bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Method of Artificial to Solve the Optimization Problems without the Violated Constraints
Authors: Raharjo Jangkung , Zein Hermagasantos , Soeprijanto Adi , Adam Kharisma Bani
Published: August 2021

There are some problems in optimization that cannot be derived mathematically. Various methods have been developed to solve the optimization problem with various functional forms, whether differentiated or not, to overcome the problem, which are known as artificial methods such as artificial neural networks, particle swarm optimization, and genetic algorithms. In the literature, it is said that there is an artificial method that frequently falls to the minimum local solution. The local minimum results are proof that the artificial method is not accurate. This paper proposes the Large to Small Area Technique for power system optimization,  which works based on reducing feasible areas. This method can work accurately, which that never violates all constraints in reaching the optimal point. However, to conclude that this method is superior to others, logical arguments and tests with mathematical simulations are needed. This proposed method has been tested with 24 target points using ten functions consisting of a quadratic function and a first-order function. The results showed that this method has an average accuracy of 99.97% and an average computation time of 62 seconds. The proposed technique can be an alternative in solving the economic dispatch problem in the power system.
Classification of Javanese Script Hanacara Voice Using Mel Frequency Cepstral Coefficient MFCC and Selection of Dominant Weight Features
Authors: Heriyanto Heriyanto , Wahyuningrum Tenia , Fitriana Gita Fadila
Published: August 2021

This study investigates the sound of Hanacaraka in Javanese to select the best frame feature in checking the reading sound. Selection of the right frame feature is needed in speech recognition because certain frames have accuracy at their dominant weight, so it is necessary to match frames with the best accuracy. Common and widely used feature extraction models include the Mel Frequency Cepstral Coefficient (MFCC). The MFCC method has an accuracy of 50% to 60%. This research uses MFCC and the selection of Dominant Weight features for the Javanese language script sound Hanacaraka which produces a frame and cepstral coefficient as feature extraction. The use of the cepstral coefficient ranges from 0 to 23 or as many as 24 cepstral coefficients. In comparison, the captured frame consists of 0 to 10 frames or consists of eleven frames. A sound sampling of 300 recorded voice sampling was tested on 300 voice recordings of both male and female voice recordings. The frequency used is 44,100 kHz 16-bit stereo. The accuracy results show that the MFCC method with the ninth frame selection has a higher accuracy rate of 86% than other frames.
Data Integration in Logic-based Models of Biological Mechanisms
Authors: Hall Benjamin , Niarakis Anna
Published: August 2021

Discrete, logic-based models are increasingly used to describe biological mechanisms. Initially introduced to study gene regulation, these models evolved to cover various molecular mechanisms, such as signalling, transcription factor cooperativity, and even metabolic processes. The abstract nature and amenability of discrete models to robust mathematical analyses make them appropriate for addressing a wide range of complex biological problems. Recent technological breakthroughs have generated a wealth of high throughput data. Novel, literature-based representations of biological processes and emerging algorithms offer new opportunities for model construction. Here, we review up-to-date efforts to address challenging biological questions by incorporating omic data into logic-based models, and discuss critical difficulties in constructing and analysing integrative, large-scale, logic-based models of biological mechanisms.
A Theoretical Analysis of the Integral Fluctuation Theorem for Accelerated Colloidal Systems in the Long-Time Limit
Authors: Lokare Yash
Published: August 2021

A quantitative description of the second law of thermodynamics in relatively small classical systems and over short time scales comes from the fluctuation-dissipation theorem. It has been well established both theoretically and experimentally, the validity of the fluctuation theorem to small scale systems that are disturbed from their initial equilibrium states. Some experimental studies in the past have also explored the validity of the fluctuation theorem to nonequilibrium steady states at long time scales in the asymptotic limit. To this end, a theoretical and/or purely numerical model of the integral fluctuation theorem has been presented. An approximate general expression for the dissipation function has been derived for accelerated colloidal systems trapped/confined in power-law traps. Thereafter, a colloidal particle trapped in a harmonic potential (generated by an accelerating one-dimensional optical trap) and undergoing Brownian motion has been considered for the numerical study. A toy model of a quartic potential trap in addition to the harmonic trap has also been considered for the numerical study. The results presented herein show that the integral fluctuation theorem applies not only to equilibrium steady state distributions but also to nonequilibrium steady state distributions of ideal colloidal systems in accelerated frames of reference over long time scales.
A New Grafting Method for Watermelon to Inhibit Rootstock Re-Growth and Enhance Scion Growth
Authors: Liu Changjing , Lin Weiguo , Feng Chongran , Wu Xiangshuai , Fu Xiaohu , Xiong Mu , Bie Zhilong , Huang Yuan
Published: August 2021

