scholarly journals Effects of Clay Minerals and External Pressures on Imbibition in Shales

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7528
Author(s):  
Li Lu ◽  
Jianting Li ◽  
Xuhui Zhang ◽  
Yingjun Li ◽  
Fujian Ma
Keyword(s):  
Pore Structure ◽  
Clay Minerals ◽  
Capillary Force ◽  
External Pressure ◽  
Low Flow ◽  
Displacement Efficiency ◽  
External Pressures ◽  
Shale Reservoirs

Imbibition is an important mechanism of recovery during waterflooding and low flow-back during fracking in shale reservoirs. Experiments were carried out to study the development of imbibition in shale samples. The effects of clay minerals, especially the illite and IS, were mainly investigated and discussed. The imbibition under different pressures was conducted and compared. The influence of clay minerals on imbibition in shale is significant and complex. It is shown that the low content of illite and IS and small capillary force lead to small imbibition mass and speed. Formation of new micro fractures due to the swelling of clay minerals can cause the permeability to increase and the imbibition to be speeded up. The pore structure, the content of IS, and the capillary force affect the imbibition process significantly. The external pressure obviously affects the imbibition speed and the final imbibition mass. The content of clay minerals is more important to the formation of new micro fractures than the external pressure. There is a peak in the curve of displacement efficiency versus the content of either clay minerals or illite and IS. The effect of illite and IS more remarkable.

scholarly journals Depressurization-Induced Nucleation in the “Polylactide-Carbon Dioxide” System: Self-Similarity of the Bubble Embryos Expansion

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1115
Author(s):  
Dmitry Zimnyakov ◽  
Marina Alonova ◽  
Ekaterina Ushakova
Keyword(s):  
Initial Rate ◽  
Initial Pressure ◽  
External Pressure ◽  
Self Similarity ◽  
Embryo Formation ◽  
Linear Behavior ◽  
Joint Influence ◽  
External Pressures ◽  
Adiabatic Cooling ◽  
Self Similar

Self-similar expansion of bubble embryos in a plasticized polymer under quasi-isothermal depressurization is examined using the experimental data on expansion rates of embryos in the CO2-plasticized d,l-polylactide and modeling the results. The CO2 initial pressure varied from 5 to 14 MPa, and the depressurization rate was 5 × 10−3 MPa/s. The constant temperature in experiments was in a range from 310 to 338 K. The initial rate of embryos expansion varied from ≈0.1 to ≈10 µm/s, with a decrease in the current external pressure. While modeling, a non-linear behavior of CO2 isotherms near the critical point was taken into account. The modeled data agree satisfactorily with the experimental results. The effect of a remarkable increase in the expansion rate at a decreasing external pressure is interpreted in terms of competing effects, including a decrease in the internal pressure, an increase in the polymer viscosity, and an increase in the embryo radius at the time of embryo formation. The vanishing probability of finding the steadily expanding embryos for external pressures around the CO2 critical pressure is interpreted in terms of a joint influence of the quasi-adiabatic cooling and high compressibility of CO2 in the embryos.

scholarly journals An Investigation of the Basic Physics of Irrigation in Urology and the Role of Automated Pump Irrigation in Cystoscopy

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Dwayne Chang ◽  
Rustom P. Manecksha ◽  
Konstantinos Syrrakos ◽  
Nathan Lawrentschuk
Keyword(s):  
Flow Rate ◽  
External Pressure ◽  
Flow Rates ◽  
Pumping System ◽  
External Pressures ◽  
Basic Physics ◽  
Traditional Irrigation ◽  
Irrigation Solution ◽  
Bladder Fullness

Objective. To investigate the effects of height, external pressure, and bladder fullness on the flow rate in continuous, non-continuous cystoscopy and the automated irrigation fluid pumping system (AIFPS).Materials. Each experiment had two 2-litre 0.9% saline bags connected to a continuous, non-continuous cystoscope or AIFPS via irrigation tubing. Other equipment included height-adjustable drip poles, uroflowmetry devices, and model bladders.Methods. In Experiment 1, saline bags were elevated to measure the increment in flow rate. In Experiment 2, saline bags were placed under external pressures to evaluate the effect on flow rate. In Experiment 3, flow rate changes in response to variable bladder fullness were measured.Results. Elevating saline bags caused an increase in flow rates, however the increment slowed down beyond a height of 80 cm. Increase in external pressure on saline bags elevated flow rates, but inconsistently. A fuller bladder led to a decrease in flow rates. In all experiments, the AIFPS posted consistent flow rates.Conclusions. Traditional irrigation systems were susceptible to changes in height of irrigation solution, external pressure application, and bladder fullness thus creating inconsistent flow rates. The AIFPS produced consistent flow rates and was not affected by any of the factors investigated in the study.

