bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deep Geothermal Well Construction Problems and Possible Solutions
Authors: Gelfgat Mikhail Yakovlevich , Geraskin Aleksandr Sergeevich 
Published: October 2021

Abstract
The geothermal energy is one of the most promising sources of electricity on the planet; it is available almost anywhere on the continents and resources are inexhaustible. The realization of these possibilities requires solving the problems of deep wells (6-10 km) construction, when the lower horizons are practically impermeable crystalline basement rocks. For effective use of the Earth's heat, bottomhole temperatures must be within 200-300°C. World experience of such deep wells construction is very limited, some examples are given in this work.
Known schemes of geothermal energy application requires at least two wells construction - for cold fluid injection and superheated fluid production. The rock - circulating fluid heat exchange in the bottomhole requires drilling of inclined, horizontal, or multi-lateral boreholes and hydraulic fracturing application. Such technologies are widely used in the oil and gas fields, but not in crystalline rocks. The article presents an analysis of the prospects for the geothermal wells construction efficiency increasing by using modern directional drilling systems, drilling with casing, technologies for complications eliminating. The possibilities of using alternative hard rock drilling methods by enhancing the standard formation destruction with drill bits are discussed. These are hydraulic hammers, high-pressure abrasive and fluid jets, laser drilling. A fundamentally new plasma drilling technology is considered. The most serious limitation of alternative drilling prospects is the need of additional "supply lines" to the bottom: high-pressure fluid; electricity; a plasma forming agent, etc. In this regard, options are being considered for the development of continuous drill strings such as coiled tubing, umbilical, flexible composite systems like subsea pipelines. Some of technological solutions for deep geothermal wells construction, and implementation of petrothermal energy schemes for potential projects are proposed.
The paper provides an idea of the geothermal well construction technologies, which can ensure the implementation of advanced geo-energy schemes. The problems of geothermal engineering and possible solutions to overcome them, which will contribute to the development of geothermal energy, as the most effective option for decarbonization, are indicated.
An Example of Building a Petrophysical Model of Unconsolidated Gas-Saturated Laminated Sediments Using Advanced Wireline and Logging While Drilling Services
Authors: Bokarev Anton Yurievich , Yezersky Dmitriy Mikhailovich , Filimonov Anton Yurievich , Dubnitsky Ivan Romanovich , Vorobiev Vladislav Viktorovich 
Published: October 2021

Abstract
Productive deposits of the Turonian age as part of the Kuznetsovskaya Formation are cover the eastern part of Western Siberia (Figure 1), but until recently they were not of wide industrial interest.
Today, most of the gas reserves in Western Siberia are produced in the Cenomanian deposits, which are in the stage of declining production. The productivity of the deposits above Cenomanian layer has been established in many fields where the Cenomanian formations are productive. In general, in Western Siberia in the Turonian deposits, there are more than 3 trillion cubic meters of gas, which allows us to consider them as high-potential sources of gas reserves. The main difficulties in the industrial development of Turonian deposits are reduced permeability, high dissection, high content of clay fraction, high macro- and microheterogeneity of the reservoir, inconsistency of effective thicknesses in plan and section. In turn, the relatively low temperature of the reservoir predetermines the operation of the field in a mode close to hydration (Avramenko et all., 2019).
Under these conditions, a good petrophysical baseline is essential to assess the exploration potential of the assets and design the development of the reservoir. Shaly gas-saturated formations are not a simple object for petrophysical modeling. Adding to this the low quality of the core material caused by the weak cementation of shallow deposits, we get a very nontrivial problem. On the other hand, modern horizontal well development scenarios dictate their requirements for petrophysical models. In other words, the petrophysical model must maintain its stability for any well logging regardless of the well trajectory (vertical or horizontal) and the logging method conveyance (wireline or while drilling).
The authors of the paper carried out work on the development of a universal petrophysical model of the Turonian reservoir, for one of the fields in the region of the north of Western Siberia, based on a modern extended GIS complex.
Application of Machine Learning for Lithology-on-Bit Prediction using Drilling Data in Real-Time
Authors: Zhekenov Temirlan , Nechaev Artem , Chettykbayeva Kamilla , Zinovyev Alexey , Sardarov German , Tatur Olga , Petrakov Yuriy , Sobolev Alexey 
Published: October 2021