Grafting is an effective way to increase plant tolerance to biotic and abiotic stressors, it is widely used in watermelon production. However, grafting is labor intensive due to the additional time is required, such as the management of rootstock regrowth. This study used a new grafting tool to destroy (remove) the epidermis of pumpkin and bottle gourd rootstock cotyledon base during grafting, we called this a new grafting method. Compared with the traditional grafting (100%), the new grafting method had significantly lower rate of rootstock regrowth (2-23%), higher watermelon scion dry weight and leaf area. In addition, the time used for the new hole insertion and one cotyledon grafting method to destroy (remove) the epidermis of rootstock cotyledon base (4.2 s/plant, 4.2 s/plant) is significantly shorter than the time required to remove the rootstock regrowth manually in the traditional grafting (9.3 s/plant, 8.8 s/plant). Thus, this study developed a new grafting method for watermelon to inhibit rootstock regrowth and enhance scion growth, and this new method is cost-effective for grafted watermelon seedlings.
Airborne Transmission of Avian Origin H9N2 Influenza A Viruses
Authors: Cáceres C. Joaquín , Rajao Daniela S. , Perez Daniel R.
Published: August 2021

Influenza A viruses (IAV) are widespread viruses affecting avian and mammalian species worldwide. Outbreaks of IAV in poultry are usually associated with substantial morbidity and mortality, significantly affecting the poultry industry and food security. IAVs from avian species can be transmitted to mammals including humans and, thus, they are of inherent pandemic concern. Most of the efforts to understand the pathogenicity and transmission of avian origin IAVs have been focused on H5 and H7 subtypes due to their highly pathogenic phenotype in poultry. However, IAV of the H9 subtype that circulate endemically in poultry flocks in some regions of the world have also been associated with cases of zoonotic infections. As a result, the World Health Organization includes avian origin H9N2 IAV among the top in the list of IAVs of pandemic concern. In this review, we discuss the interspecies transmission of H9N2 between avian and mammalian species and the molecular factors that are thought relevant for this spillover. Additionally, we discuss factors that have been associated with the ability of these viruses to transmit through the respiratory route in mammalian species.
Water Safety Plan Resources In Jordan Quantity and Quality
Authors: Fawzi Mohammad , Al Ajlouni Mousa Ibrahim
Published: August 2021

Water scarcity is a significant challenge facing Jordan today. It is a challenge in all areas that use water, and it has become certain that water is the critical factor in the population/resources equation. The water resources in Jordan have become limited with the noticeable increase in the population, mostly resulting from forced migrations in neighboring countries because of the wars and until our time. The rising natural population growth rate, along with the massive influx of refugees, has turned into a state of disproportion between the daily consumption of the population and the amount of water available. That Jordan shares most of its surface water resources with neighboring countries has exacerbated the situation. The current use of water already exceeds its renewable supply. Excessive withdrawal from aquifers, which leads to a lowering of the water table and deterioration in water quality, covered the deficit. This paper focuses on assessing the water situation in Jordan, mainly evaluating this problem and the solution being considered, the true basis for a sustainable water solution requires awareness by the population, and several governmental and non-governmental organizations are actively involved in educating residents about water shortages. The most important and 'actionable' elements of comprehensive water solutions are discussed in this paper, and these elements exist, develop extra water supplies, water harvesting, water desalination, proper wastewater reuse in the agricultural sector, and reduce the demand for drinking water. This research provides specific recommendations to address the shortage of water resources in the Kingdom and highlights the importance of water conservation and optimal use.
Anthropocene: New Geological Era or New Biophysical
Authors: Ortega Jordi Lopez
Published: August 2021

The Anthropocene has created a new cartography where various discursive levels are intertwined. It unites two fields of knowledge: geology and anthropology. In the 19th century, Romanticism challenged the separation between natural sciences and spirit sciences. With the Anthropocene a geological era is established, but with an epistemological dimension: environmental catastrophes are not a passive "object", they become an agent of social and political change. Images of the world (Weltbild) turn nature into an animated whole that challenges the dual vision: observer and observed. There is no nature without "observer", nor geology without anthropology. The Anthropocene modifies the foundations of our view of the world where we had excluded life. This is how concepts such as symbiogenesis, homeostasis, etc., which make visible and try to explain phenomena that are otherwise inexplicable. The Naturwissenschaft by J.W. Goethe is a point of support, with all these ideas that develop in the 20th century and anticipate the Anthropocene term of the 21th century. While the concepts of "belief" and "science" continue to be sharpened, rehabilitating "old quarrels" around anthropology, cosmology, theology, etc. The dignity of man is at stake.
Analysis of Efficiency for Zakat Management Organization in Indonesia: A Comparison Study of Super Efficiency and Free Disposal Hull
Authors: Ryandono Muhamad Nafik Hadi , Qulub A Syifaul , Cahyono Eko Fajar , Widiastuti Tika , Hanesti Elsi Mersilia , Ardiani Ninda , Insani Taqiyah Dinda
Published: August 2021

