bluuebunny/crossref_metadata_2025_split huggingface dataset:
Method of Integrated Seismic and Geological Support for Drilling Horizontal Wells
Authors: Samoylenko Ivan Yuryevich , Tarasov Artem Evgenievich , Belousova Natalia Alexandrovna 
Published: September 2020

Abstract
Currently, one of the most widely used methods of extracting hard-to-recover oil reserves in Russia is drilling horizontal wells. Support for drilling horizontal boreholes is based on a 2D geonavigation section using LWD and MWD data, without taking into account 3D seismic data.
In the conditions of development of deposits with hard-to-recover reserves, which have a large number of disjunctive violations and geological uncertainties, there is a need for operational use of 2D and 3D seismic data as a method of increasing the efficiency of geonavigation.
Specialists of the Department of geological support for drilling Of the branch of LLC LUKOIL-Engineering" VolgogradNIPImorneft " in Volgograd have developed a method for using seismic data in the operational mode in the process of geonavigation. The method was tested on the example of drilling and drilled wells and the analysis of the obtained material was carried out, the efficiency of using this method was determined.
Application of the Theory of Clamped Water in the Justification of Water-Oil Contact for the Purpose of Calculating Hydrocarbon Reserves on the Example of Famen Organic Deposits of the Vostochno-Lambeshorskoye Field
Authors: Dorofeev Nikita Vladimirovich , Ananyeva Evgeniya Vladimirovna , Khromova Inga Yurievna , Saetgaraev Almir Damirovich , Sheykina Angelina Fyodorovna , Garifullin Ilfat Ilsurovich , Kuzmicheva Anastasiya Vladimirovna 
Published: September 2020

Abstract
The article describes the theory of "clamped" water to justify the position of the oil-water contact of the reservoir, exposes in detail the experience of applying this theory on the example of an oil reservoir in Famennian organic deposits of the Vostochno-Lambeyshorskoye field of the Komi Republic.
During the field development, geologists have encountered a problem of different oil-water levels established in different parts of the structure, which is determined by well data with a high degree of confidence.
The analysis of reservoir pressure data shows, that the separation of the reservoir into tectonically shielded blocks with different levels of water-oil contact is impossible.
According to the results of seismic facies modeling and sequence stratigraphy, there were not identified any significant channels that could separate the reservoir by area.
The solution to the problem of substantiating the oil-water contact was found by applying the theory of "clamped" water. The idea of this theory is that during the migration of hydrocarbons into the trap, controlled by lithology and faults, there remain the so-called hydrodynamically isolated "pockets" (hereinafter referred to as "pockets") in which the formation water is sealed with oil and the oil-water contact is fixed at the level of the structure bend. The article describes the mechanism for the formation of such "pockets".
In the issue, a new conceptual model of the Famennian reservoir of the Vostochno-Lambeyshorskoye field was created as a layer-uplifted deposit, controlled by lithology, with different horizontal oil-water levels. The oil-water level is gradually increasing from north to south, along the path of hydrocarbon migration from the source rock to the reservoir. Oil-water levels are controlled by structural inflections defined on the maps of the reservoir bottom.
Method of Multivariate Seismic Tomography Based on Stochastic Analysis of Input Data Reliability
Authors: Anisimov Ruslan Gurievich , Finikov Dmitry Borisovich , Silaenkov Oleg Aleksandrovich 
Published: September 2020

