Deliverability of wells in carbonate gas condensate reservoirs and the capillary number effect

With the development of the Tazhong No. 1 carbonate gas condensate reservoir in China, it has become more and more important to study the characteristics of gas condensate well deliverability. A single-well radial simulator for dual-permeability reservoirs was established to study the influences of fluid properties, permeability, and pressure drawdown on well deliverability with and without the capillary number effect. The simulation shows that well deliverability basically maintains its initial value and is not affected by the capillary number when the formation pressure is higher than dew-point pressure. However, well deliverability drops rapidly when the formation pressure is lower than dew-point pressure. Even if the condensate dropout is very low, well deliverability without the capillary number effect reduces to 50 percent of its initial value when reservoir pressure declines to 95 percent of dew-point pressure, but well deliverability is significantly improved if the capillary number effect exists. The capillary number effect is most significant when reservoir pressure is just lower than dew point pressure, then the effect decreases; the reduction of well deliverability is mainly caused by the reduction of gas relative permeability of the matrix system near the wellbore.

The establishment of a new deliverability equation considering threshold pressure gradient

The flowing mechanism of a low permeability gas reservoir is different from a conventional gas reservoir,especially for that with higher irreducible water saturation the threshold pressure gradient exists. At present,in all the deliverability equation,the additional pressure drop caused by the threshold pressure gradient is viewed as constant,but this method has big error in the practical application. Based on the non-Darcy steady flow equation,the limited integral of the additional pressure drop is solved in this paper and it is realized that the additional pressure drop is not a constant but has something to do with production data,and a new deliverability equation is derived,with the relevant processing method for modified isochronal test data. The new deliverability equation turns out to be practical through onsite application.

A new method of deliverability prediction by steady point in gas wells

Calculating the absolute open flow potential timely and investigating production capacity so as to adjust working system of production wells is one of main means to effectively recovery gas reservoirs during intermediate and late development stage.In order to obtain the open flow potential of gas wells accurately,a new method which utilized a single steady point was proposed in this research,which was based on deliverability formula of a gas well in pseudo-steady state flow with pseudo-pressure form.The influence on factor B in binomial productivity equation caused by the changed permeability was taken into consideration.According to the stable production data,reservoir permeability K can be determined by iterative method firstly,and the coefficient A,B in binomial productivity equation can be calculated with the open flow potential subsequently.It illustrated clearly by a practical example that the new method was suitable for gas wells especially when the producing pressure drop is large.Additionally,the error between the open flow potential value and interpretation result from the multi-point test was small,which proved it to be more simple,economic and effective than the common one.

Hydrogen Storage Performance During Underground Hydrogen Storage in Depleted Gas Reservoirs:A Review

Hydrogen has emerged as a promising alternative to meet the growing demand for sustainable and renewable energy sources.Underground hydrogen storage(UHS)in depleted gas reservoirs holds significant potential for large-scale energy storage and the seamless integration of intermittent renewable energy sources,due to its capacity to address challenges associated with the intermittent nature of renewable energy sources,ensuring a steady and reliable energy supply.Leveraging the existing infrastructure and well-characterized geological formations,depleted gas reservoirs offer an attractive option for large-scale hydrogen storage implementation.However,significant knowledge gaps regarding storage performance hinder the commercialization of UHS operation.Hydrogen deliverability,hydrogen trapping,and the equation of state are key areas with limited understanding.This literature review critically analyzes and synthesizes existing research on hydrogen storage performance during underground storage in depleted gas reservoirs;it then provides a high-level risk assessment and an overview of the techno-economics of UHS.The significance of this review lies in its consolidation of current knowledge,highlighting unresolved issues and proposing areas for future research.Addressing these gaps will advance hydrogen-based energy systems and support the transition to a sustainable energy landscape.Facilitating efficient and safe deployment of UHS in depleted gas reservoirs will assist in unlocking hydrogen’s full potential as a clean and renewable energy carrier.In addition,this review aids policymakers and the scientific community in making informed decisions regarding hydrogen storage technologies.