This research aims to analyze the efficiency level of fourteen Zakat Management Organizations (ZMO) in Indonesia. This study uses a quantitative approach with the method of Free Disposal Hull (FDH) and the Super Efficiency (SE) method. Socialization Expense, Operational Expense, and Salary Expense are the input variables, while zakah fund collection and zakah distribution become the output variables. Empirical findings show that ZMO Corp 4 has the highest efficiency level, which analyzed through both methods of FDH or SE. ZMO managed by the government is the most efficient ZMO compared to the others who managed by private group and social organization. Total Potential Importance (TPI) shows that the output variable that requires the most significant adjustment is the zakat distribution, which is 12.66%
Implementasi Media Pembelajaran Dalam Keterampilan Mengajar bagi Mahasiwa Dalam Mata kuliah Media Dan Teknologi Pembelajaran Di Masa Pandemic Covid-19
Authors: Rudi Rudi Muhamad Barnansyah
Published: August 2021

Learning media is one of the things that can help the process of learning activities, but the media can also be a tool that does not support the smooth learning process, internet-based learning media is one of the infrastructures that can be used especially with today's era where everything is very easy to access. especially internet-based media which at this time have been widely used as learning materials or media that can support teaching skills for teachers or prospective teachers during the current COVID-19 pandemic, where teachers are required to be as creative as possible in providing media that will be used in teaching and learning activities. learning activities, the purpose of this research is to find out from the implementation of learning media in learning skills for students who are taking courses in Media and Learning Technology in which students especially prospective teachers must be able to adapt to the times with developments and technology. The research method used is descriptive qualitative media, where this method is to determine the extent of student knowledge in implementing a learning media on teaching skills, for the presence of researchers in this study is as an observer who designs learning activities or actions taken together with the team. The research model is a member of the research team, namely the lecturer of Islamic Religious Education. The research was carried out at the State University of Jakarta during the even semester lectures for the 2020/2021 academic year from March to July 2021. The subjects of this research were students in the PAI study program. The focus of this research is to find out the implementation of the usefulness of learning media during the covid-19 pandemic in teaching skills.
Saeculum-Mundus Politik Indonesia: Satu Kajian Filosofis dalam Perspektif Nurcholish Madjid
Authors: Mustofa Imron
Published: August 2021

This article suggests some common opinions on Muslim’s worldview, which became the center of contention. This gives rise to perspective which states that the religion participation in government will bring the world of politics into the arena of theo-centrism that ends in authoritarianism. The research is qualitative, based on library research. The approach used is descriptive critical analysis. It aims to describe factual dynamics on Indonesian social-politic from philosophical point of view. The research finds that, on the second half of twentieth century, Nurcholish Madjid’s renewal idea on Islamic political thought (secularization) gets a variety of responses. Madjid suggested the need to separate religion from social-politic arena with his slogan, ‘Islam Yes, Islamic party No’.  The basis of the idea is built on the concept of rationality as the main authority in the social science paradigm. Ideas or dogma, meanwhile, is part of historical development which has to be submissive to conditions that always change. Everything that “exist” has to change, the only absolute one is the change itself.
Kebijakan Peraturan OJK Terhadap Perbankan Syariah dalam Menghadapi Wabah Covid-19 di Era New Normal
Authors: Fauzi Inna , Anjani Yassirlana
Published: August 2021

This study aims to examine the policy of Islamic banking law in maintaining its existence in the face of the plague that is hitting Indonesia. OJK (Financial Services Authority) has also made a number of policies that are used as an effort to save the economy in Indonesia. One of the regulations is stated in POJK  Number 18 / POJK.03 / 2020 concerning "Written Orders for Handling Bank Problems". The legal policy used by Islamic banking is to measure the new OJK regulations as the organizer of an integrated regulatory and supervisory system of all activities in the financial services sector. The method used in this research is descriptive qualitative. The method used in this research is descriptive qualitative. related to the world of banking. The method used in this research is descriptive qualitative. The object of this research is Islamic banking which has more religious wisdom. The results of this study indicate that Islamic banking is making service updates, considering that the transition of the banking world to digital can increase the efficiency of work processes and improve the quality of customer service, by digitizing during the pandemic. The bank has made long-term investments and it is projected that digital services will be one of the main drivers of sustainable banking industry growth in the context of fulfilling POJK Number 18 / POJK.03 / 2020.
Peran Strategi Badan Wakaf Indonesia (BWI) Dalam Meningkatkan Profesionalisme Nazhir Kota Semarang
Authors: Harahap Muhammad Budi Buchari , Darwanto Darwanto
Published: August 2021

Nazhir's problem is one of the problems in waqf practice that is often encountered in the management of waqf today. These obstacles are due to the low quality of human resources, lack of understanding of Nazhir, and lack of guidance given to Nazhir. This paper will discuss about the security of waqf in the city of Semarang, selling nazhir and implementing strategies by the Indonesian Waqf Board in order to create Nazhir professionalism. The purpose of this research is to find out the problems between waqf assets, Nazhir and the Indonesian Waqf Board and to formulate what solutions can solve them. This study uses a qualitative method with a descriptive approach, data observation, observation, and document review. The results showed that there were still many waqf assets found without complete administration so that representatives of BWI Central Java were focused on strategies to control existing waqf assets and the training received by Nazhirs in Semarang City was not sufficient to produce professional Nazirs. The mindset, understanding and work ethic of the Nazhirs are still traditional to create a productive climate of waqf which is beneficial for the economy of society.
Implementasi Prinsip-Prinsip Muamalah dalam Transaksi Ekonomi: Alternatif Mewujudkan Aktivitas Ekonomi Halal
Authors: Maharani Dewi , Yusuf Muhammad
Published: August 2021

