bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Approach to Modelling Complex Structure Carbonate Reservoirs using Example of the Central Khoreyver Uplift Fields
Authors: Yudin E. V. , Bagmanov R. D. , Khairullin M. M. , Solovyev A. V. , Churanova N. Y. , Chorniy A. V. , Fursov G. A. , Kurelenkov S. H. 
Published: October 2017

Abstract
When planning development of fractured oil-wet reservoirs one may encounter a number of difficulties associated with the complexity and heterogeneity of their structure, uncertainty in main factors effecting the development: integral wettability of the rock, structure of the void space, presence and location of faults etc. The only instrument allowing taking into account entirely all factors relevant to the reservoir engineer dealing with such objects is a full-scale simultaion model. This paper reviews new approaches to improving quality of simulation models using the example of fields of the Central Khoreyver Uplift (CKU) belonging to the Timano-Pechora petroleum province. When characterizing the carbonate reservoir of the fields the authors have accepted a concept in whichheterogeneities of formation's properties at various levels were considered: micro-level, meso-level and macro-level. -Thin sections studies, results of routine and special core analysis were used to describe the heterogeneity at the micro-level. The results of PLT studies, selective formation flowtests, statistical processing and calculation of NTG ratio from core crossections were used to perform the heterogeneity analysis at the meso-level (well scale). Genetic algorithms of seismic attributes processing and lithofacies analysis were applied for description of macro-heterogeneities. An approach proposed in this paper is based on the concept of binding heterogeneities of reservoir's structure at various levels in the framework of a single model. It has been applied for modelling several small carbonate fields at Timano-Pechora petroleum province. At the opinion of authors the final forecast accuracy for the considered models is a unique achievement for oil-wet fractured vuggy porous reservoirs. Well locations were optimized, a program of well interventions was proposed, oil production plans were adjusted on the basis of the constructed models. The accuracy of made decisions is proven by actual results of wells drilling and operation.
Application of 3D and Near-Wellbore Geomechanical Models for Well Trajectories Optimization
Authors: Alchibaev D. V. , Glazyrina A. Ye. , Ovcharenko Yu. V. , Kalinin O. Yu. , Lukin S. V. , Martemyanov A. N. , Zhigulskiy S. V. , Chebyshev I. S. , Sidelnik A. V. , Bazyrov I. Sh. 
Published: October 2017

Abstract
For the prediction and elimination of complications in the drilling process is considered a number of examples of the three-dimensional geomechanical model and of the near-wellbore model in order to optimize the trajectory and design of the wells. During the well trajectory planning, the key point is to forecast and minimize all possible risks associated with both geological, mechanical conditions and technological parameters. An optimal solution can be obtained with the use of a detailed geomechanical analysis.
It is shown that in a number of cases, the numerical model of the near wellbore zone is more informative, in comparison with the analytical solution. The result of drilling risks minimization with help of geomechanical analysis tools is presented. A number of recommendations on wellbore construction and stability are established of the comprehensive geomechanical analysis. The discontunities that are derived of seismic field analysis are also included in the review.
The image analysis, 1D geomechanical modelling, of seismic field analysis, near-wellbore numerical simulation and full 3D goemechanical modelling were used as a geomechanics tools to optimize "fishbone" trajectory. Microimages help to determine the presence of cavernousness, natural and induced fractures, geological boundaries and bedding planes. Especially useful is a tool for determining the presence of collapse in the areas of kick-off sidetracks. 1D geomechanical modeling helps to determine favorable intervals for shearing and optimal mud density. To assess the risks during the sidetracking operation, a statistical analysis of the actual data was carried out taking into account the spatial orientation of the sidetrack and the direction relative to the currently acting stress state. Stresses and gradients of caving in the intervals of cuts are refined by the near wellbore model.
Influence of the Elastic Moduli Contrast on the Height Growth of a Hydraulic Fracture
Authors: Shel Egor 
Published: October 2017