Managing External Pressures through Corporate Diplomacy

2007 ◽  
Vol 33 (1) ◽  
pp. 33-50 ◽  
Author(s):  
Wolfgang Amann ◽  
Shiban Khan ◽  
Oliver Salzmann ◽  
Ulrich Steger ◽  
Aileen Lonescu-Somers
Keyword(s):  
Case Studies ◽  
Genetically Modified ◽  
Food Products ◽  
External Pressure ◽  
Environmental Responsibility ◽  
Genetically Modified Food ◽  
Pressure Groups ◽  
Tax Revenues ◽  
External Pressures ◽  
Public Pressure

Today's corporations face many demands from a plethora of different stakeholders, which are often incongruous. While shareholders demand a decent return on their investment, employees demand safe and well-paid jobs, communities stress upon their tax revenues and public pressure groups call for more social and environmental responsibility. Corporations thus require a great deal of corporate diplomacy to prioritise and – where necessary and possible – reconcile these different demands. This paper describes a framework for managerial/corporate attitudes and external pressure levels. Four case studies illustrate varying attitudes towards corporate diplomacy determine the outcome of controversies over genetically modified food products.

Structural, phase transition, mechanical and thermodynamic properties of TMNs under external pressures: A first-principles study

2018 ◽  
Vol 32 (15) ◽  
pp. 1850181 ◽  
Author(s):  
Xin Tan ◽  
Yinan Dong ◽  
Yuan Ren ◽  
Xuan Li ◽  
Hui Qi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Elastic Constants ◽  
Density Functional ◽  
Mechanical Stability ◽  
Structural Phase ◽  
Potential Method ◽  
External Pressure ◽  
Nanocomposite Films ◽  
External Pressures ◽  
Energy Relations

The plane-wave pseudo-potential method, which is based on density functional theory, is used to determine the structure, elastic constants and phase transition properties of transition metal nitride (TMN; TM = Ti, Zr, Hf, V, Nb and Ta) nanocomposite films under external pressures. Enthalpy–pressure and volume–energy relations of TMNs with different structures are calculated, and their relative stability is discussed. Mechanical stability of external pressure is calculated, and changes in elastic constants with external pressure are analyzed. The present study obtains influence of external pressure on the mechanical properties of material. By analyzing total energy–volume relation, enthalpy–pressure relation and mechanical stability, phase transition law of TMNs under external pressure is obtained.

scholarly journals Characterization of Shale Pore Structure by Multitechnique Combination and Multifractal Analysis and Its Significance

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Dengke Liu ◽  
Tao Tian ◽  
Ruixiang Liang ◽  
Fu Yang ◽  
Feng Ye
Keyword(s):  
Pore Structure ◽  
Pore Size ◽  
Multifractal Analysis ◽  
Ordos Basin ◽  
Pore Network ◽  
Size Distributions ◽  
Geochemical Parameters ◽  
Pore Size Distributions ◽  
Wide Range ◽  
Shale Reservoirs

Understanding pore structure would enable us to obtain a deeper insight into the fluid mechanism in porous media. In this research, multifractal analysis by various experiments is employed to analyze the pore structure and heterogeneity characterization in the source rock in Ordos Basin, China. For this purpose, imaging apparatus, intrusion tests, and nonintrusion methods have been used. The results show that the objective shale reservoir contains complex pore network, and minor pores dominant the pore system. Both intrusion and nonintrusion methods detected pore size distributions show multifractal nature, while the former one demonstrates more heterogeneous features. The pore size distributions acquired by low temperature adsorption and nuclear magnetic resonance have relatively good consistence, indicating that similar pore network detection method may share the same mechanism, and the full-ranged pore size distributions need to be acquired by multitechniques. Chlorite has an obvious impact on the heterogeneity of pore structure in narrow pore size range, while illite and I/S mixed layer influence that in wide range. Kerogen index is the fundamental indicators of geochemical parameters. With the decrease of averaged small and middle/large pore radius, the heterogeneity of pore structures increase in narrow and wide ranges, respectively. This work employed a comprehensive methodology based on multitechniques and helps to explore how pore networks affect reservoir quality in shale reservoirs.

