bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of CRM for Production and Remaining Oil Reserves Reservoir Allocation In Mature West Siberian Waterflood Field
Authors: Gladkov A. , Sakhibgareev R. , Salimov D. , Skiba A. , Drozdov O.
Published: October 2017

A Capacity-Resistance Model was matched with production and injection data. Oil and water production splits and remaining reserves were calculated per reservoir unit. The results were validated with history matched streamline and conventional simulation model.

A Capacity-Resistance Model is based on material balance and signal processing of resistor-capacitor circuits where each circuit is represented by injector-producer pair per reservoir. The calibrated model is then combined with fractional flow model fit that is used to forecast water cut. CRM is based on injection and production data and injection splits. Based on this case study an engineer would have access to equations and methods that describe CRM predictive model and comparison with simulation models.

The relative simplicity of CRM model allows to use all available production and injection data in mature West-Siberian waterflood assets with large number of wells and to save time for decision-making on injection redistribution, infill wells, conformance treatment. CRM can be applied before simulation model is built and later the CRM results can be used in history match.

In this paper, we would like to analyze connectivity factors fij of CRM model and see how well the model matches the history.
Perspective Technologies of Reservoir Stimulation, Developed in RUE Production Association Belorusneft
Authors: Lymar I. , Serebrennikov A.
Published: October 2017

In the article we present the results of laboratory and pilot-field tests of advanced technologies of reservoir stimulation aimed at intensifying and increasing oil recovery (EOR) in the conditions of the deposits of the Republic of Belarus at a late stage of development (mature field).

We describe the approaches to the planning and implementation of scientific research studies aimed at solving specific problems.

The results of laboratory and experimental-field tests of such technologies are presented: –acid treatment (AT) using a self-deflecting acid system based on a solution of hydrochloric acid and a composition of viscoelastic surfactants;–acid treatment with nitrogenous acid formulations;–foam thermo-acid treatment;–stimulation of low permeable carbonate reservoirs-collectors by acid-proppant fracturing;–hydro monitor wash out of rocks;–physical-chemical methods of EOR, including wide-scale reservoir stimulation using a system of producing abandoned wells.
Design of WAG Parameters
Authors: Valeev A. , Shevelev A.
Published: October 2017

When an oilfield reaches the final development stage it becomes crucial to plan enhanced recovery methods. In case of low and medium viscous oil in depleted reservoirs it is feasible to use water-alternating-gas (WAG) treatment. Application of the method depends, first of all, on the availability of non-commercial supply of associated gas. To evaluate the amount of gas necessary for the treatment, it is required to estimate the operation's efficiency. The important thing here is to decide on the optimal ratios of the injected water and gas. This work is dedicated to the methods of planning the required ratios of injected water and gas, which can be used for further estimations.

The issue in question is studied using the oilfields in Kogalym region as an example. Analytical evaluations, numerical and experimental simulation were employed to reach the work's objectives. The analytical approach enabled to define the efficient ratio for gas water as a mixture with the minimal mobility or with equal mobility of water and gas in a porous media. The numeric simulation was done using a 2D model of a parallel flow calculated in ECLIPSE software. The laboratory testing was done using a standard porous flow model with dry and wet gas.

As a result, the ratios of injected water and gas were found and compared, recommendations on WAG planning for Kogalym oilfields were issued.

The studies enabled to estimate the need for the gas to be used for the treatment, detailed and justified to different degrees.

Prioritizing the fields depending on the amount of gas reserves enabled to define the ones best suited for applying gas EOR methods.

The novelty of the study is the complex approach to the injected gas water ratio estimation. Comparing analytical, numerical and laboratory studies enabled to adequately consider the parameters affecting the process and to justify the means of sweep enhancing.
High-Pressure Air Injection Laboratory and Numerical Modelling in Bazhenov Source Rocks
Authors: Bondarenko T.. , Khakimova L.. , Cheremisin A.. , Spasennykh M..
Published: October 2017

In this paper, key aspects of constructing a hydrodynamic model of high-pressure air injection into Bazhenov source rocks were highlighted. Most of them are associated with the choice of pseudo-components of kerogen required to describe thermal decomposition and oxidation of kerogen and needed for construction of a kinetic model. Sensitivity analysis was carried out. As a result, high sensitivity of output to the change in the content of components reflecting the presence of kerogen in the formation and its participation in oxidation processes and thermal decomposition was confirmed.

Based on the above, a list of experimental studies was formulated, which must be carried out to determine the parameters of numerical simulation and to evaluate the effectiveness of the high-pressure air injection method.

