bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reservoir Characterization of a Naturally Fractured Reservoir Using Well Test Data Interpretation
Authors: Ibragimov Abdulmalik 
Published: November 2022

Abstract
The Karachaganak field is a massive reef carbonate structure with relatively homogeneous rock properties distribution in the platform region. In many wells in the field, well test data interpretation at late time observations show closed boundary or flow in the system with multiple sealing faults, which often contradicts with the geological interpretation of the field. The tested wells are generally located in geologically homogeneous platform region and are unlikely to have any kind of boundary effects. Author using numerical simulation models shows that these late time data behavior can be explained by large fracture corridors, which display high contrast in permeability to surrounding matrix rock, thus leading to different boundary effects at late times of the well test data.
Drilling and Cementing to Isolate Productive Series and High Pressure Zones: A Successful Case History Enables Zonal Isolation in High Pressure Gas Well with Close PPFG Margins in South Caspian Basin
Authors: Cherukuri Apparao , Ismayilov Elshan , Zeynalov Elgun , Cabbarov Fuad , Iskandarov Vusal , Karimov Elkhan 
Published: November 2022

Abstract
The objective of this paper is to share the experience of how 7-5/8" section was drilled, and cased-off to enable the zonal isolation in the depleted VII horizon and high-pressure zone with close PPFG margins by managing high risks of differential sticking and loss of circulation at Bulla gas-condensate reservoir which is one of the most complex high-pressure fields with close PPFG margins in the world.
The Bulla wells are highly complex wells the Caspian region. Before drilling into the reservoir section which requires high MW, the drilling liner was run to the cased-off VII horizon and high-pressure zone, which have significant challenges such as differential sticking and loss of circulation, previously resulting in stuck pipe and losses. To overcome the challenges, under reaming/liner cementing at MW lower than PP were evaluated and applied to have good cementing across the open hole and good shoe, to drill into the reservoir section in the project.
The study helped to identify the issues and actions taken that resulted in significant improvement in well delivery and reduced the risks despite having underbalanced condition during under-reaming/cementing. So is accepting the bitter truth, situation offering limited sets of options was very challenging as having:
high risks of differential sticking and loss of circulation due to high MW, high- pressure interval near the setting depth, which required high MW to stabilize the well, need to isolate the high-pressure zone and depleted VII horizon for drilling into the reservoir section.
However, the operation plans of managing the ECD within limits by using different MWs, higher MW for running casing and lower MW for UR and cementing have been risk-assessed with all the mitigation, and as a result, the aforementioned intervals were well isolated which was supported by CBL results. No gains or losses were observed during the operations including both casing running and cementing. Finally, having a good cement in the shoe allowed to successfully drill into the reservoir section with high MW accomplishing successful completion of the well without any major problems previously occurring. Therefore, this approach not only reduced the time, cost and also helped to deliver the quality wellbore.
The case study of liner cementing at underbalanced conditions provides useful insights of how unconventional techniques can be successfully implemented to achieve the overall accomplishment in well delivery performance.
Simulation-Based Evaluation of Concurrent CH4 Storage Potentials During CO2-ECBM in Karaganda Coal Basin
Authors: Tiyntayev Yernar , Tursymat Omirzhan , Serikov Galymzhan , Asif Mohammad , Wang Lei , Hazlett Randy 
Published: November 2022

Abstract
Karaganda Basin contains the largest coalbed methane (CBM) reserve in Kazakhstan. We previously modelled the enhanced coalbed methane (ECBM) process by injecting CO2 into a typical well group which showed high production potential. With the global agreement on carbon neutrality, it is advantageous to explore the CO2 storage potential during CO2-ECBM in Karaganda Coal Basin. The CO2 storage potential of a given coal seam volume in the Karaganda Coal Basin is evaluated by setting up an extended 5-well pattern in a compositional reservoir simulator. The CO2-ECBM process is simulated by incorporating the reservoir parameters reported for the Karaganda Coal Basin, with variable CO2 injection rate and well pressures to optimize the injection strategy, such as the necessity of well stimulation. Simulation results showed that primary depletion followed by CO2 injection is a promising win-win strategy. Based on parameter sensitivity analysis, the CO2 injection rate should have an optimal value under pressure constraint, since higher injection rate does not contribute remarkably to the recovery. With the aid of CO2 injection, the methane recovery could be enhanced from 35.1×106 kg to 40.2×106 kg by 14.5% during the 4-year CO2 injection at constant rate of 60,000 m3/day with constraint pressure of 15,000 psi. Correspondingly over 99.98% of injected CO2 can be concurrently stored in the form of adsorbed and free gas in these case scenarios. Simulation results suggest that commercial CBM production could be established in the Karaganda Coal Basin, if properly implemented; meanwhile, the process entails enormous potential for CO2storage and represents a new opportunity for the Karaganda coal industry.
Application of Software Tools to Optimize Drilling Horizontal Wells in Mature Fields
Authors: Zhiyenbayev B. , Ashimov K. , Khasanov B. , Kurmangaliyev D. 
Published: November 2022