Alternatives on Realizing Halal Economic Activities. This study aims to explain the principles of Muamalah in economic transactions as in Al-Quran and Hadith. Halal economic activity plays an important role in economic transactions in Moslem life, which is the main requirement as one of the essences of Islamic teachings. Economic activities carried out by a Moslem are part of worship to Allah the Almighty who is in the framework of aqidah and sharia. Islamic economics aims to achieve happiness in the world and the hereafter through the order of life, to establish equality between humans

 
Mathematical physics e-module: A study of students' perception based on gender
Authors: Astalini Astalini , Darmaji Darmaji , Kurniawan Dwi Agus , Simamora Nadia Natalia
Published: August 2021

Student’s perception is the student's assessment of something or information. The objective of this study was to discover how students' general perceptions and gender differences in electronic modules of mathematical physics. The research type is survey-based research with quantitative approach. The research population consists of physics education students from Universitas Jambi with the sample of 80 students from class A and class B. The data analysis techniques used in the study are descriptive statistics analysis and inferential data analysis using t-tests. The results showed that, overall, students have a positive perception with a Sig. (2-tailed) value of 0.011 < 0.005, which means that there is a significant difference in students’ perception. The perception of class A students with gender differences has a Sig. (2-tailed) value of 0.003, while the grade B students have a Sig. (2 tailed) values of 0.020 and 0.013. This means that class A and classs B students have a discernible difference of perception. Student’s perception may be used as a determining factor in the choice of learning materials. This research can be used as a guideline for the development of student perception assessment in the electronic module of Mathematical Physics in the future. The update of this study aims to compare students' perceptions of the overall online module of mathematics and gender differences.
Evaluación de dos perturbaciones simultáneas en bosques de Araucaria-Lenga, usando diferencias de índices espectrales
Authors: Peña Marco Antonio , Calderón Patricio
Published: August 2021

This study assessed the impact produced by a wildfire and an infectious outbreak led by an oomycete pseudofungi, both occurred in 2015, on the state of Araucaria-Lenga forests of the China Muerta Reserve, placed in the southern Andes of Chile. To do this, a greenness vegetation spectral index was calculated over a multitemporal set of Landsat-8 images, acquired biannually on near-anniversary dates, which was subject to subtractions between ex-ante (2013) and ex-post dates (2015, 2017, 2019). Results show the magnitude and temporal progression of both disturbances, highlighting the celerity and aggressiveness of the wildfire. Although the affected vegetation land covers currently show values close to the recovery of the primal biomass, the inclusion of field-based data to deepen the possible composition and structure variations of these forests is needed.
Survive, Revive, Thrive: Chapter 9: Apparent Horizon
Authors: Blasingame Tom
Published: August 2021

The definition of apparent horizon: the plane or line where the earth or water and sky seem to meet.

If you do nothing, you get nothing.—Aung San Suu Kyi, Burmese politician/diplomat/author, 1945

You get a lot of advice in this job. A former SPE President told me that these columns should never be about “where we (presidents) went and what we did last month; nobody’s interested in that.” While I have tried to abide by that rule, I can tell you that this past month was an extraordinarily full month, all from the computer screen, of course. I have dealt with the widest possible spectra of SPE membership from freshman students to geriatrics, like myself. It has been both exhausting and inspiring to see and feel the creativity and labor of our SPE members.

As unsolicited advice, if you are looking for inspiration, then I encourage you to talk to those who have lost their jobs or even their businesses. I have dealt with several in both groups during the past month.

Listen carefully to them. These colleagues look forward to when they can again contribute to our industry and they have that unique never-say-quit attitude that defines our industry. If you want to understand the word “resilience,” just listen. They are truly inspiring.Luck is where opportunity meets preparation. —Seneca, Roman writer, 54 BC–39 AD

Frankly, I spend almost all of my time for SPE just as Seneca suggests. The modern interpretation of this is that “the harder I work, the luckier I get” (attributed to the golfer Arnold Palmer). Specifically, I am looking for that “apparent horizon” where SPE can best serve its members in a fashion that presents a multitude of significant opportunities. In short, we are getting prepared to be lucky.

Life could be wonderful if people would leave you alone.—Charlie Chaplin, English actor, 1889–1977

The Year(s) of Living Virtually

In a recent panel I was involved in, I confess I did not expect (nor hope) to be the one to get the question “Is work-from-home here to stay?”, but I did. I thought I should share my views so you can taunt me with how wrong I am or could be. The obvious answer is yes. The efficiency and effectiveness of work-from-home (or remote working) is well documented, and probably to no one’s surprise, people are working an average of 2 or more extra hours/day when working from home.