High-pressure ramped temperature oxidation of kerogen was carried out. As a result, temperature profiles, gas composition, and volume of generated/displaced fluids were obtained. 24.8 g of water-oil emulsion were generated from 92 cm3 of rock. Kerogen in the sample was completely converted, which was confirmed by the results of conducted pyrolysis studies.
OGIP Evaluation by using Specific Drainage Volumes Method: Theory and Case Study
Authors: Kolbikov Sergey , Klimov Mikhail , Ramazanov Rinat
Published: October 2017

The paper describes the features of using the methodology for calculating the specific drainage volumes for estimating the initial gas in place and the formation water volumes invading the formation for gas condensate reservoirs. It is shown that the application of thespecific drainage volumes method is a simple tool in the engineer'shands, allowing to do analysis of the variable drainagevolumes for wells with a minimal set of initial data. The method of specific dynamic volumes allow to determine them foreach producing well and to obtain an integral curve of the drainage gas-saturated volume of the resrvoir and determine the necessary time to drain the entire hydrodynamicallyconnecte gas-saturated volume of the deposit. The knowledge of time when the entire gas-saturated volume of the deposit is envolved in drainage is a necessary basis to justify the application of the material balance methods to calculategas in place volumes. The deviation of the integral curve of the gas-saturated drainage volume from its maximum value makes it possible to assess the water invading volumesin the reservoir in time, taking into account the processes of deformation of the reservoir and the drop out of condensate. Estimation of the gas-saturated pore volume and its reduction in time due to formation water encroachmentfrom the method of specific drainage volumes application allows to reduce the limits of uncertainty for original gas in place volumes(OGIP) and the aquifer parametersin the process of geological-hydrodynamic model history matching.
Frac Size Matters: The Experience of Achimov Deposits Development in Urengoyskoe Gas Condensate Field
Authors: Yudin Alexey , Kubyshkin Dmitry , Lyapunov Konstantin , Zakharzhevskiy Yuriy , Snokhin Alexey , Romashkin Sergey , Prokhorov Alexey
Published: October 2017

Urengoyskoe oil and gas condensate field is second large conventional reserve of gas condensate in the world. Active development of Achimov deposits of this field is in progress now. Specific features of Achimov layers are low permeability, extremely high reservoir pressure and 15-90 meters of Net Pay. Increase of hydraulic fracture frac half-length is main strategy for such environment to optimize well productivity and reservoir fluid recovery. Logistic in tough arctic conditions is challenge here. Method to increase volume of hydraulic fracturing treatment and its effect on well productivity is described in this article.

Some technological tasks were solved to optimize hydraulic fracturing process of Achimov deposits. Pumped proppant volume was a main one. Treatment design was modified to be more aggressive step by step to decrease used slurry volume and enhance fracture geometry. Full laboratory support was provided for this project. Fracturing fluid composition was optimized to provide fluid stability during approx. 7 hours fracturing job as well as fluid friction decrease to meet surface limitations of treatment pressure. Using open channel fracturing technology allowed to optimize logistics in limited space well pads without additional pad construction works and increase job efficiency. The technology provides required size of hydraulic fracture due to proppant pulsing method with proppant consumption decrease.

Before 2014, fracturing treatment size was in a range from 50 to 300 tons of proppant. It did not provide parameters of optimal fracture geometry for pay zones having average Net Pays of 76 m. Increase of frac tanks amount and special frac fleet equipment units combined with permanent technological and laboratory support allowed increasing pumped proppant volume per job up to 400 tons providing high quality of operations. Implementation of open channel fracturing technology was next step in direction of frac job volume increase (up to equivalent of 700 tons of proppant) keeping the same resources and from the same size of well pad. Analysis of efficiency of open channel fracturing technology in comparison with conventional fracturing treatment in wells having similar geological conditions and stimulated with the same slurry volumes was done. It confirmed success of channel fracturing technology using results of the conducted well tests.

Implemented hydraulic fracturing optimization workflow was effective to increase well productivity in turbidite reservoir. To date, sizes of hydraulic fractures created in Urengoyskoe field are one of the largest worldwide. Experience accumulated in Achimov deposits development could be successfully used in other hydrocarbon fields having similar geological challenges.
Specifics of Development, Infrastructure Construction and Production of Oil-Gas-Condensate Fields. Integrated Model Application Experience
Authors: Konstantin Povyishev , Sergey Vershinin , Olga Vernikovskaya
Published: October 2017

This article describes specifics of engineering work performed to develop oil-gas-condensate fields and build their infrastructure facilities. Unlike conventional reservoirs, it is not unusual that oil-gas-condensate fields cannot be produced by the artificial lift method (using electrical centrifugal pumps or sucker-rod pumps). The success of any efforts to increase efficiency of an oil-gas-condensate field development project depends on balanced decisions that need to be made when drilling, building infrastructure facilities and producing both the oil and the gas part of the field. To address this issue, the global industry leaders have developed special tools and technologies that will allow meeting the emerging challenges. The goal of this work is to introduce and adapt new technologies for assessment, planning and management of oil-gas-condensate assets.

