Productivity prediction model and optimal configuration of herringbone multilateral well

In order to accurately predict the productivity of herringbone multilateral well,a new productivity prediction model was founded.And based on this model,orthogonal test and multiple factor variance analysis were applied to study optimization design of herringbone multilateral well.According to the characteristics of herringbone multilateral well,by using pressure superposition and mirror image reflection theory,the coupled model of herringbone multilateral well was developed on the basis of a three-dimensional pseudo-pressure distribution model for horizontal wells.The model was formulated in consideration of friction loss,acceleration loss of the wellbore and mixed loss at the confluence of main wellbore and branched one.After mathematical simulation on productivity of the herringbone multilateral well with the coupled model,the effects of well configuration on productivity were analyzed.The results show that lateral number is the most important factor,length of main wellbore and length of branched wellbore are the secondary ones,angle between main and branched one has the least influence.

Combined stochastic and discrete simulation to optimise the economics of mixed single-horizontal and multilateral well offshore oil developments

Multilateral wells promise cost savings to oil and fields as they have the potential to reduce overall drilling distances and minimize the number of slots required for the surface facility managing the well.However,drilling a multilateral well does not always increase the flow rate when compared to two single-horizontal wells due to competition in production inside the mother-bore.Here,a holistic approach is proposed to find the optimum balance between single and multilateral wells in an offshore oil development.In so doing,the integrated approach finds the highest Net Present Value(NPV)configuration of the field considering drilling,subsurface,production and financial analysis.The model employs stochastic perturbation and Markov Chain Monte-Carlo methods to solve the global maximising-NPV problem.In addition,a combination of Mixed-Integer Linear Programming(MILP),an improved Dijkstra algorithm and a Levenberg-Marquardt optimiser is proposed to solve the rate allocation problem.With the outcome from this analysis,the model suggests the optimum development including number of multilateral and single horizontal wells that would result in the highest NPV.The results demonstrate the potential for modelling to find the optimal use of petroleum facilities and to assist with planning and decision making.

Mathematical Reasoning of Treatment Principle Based on the Stable Logic Analysis Model of Complex Systems

The article reviews the stable logic analysis model of complex systems or steady multilateral systems with two non-compatibility relations. Energy concept in Physics is introduced to the multilateral systems and used to deal with the multilateral system diseases. By using mathematical reasoning, it is demonstrated that the treatment principle: “Virtual disease is to fill his mother but real disease is to rush down his son” and “Strong inhibition of the same time, support the weak” which due to the “Yin Yang Wu Xing” Theory in Traditional Chinese Medicine (TCM).

3D finite element modelling of multilateral junction wellbore stability

Wellbore failure can occur at different stages of operations. For example, wellbore collapse might happen during drilling and/or during production. The drilling process results in the removal of an already stressed rock material. If the induced stresses near the wellbore exceed the strength of rock, wellbore failure occurs. The production process also changes the effective stresses around the wellbore. Such changes in stresses can be significant for high drawdown pressures and can trigger wellbore failure. In this paper, the Mohr–Coulomb failure criterion with a hyperbolic hardening is used. The model parameters are identified from triaxial compression tests. The numerical simulations of laboratory tests showed that the model can reproduce the mechanical behaviour of sandstone. In addition, the simulations of multilateral junction stability experiments showed that the model was able to reproduce yielding and failure at the multilateral junction for different levels of applied stresses. Finally, a numerical example examining multilateral junction stability in an open borehole during drilling and production is presented. The results illustrate the development of a localized failure zone proximate to the area where two wellbore tracks join, particularly on the side with a sharp approaching angle, which would significantly increase the risk of wellbore collapse at the junction.

The Impact of Multilateral Imported Cases of COVID-19 on the Epidemic Control in China

While the spread of COVID-19 in China is under control,the pandemic is developing rapidly around the world.Due to the normal migration of population,China is facing the high risk from imported cases.The potential specific medicine and vaccine are still in the process of clinical trials.Currently,controlling the impact of imported cases is the key to prevent new outbreak of COVID-19 in China.In this paper,we propose two impulsive systems to describe the impact of multilateral imported cases of COVID-19.Based on the published data,we simulate and analyze the epidemic trends under different control strategies.In particular,we compare four different scenarios and show the corresponding medical burden.The results can be useful in designing appropriate control strategy for imported cases in practice.

A Test Method for the Static/Moving State of Targets Applied to Airport Surface Surveillance MLAT System

Due to the particularity of its location algorithm,there are some unique difficulties and features regarding the test of target motion states of multilateration(MLAT)system for airport surface surveillance.This paper proposed a test method applicable for the airport surface surveillance MLAT system,which can effectively determine whether the target is static or moving at a certain speed.Via a normalized test statistic designed in the sliding data window,the proposed method not only eliminates the impact of geometry Dilution of precision(GDOP)effectively,but also transforms the test of different motion states into the test of different probability density functions.Meanwhile,by adjusting the size of the sliding window,it can fulfill different test performance requirements.The method was developed through strict theoretical extrapolation and performance analysis,and simulations results verified its correctness and effectiveness.

Unilateralism or Multilateralism?

