of reservoir properties.
How to Find the Reservoir Boundaries? Integrated Application of Seismic Attribute Analysis and Welltest on the Miocene Sediments of White Tiger Field, Cuu Long Basin, Vietnam
Authors: Kurbanov Vasif , Chvertkov Andrey , Panarina Ekaterina 
Published: October 2021

Abstract
The development of clastic reservoirs can be complicated by heterogeneity both along the section and along the strike of the formations, therefore, an extended set of studies is especially necessary at such objects, both during drilling and during production. To determine the structure of the void, seismic surveys are usually used, which are limited in scale. An additional tool for defining geological boundaries is well. Well testing carried out in a timely manner, together with the analysis of production data, attribute analysis and geophysical survey data in the open hole, made it possible to identify the heterogeneity of the drainage zone in the early stages of operation and adjust the volume of geological reserves, therefore, to predict production with the highest degree of reliability.
Sweep Improvement Options for Highly Heterogeneous Reservoirs with High Temperature and Ultra-High Salinity: A Case Study in Tarim Basin, China
Authors: Yuan Chengdong , Pu Wanfen , Varfolomeev Mikhail Alekseevich , Mustafin Aidar Zamilevich , Tan Tao , Zhao Shuai , Liu Rui 
Published: October 2021

Abstract
How to control excessive water production in high-temperature and high-salinity reservoirs has always been a challenge, which has been facing many oil reservoirs in Tarim Basin (China), such as Y2 reservoir with an average temperature of 107 ℃, salinity of 213900 mg/L (Ca2++Mg2+&gt;11300mg/L), and permeability from 2 to 2048 mD. In this work, we present experimental studies to determine the potential EOR process for Y2 reservoir from foam flooding, polymer gel/foam flooding, and microgel/surfactant flooding.
To simulate the permeability heterogeneity of Y2 reservoir, a 2-D sand-pack model was used for flooding experiments. Vertically, three layers (first 0.6cm, second 0.8cm and third 1.6cm from top to bottom, respectively) were packed with different size sand to simulate permeability heterogeneity (permeability increases from first to third layer). A 0.3 cm higher permeability zone was also filled inside third layer. Horizontally, permeability gradually decreases from middle to two sides. In this model, injection well was vertical, and production well was horizontal. The effect of impermeable interlayer was also studied by isolating the second and third layer.
The results show that conformance treatments using in-situ crosslinked gel or micro-gel are necessary before foam or surfactant injection under a high permeability heterogeneity. When an impermeable interlayer existed between the second and third layer, the additional oil recovery of N2 foam flooding, in-situ crosslinked gel/N2 foam flooding, and microgel/surfactant flooding was 16.34%, 20.37%, 17.50%, respectively, which was much higher than that without impermeable interlayer (9.84%, 13.62%, 12.07%). This implies that when multiple layers exist, crossflow between layers is unfavorable for improving oil recovery, which should be paid extra attention in EOR process. Foam flooding has not only a good mobility control capacity but also a good oil displacement ability (verified by visual observations of washed sand after experiments), which, together with the strong conformance control ability of crosslinked gel, makes in-situ crosslinked gel/N2 foam flooding yield the highest displacement efficiency. Generally, for high-temperature and ultra-high-salinity reservoirs with strong heterogeneity like Y2 reservoir, in-situ crosslinked gel/foam flooding can be a good candidate for EOR.
This work provides a potential EOR method with high efficiency, i.e. in-situ crosslinked gel assisted N2 foam flooding, for the development of similar reservoirs like Y2 with high temperature, ultra-high salinity, high heterogeneity and multiple layers. Moreover, this work also highlights that, despite that foam has the ability of mobility and profile control, a conformance treatment is necessary to block high permeability zone before foam injection when the reservoirs has a strong heterogeneity.
A Workflow to Derive Rock Mechanics Correlations and Stress Profile by the Integration of Dynamic and Static Formation Evaluation Data
Authors: Qatari Ammar 
Published: October 2021