The proposed tools and algorithms can be used to identify possible losses and constraints across the entire Reservoir-Well-Infrastructure value chain. Based on analysis of reservoir and wellhead interferences, a balanced system can be created with the highest technical and economic parameters possible.

These algorithms have proven to be highly efficient as is shown by the example of an integrated development concept for Yaro-Yakhinskoe and Novoportovskoe oil-gas-condensate fields.

Yaro-Yakhinskoe oil-gas-condensate field is characterized by a fairly rapid transition from oil production to gas production, with a multi-fold increase in wellhead pressure. Because of the wellhead interference, taking into account the well drilling and commissioning schedule, joint operation of oil and gas wells results in a significantly lower production plateau and, consequently, poor economics of the project. Such integrated approach has allowed the field operator to come up with a fluid gathering and treatment system configuration that ensures a profitable return.

In case of Novoportovskoe oil-gas-condensate field, without an integrated Reservoir-Well-Infrastructure model the operator was failing to make consistent production and development decisions. Analysis of the reservoir and wellhead interference has identified the risks of not achieving the design wells flow rate numbers which would make the project uneconomical. Once the Reservoir-Well-Infrastructure model was developed the field operator could make targeted steps to ensure the desired field production performance.

Capabilities of the integrated Reservoir-Well-Infrastructure model are not limited to the conceptual engineering stage. At present, mechanisms are being developed to use this model for day-to-day monitoring and planning of production activities, engineering of gas lift operations, balancing of reservoir pressure maintenance and gas re-injection system.
EOR Miscible Gas Project in Oil-Gas Condensate Field
Authors: Glavnov Nikolay , Kuntsevich Vitaly , Vershinina Maiia , Penigin Artem , Badgutdinov Ruslan , Perevozkin Igor , Bazhenov Dmitrii , Shorokhov Aleksey , Garipov Ilnar , Ushmaev Oleg
Published: October 2017

The development of oil rims is usually accompanied by the production of a significant amount of associated gas. It is often a positive monetization through sale or generation of electricity, due to the remoteness of oil fields and/or consumers.

This work provides experience in carrying out a technological assessment of the implementation of the miscible displacement in the oil rims by rich gas, with the simultaneous injection of dry gas in the gas cap for one multizone oil field of Western Siberia.

The oil rims in the field are presented by the rims of the edge and the underlying type. The producing gas in the field is reasonably dry, with about 10% of the molar C2-C4 concentration, which prevents miscibility of gas and oil in the reservoir. In the comprehensive preparation of gas, there is a technology for the allocation of the intermediate group of C2-C4 and C1 methane, which allows the further gas to be obtained by another gas composition that satisfies the pressures and temperatures conditions of the reservoir.

The base field development plan of oil rims includes the gas return to the gas cap of the reservoir of the total amount of gas produced. This development strategy to increase the level of oil production is achieved only at the expense of maintaining the reservoir pressure. More oil can be obtained through the organization of miscible displacement by rims, by increasing the proportion of mobile oil in the reservoir (reduction of residual oil saturation) and reduce oil viscosity.

Increased detail calculations of phase and component behavior in the reservoir when changing pressure and component concentration fields was achieved by performing compositional simulation, the major task of which is to correct the forecast performance for oil and gas with optimization and selection of an effective strategy for gas cycling-process in the field.

The article describes the basic steps to build and configure compositional model, assess the effectiveness of implementation miscible displacement and its infrastructure constraints based optimization, as well as the results of the comparison of accounts with similar projects worldwide. Based on the performed calculations identified potential to increase oil recovery and improve the effectiveness of field development.
Assessment of Drained Gas Reserves in the Process of Gas and Gas Condensate Field Operation in Water Drive
Authors: Glumov Dmitry N. , Sokolov Sergey V. , Strekalov Alexander V.
Published: October 2017

The most common method for determination of drained gas reserves is a method based on the solution of material balance equation. In case of gas drive, this equation can be solved quite simple and clear. In case of water drive, the application of classic approaches on the basis of solution of material balance equation is quite complicated. Usually these approaches are not used. The alternative approach was suggested within the framework of this paper in order to develop an express method for determination of drained reserves at water drive. This approach allows to identify the amount of invaded water in the accumulation and to estimate drained gas reserves.
Integrated Laboratory Research Procedure for Core Cavernous Samples
Authors: Vahrusheva I. A. , Gilmanov Ya. I. , Nikolaev M. U. , Zagidullin M. I.
Published: October 2017

Evaluation of storage capacities with a separate evaluation of vuggy components of porous-vuggy reservoir rocks is quite complicated with the use of conventional logging methods. The use of nuclear-magnetic logging (NML) makes it possible to increase the reliability of evaluation of storage capacities of such reservoirs, but to adjust algorithms for NML interpretation, it is required to perform petrophysical study of core, which in turn are complex for practical implementation under the laboratory conditions. The solution of this issue requires an integrated approach and leads to development of integrated methodology of core studies. Two methods are used as a basis: X-ray computed tomography (X-ray CT) and laboratory nuclear magnetic resonance studies (NMR).