The positives of work-from-home are obvious. Professionals can work very well with less supervision than anyone might have thought possible before the COVID pandemic. Occasional, or minimal commuting, provides a generally better home life and better time management, and there are exceptional (potential) cost savings from less commuting, travel, etc.

There are also negatives for work-from-home. The really bad news is that we probably don’t need as many management personnel. There is significant meeting overload. A rule of thumb is that for 80% of the people, 80% of the meeting time is wasted time. Historically people must be seen in order to be seen as relevant. The presumption being that if one is not seen, then they are not working.
A Big Question for Digital Experts: What Is the Driller Trying To Do?
Authors: Rassenfoss Stephen
Published: August 2021

Digital drilling experts spend a lot of time wondering “what was the driller thinking?”

They are not being sarcastic. The question matters for those doing analysis or writing control algorithms because the significance of readings, such as level of torque at any moment, depends on what the driller is doing at the time.

The interpretation is different if the rig is drilling, where significant torque is required, or reaming, where the resistance is likely minimal.

“During the reaming process, a spike in torque indicates something altogether different from a similar spike while drilling. So, the machine must recognize at least these two states: drilling and reaming,” said Fred Florence, a drilling consultant.

He is among a group of drilling automation advocates who put rig state on a short list of issues that must be addressed to make it possible to create drilling systems where multiple devices can read and react in sync to changing drilling conditions.

In other words, they want to know the information in the driller’s head now, said Moray Laing, director of digital value well construction engineering for Halliburton.

That means an automated device needs to know what the driller is doing and also be aware of concerns that could require quick reactions.

“Unless we can give it the same situational awareness of a human, it will not be able to manage the complexity of the process,” said Darryl Fett, Total’s manager of research drilling and wells in Houston.

Rig state differences also plague those trying to analyze drilling data who need to know what else was going on at the time. They struggle with multiwell data where different methods of calculating the rig state were used.

Drillers leave a record of their work in drilling logs. But this after-the-fact report typically lacks the precise timing sought by digital analysts using high-frequency data to analyze events that can happen suddenly.

“A data scientist working on drilling will tell you that one of their biggest pains is someone will ask them to build a model on lost circulation and here is some data,” Laing said. That analysis is not possible unless someone can offer details about when the fluid losses began, how long they lasted, and other bits of context that might matter, such as the drilling fluid properties at the time.

When asked for a basic explanation of the rig state, Crispin Chatar, drilling subject matter expert for Schlumberger, compared it to bringing a car that has been overheating to the shop. The mechanic will ask what was happening when the trouble began. Did the trouble start while driving fast on a freeway? While stuck in traffic? Did it happen after the radiator fluid warning light went on?

“Every single engineer who works in drilling optimization, drilling analytics, or any one of our remote operation centers uses rig state to quickly and clearly understand what is going on at the well-site in terms of drilling operations or what the system might be seeing downhole,” Chatar said.
Technology Focus: Coiled Tubing (June 2021)
Authors: Crabtree Alex
Published: August 2021

Last year, this feature opened, almost inevitably, with comments on the effects the COVID-19 pandemic might have on our industry. Unfortunately, a year later, we probably have all experienced the effects, both personal and work-related.

One of these effects is that there has been re-evaluation of what’s important. To understand what is important takes some reflection and evaluation of the past. In previous features, the focus has been on what is new or reimagined. Therefore, I thought that, in selecting papers for this year’s feature, it would be useful to select ones that look at coiled tubing operations performed and that have been evaluated in one way or another.

From Bolivia comes a paper that reviews some 25 well interventions performed. Most of these operations are of a type that will be familiar to the reader. Also, some of the challenges that were faced in performing these coiled tubing operations will be familiar. These operations used a range of established types of coiled tubing operations and blended the techniques to meet particular operating conditions, especially location and logistics challenges. All conclusions and best practices that resulted, however, may not be familiar to all readers.

During the past few years, many coiled tubing papers have focused on the use of coiled tubing in multizone fracturing operations, especially plug milling. An area of coiled tubing use in fracturing operations that has had less of an audience recently has been the use of coiled tubing in annular fracturing operations. This activity is still routinely being performed, particularly in Canada. The question has long existed about how the pipe is being eroded. In the related paper in this feature, the authors explain how they have tried to answer that question and have shared some of their review insights.

In the past decade, coiled tubing size, weight, and grade all have continued to increase. Looking back at this trend and thinking about its effect on pressure control equipment led the developers in the third of this year’s papers to work on solutions for shear rams. This is particularly relevant after having just passed the 11th anniversary of the tragic Macondo disaster.

Again, this year, I ask everyone to stay well.

Recommended additional reading at OnePetro: www.onepetro.org.