Abstract
Rock mechanics utilizes empirical formulas which are based on studies of certain environments. The shortcoming of such criteria is having estimations of rock physical properties with high uncertainty and not field/formation specific. The objective of this paper is to apply a core-log integration to convert dynamic mechanical properties captured from formation evaluation logs and calibrate them with core static data to generate a continuous profile of data with low uncertainty and generate correlations applicable to the specific physical environment.
To obtain proper rock mechanical correlations, building a mechanical earth model (MEM) calibrated with core data and stimulation data is essential. Multiple wells drilled in a certain sandstone field with rock mechanical physical tests are analyzed. Multi-arm caliber data is also put in use to establish knowledge about in-situ stress directions. The procedure starts with gathering and filtering acoustic slowness & shear, formation pressure, density, and oriented multi-arm caliper logs. Next, calibration of dynamic to core static mechanical data collected in the lab is established. The geomechanical analysis includes an understanding of the state of stresses in a chosen reservoir along with rock elastic and failure properties. The complied data is then integrated using different workflows to develop Mechanical Earth Model (MEM). The intended rock mechanics correlations include elastic constants (Young's Modulus and Poisson's ratio), and rock failure parameters. Once Mechanical Earth Model (MEM) is established, dynamic logging data and core static data are correlated to produce key rock mechanics elements that are field and formation specific. The correlations include Young's Modulus, Poisson's Ratio, Unconfined Compressive Strength (UCS) correlation, and Friction Angle (FANG) correlation. A range of each rock mechanic element is also highlighted for the specific environment showcasing the limits expected for collapse and fracture. Ultimately, stress profile is generated with low uncertainty highlighting magnitudes of maximum and minimum horizontal stresses along with the given interval.
Prospect Evaluation Based on Integrated Petroleum System Analysis: Block E Case Study, South-Eastern Edge of Precaspian Basin Kazakhstan
Authors: Zhanserkeyeva Ainura , Kassenov Akzhan 
Published: October 2021

Abstract
Positive geological and geochemical prerequisites have been identified for the purpose of increasing hydrocarbon resource potential in the under-explored study area. A methodology has been developed for assessing the hydrocarbon potential and prospecting for new promising oil and gas accumulation zones using the technology of basin modeling, provided there is a lack of initial data. A high hydrocarbon source rock generative potential and the degree of thermal maturity of the Lower Permian, Mid Carboniferous and Upper Devonian strata of the south-eastern part of the Precaspian depression have been revealed. Seismostratigraphic interpretation and geodynamic analysis were carried out and the main stages of the geodynamic evolution of the study area were reconstructed based on combination of all available geological and geophysical information, recent exploration drilling results and unpublished subsurface studies. The results of thermotectonic modelling confirm the possibility of vertical migration of hydrocarbons generated in Upper Paleozoic source rocks. A revision of the previously performed interpretation of 3D seismic data has been carried out; and for the first time, intrasalt sedimentary packages of presumably Upper Permian age have been identified as independent objects, which can be potential hydrocarbon traps.
For the Lower Permian deposits, type III kerogen predominates, which may be associated with an increase in collisional processes in the Late Paleozoic time and an active input of plant organic matter. For Mid Carboniferous sediments, type II or mixed type II / III kerogen prevails. Analysis of the evolution of thermal maturity indicates the unevenness of the entry of potential source rocks into the main zone of oil generation. For kerogen type III of the Lower Permian source rocks, the peak of oil generation falls on the Late Cretaceous. For predominantly carbonate and terrigenous-carbonate Middle Carboniferous source rocks the peak of generation falls on the Jurassic. The most buried Devonian source rocks presumably entered into the zone of wet gas generation.
The development of salt tectonics from Late Triassic to Cenozoic contributed to the vertical migration of hydrocarbons into the post-salt complex. The identified petroleum accumulations in the Upper Triassic-Jurassic stratigraphic section are mainly confined to the four-way dip structural closures above the steep flanks of salt diapirs.
Diagnostic Results of Current Distribution Injected Water Flow in the Productive Formation for Neft Dashlary Oilfield
Authors: Ibragimov Khidir Mansum , Huseinova Nahide Ismat , Gadzhiev Aliabas Alipasha 
Published: October 2021

Abstract
For controlling the oil field development proposed an economically efficient express calculation and visualization method of the hydrodynamic parameters current values distribution in the productive formation.
The presented report shows the results of applying this technique for determining the injected water propagation direction into the productive formation (X horizon) at the «Neft Dashlary» field. Based on the calculated results, the current distribution of the injected water was visualized in the selected section of the formation. High accuracy of the calculation was confirmed by comparing obtained results with the results of a simultaneous tracer study conducted in the field conditions. During tracer studies it was tested a new tracer material, more effective than its analogs. According to laboratory and experimental studies, the addition of 0.003% of this indicator substance to the volume of injected water is the optimal amount for its recognition in the well's product. At the allocated area of the "Neft Dashlari" field, the benefits from the use of the calculation method amounted to 62.9 thousand manats.
Based on the obtained satisfying results of the new method for calculating hydrodynamic parameters and the use of a tracer indicator application at the «Neft Dashlary» oilfield, it is recommended to apply these developments in other oil and gas fields for mass diagnostic of the reservoir fluid distribution in a selected area of productive formations.
Non-Stationary Flooding Based on Application of a Thermoactive Polymer Composition at Offshore Fields
Authors: Suleimanov Baghir Alakbar , Latifov Yashar Aydin , Ibragimov Khidir Mansum 
Published: October 2021