At the first stage of the research, X-ray CT method is used to determine the cavernosity in the available whole core, on which the targeted zones are identified, and then whole core samples (100mm) are prepared. After that 100mm samples are extracted, conventionally tested to determine gas and liquid porosity, reextracted, and then samples of 50mm in diameter are drilled out to be compatible for testing in NMR-spectrometer (relaxometer). 50mm samples are restudied with the use of X-ray CT method to determine gas and liquid porosity at saturation with formation water or kerosene, after which a complex of studies is performed in NMR-spectrometer (relaxometer) to determine the total porosity by using NMR method, to identify cavernous porosity and to specify transverse relaxation time boundaries for caverns, T2cav. cutoff which are the values separating the cavernous porosity from the matrix porosity obtained by NMR curves of transverse relaxation time distribution T2. Ultimately, the methodology is based on the knowledge of cavernous porosity value, obtained by X-ray CT method on NMR curves, as a result of which it is possible to determine the value T2cav. cutoff, which can be used for determination of cavernous porosity on NMR curves. Additional methods of petrophysical studies (extraction, gas and liquid porosity) are required to obtain additional reference data on the properties of studied core samples.

The distinctive feature of this work is the study of the method combining laboratory X-ray CT and NMR, to examine oversized cavernous core samples of 50mm with the suggestion to use method based on the developed design for retention liquid in the caverns during the laboratory NMR studies, on which application for a patent was made (invention). Conclusions on the good potential of the suggested methodology were made; a list of practical remarks for further works and improvement of suggested method of laboratory studies was prepared and includes the following: design modification, account of "undesired" components in the NMR results, optimization of studies consequences.
Experimental and Theoretical Study of Microstructural Wettability of Oil and Gas Reservoirs
Authors: Mikhailov N. N. , Motorova K. A.
Published: October 2017

Wettability of the rock surface is an important parameter. Wettability of the rock surface is a key parameter which determines the development efficiency of any field. Effective solution of such problems as evaluation tasks of reservoir properties, simulation of two-phase filtration processes, determination of oil recovery factor, substantiation of formation and bottom oil area stimulation methods is associated with the adequacy of the existing concepts of wettability determination and the real wettability of the formation. However, the established ideas about wettability, laid down in standards and techniques, were based on research conducted in the last quarter of the XX century and currently need to be updated, as it was based on homogeneous type of wetting. Thus, substantiating of the new perception about wettability and determination methods is an actual task for effective enhancement of oil and gas fields development. In this paper the results of theoretical and experimental studies of the effect of the pore space microstructure on the hydrophobization of oil and gas reservoirs are presented. A new type of heterogeneous wettability – microstructural wettability, and a possible mechanism of formation is described here. The mechanism of the microstructural wettability formation demonstrates that hydrophobization of the inner pore space in mixed wettability can be associated either with large or small pore sizes. It was proven experimentally that the process of hydrocarbon adsorption depends on the shape, size, and distribution of pores, the mineralogical composition (particle composition and size, presence of clay), as well as on the time of contact of hydrocarbons with the inner pore surface. The concept of the hydrophilic nature of rock prior to the migration of oil into it can be considered as accurate. However, as was shown in the experiments, oil can present in the small pores (up to 10 μm), which is especially significant for the carbonate reservoirs.
Evaluation Method of Influence of Catalyst Precursors on Initiation of In-Situ Combustion and It's Dynamics
Authors: Sadikov Kamil , Larionov Victor , Varfolomeev Mikhail
Published: October 2017

The growing demand for energy requires alternative technologies for the development of new deposits with tar sands and heavy oil, as well as the rehabilitation of depleted, abandoned deposits. Combining all the advantages of thermal methods, the method of in-situ combustion in the presence of catalyst precursors caused interest in petroleum industry due to the possibility of upgrading or primary refining of heavy oils directly in the reservoir.

This article describes an experimental method for studying the effect of catalyst precursors on initiation of in-situ combustion of heavy oils. Thermograms in air atmosphere (combustion curves) for oil-saturated sandstones from Permian deposits in the presence of different precursors were obtained. As a precursor, resinates of copper, cobalt, iron and nickel were used. The possibility of evaluation the catalyst effect on the initiation of in-situ combustion was shown.
New Take on Mechanical Core Testing Methods and Results Interpretation for Geomechanical Rock Properties Evaluation
Authors: Zinovyev A. , Kostina A. , Maximov D. , Korelskiy E. , Samohvalov A. , Strakhov S. , Kharchenko A.
Published: October 2017

Within the framework of the article, detailed comparative study of Russian normative documents (GOST) and international standards (ASTM) related to elastic properties and rock strength was done. In the article, strength and weakness analysis of existing methods of core sample testing was done and necessity of their revision was shown. It was demonstrated that rock strength characteristics, such as uniaxial compression strength (UCS) and angle of internal friction (FANG), determined following GOST’s procedures, do not always meet the requirements of geomechanical modelling.