Abstract
Analysis of previously drilled horizontal wells in mature fields showed a lack of monitoring of drilling parameters in real time. For example, complications during the drilling process (slack off / pick up), low rate of penetration, poor wellbore cleaning, and as a result mechanical and differential, increased uncertainty of the location of wells leading to the risk of collision with other wellbores, also casing running problems and cementing.
The issue of monitoring drilling parameters in real time, considering the actual drilling parameters obtained from the well, is extremely important and in demand.
The workflow includes linking preplanned engineering calculations with actual data while drilling using software applications to optimize the following parameters:
mechanical integrity of the drill string and efficiency of the BHA depending on the type of operation (tripping in, tripping out, rotary drilling, slide drilling and etc.); drilling fluid circulation in the wellbore to ensure its cleaning and downhole pressure control (minimum flow rate and equivalent circulating density); calculation of running casing strings (trip speed, circulation, calculation of lateral forces etc.).
The described process of real-time monitoring of horizontal wells makes it possible to identify and prevent deviations from drilling technology at early stages and during drilling, thereby significantly reducing the likelihood of drilling problems and accidents, and as a result, it had a positive effect on the timing of well construction and its quality. This article demonstrates the method of control and production of calculations in accordance with actual data to optimize the drilling of horizontal wells in the fields. Examples of wells from several fields in the West Kazakhstan region where this technique is used are shown.
Mini-Acid: Novel Technical Solution for Wireline Formation Testing Efficiency Enhancement in Carbonate Reservoirs
Authors: Dzhalatyan Yakov , Kazakevich Eduard , Shelomikhina Irina , Belyakova Ludmila , Oparin Ivan , Malofeev Mikhail , Mayorov Andrey , Lukyantseva Ekaterina , Budko Artem 
Published: November 2022

Abstract
Carbonate reservoirs are widely spread all over Russian Land. Quite common methodology of carbonate wells productivity enhancement is reservoir stimulation with hydrochloric acid solutions (HCl).
However, deteriorated reservoir properties during formation evaluation and Wireline Formation Testing (WFT) in open hole, could significantly impact on reservoir characterization results.
This paper presents an innovative technique and several examples of its practical implementation, aimed to enhance WFT platforms performance in carbonate reservoirs. Technique involves low perm carbonate reservoirs stimulation using relatively low-volume acid solutions, immediately before performing formation testing with WFT platform. In addition, this technique allows to perform in-situ acid solutions effectiveness evaluation at reservoir conditions, naturally fractured reservoirs stimulation, as well as borehole surface clean-up in open hole and remedy work in cased hole, designated to scales removal from completion string components in cased hole.
Development of a Semi-Analytical Model of Gas Breakthrough to Horizontal Wells in Gas Cap Zones of Oil Rims Considering Heterogeneity of Reservoir Distribution
Authors: Elesin Artem Viktorovich , Samolovov Dmitry Alexeyevich , Apasov Renat Timergaleevich 
Published: November 2022

Abstract
The paper describes the experience of creating a semi-analytical model of gas breakthrough to a horizontal oil well located in the subgas zone of an oil rim. A physical-mathematical model is described, examples of using the model to predict the displacement characteristics of actual wells and using the model in the process of reservoir history matching are considered.
The Discrete-Imitational Modeling of the Pump-Well-Reservoir System with a Intermittent Sucker-Rod Pumping
Authors: Jamalbayov Mahammad , Valiyev Nazim 
Published: November 2022

Abstract
The work is devoted to the problem of modeling the filtration processes of light and non-volatile oils in compressible reservoirs with low reservoir pressure, inflow to the well and intermittent pumping of oil from the well by a sucker-rod pump in a integrated system.
The system under study is considered in the context of discrete simulation modeling. It consists of the following objects: Pump, well and reservoir (well-drained zone). An algorithm has been developed for determining the pump idle time based on the criterion of the minimum cost of oil extracted during a full pump cycle.
For the first time, a computer model of the pump-well-reservoir system was created on the base of the discrete-imitational modeling concept taking into account the PVT properties of reservoir fluids and the compressibility of the reservoir rocks. The sucker-rod pumping process in a intermittent mode has been studied, the nature of the influence of the pump idle time on the efficiency of the pumping at various reservoir permeabilities has been established. The developed algorithms can be used to create smart wells.
Modeling and Optimization of ESP Wells Operating in Intermittent Mode
Authors: Yudin Evgeniy , Piotrovskiy George , Smirnov Nikita , Bayrachnyi Daniel , Petrushin Michael , Isaeva Sabina , Yudin Paul 
Published: November 2022