Abstract
Seismic tomography is one of the main tools for obtaining a depth velocity model. Its result largely determines the estimated geometry of oil and gas reservoir. Tomography is a deterministic procedure and does not provide an opportunity to assess the reliability of the results. However, in fact these results directly affect the subsequent economic decisions. For this reason, the aim of the current work is to develop a method of multivariate tomography which allows to determine the reliability of the results. The paper considers several factors of multivariance. Factor of input data quality is generally considered and stochastic averages tool is proposed for estimating input data reliability. Typically, input data estimation involves calculating supergathers. Usage of equivalent weights for supergathers accumulation means that all gathers have an equivalent quality but in practice this is far from the truth due to various regular noises. Replacing weights by random ones is equivalent to filtering with random kernel. These means assigning a random confidence levels to input gathers. This allows to generate many realizations of the input data for inverse problem. Also incorporation of tomography smoothness parameters variation to inverse problem is proposed. Such approach differs from traditional ones where these parameters are set by a specialist based on purely personal ideas. All together this allows to generate many realizations of depth velocity model and estimate its reliability. The proposed method of multivariate tomography doesn't use the known statistical distributions of the input data errors, thus, it is the most general and realistic. Its result can be utilized in the assessment of economic risks.
Development of Hazard Assessment Matrix for Wells as an Industrial Safety Assurance Method When Designing Oil and Gas Well Construction
Authors: Shirieva Nadezhda Sergeevna , Shiriev Artur Kamilevich , Tlyasheva Rezeda Rafisovna , Kafisov Fanil Shamilievich 
Published: September 2020

Summary
The article considers statistical data on accident rate in oil production: types of accidents, accident distribution over constituents of the Russian Federation, number of fatalities, incident distribution over constituents of the Russian Federation. Causes initiating fire and explosion hazardous situations on a drill site are studied.
Executed analysis of statistical data clearly demonstrates that accident rate and fatal injuries in the industry still remain at high level, therefore necessity to develop scientifically validated methods for assessment of well hazards from various condition is relevant. In its turn, it will enable to promptly provide preventive measures aimed at assurance of the required industrial safety level.
As drill sites belong to hazardous industrial facilities (HIF), when managing industrial safety, at construction design stage, it is necessary to carry out accident risk analysis in order to identify hazards and undesired events.
According to the analysis of problem statistics, criteria that influence on occurrence probability of problems initiating fire and explosion hazardous situations, as well as the factors, on which severity of accident consequences depend, are determined.
As a result of the work executed a method for calculation of quantitative risk assessment indices that considers well construction conditions is proposed on the basis of the developed well hazard level matrix. The proposed approach can be applied to forecast risk level for any territory when using initial data on accident rate of the specific field or group of fields.
Automated Geosteering While Drilling Using Machine Learning. Case Studies
Authors: Denisenko Ivan Denisenko , Kuvaev Igor Andreevich , Uvarov Igor Borisovich , Kushmantzev Oleg Evgenievich , Toporov Artem Igorevich 
Published: September 2020

Abstract
Today's oil & gas industry faces a number of different challenges. Drilling activities are ramping up due to an increase in hydrocarbon demand combined with a reduction of easy-to-recover reserves. Horizontal drilling is growing and has become an integral part of field development. The geology is becoming more and more complex requiring drilling through dense layers targeting thin-layered reservoirs with lateral changes and anisotropy. In recent years, companies have been looking at the ways of optimizing drilling costs by increasing efficiency and process automation. This has been a driver for many companies to stay profitable and efficient in the market.
One of the areas of interest for process automation has been a geosteering. Geosteering is the real-time adjustment well trajectory while drilling to maximize effective footage in the target zone. In this paper, innovative new approaches to automation of the geosteering process will be discussed. This approach has been successfully tested and deployed in several leading O&G companies.
The main objective of automated geosteering is to optimize horizontal well placement while freeing up time operational geologists had spent doing routine work in order to focus on complex and more intense tasks as well as the reduction of operational errors related to human factors. This paper will provide details on several automated geosteering algorithms. They have been tested successfully on large numbers of wells. The results of automated geosteering were as close as 90% to the manual interpretations done by geologists. When the results diverged, the geologists often "agreed" with the interpretation proposed by the algorithm.
TIV-Anisotropy in Geomechanical Modeling for Planning of Hydraulic Fracturing at the Kharampurskoye Field
Authors: Pavlyukov Nikolay , Pavlov Valeriy , Samoilov Mikhail , Prokhorov Alexey , Korolev Aleksandr , Yagudin Radik , Kamionko Maria , Aleksandrov Aleksandr , Savchuk Danil 
Published: September 2020