The results gathered within the scope of the study could be used as methodological foundations for triaxial compression tests (TXC). The described technique of core sample testing implies confining pressure values different from those in GOST procedures; this allows specifying the values of UCS, FANG, and elastic constants measured by core sample tests. In addition, an algorithm was developed to determine strength characteristics based on results of reinterpretation of strength failure envelopes, also known as rock strength passport, compiled according to GOST.

The study shows that the proper selection of core sample test parameters such as confining pressures corresponding to reservoir conditions is a critical consideration and is directly linked to obtaining reliable results from geomechanical modelling in the future.
Image Processing and Machine Learning Approaches for Petrographic Thin Section Analysis
Authors: Budennyy Semen , Pachezhertsev Alexey , Bukharev Alexander , Erofeev Artem , Mitrushkin Dmitry , Belozerov Boris
Published: October 2017

The article presents the methodology of petrographic thin section analysis, combining the algorithms of image processing and statistical learning. The methodology includes the structural description of thin sections and rock classification based on images obtained from polarized optical microscope. To evaluate the properties of structural objects in thin section (grain, cement, voids, cleavage), first they are segmented by watershed method with advanced noise reduction, preserving the boundaries of grains.

Analysis of segmentation for test thin sections showed a fairly accurate contouring of mineral grains which makes possible automatically carry out the calculation of their key features (size, perimeter, contour features, elongation, orientation, etc.). The paper presents an example of particle size analysis – definition of grains size class. The roundness and rugosity coefficients of grains are estimated also. Statistical analysis of templates for manual determination of roundness and rugosity coefficients revealed drawback of examined templates in terms statistical accuracy (high dispersion of coefficient for all grain within one template, outliers presence).

In the frame of classification problem the feature importance analysis and clustering of non-correctly segmented grains are handled. The classifier for rock type definition (sandstone, limestone, dolomite) is trained with decision tree method, while the classifier of mineral composition of sandstones (greywackes, arkose) is learnt with "random forest" method. Both classifiers are learnt in the feature space generated from segmented grains and their evaluated properties.

As a result, we proved the possibility to conduct automatic quantitative and qualitative analysis of thin sections applying image processing and statistical learning methods.
Estimation of Abilities of Surface Microseismic Monitoring during Hydraulic Fracturing
Authors: Dyagilev R. A. , Shumilov A. V.
Published: October 2017

This paper deals with methodical aspects of the microseismic monitoring as used to localize cracking which accompanies hydraulic fracturing (HF), and with the issue of recording useful signals from the surface where reception conditions are highly adverse due to strong attenuation of waves. Surface based seismic observation systems are shown to be usually able to record only a low-frequency component of microseismic radiation within the first hundred of Hertz. The comparative characteristic of resolution of methods of absolute and relative microfracture location in relation to the considered situation is provided. It is shown that only relative location is capable to provide acceptable accuracy at layer intersection area. The conclusion shows the major technical, methodical and natural factors which either facilitate increase in informational content of surface microseismic monitoring of hydraulic fracturing, or interfere with unbiased fracturing patterning.
Numerical Modeling of Microseismic Events on the Surface
Authors: Butorin A. V. , Krasnov F. V.
Published: October 2017

The urgency of conducting microseismic studies in the process of hydraulic fracturing is considered in the article.

The increased interest in this area in domestic geophysics is a reflection of the current challenges of the oil industry: an increase in the share of non-traditional and hard-to-recover reserves in the structure of the assets being developed. Increased interest of researchers in the issue of microseismic monitoring makes it necessary to develop methodological recommendations for the most effective positioning of field observation systems, as well as for choosing the most correct method for solving the inverse problem. Achieving this goal is impossible without digital modeling, which will allow, in conditions of a priori known solution, to develop recommendations for optimizing each of the MSM.

Within the framework of the article, the first stage of this large-scale work is considered, which consists in setting up a digital experiment - obtaining synthetic seismograms of MSM.
A Quantitative Assessment Method of the Productive Formation Wettability Indicator According to the Data of Geophysical Surveys
Authors: Akhmetov R. , Mukhametshin V. , Andreev A.
Published: October 2017

The reservoir wettability nature should be taken into account while well logging conducting, reservoir engineering, methods of oil recovery enhancement and intensification selecting with the aim of residual oil reserves involvement into the development.

In this respect, the development of a methodology for reservoirs’ wettability quantitative assessment on the basis of well logging data is very urgent and relevant.

In this article, basing on the analysis of laboratory data on the wettability index and reservoir characteristics, a methodology for quantifying the wettability index from field geophysical data assesment has been developed, and the results of the method application in carbonate reservoirs of the Ural-Volga region are presented.