Abstract
In mostmodern models and simulatorsfor the hydraulic fracture growth, only stress contrast is taken into account correctly. For the distribution of elastic moduli, a simplified model for averaging the elastic characteristics over crack height is used, in which a composition of several media with different elastic moduli is replaced by one medium with average characteristics.
In this paper, a more accurate method for crack opening evaluation is found, which takes into account the contrast of the elastic moduli of rocks. The problem of the elastic-strength problem was solvedwith the apparatus of singular integral equations. The obtained result is compared with the analytical solution for the widely spread averaged elastic moduli model. It is revealed that the averaged model gives a smoother profile of the crack.
The problem is solved within the assumptions of the plane theory of elasticity and the mechanics of brittle fracture. The medium is assumed to be homogeneous in each separate layer, with contrast of Young's moduli, Poisson's coefficients and stresses between adjacent layers. For the brevity, fluid pressure along the vertical contour of the crack is assumed to be uniform, as in the Pseudo3D model. The problem is solved by means of singular integral equations in which the pressure is equal to the integral of the fracture's opening derivative with the kernel of the equation. The contrast of the elastic moduli does not allow an analytical solution of the problem, in contrary to the case for a completely homogeneous media, which has been observed in classical works.
The contrast of the elastic moduli leads to a sharper distribution of the opening in height, in comparison with that predicted by a simplified model of averaged elastic moduli. In media with higher Young's moduli, the actual opening of the fractureis lower, and in media with lower moduli the opening is higher than model ofthe average elastic moduli predicts. Thus, in a multilayered medium, local narrowing in the vertical crack profile is possible, which hinders the passage of proppant into the productive interlayers lying above and below the initiation pay layer. Also, significant deviations are possible for the area of the crack profile, which can significantly affect length due to material balance. To predict the growth of a crack, not only investigations of the productive interval are important, but also the clay bridges separating the target layers, are needed.
Development of 3D Geomechanical Model: Case Study from One Off-Shore Sakhalin Field
Authors: Ershov A. , Eidinov A. , Popova A. 
Published: October 2017

Abstract
In modern conditions, optimal production field development and explotation require detailed and reliable information on the geomechanical behavior of the rock massive. 3D geomechanical model of the field was developed. A technique for its creation and verifying as well as some application results are presented bellow.
On a base of available geological and geophysical data and core analysis data of reference wells was defined the following: distribution of elastic - mechanical and strength properties of rocks; distribution of pore / reservoir pressures; principal stresses orientations and magnitudes.
The resulting 1D geomechanical models of reference wells were calibrated based on the results of existing well tests and special studies, including data on drilling accidents. 3D grid was created on which petrophysical, elastic-mechanical, strength and other data on reference wells were transferred. A 3D geomechanical model of the whole field (from the seabed to the acoustic basement) was created. The model was matched with all available data. The reliability of the model was further confirmed by the results of the "blind test". The essence of the test is reduced to the construction of a three-dimensional model based on an incomplete set of reference wells with further calculation of the parameters of the wells removed from the modelind process and its compareing with the actual ones.
Analysis of fault tectonics, including the determination of the tectonic regime and the identification of active faults, was performed. The source of anisotropy of horizontal stresses was determined. Estimation of horizontal stresses was made on a base of determination of their regional components, which arose as a reaction of the medium to the applied boundary loads. The boundary conditions were defined by the way of matching modeling calculation results with the results of observations. A forecast for the development of fracture zones near the faults was given also.
Laboratory Studies of Sand Control Systems Used for Heavy Oil Production from Unconsolidated Rocks
Authors: Betekhtin A. N. , Kostin D. K. , Tikhomirov E. V. , Nikolaev M. N. , Lyapin V. V. , Misbakhov R. Zh. 
Published: October 2017

Abstract
The paper addresses issues related to selection of sand control systems applied when producing heavy oil from unconsolidated rocks. A sharp productivity reduction was noticed during the operation of wells with filters. A methodology accounting for subsurface features has been developed for laboratory testing of well-completion systems to reduce uncertainties. Damage related to undesirable drop in flow rate was analyzed. As a result, corrections were promptly introduced to the size of filters used in well completions, which led to increased productivity of newly commissioned wells.
Innovative Technologies and Approaches to Interpreting Logging Data in Horizontal Wells
Authors: Shchetinina N. V. , Malshakov A. V. , Basyrov M. A. , Zyryanova I. A. , Ganichev D. I. , Yatsenko V. M. 
Published: October 2017

Abstract
The article addresses the evolution history of interpretation of logging data from horizontal wells in Russia and abroad. Key problems of interpreting logging data are analyzed. It also describes the application of new technologies and approaches that have increased the validity of logging interpretation. The authors substantiate the need to integrate the full spectrum of geological and geophysical information. Further ways to develop approaches are proposed.
Determination of Oil/Water Contact While Drilling by Interpreting Data from the Azimuthal Deep Resistivity Tool under Conditions of Uncertainty Associated with the Measurements of Inclination
Authors: Zaboev Konstantin , Ruzaev Rinat , Mikhailov Alexander , Grechiho Pavel 
Published: October 2017