SUMMARY
Researchers base their analysis on basic drilling parameters obtained during mud logging and demonstrate impressive results. However, due to limitations imposed by data quality often present during drilling, those solutions often tend to lose their stability and high levels of predictivity. In this work, the concept of hybrid modeling was introduced which allows to integrate the analytical correlations with algorithms of machine learning for obtaining stable solutions consistent from one data set to another.
Propogation LWD Tool Analysing for Better Saturation Estimation in High Angle Horizontal Well Conditions
Authors: Mingazov Airat , Zhidkov Andrey , Nukhaev Marat 
Published: October 2021

Abstract
Multidepth electromagnetic logging tool is considered as traditional measurements of formation resistivity estimation while drilling. When considering data in wells with high angles trajectory, more than 70 degrees, the resistivity measurements could be affected by several factors associated with geological conditions and logging tool specifications. As the result, during water saturation estimation formation properties could be distorted, which will lead to significant effect of reservoir properties assessment and the design of the horizontal well completion.
Within the framework of this paper, various methods of influence on the resistivity readings will be considered, especially with cross boundary effects and reservoir formations with anisotropy. At the same time, propagation resistivity logging technologies while drilling with interpretation and boundary propagation technologies will be observed, which has tilted azimuthal oriented receivers for geosteering service of horizontal wells and additionally helps with take into account of boundary enflurane on standard resistivity logging.
Survey Management During Geosteering
Authors: Sabirov Ilnar Nailevich , Kristya Anton Vladimirovich 
Published: October 2021

Abstract
Geosteering is usually responsible for addressing geological uncertainties, such as the uncertainty in the position of the horizon structure or the structural dip angle. During drilling, the directional survey measurements are taken as true, whilst the uncertainties related to the instruments are not considered. Measurement errors cannot be completely excluded, but they can be reduced to a minimum (reducing the "ellipse of uncertainty" of measurements) by considering the variability of the Earth's magnetic field and the influence of the external factors on the tool (by employing quality control and correction of directional measurements), as a result, reducing the risks of crossing the fluid contacts by the wellbore.
This work is devoted to the methods of detecting and minimizing the inclinometer measurement error while drilling, as well as the application of the results for geological support of drilling. The article describes the principle of the methodology for correcting the inclinometer measurements while drilling and indicates the cases in which the correction method is applicable. The paper considers the prerequisites for using the measurement quality control method and tools to reduce the measurement error in these cases. The possibility of using the method of geomagnetic referencing IFR, as well as methods for correcting measurements of the telemetry system BHA Sag and MSA, to fulfill geological tasks is considered.
This paper provides an example of quality control of directional measurements after drilling a well with an extended horizontal section. In the course of the work, the values of measurement errors along the vertical and lateral were established at a large deviation from the wellhead of the considered well. Attention is focused on the analysis of the identified inclinometry errors, their consequences and impact on the geological drilling of the wellbore and considered an example of improving the quality of geological support using the method of correcting directional measurements while drilling.
Sectorial Scanning Electromagnetic Defectoscope: The Next Stage in Well Integrity Diagnostics
Authors: Ganiev Bulat , Lutfullin Azat , Karimov Ildar , Shaydullin Rinat , Nagimov Vener , Volkov Maxim , Vdovin Alexey , Trusov Alexander , Sviridov Alexander , Elkadi Antoine 
Published: October 2021

Abstract
The paper presents a new technology for the oil and gas industry for azimuthal electromagnetic scanning of the first tubular wall defects, the basis of which is a small-sized sector scanning tool that measures the pipe wall thickness. The paper presents the results of laboratoryand well tests, as well as the early field surveys using this technology. These constitute thebasis on which the actual sensitivity of the technology and its prospects in diagnosing well integrity are determined.
Remote Bed Boundary Detection Tool Data Interpretation Without Special Geosteering Support to Drill Horizontal Wells
Authors: Nazipov Danis , Shpakov Pavel 
Published: October 2021

Abstract
Today, one of the most modern and successful geosteering methods in terms of net to gross value (NTG) is a proactive geosteering.
The purpose of this article is to share the experience of using Remote Boundary Detection Tools to solve various geological problems and describe the ways of using the data from it.
The method provides the ability to detect the approaching boundary (usually reservoir top) with resistivity contrast before entering it with the bit or BHA sensors. It allows to adjust well trajectory proactively and, therefore, increase Net to gross ratio.
The article shows the ways to implement global experience in horizontal wells drilling and proposes ways to reduce the cost of well construction without elimination of High-Tech equipment in BHA.
The article explains the methods of interpreting the output data from the tool that can determine the approach to one or several boundaries with resistivity contrast.
Application of Artificial Neural Networks for Processing and Interpretation of Data from a Scanning Magnetic Introscope
Authors: Kosarev Victor Evgenevich , Yachmeneva Ekaterina Anatolevna , Starovoyto Aleksandr Vladimirovich , Kirgizov Dmitrii Ivanovich , Mukhamadiev Rustem Ramilevich , Sudakov Vladislav Anatolevich , Akhmetov Bulat Feliksovich , Savlenkov Aleksandr Borisovich 
Published: October 2021