Abstract
The choice of the optimal trajectory of horizontal and directional wells, the placement of frac-ports for multistage hydraulic fracturing, taking into account prepared input data (using geological and geomechanical modeling with the rock properties anisotropy), provide optimization of hydraulic fracturing operations and field development. Formation T contains more than 3 trillion m3 of gas, and is already an object of close attention of the largest oil and gas companies. The unique character of the object is due to the high reservoir compartmentalization of the collector and low permeability. Therefore, the main development strategy for the reservoir is to drill low-angle and horizontal wells, followed by multistage hydraulic fracturing. The main goal of multistage hydraulic fracturing is to join productive intervals and at the same time avoid undesirable fracture breaks into neighboring layers. To achieve this goal, several tasks were solved: creation of a petrophysical and geological basis for geomechanical modeling, creation 1D and 3D geomechanical models taking into account the rock properties anisotropy due to the high layering of the reservoir, and preparing input data for hydraulic fracturing design.
For the qualitative creation of the geomechanical model at the observation wells of the field, an expanded complex of special well logging studies has been performed, borehole measurements of reservoir pressure and minimum horizontal stress have been carried out according to the results of stress tests, core sampling and research to determine petrophysical and mechanical properties. The analysis of the obtained information revealed the features of the stress state along the section and reservoir area, which were taken into account in the design of hydraulic fracturing. Geomechanical modeling was carried out in a uniform work procedure, which made it possible to unify the result, improve the quality of calculations and forecast parameters for horizontal wells.
Experience with 6/10 and 10/14 Mesh Size on Mid-Permeable Reservoirs
Authors: Chaplygin Dmitry , Khamadaliev Damir , Chernyshev Alexey 
Published: September 2020

Abstract
One of the engineering tasks of hydraulic fracturing design is the correct selection of the propping agent. Ceramic proppant, which is used in most fields in Western Siberia, makes a proppant pack that is several times more permeable than the formation (sometimes even 1000 times). However, the gelling agent used for treatment, depending on the size of the proppant, reduces the permeability of the proppant pack from 2 to 5 times. However, workover operations after hydraulic fracturing and during production period has a significant colmatage effect on the near-wellbore zone and can significantly reduce the productivity of the well.
A common practice in the fields of Western Siberia is to prop a fracture at the near-wellbore zone with a proppant of mesh size 12/18. Despite a small difference in the calculated skin factor, the analysis of operations at the Salym group of oilfields shows a significant change in the production decline rate on wells with 16/20 and 12/18 mesh size propping agents.
Engineering group of the Salym group of oilfields conducted trials on hydraulic fracturing treatments with a mesh size 10/14 and, after successful results, 6/10 proppant. The treatment results, lessons learned and the analysis of production of these wells is the scope of this work.
Practical Experience of Unconventionals’ Multistage Fracturing in Belarus
Authors: Mironenko Kirill Viktorovich , Drabkin Andrew Valerjevich , Shakulja Maksim Ivanovich , Serebrennikov Anton Valerjevich 
Published: September 2020

Abstract
Nowadays, the vast majority of the oil fields of the Republic of Belarus are at the last stage of development. In this connection, the goal of Belarusian oil industry is to search, to explore and to develop ultra-low permeable tight fractured carbonate rocks. Commercial production of such resources is only possible with the use of advanced stimulation methods, such as hydraulic fracturing / multi-stage hydraulic fracturing.
Taking into account the features of tight carbonate rocks, the use of conventional hydraulic fracturing technologies cannot provide optimal results, and therefore, selection of more advanced approaches to hydraulic fracturing is necessary. Selection and optimization of technologies based on theoretical research is not possible, instead it requires practical implementation, and according to our experience, flexibility in decision making.
This article presents the experience of unconventional reservoir development in the Republic of Belarus from 2014 to 2020. We briefly described the main technologies used and how these technologies evolved depending on the resulting operational and economic effect. The technology of repeated multi-stage hydraulic fracturing in an unconventional reservoir is described; the possibility of producing from previously untapped reservoir zones within the horizontal wellbore by creating additional flow channels (hydraulic fractures) was confirmed.
Logging, Well Testing and Microseismic Fracture Geometry Investigations: Mistakes, Lessons Learnt and Challenges
Authors: Salishchev Mikhail Vsevolodovich , Shirnen Alexander Alexandrovich , Khamadaliev Damir Mudarisovich , Chaplygin Dmitry Alexandrovich 
Published: September 2020