OTC 30408 Design and Safety Considerations To Perform Coiled Tubing Operations in Large-Diameter, High-Temperature Geothermal Wells by Ishaan Singh, Schlumberger, et al.

SPE 204446 Implementing Business Analytics Software To Optimize Coiled Tubing Operations: A Digital Approach to Operations Efficiency by Xaymaca Bautista Alarcon, Royal Oaks Energy Services, et al.

SPE 203272 The Reinvention of a Well-Established Coiled Tubing Intervention Work Flow Creates New Perspectives for Acidizing Openhole Horizontal Tight Carbonate Water Injectors by Sameer Punnapala, ADNOC, et al.
Reservoir Stimulation Technique Combines Radial Drilling Technology With Acid Jetting
Authors: Carpenter Chris
Published: August 2021

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 202661, “Combination of Radial Drilling Technology With Acid Jetting: New Approach in Carbonate Reservoir Stimulation,” by Ayrat Bashirov, Ilya Lyagov, and Ilya Galas, Perfobur, prepared for the 2020 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, held virtually 9–12 November. The paper has not been peer reviewed.

The complete paper describes an approach to stimulate carbonate formations with bedding water or a gas cap. The technique is a combination of acid jetting and a radial drilling technology that uses mechanical radial drilling with a slim mud motor. The primary advantages of the technology include controlled trajectory and the possibility of re-entry into channels. The novelty of the technology is in its ability to deploy acids in the rock far away from the wellbore through the mechanically drilled holes with known depths and azimuths.

Reservoir Description

The mature field is in central Russia in the Republic of Bashkortostan. The field contains both sandstone and carbonate reservoirs. Oil depth is from 780 to 1830 m. Six reservoirs are in development. This study concentrates on projects in a carbonate formation that is a substage of the early Pennsylvanian Period. This formation is highly heterogeneous with closely underlying water. Permeability of the reservoir is approximately 43 md; reservoir pressure is 1,000 psi, and oil density is 0.891 g/cm3. Two adjacent well candidates with identical reservoir properties were selected for the study, with a distance between wells of approximately 136 m. Net oil thickness in Well A is 4.4 m and 3 m in Well B.

Mechanical Radial Drilling Technology

The technology described by the authors uses mechanical radial drilling with a slim mud motor. The technology allows the drilling of a network of radial channels up to 15 m long with up to four channels of different trajectories on one level. The technical system features a modular construction for ease of assembly at the wellhead area and increased operational efficiency. The main elements of the technical system include the following:

- Pipe pusher connected at the top with an overflow valve module and, at the bottom, with a guiding device connected by means of a hydraulic pusher

- Flexible pipe assembly with a small (nonstandard) sectional mud motor

- Drilling bit (milling cutter for window cutting)

- Special whipstock and an anchor module with an orienting funnel connected from below to the pipe frame
Technology Focus: Hydraulic Fracturing Operations (June 2021)
Authors: Carpenter Chris
Published: August 2021

This issue marks the debut of the Hydraulic Fracturing Operations feature in JPT. While hydraulic fracturing has long been a feature topic, this year, we are branching this major area of interest into both this feature and a Hydraulic Fracturing Modeling feature, which will appear in the November issue of the magazine.

For this issue, reviewer Nabila Lazreq of ADNOC has selected three papers that reflect industry efforts to achieve new goals in production and sustainability. Paper 201450 investigates the potential of natural gas (NG) foam fracturing fluid to reduce the major water requirements seen in stimulation. The authors write that such requirements can be reduced up to 80% in some cases by the use of NG foams. Although modeling is used to reach their conclusions, the authors point out that NG foam fracturing fluids have great promise in operational scenarios in areas such as the Duvernay Shale.

Paper 203226 reviews the challenges and conclusions reached by an operator implementing multistage fracturing for the first time in a horizontal well in a UAE tight carbonate reservoir. A cross-disciplinary approach proved effective when conventional stimulation methods were not successful in this challenging formation.

Finally, paper 201611 returns to the topic of NG foams, investigating their utility as an alternative to fracturing fluids composed of nitrogen and carbon-dioxide foams. The pilot-scale study leads the authors to conclude that NG foams are effective fracturing fluids that exhibit stable viscosity at elevated pressure and temperature conditions.

We hope that you enjoy the inaugural Hydraulic Fracturing Operations feature. Feel free to access the complete papers, and others that reflect recent achievements of SPE conference authors, in the OnePetro online library.

Recommended additional reading at OnePetro: www.onepetro.org.

SPE 204190 Optimization of Coal-Seam Connectivity by Multiseam Pinpoint Fracturing Operations in the Walloons Coal Measures, Surat Basin by Vibhas J. Pandey, ConocoPhillips, et al.

SPE 204140 An Eagle Ford Case Study: Monitoring Fracturing Propagation Through Sealed Wellbore Pressure Monitoring by Kourtney Brinkley, Devon Energy, et al.

