Preformed Particle Gel for Conformance Control: Factors Affecting Its Properties and Applications

2007 ◽  
Vol 10 (04) ◽  
pp. 415-422 ◽  
Author(s):  
Baojun Bai ◽  
Liangxiong Li ◽  
Yuzhang Liu ◽  
He Liu ◽  
Zhongguo Wang ◽  
...  
2019 ◽  
Vol 946 ◽  
pp. 380-385
Author(s):  
Boris A. Chaplygin ◽  
Viacheslav V. Shirokov ◽  
Tat'yana A. Lisovskaya ◽  
Roman A. Lisovskiy

The strength of abrasive wheels is one of the key factors affecting the performance of abrasive machining. The paper discusses ways to improve the strength of abrasive wheels. The stress-state mathematical model presented herein is a generalization of the existing models. It is used herein to find for the first time that there are numerous optimal combinations of the elastic modulus and reinforcing material density, which result in the same minimum value of the objective function. It is found out that increasing the radius of the reinforcing component while also optimizing the mechanical properties of its material may increase the permissible breaking speed of the wheel several times. We herein present a regression equation and a nomogram for finding the optimal combination of control factors. Conventional methods for testing the mechanical properties of materials, which have been proven reliable for testing metals and alloys, are not as reliable for testing abrasive materials, as the test results they generate are not sufficiently stable or accurate. We therefore propose an alternative method that does not require any special equipment or special studies.


2016 ◽  
Vol 36 (5) ◽  
pp. 537-548 ◽  
Author(s):  
Ming-Shyan Huang

Abstract The industrial use of plastic injection moulding machines is widespread. However, few studies have examined the injection screw, which is one of the key components of moulding machines. Studies have demonstrated that a properly designed injection screw improves both the moulding quality and the production rate. Factors that affect the plasticisation properties of conventional standard reciprocating screws include the screw geometry, the screw operation settings, and the processed resins. An ideal standard reciprocating screw exhibits a high plasticising capacity and excellent melt temperature homogeneity; however, these properties typically conflict. Through simulation analysis, this study investigated the optimal design of a standard reciprocating injection screw used for plasticising polycarbonate resins. First, the Taguchi method was integrated with a commercial simulation programme to identify the key control factors affecting the plasticising rate of a screw and the temperature uniformity of the melt. Simulation results revealed that the screw diameter, rotation speed, metering channel depth, ratio of the screw length to the screw diameter, and compression ratio substantially influence performance. Consequently, grey relational analysis was adopted to optimise the design of an injection screw that ensures sufficient quality according to the plasticisation rate and the homogeneity of molten plastic.


Author(s):  
Victor Odhiambo Shikuku ◽  
Wilfrida N. Nyairo ◽  
Chrispin O. Kowenje

Biochars have been extensively applied in soil remediation, carbon sequestration, and in climate change mitigation. However, in recent years, there has been a significant increase in biochar research in water treatment due to their stupendous adsorptive properties for various contaminants. This is attributed to their large surface areas, pore structures, chemical compositions, and low capital costs involved making them suitable candidates for replacing activated carbons. This chapter discusses the preparation methods and properties of biochars and their removal efficacy for organic contaminants and microbial control. Factors affecting adsorption and the mechanisms of adsorption of organic pollutants on biochars are also concisely discussed. Biochars present environmentally benign and low-cost adsorbents for removal of both organic pollutants and microbial control for wastewater purification systems.


2015 ◽  
Vol 7 (1) ◽  
pp. 17-31
Author(s):  
Rasoul Ramezanian ◽  
Akram Emdadi

In a testing session, students may want to use the information of other students, which is cheating. The authors of this paper develop an artificial society to model and simulate this situation. They consider two control factors to increase the incentive of students to not cheat. The first factor is the penalty for similarity between responses (as much as two answer-sheets of two students are the same, their final grades decrease). The second factor is the observers who look into the students and do not allow the observed students to cheat. In this model, agents participate in a test based on their level of knowledge, location and two above factors, deciding whether or not to cheat. These components are used to formulate the utility function. Taking advantage of the developed artificial society, the authors now study the above factors affecting the amount of cheating in a test session.