Abstract
Geological objectives during horizontal well drilling operations are increasingly challenging. The objective during geosteering in uncertain conditions is the determination of the oil/water contact (OWC). Understanding the OWC position is crucial to oilfield production. Typically, the OWC position is determined by evaluating exploration wells. However, there is uncertainty in how it is transposed across a field when faulting is evident or water injection operations are in place. There is additional uncertainty regarding the well position because various corrections can be made to the directional measurements from the survey tools. Therefore, when geologists are faced with the task of holding a well a certain distance from the OWC, it is not always correct to fully rely on inclinometer measurements. The absolute mark can be any mark with a certain probability within the ellipse of uncertainty. This paper presents an example of how a trajectory based on static measurements with a discreteness of 10 m could differ from a trajectory constructed from a dynamic survey with a much smaller sampling rate. The method proposed uses an azimuthal deep resistivity tool to identify and quantify the distance to the OWC.
Tailoring of the Fracturing Technologies to Challenging Geological Conditions of Jurassic Formation of Yamal Peninsula
Authors: Ishangaliev Askhat , Yudin Alexey , Borisenko Alexey , Vernigora Denis , Gromovenko Alexander , Korepanov Alexander , Olender Oleg 
Published: October 2017

Abstract
Novoportovskoe field is one of the largest oil, gas and condensate fields on the Yamal Peninsula. The Jurassic reservoir is the main productive horizon at that field. It contains 50 % of oil reserves and it is described by a 45-meter deposit with a gas cap and bottom water. The main risk during hydraulic fracturing, in the absence of barriers, is the proximity of gas- and water-bearing formations. The hydraulic fracture breakthrough into gas and water zones leads to a significant decrease of oil production rate. The main objective of the described project was a selection of fracturing technologies, which would minimize the indicated risk.
A number of technologies was introduced to control the vertical growth of the hydraulic fracture: polymer-free fracturing fluid to reduce the viscosity and enhance the hydraulic fracture cleaning. The technology of enzyme fluid breaker that enables to significantly improve the retained conductivity of the hydraulic fracture compared to standard oxidative breakers. The efficiency of enzyme breaker does not directly depend on the concentration but advantages of the enzyme breaker increase at low formation temperatures. The safe ball launcher allows minimizing the amount of fluid injected during hydraulic fracturing.
A series of studies was conducted to analyze the hydraulic fracture geometry: Microseismic Monitoring at Multistage Hydraulic Fracturing; Long-Spaced Cross-Dipole Sonic Log, which allows determining the hydraulic fracture height. Production logging tests were performed to assess the productivity and identification of ports with a breakthrough into water- and gas-bearing horizons. The implementation of various technologies and methods of hydraulic fracturing ensured to significantly enhance the well productivity and influenced the field development plan.
The obtaining of a low gas ratio and water encroachment percentage was a key criterion for success of the performed operations. As a result, in most of the wells, the gas ratio does not exceed 500m3/t and water encroachment is not more than 40%. Currently, the enzyme breaker and ball launcher are the preferred methods for multistage hydraulic fracturing in the Jurassic formations of Novoportovskoe field. The well treated with polymer-free fracturing fluid has one of the lowest gas ratio (387 m3/t) and oil production rate of 100 t/day. The ball launcher made it possible to reduce the volume of the injected fluid during hydraulic fracturing by 30% and to decrease the operation time from 5 days to less than 2 days. The approach developed and technologies selected showed a stable growth of productivity and complete applicability of hydraulic fracturing under Jurassic horizon conditions of this unique field.
Stimulation operations under complicated geographic and geological conditions give some opportunities for the oil industry in the Arctic.
Unconventional Basement Reservoir: From Studying to Prediction on the Example of North-Var’yegansky Field
Authors: Kazakova Anastasiia S. , Rykus Mikhail V. 
Published: October 2017

Abstract
As a rule, unconventional reservoirs of pre-Jurassic sequence are characterized by a complex structural and tectonic pattern, sharp variability of net pay thickness and properties. Therefore, using standard approaches often leads to unreliable forecasts. To find effective forecast tools, authors holistically analyze various types of well data and seismic survey, which results in identifying the most efficient tools for studying geological aspects and the way they influence field development, and forecasting.
Stages of this work include identifying productive methods for well correlation, core analises, description of thin sections and well log methods and their matching for the purpose of detecting regularities for various rock types using well tests and well performance data. When data were analyzed, the focus was placed on physical properties of reservoir rocks. Besides, the field structure is studied as a whole unit using tectonic history reconstruction.
One of the main results of this work is a comprehensive study of the geological development of the upper part of the Paleozoic basement on North-Var’yogansky field area for the purpose of a further identification of reservoir extension zones and prediction of well performance depending on rock and void types. Taking into account the new geological image, rock typing is carried out. It is identified that development of rocks with reservoir properties depends on the following factors: primary rock composition, existence of the intake centers of hydrothermal solutions and channels though which they arrived (faults, cracks, fractures) and a set of secondary processes. In the result of this work a complete compliance of well data with seismic survey was achieved. This provided for identification of promising drilling zones and making a plan for geological modeling. Justification of the recommended well logging list and conclusions as to the efficiency of various study methods are important points in studying this kind of fields of the Paleozoic basement.
Nowadays, the discussed approach to studying the Paleozoic basement reservoir is the most appropriate one. In this paper, authors show matching rocks and void properties with field development, which is a top-priority goal for modern geology.
Digital Field as a Field and Production Managment Tool
Authors: Chagirov P. S. , Korobeynikova E. V. 
Published: October 2017