scholarly journals Differences of microscopic seepage mechanisms of water flooding and polymer flooding and prediction models of final oil recovery for conglomerate reservoir

2019 ◽  
Vol 74 ◽  
pp. 13
Author(s):  
Fengqi Tan ◽  
Changfu Xu ◽  
Yuliang Zhang ◽  
Gang Luo ◽  
Yukun Chen ◽  
...  
Keyword(s):  
Pore Structure ◽  
Polymer Solution ◽  
Oil Recovery ◽  
Particle Surface ◽  
Polymer Flooding ◽  
Water Flooding ◽  
Residual Oil ◽  
Displacement Efficiency ◽  
Oil Saturation ◽  
Oil Displacement Efficiency

The special sedimentary environments of conglomerate reservoir lead to pore structure characteristics of complex modal, and the reservoir seepage system is mainly in the “sparse reticular-non reticular” flow pattern. As a result, the study on microscopic seepage mechanism of water flooding and polymer flooding and their differences becomes the complex part and key to enhance oil recovery. In this paper, the actual core samples from conglomerate reservoir in Karamay oilfield are selected as research objects to explore microscopic seepage mechanisms of water flooding and polymer flooding for hydrophilic rock as well as lipophilic rock by applying the Computed Tomography (CT) scanning technology. After that, the final oil recovery models of conglomerate reservoir are established in two displacement methods based on the influence analysis of oil displacement efficiency. Experimental results show that the seepage mechanisms of water flooding and polymer flooding for hydrophilic rock are all mainly “crawling” displacement along the rock surface while the weak lipophilic rocks are all mainly “inrushing” displacement along pore central. Due to the different seepage mechanisms among the water flooding and the polymer flooding, the residual oil remains in hydrophilic rock after water flooding process is mainly distributed in fine throats and pore interchange. These residual oil are cut into small droplets under the influence of polymer solution with stronger shearing drag effect. Then, those small droplets pass well through narrow throats and move forward along with the polymer solution flow, which makes enhancing oil recovery to be possible. The residual oil in weak lipophilic rock after water flooding mainly distributed on the rock particle surface and formed oil film and fine pore-throat. The polymer solution with stronger shear stress makes these oil films to carry away from particle surface in two ways such as bridge connection and forming oil silk. Because of the essential attributes differences between polymer solution and injection water solution, the impact of Complex Modal Pore Structure (CMPS) on the polymer solution displacement and seepage is much smaller than on water flooding solution. Therefore, for the two types of conglomerate rocks with different wettability, the pore structure is the main controlling factor of water flooding efficiency, while reservoir properties oil saturation, and other factors have smaller influence on flooding efficiency although the polymer flooding efficiency has a good correlation with remaining oil saturation after water flooding. Based on the analysis on oil displacement efficiency factors, the parameters of water flooding index and remaining oil saturation after water flooding are used to establish respectively calculation models of oil recovery in water flooding stage and polymer flooding stage for conglomerate reservoir. These models are able to calculate the oil recovery values of this area controlled by single well control, and further to determine the oil recovery of whole reservoir in different displacement stages by leveraging interpolation simulation methods, thereby providing more accurate geological parameters for the fine design of displacement oil program.

scholarly journals EXPERIMENTAL, NUMERICAL AND ANALYTICAL INVESTIGATIONS OF WIND-INDUCED NET PRESSURES FOR INDUSTRIAL BUILDINGS WITH ENVELOPE POROSITIES