SPE 202760 Tight Oil From Shale Rock in UAE: A Success Story of Unconventional Fracturing by Nabila Lazreq, ADNOC, et al.
Advances in Midland Basin Expand Boundaries of CO2 EOR in Marginal Pay Areas
Authors: Feder Judy
Published: August 2021

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper SPE 200460, “A Case Study of SACROC CO2 Flooding in Marginal Pay Regions: Improving Asset Performance,” by John Kalteyer, SPE, Kinder Morgan, prepared for the 2020 SPE Improved Oil Recovery Conference, originally scheduled to be held in Tulsa, 18–22 April. The paper has not been peer reviewed.

As one of the first fields in the world to use carbon dioxide (CO2) in enhanced oil recovery (EOR), the Scurry Area Canyon Reef Operators Committee (SACROC) unit of the Kelly-Snyder field in the Midland Basin of Texas provides a unique opportunity to study, learn from, and improve upon the development of CO2 flood technology. The complete paper reviews the history of EOR at SACROC, discusses changes in theory over time, and provides a look at the field’s future.

Field Overview and Development History

The first six pages of the paper discuss the field’s location, geology, and development before June 2000, when Kinder Morgan acquired the SACROC unit and took over as operator. Between initial gas injection in 1972 and 2000, approximately 1 TCF of CO2 had been injected into the Canyon Reef reservoir. Since 2000, cumulative CO2 injection has sur-passed 7 TCF and yielded cumulative EOR of over 180 million bbl.

The reservoir is a primarily limestone reef complex containing an estimated original oil in place (OOIP) of just under 3 billion bbl. The reservoir ranges from 200 ft gross thickness in the south to 900 ft in the north, where the limestone matrix averages 8% porosity and 20-md permeability. The Canyon Reef structure is divided into four major intervals, of which the Upper Canyon zone provides the highest-quality pay.

The field was discovered in 1948 at a pressure of 3,122 psi. By late 1950, 1,600 production wells had been drilled and the reservoir pressure plummeted, settling as low as 1,700 psi. Waterflooding begun in 1954 enabled the field to continue producing for nearly 20 years, at which time the operators deter-mined that another recovery mechanism would be needed to maximize recovery and reach additional areas of the field. The complete paper discusses

various CO2 injection programs that were developed and applied—including a true tertiary response from a miscible CO2 flood in 1981—along with their outcomes.

Acquisition and CO2-Injection Redevelopment

In June 2000 Kinder Morgan acquired the SACROC Unit and took over as operator. Approximately 6.7 billion bbl of water and 1.3 TCF of CO2 had been injected across the unit to that date, but the daily oil rate of 8,700 B/D was approaching the field’s economic limit. An estimated 40% of the OOIP had been produced through the combination of recovery methods that each previous operator had used. Expanding on the conclusions of its immediate predecessor, the operator initiated large-scale CO2-flood redevelopment in a selection of project areas. These redevelopments were based on several key distinctions differentiating them from previous injection operations.
Joint Optimization of Well Completions and Controls for CO2 Use and Storage
Authors: Carpenter Chris
Published: August 2021

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 200316, “Joint Optimization of Well Completions and Controls for CO2 Enhanced Oil Recovery and Storage,” by Bailian Chen, SPE, and Rajesh Pawar, Los Alamos National Laboratory, prepared for the 2020 SPE Improved Oil Recovery Conference, originally scheduled to be held in Tulsa 18–22 April. The paper has not been peer reviewed.

Carbon dioxide (CO2) storage through CO2 enhanced oil recovery (EOR) has been considered an option for larger-scale deployment of CO2 storage because of the economic benefits of oil recovery, 45Q tax credits, and the use of existing infrastructure. The complete paper investigates how optimal reservoir management and operation strategies can be used to optimize both CO2 storage and oil recovery. Results of the authors’ study showed that joint optimization of well completions and well controls can achieve a higher final net present value (NPV) than that obtained from the optimization of well controls only.

Introduction

In CO2 EOR associated with storage processes, poorly designed well-operating conditions or completions can lead to low oil recovery factors and suboptimal CO2 storage. Co-optimization of oil production and CO2 storage has been recognized as a feasible technique to maximize benefit in terms of oil production and CO2 storage tax credit.

To the best of the authors’ knowledge, settings for well completions have not been considered as optimization variables in a CO2 EOR and storage co-optimization process. The objective of this study is to conduct joint optimization of well completions and controls [well rates or bottomhole pressures (BHP)] that maximize life-cycle NPV in CO2 EOR and storage processes and demonstrate the superiority of joint optimization over well-control-only optimization.

Optimization Problem

In this study, the optimization problem considered is the joint optimization of well completions and well controls for a CO2 EOR and storage process. The mathematical process behind this determination is detailed in the complete paper.