1992 ◽  
Vol 294 ◽  
Author(s):  
P.W. Tasker ◽  
S.J. Wisbey ◽  
C.B. Boyle

ABSTRACTIn developing a national strategy for the disposal of radioactive wastes, each country will consider isolation options that are appropriate to the types of waste that are produced. The options are developed in response to specific national regulatory requirements, and thus will focus on different aspects of performance. However, there are a number of technical concerns that are common to all programmes. The major issues concerning the behaviour of the chemical and physical barriers in the near field of a radioactive waste repository are discussed in this paper.The description of key issues has been divided into the following categories: barrier design, barrier evolution, scientific understanding through modelling, and validation of performance. The near-field barriers are selected and designed to provide appropriate radionuclide containment and control. Factors affecting the evolution of these barriers, such as container degradation and gas generation, determine the subsequent release of radionuclides to the human environment. Modelling repository evolution is therefore an integral feature of performance assessments, and issues such as the treatment of inhomogeneities and non-equilibrium chemistry may need to be addressed. However, the use of mathematical and computer models implies a requirement for validation. The use of demonstration experiments and natural analogues builds confidence in the predictions of repository performance models, and provides a degree of validation for otherwise inaccessible timescales.


2018 ◽  
Author(s):  
Jingyang Pu ◽  
Baojun Bai ◽  
Ali Alhuraishawy ◽  
Thomas Schuman ◽  
Yashu Chen ◽  
...  

SPE Journal ◽  
2019 ◽  
Vol 24 (05) ◽  
pp. 2398-2408 ◽  
Author(s):  
Ze Wang ◽  
Baojun Bai ◽  
Yifu Long ◽  
Lizhu Wang

Summary Gel treatment is an important technique to solve early CO2 breakthrough and excess–CO2–production problems, caused by the low viscosity and low density of CO2, as well as the heterogeneity of reservoirs with fractures or fracture–like channels. However, there is no reported work on gel that increases its volume after reacting with CO2 (termed CO2–responsive gel) for the conformance control of CO2 flooding. In this paper, the intrinsic properties of a CO2–responsive preformed particle gel (CR–PPG) were evaluated in a water/supercritical–CO2 (scCO2) environment in high–pressure vessels. Continuous scCO2 injection and CR–PPG treatment were conducted in fractured sandstone cores, to probe their plugging performance to scCO2 flow in a high–permeability–contrast system. The volumetric swelling ratio (VSR) of the CR–PPG increased by approximately two times in the presence of scCO2, compared with a sample under similar conditions in the absence of scCO2. The CR–PPG swelling ratio decreased with increasing NaCl concentration. Under the same conditions, the temperature did not have an apparent effect on the swelling ratio after 31 days of swelling. In coreflooding experiments, the placed CR–PPG resisted a considerable pressure up to 617.0 psi before breakthrough. After a shut–in process, CO2–breakthrough pressure was detected at 437.2 psi. It is observed that the shut–in process improved the plugging performance of CR–PPG to CO2 as revealed by the increase in the residual resistance factor. Controlling the shut–in time was found to be effective in augmenting the increase in the residual resistance factor, by increasing the VSR of placed CR–PPG. Resistance of CR–PPG to some real field challenges, including a high pressure gradient and long–term exposure to CO2, was also reported for field–applicability concerns.


2013 ◽  
Vol 734-737 ◽  
pp. 1171-1174
Author(s):  
Qi Zhou ◽  
Yan Yi Yin

Discovered in recent years, Chang 4+5 reservoir group of Yanchang Formation in Jiyuan area is ultra-low permeability reservoir. The evaluation and prediction of the reservoir is the most critical technology in reservoir development. Comprehensive analysis with multiple research approaches shows that the storage potential of the ultra-low permeability reservoir is jointly controlled by sedimentation and diagenesis. Sedimentary factor includes lithology and sedimentary facies, two basic factors affecting the storage potential. The reservoir lithology is of fine-grained debris-arkose and miliary arkose. Pore types are mainly intergranular pores and dissolved pores. The sandstone microfacies in the delta front underwater distributary channel has the best storage potential. Diagenetic factors, including diagenesis types, evolution, intensity, combination etc., have direct influence on the reservoir storage potential. Compaction and calcite cementation are the main factors that weaken the storage potential, whereas carbonate dissolution, especially the dissolution of feldspar plays an important role in the improvement of the storage potential.


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