Summary
This paper presents the efficiency of using artificial neural networks for solving problems of processing and interpreting geophysical data obtained by scanning magnetic introscopy. Neural networks of various architectures have been implemented to solve the problems of processing primary material, searching for well structure objects,identifying casing defects. The analysis of the capabilities of neural networks in comparison with mathematical algorithms is carried out. To test machine learning algorithms and mathematical algorithms for processing, visualizing and storing the results, a software shell was created in which all tasks are solved using a set of tools. It was found that the use of artificial neural networks can significantly speed up the process of data processing and interpretation, as well as improve the quality of the results in comparison with individual mathematical algorithms. Nevertheless, the use of mathematical algorithms in solving some problems gives consistently better results. In particular, the problematic aspects were identified at the stage of interpretation when identifying defects. This is due to the presence of conventions in the isolation of defects by the operator at the stage of preparing data for training neural networks, which is a subjective factor and requires a deeper study.
Integrated Geomechanical Modeling and Hydraulic Fracturing Design: From Particular Cases to the Overall Result
Authors: Samoilov Mikhail , Pavlov Valeriy , Pavlyukov Nikolay , Timirtdinov Aleksandr 
Published: October 2021

Objective and scope
The objective of the work is to present an adequate workflow for conditioning geomechanical data and hydraulic fracturing design, adjustment and simultaneous verification of a MEM and hydraulic fracture models. These approaches are relevant for greenfields and also can be used when changing field development systems: from vertical fracked wells to a system of horizontal wells with multistage fracs.

Methods, techniques, and process description
The paper provides examples of issues in hydraulic fracturing planning due to poor attention to the reliability and robustness of geomechanical data. Given the critically of data quality, the authors describe a holistic approach used in collecting, analysing and conditioning data for building a MEM (1D; if necessary, 3D) as the basis of a frac design.
Mini-frac is considered not only as a tool for setting the hydraulic fracturing design parameters, but also as a source of data for cross-calibration between the MEM and the hydraulic fracture models. Case studies of various HF models will demonstrate the influence of MEM-and-frac uncertainties and the tools for considering them in practical HF modelling. An approach to systematic clustering of input data for HF designs is described. The importance of measuring the fracture heights is stressed as a source of data for cross-calibration of HF and GM models.

Results and conclusions
The correct sequence of work, data consolidation and successive data refinement helps to maintain the database of elastic and strength properties of various target reservoirs, which proves the demand for core analysis and well logging, as well as geomechanical modelling. The improved quality of HF designs leads to better reliability of forecasts and proposed field development and individual wellwork strategies.
The close integration of GM studies and modelling with HF design building enhances the operation culture, accelerates and streamlines the HF model build and validation processes, which can be a pace-setting experience for other oil and gas industries that are GM data users.

Novelty and achievements
The TNNC and RN-CEPiTR teams work in close cooperation and provide GM and HF integration to assess the fracture height in the target reservoirs at the Company's assets in order to improve the quality of HF modelling. The uncertainty influence on the HF design is reducing, so as the risks of screen-out and the risks of breakthrough into undesirable zones.
The approach streamlines the engineering support for the hydraulic fracturing activity and understanding of the fracture parameters as the operations move from single-stage hydraulic fracturing to the optimized field development using horizontal wells with multi-stage hydraulic fracturing.
Evaluation of Accuracy and Uncertainty of ISO 13503-2 Proppant Testing
Authors: Makashova Galina , Yukhtarov Stepan 
Published: October 2021