2016 ◽  
Vol 7 ◽  
pp. 58
Author(s):  
Vanessa Saubke ◽  
Rüdiger Höffer
Keyword(s):  
Spatial Distribution ◽  
Numerical Model ◽  
Wind Tunnel ◽  
External Pressure ◽  
Navier Stokes ◽  
Industrial Building ◽  
Wind Tunnel Experiments ◽  
Industrial Buildings ◽  
External Pressures

The magnitude and the spatial distribution of wind-induced net pressures (external and internal) on buildings are frequently discussed among research communities and construction industries. This paper deals with this topic based on a case study about an industrial building in Denmark, which was damaged due to the wind impact during a storm when a large part of the roof covering was blown off. In order to detect the reason for the damage the wind-induced loads were studied by i) wind tunnel experiments on the external pressures due to different wind directions, ii) analytical investigations of internal pressure due to envelope porosities and planned openings and iii) numerical analyses for the internal and the external pressure. The Reynolds averaged Navier-Stokes (RANS) method is employed to build a numerical model. The experimental, analytical and numerical results are compared with the indicated characteristic loads from the Eurocode.

scholarly journals Determinants in detecting fraud triangle of financial statements on companies registered in Jakarta Islamic Index (JII) period 2012-2018

2020 ◽  
Vol 2 (1) ◽  
pp. 117
Author(s):  
Iwan Budiyono ◽  
Melati Sari Dewi Arum
Keyword(s):  
Financial Stability ◽  
Secondary Data ◽  
Financial Statements ◽  
External Pressure ◽  
Financial Statement ◽  
Fraud Triangle ◽  
Analysis Model ◽  
Financial Statement Fraud ◽  
External Pressures ◽  
Fraudulent Financial Statements

<p class="IABSSS"><strong>Purpose</strong> - The purpose of study was to examine the effect financial statement fraud based on the fraud triangle with a number of variables such as financial stability, external pressure, financial target, personal financial needs, opportunity and rasionalization in companies listed in Jakarta Islamic Index (JII) period 2012-2018.</p><p class="IABSSS"><strong>Method </strong>- The population are all companies listed in JII period 2012-2018. The sample is 6 companies that were feasible to analyze. The data used in this research is secondary data obtained from the annual report. The data analysis model applied multiple linier regression data panel  using SPSS 25.</p><p class="IABSSS"><strong>Result</strong> - The results showed that the fraud triangle in the categories of financial stability, external pressure, financial targets, personal financial needs, opportunity and rationalization simultaneously affect the fraudulent financial statements. Furthermore financial stability, personal financial needs and opportunity partially negatively related and had no significant effect on financial statement fraud; while external pressures, financial targets and rationalization have positive and significant effects on financial statement fraud on companies listed in JII period 2012-2018.</p><p class="IABSSS"><strong>Implication</strong> - Companies Registered in JII are suggested to improve the financial performance in accordance with sharia principles.</p><strong>Originality</strong> - This research is the first study using multiple linier regression data panel.

scholarly journals The Study of Effect of Pore Structure on Oil Displacement Efficiency of Polymer Flooding

2016 ◽  
Vol 9 (1) ◽  
pp. 55-64
Author(s):  
Ma Wenguo
Keyword(s):  
Pore Structure ◽  
Oil Recovery ◽  
Water Flooding ◽  
Displacement Efficiency ◽  
Throat Radius ◽  
Oil Displacement ◽  
Oil Displacement Efficiency ◽  
Ct Technology ◽  
Micro Level ◽  
The Relationship

Characteristics of pore structure have an important influence on the development of water flooding. In order to improve the recovery rate, it is important to investigate the relationship between pore structure and oil displacement efficiency. The permeability of the artificial cores in this experiment is 189×10-3μm2, 741×10-3μm2and 21417×10-3μm2. We used the CT technology method to scan the pore structure of the three cores, and did oil displacement experiment to investigate the effect of pore structure on the oil displacement efficiency. The result shows that the pore and throat common affect oil displacement efficiency: the bigger the pore and throat radius, the better is the oil displacement efficiency; the smaller the pore and throat radius, the worse is the oil displacement efficiency. The experiment studied the influence of pore structure on oil displacement efficiency deep into microcosmic pore structure without damaging the core skeleton, thereby improving the basis of oil recovery from the micro level and the mechanism.

Sign in / Sign up

Export Citation Format

Share Document