Ever since the Bush administration took office, the U. S. national security strategy has given rise to much controversy. Whether the U. S. national security strategy is of unilateralism or multilateralistm is a question in dispute. Many people think it is a unilateralist strategy. According to their views, to achieve its own objective, the U. S. administration has rarely considered the interests and feelings of other coun-

The New Industrial Revolution, Global Governance Reshaping and Multilateralism

Currently,a new industrial revolution characterized by artificial intelligence,the internet of things,and digitalization is in a critical transition from initiation to allaround expansion.While injecting new dynamism into global economic growth,and promoting inclusive development and human welfare,the new industrial revolution will reshape the pattern of international competition,and provide a window period for latemoving countries to compete and catch up with developed nations.Amid the shocks of the new industrial revolution,countries must adhere to the principles of openness,multilateralism and reciprocity to share the dividends of the new industrial revolution and effectively cope with its challenges.Therefore,multilateralism,rather than protectionism and unilateralism,should dominate the mainstream of change in future global governance.The reform of existing multilateral organizations such as the World Trade Organization(WTO)must proceed under the principle of multilateralism.

China Champions Multilateralism and Free Trade

THE G20 Osaka Summit in Japan convened on June 28-29 had the world hold its breath. Not only were front-burner issues, such as WTO reform and digitalization of the economy, discussed there, but there was much fanfare around the first high-level meeting between China and the United States since the last G20 summit in Buenos Aires late last year. Given the mounting trade tensions between the two countries, the meeting took global center stage.

Multilateral Investment Agreement Negotiations and China's Policies

Of late,Chins’s joining in the WTO has again claimed the focus of attention at home and abroad.What is most talked about at home is

Japanese Prime Minister Abe Shinzo’s Multilateral Role Conception and US and China Policies

Promotion of multilateralism has been one of key Japanese roles.It is not limited to support to the United Nations but also related to the promotion of global and regional free trade in Asia-Pacific.This article shows the result of a research based on Japanese,United States,and Chinese political leaders’statements and behaviors related to economic multilateralism during the second Abe administration.The research uses role theory as a theoretical framework.This article proves that Prime Minister Abe has consistently endorsed multilateralism,deepening economic ties both Asia-Pacific and European countries by examining Japanese,US,and Chinese political leaders’speeches,interviews,and remarks on the media.His foreign policy does not indicate unilateralism or dismissal of international cooperation because he perceives multilateralism is essential for Japan’s prosperity and security.In addition,Abe does not break the ties with the US but it is difficult to say that Japan-China relations improved during his tenure.This is because China’s influence will grow and the importance of Japan will relatively decline in Asia-Pacific.

Financing and the Role of Multilateral Development Banks are the Highlights

For me,the highlights of these recommendations are the financing and the role of Multilateral Development Banks.The recommendations I follow with most interest are the ones that protect and insure against political risk and regulatory risk.These

The Role of Multilateral Development Banks and Institutions Are Important

These five recommendations cover the most critical aspects of infrastructure development:an attractive pipeline of projects,diversity of financial instruments and a conducive regulatory environment,the role of multilateral development institutions,as well as the management of project life-cycle pro-

Impact of Institutional Quality on Multilateral Aid in Nigeria

The linkage between quality of institutions and economic performance of nations has generated a lot of interest among scholars,due to their influence on development of many countries and effective use of resources including foreign aid from multilateral organizations.Two strands of theories emerge on the institutions-multilateral aids nexus:those for benefits of aid to growth and development;and those for harms caused by aid.The research objective is to investigate the impact of institutional quality on multilateral aid in Nigeria.To do this,the study applied auto-regressive distributed lag(ARDL)bounds testing approach.Data for the study were sourced from the ICRG data,WGI data,QoG database,Transparency International,and World Development Indicators(WDI).The findings show that institutional quality variables do not have any influence on the multilateral aid in Nigeria,except the‘independence of judiciary’which appeared statistically significant.In the short-run analysis,the disequilibrium in the long-run equilibrium is corrected for in the next quarter period by about 25%;almost all the variables are statistically and significantly influencing multilateral aid.It is therefore recommended that donor agencies should consider other factors that negatively influence official development assistance(ODA)such as politics,location and colonial history.

Actively Promoting Regional Space Cooperation——Vice Administrator, Loan Enjie headed a delegation to attend the Second Asia-Pacific Conference on Multilateral Cooperation in Space Technology and Applications

A Chinese delegation of 24 persons headed by Mr. Luan Enjie, Vice Administrator of China National Space Administration (CNSA) attended the Second Asia-Pacific Conference on Multilateral Cooperation in Space Technology and Applications held at Islamabad, the Capital of Pakistan from April 22 to 26, 1995. Following the First AsiaPacific Workshop held in Beijing in December, 1992, and the First Asia-Pacific Conference on Multilateral Cooperation in

Making Cooperation in Space for Better Future Summary of the Keynote Speech at the Second Asia Pacific Conference on Multilateral Cooperation in Space Technology and Applications

Since the Asia Pacific Workshop on Multilateral Cooperation in Space Technology and Applications was held in Beijing in December, 1992, the preparatory committee for Asia-Pacific Space Cooperation Mechanism and the Liaison Committee for AP-MC-STA have done many fruitful works. Thanks to the First Asia Pacific Conference on Multilateral Cooperation in Space Tech-

Prosperous Multilateral Space Cooperation

The civilization of the world develops with the range of human activity expanding from regional to global,from land to ocean,air and ultimately to space.A new concept of ownership would appear whenever the horizon of human activities was extended.Nations define the limits of land territory,territory of sea and territory of air