图片新闻

On July 4,2024,Chinese President Xi Jinping attends the“Shanghai Cooperation Organization Plus”meeting in Astana,Kazakhstan,and delivers a speech titled“Joining Hands to Build a More Beautiful Home of the Shanghai Cooperation Organization”.

Test and Study of the Rock Pressure Sensitivity for KeLa-2 Gas Reservoir in the Tarim Basin

KeLa-2 gas reservoir is the largest uncompartimentalized gas field so far discovered in China, with a reserve of hundreds of billions of cubic meters of dry gas. It has such features as extremely long interval (550m), high pressure (74.5MPa) and pressure coefficient (2.022). Gas reservoirs with a pressure coefficient of over 2.0 are not commonly found. The abnormal high-pressure reservoirs are quite different in characteristic and performance during the process of depletion exploitation. Therefore, it is necessary to know the property of pressure sensitivity for this abnormal high-pressure reservoir. The aim of this paper is to test the reservoir pressure sensitivity and to analyze its effect on the deliverability of gas. Through some experiments, the permeability change with the confining pressure of rock samples from KeLa-2 abnormal high-pressure gas reservoir is measured. A power function is used to match the measured data, and to derive an empirical equation to describe the change of permeability through the change of the reservoir pressure or effective overburden pressure. Considering the permeability change during the development of reservoirs, a conventional deliverability equation is modified, and the deliverability curve for KeLa-2 gas reservoir is predicted. The research indicates that the extent of the pressure sensitivity of rock samples from KeLa-2 is higher than that from the Daqing oilfield. KeLa-2 reservoir rock has the feature of an undercompaction state. The pressure sensitivity of a reservoir may decrease the well deliverability. It is concluded that for KeLa-2 reservoir the predicted absolute open flow (AOF), when the pressure sensitivity is taken into account, is approximately 70% of the AOF when permeability is constant and does not change with pressure.

Building an All-Weather Community

FOCAC sends the powerful message that China and Africa are pursuing joint development,modernisation and growth.The recently held 2024 Summit of the Forum on China-Africa Cooperation(FOCAC)in Beijing under the theme Joining Hands to Advance Modernisation and Build a High-Level China-Africa Community with a Shared Future unequivocally demonstrated that FOCAC remains the most important flagship collaborative platform between China and Africa and continues to deliver wide-ranging.

Geologically controlling factors on coal bed methane （CBM） productivity in Liulin

It is of great significance to forecast high yield of CBM wells and analyze dynamic production by having an overall study on the characteristics of the produced CBM and determining the main factors influencing the productivity of CBM. With the test report and the related geological parameters of a single well, methods of combining the productivity data and typical production curves were used to analyze different geological factors and how to influence the capacity of a single layer. Then, the paper proposed a new understanding about capacity characteristics of the study area and geological control factors： First, the Shanxi formation production capacity characteristics was divided into two-stages, showing signs of gas and gas break- through for 100 days. Second, two parameters, which include potential of gas production and gas production capacity, were bet- ter than the single parameter, such as gas content, coal thickness, and penetration to analyze affecting factors of single well pro- duction. Finally, comprehensive analysis concluded that the ratio of critical desorption pressure to reservoir pressure has greater influence on the production of vertical CBM wells. Besides, the potential of gas production capacity has greater impact at stage of showing gas signs; the coal reservoir pressure and gas production capacity have greater impact at stage of gas breakthrough for 100 days. Thus, to seek the coal bed methane with high ratio of critical desorption pressure to reservoir pressure and high yield of gas will be important guarantee to the success of the coal bed methane exploration and development.