Abstract
The problem of effective oil reservoir managing becomes quite challenging during the late stages of its production. That's why, going for the intermittent operational mode is typical use-case for low-rate wells with electrical submersible pump since it's more efficient from both economical and engineering point of view. So, finding optimal parameters becomes crucial for the getting best value from the changes made. Tackling this problem leads to creation of the complex algorithm which will allow to compose an accurate physically motivated mathematical representation of a real-world object and provide functionality of calculating the best-possible operating regime.
The physically driven mathematical model was designed which represents system of three key elements: "tubing–annulus–drainage area". They are connected with each other through boundary conditions defined in the submersible pump intake by mass conservation equations.
The optimization task can be split into two blocks. The first stage, adjusting the model to the real operational data to match calculated dynamics, is handled by introducing "adaptation" parameters which represents specifics of a certain tubing system and varying IPR curve.
The second stage, optimization itself, is implemented by various optimization-aimed algorithms which objective is maximizing income while following operational and geological constraints.
As the result the physically motivated model of well operated in intermittent mode was obtained. The program module was developed with use of designed model. This software provides functionality to predict operational dynamics of production, hydraulic and electrical behavior. The accuracy of this approach to representing periodic well was verified by close analysis of convergence with well-trusted transient flow oil and gas simulator.
Developed modeling tools were the core for optimization program which are developed for the sake of finding the best possible parameters for a well with an ESP pump operated in periodic mode. It is worth to mention that this algorithm is also takes into account all geological and mechanical constraints.
Intelligent Methods for Analyzing High-Frequency Production Data to Optimize Well Operation Modes
Authors: Judin Evgeniy , Andrianova Alla , Ganeev Timur , Kobzar Oleg , Isaev Danil , Polinov Mikhail , Gudilov Mikhail , Shestakov Aleksandr , Mosyagin Grigoriy , Chadin Evgeniy , Sirotkin Artem , Chervyak Artem , Kradinov Ivan , Bagaziy Artem , Ovechkin Vlas 
Published: November 2022

Abstract
The digital transformation implies a new approach to petroleum engineering. It based on the analysing of high-frequency data, automatization of business processes and the spread of artificial intelligence.
Now modern wells are highly equipped, their operation is monitored by more than 50 sensor types (pressures and temperatures in different system units, electric telemetry data from submersible equipment and etc.). More than 10,000 measurements are accumulated daily for the well. Manual processing of such a large amount of information is impossible. A petroleum engineer usually analyses average values and only when there are problems does it necessary to check high-frequency data. Cause of high frequency measurements contain valuable information, the task of developing algorithms for the automatic analysis of large amounts of field data is relevant.
In addition, oil reserves are decreasing, the physics of processes in the reservoir, well and surface facilities is becoming more complex. Highly productive oil reservoirs are being replaced with hard-to-recover reserves, oil and gas condensates and fringes. In those conditions it is highly relevant to apply advanced methods of information analysis and mathematical models.
Methods of automatic analysis of high-frequency telemetry data are at the stage of active development and introduction into technological processes in petroleum industry [1]. The article presents the solutions of various problems of petroleum engineering by using advanced methods of data analysis and shows the tools that have allowed to achieve economic effects.
The most important intraday data reviewing duties are quickly identification of down time, well mode regime optimization, preventing frow rate deviations from the planned one. The prompt decision allows to identify decrease of oil rate and cut back non-production expense.
Offshore Natural Gas Hydrate Prevention: A Promising Cavitation Method
Authors: Wang Mingbo , Wang Wei , Guo Li-bo 
Published: November 2022

Abstract
The high-pressure, low-temperature environment prevailing in offshore gas production and transportation is prone to forming methane hydrates inside the tubings or pipelines, resulting in reduced production and flow assurance problems. Conventional hydrate prevention relies on the continuous injection of chemicals to alter the chemical potential of the mixture stream. Such a method has the disadvantages of high cost, high toxicity, and high environmental impact. Effective hydrate prevention methods are urgently needed in offshore petroleum engineering.
When fluid in nozzles or near turbine blades experiences an abrupt pressure drop, cavitation bubbles form and accumulate in the fluid. Bubbles collapse as they move downstream along the flow. As the bubble collapse, extremely high temperature and high pressure are generated, and the ambient fluid around the bubble is heated. In this paper, the thermal effect of cavitation is introduced into methane hydrate prevention. A numerical simulation of cavitation inside an injector was performed, an experimental setup was established, and the influences of various working parameters such as injection pressure, injection frequency, and fluid temperature on the thermal effect of cavitation were analyzed.
Computational fluid dynamics studies have revealed the bubble collapse process. The evolution of pressure and temperature inside and outside the bubble has been analyzed and validated by previous experimental observations. Different impact chambers have been tested for their cavitation performance, and the one with a cone shape shows superior performance over the other two. In the experimental observations, an increase in the injection pressure leads to an increase in the fluid temperature. An increase in injection frequency and chamber pressure facilitates the increase in ambient fluid temperature, while a further increase in fluid temperature hinders the cavitation heating process. A tubing configuration with a cavitation method is also proposed in this paper.
A Digital Analytics Solution for Analyzing a Population of Electric Submersible Pumps
Authors: Sutyrina Olga , Ovchinnikov Semyon , Yuldasheva Aliya , Lyzhin Boris , Sofronov Ivan , Pico Yamid 
Published: November 2022