The optimization problem was focused on jointly estimating the well completions (i.e., fraction of injection/production well perforations in each reservoir layer) and CO2 injection and oil-production controls that maximize NPV in a CO2 EOR and storage operation. The authors used a newly developed stochastic simplex approximate gradient algorithm to solve the optimization problem. The performance of the joint optimization approach was compared with the performance of the well-control-only optimization approach. In addition, the performance of the co-optimization of CO2 storage and oil-recovery approach was compared with that of the maximization of only-CO2-storage and only-oil-recovery approaches.
Prediction of High-Pressure/High-Temperature Rheological Properties of Drilling Fluids from the Viscosity Data Measured on a Coaxial Cylinder Viscometer
Authors: Gautam Sidharth , Guria Chandan , Gope Laldeep
Published: August 2021

Determining the rheology of drilling fluid under subsurface conditions—that is, pressure > 103.4 MPa (15,000 psi) and temperature > 450 K (350°F)—is very important for safe and trouble-free drilling operations of high-pressure/high-temperature (HP/HT) wells. As the severity of HP/HT wells increases, it is challenging to measure downhole rheology accurately. In the absence of rheology measurement tools under HP/HT conditions, it is essential to develop an accurate rheological model under extreme conditions. In this study, temperature- and pressure-dependence rheology of drilling fluids [i.e., shear viscosity, apparent viscosity (AV), and plastic viscosity (PV)] are predicted at HP/HT conditions using the fundamental momentum transport mechanism (i.e., kinetic theory) of liquids. Drilling fluid properties (e.g., density, thermal decomposition temperature, and isothermal compressibility), and Fann® 35 Viscometer (Fann Instrument Corporation, Houston, USA) readings at surface conditions, are the only input parameters for the proposed HP/HT shear viscosity model. The proposed model has been tested using 26 different types of HP/HT drilling fluids, including water, formate, oil, and synthetic oil as base fluids. The detailed error and the sensitivity analysis have been performed to demonstrate the accuracy of the proposed model and yield comparative results. The proposed model is quite simple and may be applied to accurately predict the rheology of numerous drilling fluids. In the absence of subsurface rheology under HP/HT conditions, the proposed viscosity model may be used as a reliable soft-sensor tool for the online monitoring and control of rheology under downhole conditions while drilling HP/HT wells.
Application of the Delayed Royalty Framework for Onshore Petroleum Investment in Nigeria
Authors: Egede Frank , Ogolo Oghenerume , Anochie Victor , Danmadami Amina , Ajibade Zephaniah
Published: August 2021

Nigeria uses the concessionary petroleum fiscal system for onshore investment in the country where the ownership of the hydrocarbon resources belongs to the contractor's. The government then gets her revenue through payment of royalties and taxes. A fixed royalty rate of 20% is specified for onshore petroleum investment in the country. This kind of royalty payment system is regressive in nature and affects the sustainability of E&P firms during period of low oil price. This research considered the incorporation of a delayed royalty framework into the concessionary petroleum fiscal system in Nigeria. Two economic models were built to evaluate upstream petroleum investment in Nigeria onshore environment using the spreadsheet modeling technique. The delayed royalty framework was incorporated into one of the model. The delay in royalty payment was made as a function of the time it takes the contractor to recoup his capital before payment of royalty and taxes. Oil price was varied in the model between $30-$90/bbl to see the impact of the delay in royalty payment on the sustainability of the investment under the delayed royalty framework. It was observed that the delayed royalty framework made the contractor to recoup his capital early during the life of the investment. It also increased the contractor's revenue which will help to increase the sustainability of the investment during period of low oil price.
Tracing ovarian follicles growth in vitro by three-dimensional culture system
Authors: Zhang Yan , Feng Xie'an , Zhang Shuo , Zhang Hua
Published: August 2021

In female mammals, the basic reproductive unit in the ovaries is the follicle, which is composed by the oocyte and surrounding somatic granulosa cells (GCs). The development of follicles is a highly programed progress and is regulated by both the paracrine and endocrine factors. To culture the follicle in vitro, various approaches were established in different groups including the 2-dimensional culture and 3-dimensional culture. In this study, we improved a three-dimensional Matrigel system to culture the mouse follicles from secondary stage. In this system, the 3D culture guaranteed spherical structures of the follicles, which was utilized to trace the difference of growth dynamics of follicles in mutant and wild type females.
Business Strategy, Market Power and Stock Price Crash Risk: Evidence from China
Authors: Safi Adnan , Chen Yingying , Qayyum Abdul , Wahab Salman
Published: August 2021

Business strategies play a vital role in a firm’s success but, if not properly executed, can lead to financial irregularities and mispricing, influencing the firm’s performance and leading to stock price crash risk. The present study examines the impact of a firm’s business strategy and market power on stock price crash risk. Following Miles and Snow’s (2003) model, we classify Chinese firms listed on the Shenzhen and Shanghai stock exchanges into defenders (conservative) and prospectors’ (aggressive) business strategies over a period of 2006–2019. We employed industry and year fixed effects regression to show that prospectors who follow aggressive strategies are more prone to stock price crash risk than defenders who follow conservative strategies. Additionally, we show that firms with high market power also contribute to increased stock price crash risk. Our results are also robust to alternative control variables and different statistical models like the two-stage least squares method.