Abstract
A high performance technology has been developed for unstable waterflooding of layered-heterogeneous producing reservoirs of oil fields with a thermal gradient. The technology is based on cyclic injection of a thermoactive low-viscosity oil-soluble liquid polymer composition into the formation, which passes into a high-viscosity phase in situ, blocking the produced formation water flow. Application of the technology results in the increase of area of stimulation, both along the strike and vertical sweep efficiency. Monitoring the reservoir filtration characteristics enables control of the profile of the mixture advance in the formation. The effect of unstable injection of the proposed thermoactive polymer composition on the residual resistance factor was studied in an experimental setup consisting of two parallel-connected linear reservoir models with different permeability. The composition contains a working agent, a dispersant and sea water. The optimal ratio of the components that make up the composite mixture was determined as a result of laboratory and experimental studies. The viscosity behavior of the composite mixture at different temperature values for reservoir conditions is determined. Monitoring techniques for reservoir filtration properties have been developed in order to control the flow profile of the mixture in the reservoir. The analysis of the obtained results showed the efficiency of this technology for layered-heterogeneous reservoirs with a thermal gradient and the availability of overflows. This technology enables aligning area of stimulation, both along the horizontal and vertically using smaller volumes of the agent and with a slight change in the injection pressure. Unstable injection of the composite system provides a significant additional removal of residual oil. Thermoactive polymer composition should be injected cyclically in order to increase the reservoir coverage, align the frontal advance and for enhanced oil recovery due to the involvement of low-permeability oil-saturated areas into the development. This method allows you to change the direction, flow rates, and create unsteady cyclic pressures. A redistribution of formation fluids, a decrease in capillary pressures and the flow of a working agent into oil-saturated low-permeability zones occurs under the positive and negative pressure drops in the formation. The proposed technology was implemented in the section V of the block of the «Neft Dashlary» field (X horizon) in April-June 2016 and in the section of the «Pirallahi» field (KSw) in February-March 2017. At the pilot site of the «Neft Dashlary» field, the impact effect continued until May 1, 2017. Additional oil production in the period from 01.05.2016 to 01.05.2017 made up 3201.4 tons. Additional oil production at the selected area of the Pirallahi field by the end of 2017 made up 170 tons.
The Use of Tracer Based Dynamic Production Profiling in Estimating Hydrocarbon Recovery in Directional Wells
Authors: Moroz Alexander , Myakishev Pavel , Titovsky Nikita , Buyanov Anton , Gorbokonenko Oksana 
Published: October 2021

Abstract
Production surveillance in the producing wells has been an important task for many years in oil and gas development since it provides relevant information useful for the effective management of the HC production. The main objective pursued by operators is to increase the production volume and enhance the oil recovery rate, which often requires some additional well interventions in the existing producing wells. For this purpose, it is necessary to understand how and where to perform stimulations and properly select adequate EOR technologies in order to avoid the risks associated with premature complications of well operation. Usually, production surveillance can be performed using standard logging methods (PLT complex), aimed at the inflow profile monitoring in a well. There are many factors, however, that may complicate the data recording and affect the reliability of the study results. In addition, it is not always possible to shut down the well for production logging purposes. As an alternative approach, it is proposed to consider a technology that involves the placement of special marker-reporters in the bottom-hole zone of the well [3]. The inflow tracers are gradually washed out in the course of production, thus providing the possibility to directly assess the current flow rate, while different codes of productive intervals enable quantification of the production with a phase-wise analysis (hydrocarbon and water) [5].
This paper presents the results of the analysis of reserves recovery in a multi-layer reservoir characterised by relatively low porosity and permeability parameters by means of a tracer-based technology designed for production profiling in directional wells. Surveillance of each productive interval's performance over time was conducted by taking reservoir fluid samples from the mouth of several wells during stable production without well shut-down.
Offshore Caspian Sea: Appraisal Well Monitoring Using Inflow Tracer Technology
Authors: Galimzyanov Artem , Heydarov Orkhan , Jafarov Bakhtiyar , Mirzayev Rufat , Kamalov Kamal , Kilic Akgun 
Published: October 2021