For the first time, the analytical expressions between wettability and reservoir characteristics are obtained. It is shown that the formation wettability at its microlevel is determined by the average thickness of the residual water film on the filtration channels surface, and at the macrolevel – by the residual water saturation volume of the effective part of the productive strata void space.

A methodology for wettability index by the residual reservoir water saturation volume quantitative assessment was worked out, and the necessary analytical expressions were obtained.

The proposed methodology is as follows: –on the reservoir core samples collection in the laboratory environment, the following parameters are determined: wettability index, porosity, residual water saturation;–using the laboratory core studies data, the dependence diagram of the wettability index on the residual water saturation volume (volumetric moisture content) is plotted;–basing on the reservoir resistivity, determined by the prior to development geophysical studies, the residual water saturation volume of the formation is estimated and, using the graph, the wettability index is determined.

The worked out wettability index quantitative assessment methodology has been successfully proven in the Ural-Volga region carbonate reservoirs. The method allows the wettability degree according to the geophysical data in every layer intersection assessment both in the cross-section and in the deposit area. The information about the reservoir nature and wettability degree will make it possible to proceed more rationally to the development analyzing, controlling, regulating and enhanced oil recovery methods engineering and, as a consequence, to reduce the risks of their practical implementation.
Identification of Inflow Zones in Low-Rate Horizontal Wells by Spectral Noise Loggin
Authors: Aslanyan I. Y. , Minakhmetova R. N. , Pimatyev V. G. , Kozlov A. A. , Kuznetsova A. G.
Published: October 2017

The modern petroleum industry in Russian Federation has been lately focusing on developing fields with complex flow properties typical, for example, to low-permeability reservoirs. Therefore, it is important to identify flow zones in wells, mostly horizontal ones, when producing from such low-permeability reservoirs. This task is complicated not only by the effect of complex well completion components but also by the small specific rates of inflows into the wellbore. The conventional logging techniques do not always yield sufficient information under such conditions.

This paper presents the results of a conventional downhole logging suite supplemented with High-Definition Spectral Noise Logging (SNL-HD) and targeted at determining flow profiles in low-rate horizontal producers. A separate objective was to evaluate the SNL-HD efficiency in identifying flow zones in low-permeability carbonate reservoirs. Upon SNL-HD data analysis, depth-specific broadband noises typical to turbulent flows from naturally fractured carbonate reservoirs into the wellbore were identified.

The proposed technique is illustrated with four case studies performed in an oilfield situated in Krasnoyarsk Region in the south of the Evenk Municipal District. These cases studied dealing with the survey, results of which that application of SNL-HD in combination with the conventional downhole logging techniques helps to identify flow zones and thereby monitor horizontal well production and work out recommendations on well performance enhancement.
Novel Approach for Evaluation of Petrophysical Parameters from Time-Lapse Induction Logging-While-Drilling Measurements in Deviated and Horizontal Wells
Authors: Podberezhny Maxim , Polushkin Sergey , Makarov Alexander
Published: October 2017

Selection of the chemical composition of the mud, as well as an appropriate strategy for the future development of the well, requires knowledge of properties of the invaded zone and reservoir quality. The main objective of this study was to determine the evolution stages and properties of the invaded zone using induction logging while drilling (LWD propagation resistivity) and repeated measurements. For this purpose, numerical modeling of the invasion zone evolution, modeling of the induction logging signals, evaluation of mud/mudcake properties (measured in the lab) and analysis of drilling data were performed.

As input data to simulate invasion zone evolution, the following parameters were used: formation fluid and drilling mud filtrate viscosities; Corey-Brooks constants in phase-permeability functions; formation brine and mud-filtrate resistivity; Waxman-Smits equation constants; mudcake filtration properties and drilling data. All these parameters are measured at the surface level both while drilling and while performing petrophysical measurements.

The invasion simulation enables water saturation and salinity distribution to be obtained in the near-wellbore area at different moments in time. These characteristics are used to calculate resistivity distribution using the Waxman-Smits equation. The obtained distributions are utilized to calculate synthetic induction log signals. Joint analysis of the synthetic and measured signals make it possible to correct the formation evaluation. After the formation properties are corrected, the invasion simulation and induction log modeling is iterated again until the formation properties are found providing the best match between synthetic and measured signals. In other words, the induction time-lapse measurements were inverted to obtain the porosity, permeability and water saturation of the formation at given mudcake parameters. The obtained formation properties were compared against the reservoir properties determined for the neighboring wells with full logging suite and showed good correlation.