Abstract
Proppant is one of the key aspects of a successful fracturing treatment and subsequent well production, and its quality is strictly controlled by ISO 13503-2, an international standard for proppant testing. Proppant suppliers, oilfield companies and their clients all around the world rely on the standard measurement procedures and limit values to ensure the quality of a product they produce or use for fracturing operations. ISO 13503-2 prescribes testing procedures; however, the standard does not contain information about uncertainty of final measurements. This information is essential for consistent quality assurance, for resolving inconsistencies between different laboratories, and for comparing properties of different products.
An interlaboratory study was organized to evaluate the precision of ISO 13503-2 proppant testing. Four proppant samples were distributed among proppant quality control laboratories all around the world; 17 laboratories participated in the study. The obtained test data were used to calculate repeatability and reproducibility standard deviations (in accordance with ISO 5725-2) and uncertainty of ISO 13503-2 test data (in accordance with ISO 21748).
The study showed that most proppant parameters measured using ISO 13503-2 methods yielded high uncertainty. For example, for turbidity and acid solubility values, the uncertainty was up to ±50%. Uncertainty of roundness and sphericity values was ±0.1 since the values are estimated by operator, making the test quite subjective. For crush resistance, the highest uncertainty among tested samples, ±40%, was observed for an HSP 30/50 sample measured at 15,000 psi stress. For absolute density, a systematic difference between values obtained using gas pycnometers from different manufactures was observed; also, the equipment differs by repeatability characteristics.
The results of the interlaboratory study allowed estimating the uncertainty of ISO 13503-2 test methods. It was shown that high measurement uncertainty for some critical proppant parameters should be considered for correct interpretation of the obtained test results.
Halite Precipitation in Brine Reservoirs: Prediction and Control by Numerical Model, Optimization of the Fresh Water Treatments and Well Production Regimes
Authors: Andryushchenko Aleksei Dmitrievitch 
Published: October 2021

Abstract
The aim of the work is to optimize the fresh water treatment design, frequency and production regimes (maximize NPV of the well operation) for wells with high NaCl content formation water (brines) production, which are very common for the Eastern Siberia, and forecast productivity index (PI) decline rates and production profiles for the wells by means of halite deposition model for brine flow in porous media united with fresh water treatment model and economic model.
New numerical halite deposition model for brine flow in porous media is developed based on Darcy's law and equation of halite precipitation dynamics from formation water taking into account the fresh water treatments, solubility of descipitated halite in the fresh water and permeability profile. It enables to predict deposited halite saturation (Shalite), dynamic porosity and permeability radially and versus time. Thus, we can forecast PI versustime and unite production and economic models,vary fresh water treatment design, frequency andproduction regimes for the given geological conditions and to determine treatment design, frequency and production regimes that brings the maximum NPV.PI decline rates and exploitation factor are calculated and analyzed for different scenarios of the fresh water treatment design, frequency and production regimes.
These main conclusions are made from the results of the work:
New Analytical Approach to Operational Assessment of Fractured Well Productivity with Variable Permeability
Authors: Yudin Evgeniy Viktorovich , Piotrovskiy George Aleksandrovich , Petrova Maria Vladimirovna , Roshchektaev Alexey Petrovich , Shtrobel Nikita Vladislavovich 
Published: October 2021

Abstract
Requirements of targeted optimization are imposed on the hydraulic fracturing operations carried out in the conditions of borderline economic efficiency of fields taking into account geological and technological features. Consequently, the development of new analytical tools foranalyzing and planning the productivity of fractured wells, taking into account the structuralfeatures of the productive reservoir and inhomogeneous distribution of the fracture conductivity, is becoming highly relevant.
The paper proposes a new approach of assessing the vertical hydraulic fracture productivityin a rectangular reservoir in a pseudo-steady state, based on reservoir resistivity concept described in the papers of Meyer et al. However, there is a free parameter in the case of modeling the productivity of a hydraulic fracture by the concept. The parameter describes the distribution of the inflow along the plane of the fracture. This paper presents a systematic approach to determining of the parameter. The resulting model allows to conduct an assessment of the influence of various complications in the fracture on the productivity index.
During the research a method of determining the free parameter was developed,it was based on the obtained dependence of the inflow distribution on the coordinate along the fracture of finite conductivity. The methodology allowed to refine existent analytical solution of the Meyer et al. model, which, in turn, allowed to assess the influence of different fracture damages in the hydraulic fracture on the productivity index of the well. The work includes the cases of the presence of fracture damages at the beginning and at the end of the fracture. A hydraulic fracture model was built for each of the types of damages, it was based on the developed method, and also the solution of dimensionless productivity ratio was received. The results of the obtained solution were confirmed by comparison with the numerical solutions of commercial simulators and analytical models available in the literature. The advantage of the methodology is the resulting formulas for well productivity are relatively simple, even for exotic cases ofvariable conductivity fractures.
The approaches and algorithms described in the paper assume the calculation of the productivity of a hydraulic fracture with variable conductivity and the presence of other complicatingfactors.The methodology of the paper can be used for analysis and diagnosis problems with formation hydraulic fracturing. The efficiency of the calculations allows using the presented methodology to solve inverse problems of determining the efficiency of the hydraulic fracturing operation.