Abstract
As the number of stages of hydraulic fracturing along the horizontal wellbore increases, the cost of fracturing starts to exceed the cost of drilling the well. Therefore, the issue of costs optimization for hydraulic fracturing in general become highly important problem.
In this regard, for optimization calculations, it is necessary to operate with such important geometric characteristics of fracture as half-length and height of the fracture, which can be determined by logging, well-testing and micro-seismic studies.
This paper analyzes all types of studies to determine the geometric characteristics of the fracture, except its width. Logging surveys, which have been carried out on vertical and inclined wells, allow to determine with some degree of accuracy the height of the fracture, provided that the conditions of applicability of these surveys considering well azimuth and inclined angle in the zone of fracturing & logging.
Among the logging methods that have been applied to that kind of problem, the highest priority in terms of the reliability of the results obtained is given. Well testing allow us to determine the effective half-length of a fracture, but with some limitations. Micro-seismic studies allow comprehensively and in three-dimensional view to determine the configuration of a fracture in a orientational well or a system of fractures in a horizontal borehole to a certain degree of accuracy.
Acidizing Combined with Heat Generating System in Low-Temperature Dolomitized Wax Damaged Carbonates
Authors: Folomeev Aleksey Evgenyevich , Magadiev Azat Failievich , Khatmullin Arslan Rustemovich , Taipov Ildar Azatovich , Vakhrushev Sergey Aleksandrovich , Galiev Timur Railevich , Mukhametov Flyus Khanifovich 
Published: September 2020

Abstract
The article demonstrates the results of experimental and field studies of the thermal foam-acid treatment technology with the use of water solutions of heat and gas generating system. The potential temperature of the heat-generating reaction upon mixing of agents was estimated in laboratory conditions and the physical and chemical properties of acid solutions were determined. A series of filtration experiments was conducted on treating dolomitized core samples with a basic hydrochloric acid solution.The constant of the rate of reaction between the basic acid solution and dolomitized carbonate rock was determined based on the experiment results.
The article provides a brief analytical overview of world experience of the thermochemical treatment of the bottomhole area. The technology selected for the tests called thermo-foam-acid and implies the step-by-step injection of water heat and gas generating solutions with an addition of surfactants and an initiator into the bottomhole area. The heat-generating reaction is accompanied by the generation of a large amount of heat, gases and hot foamed acid. Heating melts high molecular weight oil compounds, washes oil sheen from rock surface and increases the speed of its dissolution with hydrochloric acid. This foam acts as a diverter for the next portion of active acid and prevents undesired stimulation of high-permeability interlayers and fractures. Surfactants in the acid solution increase its ability to penetrate pores and microfractures. The physical modeling of a thermal foam-acid treatment has been performed.
Arlanskoe (Kashirskian-Podolskian deposits) and Nadezhdinskoe (Famennian stage) fields where carbonate formations are characterized by high and increased oil viscosity, low reservoir temperature, fractured and dolomitized reservoirs were selected as a site to perform field tests. Well operation at these formations is complicated by the precipitation of asphaltenes, resins and paraffins in the bottomhole area.
Solution injection parameters were recorded during treatments based on this technology. The technological efficiency of this treatment was confirmed based on bottomhole pressure and temperature changes during injection operations. Technology efficiency was analyzed and the well flow rate was monitored based on the field test results.
The main stages of this work are shown in Figure 1.Figure. 1Project stages
Advanced Pressure Monitoring Technique – New Horizons of Workover in Russia
Authors: Borisenko Alexey , Parkhonyuk Sergey , Zotov Kirill , Korkin Roman , Kiselev Nikita Vladimirovich , Laptev Artem , Rapeyko Vitaly Tadeushevich 
Published: September 2020