The main advantage of the method is the use of additional available measurements such as drilling data and mudcake tests that are usually available on the rig site, but are not applied for formation evaluation. Extra core filtration tests with mudcake growth are used for fine model adjustment. In addition, the method can be recommended to estimate reservoir properties in sidetrack wells that are usually drilled with a limited set of LWD tools (gamma ray and induction logging). The main condition for successful application of the method is a presence of repeated time-lapse LWD induction logs.
New Approach to Interpretation of Hydrodynamic Study of Horizontal Wells Located in Under-Gas-Cap Zones
Authors: Fedorov Aleksei E.
Published: October 2017

One of the main tasks of oil and gas production companies is increasing the efficiency of wells operation while gas-cap oil reservoirs development. In particular, a successful solution of this task can contribute to a significant increasing of production rates of wells located in under-gas-cap (UGC) zones or near the gas-oil contact (GOC) zones with a small thickness of the gas cap, which is in direct interaction with an oil-saturated part of a reservoir.

In such conditions, the task of estimating the thickness of the gas cap, which directly affects the value of the gas-oil ratio (GOR) and the regulation of the well operation mode acquires special importance. In particular, this ensures the growth of well productivity with a low GOR, which allows a substantial increase in oil production and net present value (NPV).

In this paper the new approach to interpretation of hydrodynamic study of horizontal wells by numerical methods in the Saphir software and an analytical method for GOR evaluation are proposed. The proposed solutions allow: To correctly interpret the hydrodynamic studies of horizontal wells located in UGC or near the GOC;To determine the thickness of the gas cap above the horizontal well, to evaluate "expansion" of the gas cap and to correct the map of the GOC distribution;To regulate an operating mode of production wells.
Design of 5 Liner Drilling System for Directional Drilling
Authors: Agishev A. R. , Gelfgat M. Ya.
Published: October 2017

The application of classical field development systems in the modern world is becoming more and more complicated. The global portfolio of oil and gas fields virtually ran short of reservoirs located in favorable conditions for geologists and drilling & completion engineers. New fields are either located in adverse climatic conditions (e.g., Arctic projects) or are faced with various problems related to unconventional reservoirs, complex geological structure, high pressures and temperatures.

One of those problems, which has become a particularly pressing issue in recent years, is the problem of incompatibility of borehole pressures, which causes complications in the well construction: borehole wall collapses, fluid losses and sticking of drilling tools. For the well construction process this means an increased non-productive time (NPT) and extra costs. One of the solutions to such challenges is a liner drilling technology, which is actively used as a means to lower NPT and operational risks.

Liner drilling systems, including those for directional drilling, are available, but for strings 178 mm (7″) and more in diameter. Smaller diameter liner drilling is carried out using directionally-uncontrollable systems, which restricts the application of the technology. In this regard the authors are offering the technology of directional drilling with a 127 mm (5″) liner, which would reduce the rig time and address the above technical problems.

The task is completed by the use of a disposable bottom-hole directional assembly - a drilling bit and a bent-housing positive displacement motor (PDM with adjustable bent sub) and a retrievable telemetry system. The coil tubing (CT) can be used to extract the retrievable telemetry system. All the system elements are available on the market, the article describes the calculation results that demonstrate the possibility of the use of such a system in drilling of deep directional and horizontal wells.
Opportunity in Adversity: A Paradigm Shift in Chemical Stimulation
Authors: Rylance M. , Hoq A.
Published: October 2017

Chemical stimulation has a strong track record of production improvement, and has always adapted to suit ever new environments, regulations and scenarios. From early arsenic based chemical techniques, the approaches have moved on and matured to HF and HCl solutions, and more recently with environmentally friendly additives. However, the pendulum continues to move and due to an increasing impact of conventional acid systems on ageing production infrastructure, facilities and pipelines as well as an inability to commercially support independent intervention and/or flow-back, even these systems are sometimes considered unacceptable.

Fortunately, the industry is now in the privileged position of being able to address these issues, it simply does not yet appear to have fully appreciated this widely. All too often stimulation interventions are reasonably justified on the basis of poor well performance; only to be disregarded when it becomes clear that simplistic deployment and flow-back are not considered available options, due to corrosive stimulation fluid behaviour. However, more recently synthetic acid formulations have removed the majority of these concerns; with neutral pH, inert corrosion behaviour and environmentally acceptable chemistry, they are the ideal answer to the range of issues that have mounted over recent years.

This paper will demonstrate that the oilfield has recently developed the necessary solutions, that when combined together provide for a low cost, environmentally friendly, low impact, integrity aligned approach to well stimulation operations under the majority of conditions. Certainly requiring a multi-disciplinary deployment approach, these new chemistries and methodologies offer the very tantalising prospect of a reinvigorated chemical stimulation business, particularly in mature/high-cost/remote basins. With case histories, process considerations and holistic intervention considerations; the paper will demonstrate the extensive opportunity that is currently simply waiting to be accessed by these techniques throughout the brownfield environment. No longer referred to as "acid treatments", these twenty-first century approaches to stimulation, offer the industry the unique potential to redefine and reclassify the delivery from these operations.