Experimental evaluation on well pattern adaptability of ultra-low permeability reservoir using sandstone flat model

As for ultra-low permeability reservoir,the adaptability of common nine-spot well pattern is studied through large-scale flat models made by micro-fractured natural sandstone outcrops.Combined with non-linear porous flow characteristics,the concept of dimensionless pressure sweep efficiency and deliverability index are put forward to evaluate the physical models' well pattern adaptability.Through experiments,the models' pressure distribution is measured and on which basis,the pressure gradient fields are drawn and the porous flow regions of these models are divided into dead oil region,non-linear porous flow region,and quasi-linear porous flow region with the help of twin-core non-linear porous flow curve.The results indicate that rectangular well pattern in fracture reservoirs has the best adaptability,while the worst is inverted nine-spot equilateral well pattern.With the increase of drawdown pressure,dead oil region decreases,pressure sweep efficiency and deliverability index increase; meantime,the deliverability index of rectangular well pattern has much more rational increase.Under the same drawdown pressure,the rectangular well pattern has the largest pressure sweep efficiency.

Possible Truths Inside Mistranslations―An Attempt at Understanding Mistranslations

This paper examines five cases of mistranslation to shed light on the deliverability and truthfulness of mistranslations.In some cases,a“mistranslation”turns out to be a brilliant translation.Case 1:At a meeting for the UN Security Council Resolution 242,an intentional mistranslation may have been conducted between English and French texts,so Arab nations and Israel would agree.Case 2:At the time of the Sino-Japan diplomatic normalization,Japanese Prime Minister Tanaka made an apology to China that was mistranslated into something banal sounding.Case 3:During his US visit to see President Reagan,Japanese Prime Minister Nakasone’s remarks for an aircraft carrier were mistranslated.Case 4:In TPP negotiations,an ultimatum was pronounced by a Japanese interpreter,although the Japanese negotiator had not said it.Case 5:At a Japanese event,a supposedly deaf composer was dubbed a“digital-age Beethoven”in English;but he replaced it with a“modern-day Beethoven”in Japanese to make himself sound more significant.In hindsight,some cases of mistranslations are hard to judge as mistakes.However,identifying mistranslations helps reveal cultural differences and complicated political differences,and can help improve the quality of translation and interpretation.

Enhanced resistance of marine shrimp Exopalamon carincauda Holthuis to WSSV by injecting live VP28-recombinant bacteria

Recombinant bacteria secreting the transmembrane-truncated region of white spot syndrome virus （WSSV） envelope protein VP28 named DhpVB were constructed, using live Escherichia coli as a deliverer and a con- stitutive secretory expression plasmid as the expression vector. With the ability to deliver recombinant pro- tein products outside, DhpVB could make VP28 directly interact with the shrimp when injected into shrim- p. In order to test the protection potential, live DhpVB were injected into the marine shrimp Exopalamon carincauda Holthuis for three times and WSSV challenge was performed twice simultaneously at the last two injections of the bacteria. The results showed that DhpVB displayed statistically significant advantage over bacteria without VP28 after the second challenge with an average RI （Resistance index） of 0.67±0.08, compared with 0.41±0.09 of bacteria without VP28 （P 〈0.05）. The data suggested that a quasi-immune response may exist in E. carincauda and live bacteria carrying VP28 could enhance the shrimp resistance against WSSV.

HOW ACUPUNCTURE-MOXIBUSTION SHOULD GO FORWARD INTO THE TWENTY-FIRST CENTURY

Mr.Chairman,Ladies and Gentlemen,It is a great honour and pleasure for me tohave the opportunity to deliver this lecture on“How Acupuncture-Moxibustion Should Go For-ward into the 21st Century”.In 1978,the International Conference onPrimary Health Care held in Alma-Ata recog-nized the potential of traditional medicine in ex-tending primary health care to underserved pop-ulations.In many developing countries,in fact,people have always used both traditional

Reducing energy consumption optimization selection of path transmission routing algorithm in opportunistic networks

Opportunistic networks are random networks and do not communicate with each other among respective communication areas.This situation leads to great difficulty in message transfer.This paper proposes a reducing energy consumption optimal selection of path transmission(OSPT) routing algorithm in opportunistic networks.This algorithm designs a dynamic random network topology,creates a dynamic link,and realizes an optimized selected path.This algorithm solves a problem that nodes are unable to deliver messages for a long time in opportunistic networks.According to the simulation experiment,OSPT improves deliver ratio,and reduces energy consumption,cache time and transmission delay compared with the Epidemic Algorithm and Spray and Wait Algorithm in opportunistic networks.