Abstract
Digital Field Data Analytical System is a tool for managing the operation processes of the enterprise, covering a range of tasks to monitor hydrocarbons movement from the bottom of a well to the inlet facilities of the LNG plant. The system allows online monitoring and control of the development and operations at the field by issuing advance alerts about possible complications in the wells and pipeline segments in the gas gathering system. The system is unique because it is based on the integrated approach of the production management and a multidisciplinary team to promptly prevent well and pipeline problems and make decisions on the operating parameters of the wells, pipelines and the entire field. The system allows to respond proactively to possible multimillion risks caused by the failures in the stable operation of the field (including the disruptions in the operation of expensive project facilities), the uninterrupted utilization of the plant's capacity and, as a consequence, the regularity of LNG offloading to tankers.
First in Russia Large-Scale Implementation of the Channel Fracturing Technology in Horizontal Wells
Authors: Yudin Alexey , Sypchenko Stella , Gromovenko Alexander , Romanovskiy Rostislav , Chebykin Nikolay , Serdyuk Andrey , Bukharov Dinar , Faizullin Ildar , Churakov Artem 
Published: October 2017

Abstract
Main producing horizons of the southern license block of the Priobskoe oil field are low-permeable sandstone formations AS10–AS12. Here, horizontal drilling and multistage stimulation (MSS) involving hydraulic fracturing have proved to be an effective way of field development. Full-scale testing of the channel fracturing technology has become the next stage of MSS optimization. This paper is dedicated to analyzing the efficiency of this method based on data from 40 wells.
Centered around creation of channels inside the fracture, the new method of hydraulic fracture allows better reliability of proppant placement without conductivity restraint; this is achieved by pulsing the proppant on surface, and use of fibers. Moreover, the channel fracturing technique provides significant savings in materials needed for a stimulation job – particularly, up to 45% of proppant and up to 20% of fluid – accelerating bringing-in of the as well as reducing the environmental footprint. The screenout risk is mitigated by pulsing the clean fluid and using fibers while using higher proppant concentrations at the same time.
Over the course of three years, more than 240 channel fracturing jobs were executed in 43 wells. This paper contains a detail analysis of performance of the wells put on production with implementation of the new MSS technique, compared to neighbor wells where conventional stimulation techniques were used. The wells are divided into groups, e.g. by fracture direction (transverse and longitudinal) and water content in the area, i.e. water-free sections and high water cut sections. The obtained production data proves that wells stimulated with channel fracturing show at least the same efficiency than wells where conventional fracturing was used, and involve better utilization of less resources.
The project described in this paper is the first experience of mass use of channel fracturing technique for horizontal wellbores in Russia. Lessons learnt from this experience, efficiency analysis, and applicability criteria defined in the scope of this project will help assess the potential of this new technique for other oil and gas fields in Russia.
Mathematical Modeling of Proppant Embedment and Its Effect on Conductivity of Hydraulic Fracture
Authors: Pimenov A. A. , Kanevskaya R. D. 
Published: October 2017

Abstract
The proppant embedment into rock during the operation of the hydraulically fractured well is one of the reasons for the production rate decrease. Most researchers analyze this problem on the basis of laboratory experiments and do not take into account the well production data. The article proposes a mathematical model of proppant embedment, which makes it possible to estimate the change in the fracture conductivity. A joint calculation of the stress and pressure fields is carried out. The stress values are used to check the conditions at the start of proppant embedment. The discussed example shows a decrease in the width and conductivity of the fracture due to the proppant embedment, and the conditions are found under which this effect is significant. Usually, in order to assess the fracture conductivity, well tests are carried out. Using proposed mathematical model together with the well test results, makes it possible to estimate the contribution of proppant embedment to the change in fracture conductivity, as well as to identify additional factors leading to well production rate decrease.