Abstract
In the case of many workover operations associated with fluid loss inside the well or multistage refracturing, one of the most significant uncertainties is the fluid entry point. Starting from uneven depletion of the horizontal part of the well, not knowing the fluid entry point may lead to ineffective well restimulation and absence of any positive effect. In this paper new technique will be reviewed for several locations across Russia.
Implementation of high-frequency pressure monitoring (HFPM) method and based on it, Well Watcher Stim technology, allows locating downhole events caused during well workover and refracturing without interruption of the well stimulation operations. The high frequency pressure monitoring technology is based on automatic processing of wellbore pressure oscillations recorded at the wellhead. The wellbore completion elements such as hydraulic fractures, casing diameter changes or wellbore restrictions serve as effective reflectors for the tube waves. In this paper, we will demonstrate an integrated approach to the utilization of high-frequency pressure monitoring technique, which has served as an engineering tool for fluid entry point validation in the projects all across Russia. The project validated the intrinsic benefits of the new approach in solving uncertainties about the fluid entry point.
The Well Wacther Stim technology requires minimum changes in operational procedures, is easy and safe to install and provides real-time answers that allow the frac engineer to take decisions on location and optimize the re-fracturing process
Selected stimulation approach enables the horizontal well refracturing operation to be concluded within 2-3 days, minimizing well intervention operations and reducing the overall costs and risks of the restimulation. The selected workover approach demonstrates reliable technique for fluid loss extensional control in well workover.
One of the opportunities which is became available with high-frequency monitoring is analyze of conditions of well construction and downhole equipment. That was practically confirmed at a well with completion for multi-stage fracturing. Suspicion about damage of casing or sliding sleeves and corrosion of isolation packers was verified and localized. Further application of Well Watcher Stim made possible to decrease leakages by conventional reservoir dynamic fracture diversion technology and provide multi-stage fracturing with constant control of identified zones.
This paper presents case studies of the technology that was used widely in Russia in the recent years proving reliability of high-frequency pressure monitoring technique. It will provide meaningful insight for the petroleum engineer who will look after solving uncertainties during well workover operations and refracturing.
Support Vector Regression for Petroleum Reservoir Production Forecast Considering Geostatistical Realizations
Authors: Da Silva Luciana Maria , Avansi Guilherme Daniel , Schiozer Denis José 
Published: September 2020

SummaryDecision analysis related to petroleum field development and management phases with complex models can be time-consuming, especially in highly heterogeneous fields. Probabilistic approaches require a large number of simulation runs to cover all possible solutions, and this can be slow. In this study, we present a methodology to include high-dimensional spatial attributes (geostatistical realizations) in proxy modeling, based on support vector regression (SVR), for building risk curves with decreased run time. The proposed workflow accomplished the following: definition of uncertain inputs, such as porosity and horizontal and vertical permeabilities; selection of outputs from the simulator (cumulative oil, water and gas productions) to be mimicked by the proxies; sample inputs to generate scenarios for training and proxy building; and consistency check to evaluate if the proxy model is reliable to mimic simulator output. We then used proxy models to generate risk curves at the final forecast period (7,305 days) as an application. Using the SVR with high-dimension inputs, we show that the proxy was able to provide reliable results with 300 scenarios, which represent 35% less computational effort compared with using only a reservoir numerical simulator. As a result, we can use this proxy to perform a risk analysis with a high level of accuracy [mean absolute percentage error (MAPE) lower than 0.5%] to predict the production curves. In conclusion, we can use the SVR proxy model technique as an alternative to a reservoir simulator when spatial uncertainty attributes (geostatistical realization) are present.