Maximising recovery from existing assets is heavily relied upon in annual wellwork; particularly in challenging commercial environments. While wellbore stimulation can deliver this, historically, the percentage of delivery from intervention has reduced, due to increasing issues related to environmental, integrity and commercial challenges. The deployment of synthetic acids as environmentally, integrity and commercially attractive solutions; offers an opportunity for a complete revitalization of chemical stimulation in mature and commercially challenged basins.
A Case Study of the Verkhnechonskoye Field: Theory and Practice of Eastern Siberia Complex Reservoirs Development
Authors: Chirgun A. , Levanov A. , Gordeev Y. , Lazeev A. , Timchuk A.
Published: October 2017

A number of large greenfields has lately been brought into development in Eastern Siberia, Russia, one of which being the Verkhnechonskoye oil and gas condensate field. There, for the first time in the history of domestic oil and gas production at regional scale, geologists faced a high-mineralized section, where the pore space of productive horizons is partially or fully filled with salt, which defines differential characteristics when developing new assets.

This study highlights the field development in the context of uncertainties, and the risk control strategy. It describes solutions for well operation in low temperature formations and for maintaining the oil-rate plateau using new approaches to development of sections of low formation reservoir properties (FRP) and under-gas-cap zones with the contact reserves of oil.
Optimal Rate of Organic Fertilizer during the Vegetative-stage for Cannabis Grown in Two Coir-based Substrates
Authors: Caplan Deron , Dixon Mike , Zheng Youbin
Published: October 2017

Cannabis producers, especially those with organic operations, lack reliable information on the fertilization requirements for their crops. To determine the optimal organic fertilizer rate for vegetative-stage cannabis (Cannabis sativa L.), five rates that supplied 117, 234, 351, 468, and 585 mg N/L of a liquid organic fertilizer (4.0N–1.3P–1.7K) were applied to container-grown plants with one of two coir-based organic substrates. The trial was conducted in a walk-in growth chamber and the two substrates used were ABcann UNIMIX 1-HP with lower water-holding capacity (WHC) and ABcann UNIMIX 1 with higher WHC. No differences in growth or floral dry weight (yield) were found between the two substrates. Pooled data from both substrates showed that the highest yield was achieved at a rate that supplied 389 mg N/L (interpolated from yield-fertilizer responses) which was 1.8 times higher than that of the lowest fertilizer rate. The concentration of ∆9-tetrahydrocannabinol (THC) in dry floral material was maximized at a rate that supplied 418 mg N/L, and no fertilizer rate effects were observed on Δ9-tetrahydrocannabidiolic acid (THCA) or cannabinol (CBN). The highest yield, cannabinoid content, and plant growth were achieved around an organic fertilizer rate that supplied 389 mg N/L during the vegetative growth stage when using the two coir-based organic substrates.
Fruit Quality, Antioxidant Capacity, Related Genes, and Enzyme Activities in Strawberry (Fragaria ×ananassa) Grown under Colored Plastic Films
Authors: Miao Lixiang , Zhang Yuchao , Yang Xiaofang , Xiao Jinping , Zhang Huiqin , Jiang Ming , Zhang Zuofa , Wang Yuezhi , Jiang Guihua
Published: October 2017

The influence of colored plastic films (red, yellow, green, blue, and white) on fruit quality, antioxidant capacity, and gene transcripts was studied in greenhouse-grown strawberries. Fruits grown under white plastic film were used as the controls. Results indicated that there was no difference in single fruit weight due to colored plastic films in the present study. The colored plastic films had significant effects on sugar and organic acid content. The content of total sugar (SUG) was increased by 10.39% and total organic acid (ACID) was decreased by 16.58% in fruit grown under blue plastic film compared with the controls. Fruit grown under blue plastic film had significantly higher SUG content and lower ACID content than fruit subjected to yellow and green plastic films and had the highest SUG/ACID ratio of 11.46. Colored plastic films had significant effects on bioactive compound (anthocyanin, flavonoid, phenolic) content and antioxidant capacity. The highest level of bioactive compound content was detected under red plastic film. The content of total phenolics, total flavonoids, and total anthocyanin (TAC) in fruits grown under red plastic film was respectively 23.10%, 25.37%, and 74.11% higher than that of the fruits grown under the control. The antioxidant capacities were highest in fruits grown under red plastic film. Fruits grown under red and yellow films had higher sucrose phosphate synthase (SPS) and sucrose synthase (SS) activity than those fruit covered with green, blue, and white plastic films at whole fruit development stages. Acid invertase (AI) activity was high in fruit grown under green plastic film and declined during development. Blue plastic film had mainly increased the FaSPS and FaAI transcript at the green stage, and decreased the expression of FaSS. It is proposed that colored plastic films can regulate the expression of genes involved in the flavonoid biosynthesis pathway, especially FaPAL, FaF3H, FaFGT, and FaMYB10, at half-red and red stages.