Abstract
A gas condensate field development in the offshore Caspian Sea experienced monitoring challenges and costly operations. In regular field-wide surveillance it is a challenging task to evaluate the numerous well monitoring options on the market, such as production logging, permanent downhole gauges, and distributed temperature sensing along the wellbore. These solutions require wellbore interventions and introduce operational risk during well logging or completion installation risk when fiber is installed. Permanently installed inflow tracer technology is an alternative monitoring solution which avoids the above-mentioned risks but still obtain valuable inflow information concerning well performance over several years.
An appraisal well in the field was selected to pilot inflow tracing technology for assessment of reserves and productivity, for the first time in the Caspian Sea. Multiple sampling campaigns to capture the data was incorporated into a well testing programme to complement the pressure transient data collection and interpretation. The inflow tracer interpretations were successful in providing additional insight towards clean-up efficiency and flow distribution between zones. The latter was verified later by production logging, strengthening confidence with inflow tracer technology.
The application of the permanent inflow tracers has proven to be a viable alternative to other well monitoring solutions without any risk and will become an effective long-term monitoring solution for planned production wells in the field development.
Abnormal Lipid Droplets Accumulation Induced Cognitive Deficits in Obstructive Sleep Apnea Syndrome Mice via JNK/SREBP/ACC Pathway but Not Through PDP1/PDC Pathway
Authors: Li Dongze , Yu Yan , Xu Na , Li Wanting , Hou Yanyan , Wang Xi , Sun Yeying , Lu Wenxue , Qu Guiwu , Lv Changjun , Han Fang 
Published: October 2021

Abstract
The mechanisms of chronic intermittent hypoxia (CIH)-induced cognitive deficits remain unclear. Here, our study found that 12 weeks CIH treatment induced lipid droplets (LDs) accumulation in hippocampal neurocytes of C57BL/6 mice, and caused severe neuro damage including neuron lesions, neuroblast (NB) apoptosis and abnormal glial activation. Studies have shown that the neuronal metabolism disorders might contribute to the CIH induced-hippocampal impairment. Mechanistically, the results showed that pyruvate dehydrogenase complex E1ɑ subunit (PDHA1) and the pyruvate dehydrogenase complex (PDC) activator pyruvate dehydrogenase phosphatase 1 (PDP1) did not noticeable change after intermittent hypoxia. Consistent with those results, the level of Acetyl-CoA in hippocampus did not significantly change after CIH exposure. Interestingly, we found that CIH produced large quantities of ROS, which activated the JNK/SREBP/ACC pathway in neurocytes. ACC catalyzed the carboxylation of Acetyl-CoA to malonyl-CoA and then more lipid acids were synthesized, which finally caused aberrant LDs accumulation. Therefore, the JNK/SREBP/ACC pathway played a crucial role in the cognitive deficits caused by LDs accumulation after CIH exposure. Additionally, LDs were peroxidized by the high level of ROS under CIH conditions. Together, lipid metabolic disorders contributed to neurocytes damage, which ultimately caused behavioral dysfunction. An active component of Salvia miltiorrhiza, SMND-309, dramatically alleviated these injuries and improved cognitive deficits of CIH mice.
Emodin Ameliorate High Glucose-induced Podocyte Apoptosis via Regulating AMPK/mTOR- mediated Autophagy Signaling Pathway
Authors: Liu Hong , Hu Yanglin , Shi Ge , Yang Wenqiang , Xiong Fei , Hu Taotao , Wang Huanlan , Zhang Yanmin , Chen Weidong 
Published: October 2021

Abstract
Background: Podocyte apoptosis and autophagy dysfunction have been considered to be one of the important causes of diabetic nephropathy (DN). Emodin has the function of regulating autophagy. The present study was performed to investigate the effect of emodin on high glucose (HG)-induced podocyte apoptosis and whether the potential anti-apoptotic mechanism of emodin is related to the induction of AMPK/mTOR-mediated autophagy in MPC5 cells in vitro.Methods: The viability and apoptosis of podocytes (MPC5 cells) were detected using CCK-8 assay, trypan blue exclusion assay and flow cytometry analysis, respectively. The expression levels of Cleaved caspase-3, autophagy maker LC3 I/II, and AMPK/mTOR signaling pathway-related proteins were evaluated with western blot analysis. The changes of morphology and RFP-LC3 fluorescence were observed under microscopy.Results: HG (20-160 mmol/L) dose-dependently induced cell apoptosis in MPC5 cells, whereas emodin (4 μmol/L) significantly ameliorated HG-induced cell apoptosis and caspase-3 cleavage. Emodin (4 μmol/L) significantly increased LC3-II levels and induced RFP-LC3-containing punctate structures in MPC5 cells. Furthermore, the protective effects of emodin were mimicked by rapamycin (100 nmol/L). Moreover, emodin increased the phosphorylation of AMPK and suppressed the phosphorylation of mTOR. The AMPK inhibitor compound C (10 μmol/L) abolished emodin-induced autophagy activation.Conclusion: Emodin ameliorated HG-induced apoptosis of MPC5 cells in vitro that involved induction of autophagy through the AMPK/mTOR signaling pathway, which might provide a potential therapeutic option for DN.