An Inversion Evolutionary Algorithm on How to Convert FDP to TSP

The Film Copy Deliverer Problem (FDP),much more difficult than TSP,is a new problem in the combination optimization. In this paper,a new algorithm is introduced. First,the FDP is converted to TSP. Then an evolutionary algorithm based on inversion operator is adopted. Compared with other Genetic Algorithms,it is not only more simple and easier to realize but also faster and more accurate.

Cost and value in medical education：the role of statistical process control

Medical education is associated with significant costs[1].These costs have led to a growing interest in how to deliver high quality or high quantity education on a limited budget.This in turn has led to an interest in how best to measure quantity,quality and cost and how to track these variables over time.The ultimate aim of the interest in cost and value in medical education is to

Design and Realization of an NFC-Driven Smart Home System to Support Intruder Detection and Social Network Integration

The Internet of thing（Io T） emerges as a possible solution to realize a smart life in the modern age. In this article, we design and realize a novel near field communication（NFC）-driven smart home system for Io T, which integrates the wireless sensor network（WSN）, social networks, and the cloud computing. NFC technology provides a way for users to exchange information between them and the system by simply contacting. So, we propose to use NFC as the system drive in the architecture, such that users can intuitively interact with the system and deliver their intentions. Then, the corresponding service over the system will control or adjust the “things” at home to fit users＇ needs. Furthermore, the proposed system provides a platform for developers to easily and rapidly implement their smart home related services. In the system, WSN sensing and control, NFC communications and identification, user profile management and preference analysis, and social network integration are all provided as platform services. We will show how the system works for home automation, intruder detection, and social network sharing.

Standards digitalization is the trend of the times--Interview with Wu Hequan, Academician of the Chinese Academy of Engineering and Chair of National Standardization Expert Advisory Committee

Standards digitalization is a priority of future standardization work in China,as the National Standardization Development Outline puts forward“promoting the transformation of standardization in a digital,networked and smart way”.When delivering a report at the National Standardization Work Conference earlier this year.

高中英语“阅读写作一体化”写作教学模式初探

英语写作能力是英语听、说、读、写四种基本能力之一,更是语言能力的重要表现形式。通过写作,英语知识不断得到巩固并内化,有利于英语技能的全面发展。但是,英语写作教学一直是我国英语教学中最薄弱的环节,教师大都只注意写作结果,而忽视写作前的指导和铺垫过程,学生的习作也多表现为信息处理凌乱,表达欠逻辑性且多中式英语,以致出现了＂听到写作学生心烦,见到习作教师头痛＂的现象。

Modular Hydrogels for Drug Delivery

The development of novel drug delivery systems is an essential step toward controlled site-specific administration of therapeutics within the body. It is desirable for delivery vehicles to be introduced into the body through minimally invasive means and, these vehicles should be capable of releasing drug to their intended location at a controlled rate. Furthermore, it is desirable to develop drug delivery systems that are capable of in vivo to suffer degradation and to deliver the drug completely, avoiding the need to surgically remove the vehicle at the end of its useful lifetime. Hydrogels are of particular interest for drug delivery applications due to their ability to address these needs in addition to their good biocompatibility, tunable network structure to control the diffusion of drugs and, tunable affinity for drugs. However, hydrogels are also limited for drug delivery applications due to the often quick elution of drug from their highly swollen polymer matrices as well as the difficulty inherent in the injection of macroscopic hydrogels into the body. This paper presents an overview to the advances in hydrogels based drug delivery. Different types of hydrogels can be used for drug delivery to specific sites in the gastrointestinal tract ranging from the oral cavity to the colon. These novel systems exhibit a range of several peculiar properties which make them attractive as controlled drug release formulations. Moreover, such materials are biocompatible and can be formulated to give controlled, pulsed, and triggered drug release profiles in a variety of tissues.