Abstract
The electrical submersible pump (ESP), an efficient artificial lift method, was developed to increase production rates from wellbores (Bates et al. 2004). As the number of ESP installations increases annually, there is a greater awareness of their environmental impact and a growing responsibility to reduce the associated carbon footprint because frequent workovers to replace failed ESPs are primary sources of carbon dioxide emissions from the oil and gas industry. Because of this, companies are beginning to pursue cost reductions and look for methods to mitigate the consequences of production. Systems for monitoring ESP performance in real time are currently being developed on the basis of data analysis to detect potential problems in advance.
This paper presents a digital solution for tracking ESP performance that includes an automated data processing pipeline and the use of statistical metrics to analyze the dynamics of failure and run life at the system node level. This comprehensive analysis helps diagnose problematic equipment nodes using developed web applications. The recommendation system determines the most-reliable ESP configurations under the necessary operating conditions.
Enhanced Oil Recovery Techniques to Develop Mature Oilfields
Authors: Isaev Anatoliy Andreevich , Takhautdinov Rustem Shafagatovich , Yunusov Irek Miyassarovich , Novikov Maxim Gennadievich , Malykhin Vladimir Ivanovich 
Published: November 2022

Abstract
Enhanced recovery of residual deposits from the mature fields with steadily increasing water cut is considered one of the most important tasks in oil field development. This is particularly relevant for terrigenous deposits of minor oil fields under the third and fourth stages of development, when the water cut may grow but fail to reach the expected stabilization asymptote, thereby bringing the issue of economic feasibility of further operation into discussion. Efforts to solve these problems through the conventional techniques of cyclic injection (huff ‘n’ puff process), inflow/conformance control, filtration flow modification, and polymer flooding are generally unsuccessful.
The paper reviews information on methods of steadying oil production, reducing water cut and preventing its growth, as well as on a set of measures to improve the efficiency of developing the Zarechnoye field in the Republic of Tatarstan.
Mature Fields Oil Production Enhancement by Pulse Code Testing
Authors: Ganiev Bulat , Lutfullin Azat , Karimov Ildar , Mukhliev Ilnur , Krichevsky Vladimir , Zinurov Linar , Mingaraev Ramil , Gulyaev Danila , Farakhova Rushana 
Published: November 2022

Abstract
Over the course of many years of production, fields that were producing for decades begin to reach mature stages. Most producers at these oilfields have high watercut, and these negative effects the oil production. However, the reason why the wells have a high watercut may not even be related to injectors which cause reservoir flooding, or to bottom-water coning. Typically, the cause of flooding in producers are behind casing and inside casing circulations, tubing leaks, bottom hole leaks, etc., while hydrocarbon reserves around such wells remain unprocessed. After performing water shut-offs on wells with these complications, it is now possible to reduce watercut and also develop poorly drained reserves. The purpose of this paper is to identify "problematic" wells which have high watercut and contain potentially uncovered reserves, which can be fixed by water shut offs to increase recovery factor.
Scure 2-domination in graphs
Authors: Boufelgha Ibrahim , AHMIA Moussa , Guettiche Mourad 
Published: November 2022

Abstract
Let G = (V, E) be a simple graph. A set D ⊆ V is a dominating set of G if every vertex in V \ D is adjacent to at least one vertex in D. D is 2-dominating if every vertex in V \D has at least two neighbors in D. A secure dominating set S of a graph G is a dominating set with the property that every vertex u in V \S is adjacent to a vertex v ∈ S such that (S\{v}) ∪ {u} is a dominating set. In this paper, we define and study a new invariant of domination in graphs which is the secure 2-dominating set. A 2-dominating set S is secure 2-dominating if for every vertex u in V \S, ∃v ∈ (S ∩ N(u)) such that (S\{v}) ∪ {u} is a 2-dominating set. The secure 2-domination number γs2 (G) is equal to the minimum cardinality of a secure 2-dominating set. First, we establish lower and upper bounds on γs2 (G) of a graph and a triangle-free graph. Then we determine the secure 2-domination number γs2 (G) of paths and cycles. After, we study the complexity of secure 2-domination problem by proving that the determining of the parameters value is NP-complete, also for split and bipartite graphs. Finally, we provide an upper bound of parameter in terms of clique number and independent number for perfect graphs.