bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Holistic Approach to Improving ESP Reliability and Energy Efficiency at Van-Yogan Field
Authors: Fastovets Andrey , Samoylin Vladimir , Sharafeev Rafael , Yakimov Sergey , Kaverin Mikhail , Firsov Anton 
Published: October 2016

Abstract
The paper describes the methodology and specific action items developed and applied jointly by the operating company and contractor teams to achieve significant improvements in reliability (run life) and reduce power consumption in more than 300 artificially lifted wells equipped with electric submersible pumps (ESPs) in the harsh environment of Van-Yogan field in Russia, Western Siberia. The extended duration of the project, which started in January 2012 and is currently ongoing, offers a unique opportunity to review and analyze the longer-term contribution and efficacy of the various methods presented.
To date, the project has delivered consistent improvements in both energy efficiency and equipment reliability, translating to substantial savings in the lifting costs for the operator. Average pump efficiency increased by 4.3 percentage points (from 60.4% to 64.7%), which is an excellent result considering the average pump flow rate decreased from 240 m3/d to 182 m3/d during the same period due to overall aging of the field. It is widely known in the industry that smaller pumps generally return lower power efficiency figures; therefore more efficient novel pump designs and operating procedures had to be introduced to facilitate this efficiency improvement.
Despite continuously deteriorating well conditions under the adverse influence of scales, corrosion and production of high volumes of free gas and solids through the ESP, average pump run life was extended by 101 days since the project start date (from 335 days at the beginning of 2012 to 436 days at the end of 2015, or by more than 30%). At the same time, Mean Time Before Failure (MTBF) improved by more than 56% over the same period (from 511 to 796 days), decreasing workover costs and deferred production.
The comprehensive approach includes accurate ESP selection to better match well conditions, use of high-efficiency ESP pump and motor designs, flawless field service execution, and continuous monitoring and fine tuning of equipment performance. Inspection of dismantled equipment and failure root cause analysis (RCA) plays a fundamental role to ensure that adverse well factors are properly addressed by ESP design and operating procedures.
Performance Analysis Of Different Formation Testing Technologies In Complex Carbonate Reservoirs Of West Kazakhstan
Authors: Charupa M. , Ramatullayev S. , Mendybaev N. , Zhabagenov M. , Alzhanov A. , Kravets P. 
Published: October 2016

Abstract

Objectives & Scope
The case study presents an application and comparison of different wireline formation testing technology to acquire vital pressure data and downhole fluid samples in tight sub-milidarcy heterogeneous carbonate fields. Examples from Kazakhstan, where tools with different configuration of fluid intake positions and shapes, various flowing areas, are presented to allow us to compare and contrast the performance of each in more complex and challenging reservoir conditions.

Methods, Procedures, Process
First part of the study discusses the comparison between inflatable straddle packer and radial probe in terms of their data quality and efficiency of the acquisition, where both of the tools were deployed to measure formation pressure, conduct downhole fluid analysis and acquire downhole fluid samples. While the second part focuses on comparison between single probe and radial probe, where both of them were deployed in the well together and were intended to get formation pressure measurements in the zones with the lowest porosity.

Results, Observations, Conclusions
Extreme downhole conditions pose a challenge to formation testing, acquisition of accurate reservoir pressure data and representative formation samples have proved difficult in cases of highly heterogeneous low porosity and low permeability reservoirs. In the first part of the study, the performance of the each tool compared with different observations such as: average time to first hydrocarbon, average volume to first hydrocarbon, water fraction content, and sampling and downhole fluid analysis by formation zones and by mobility ranges. In the second part, the study elaborates on pressure survey conducted in tight highly heterogeneous carbonate reservoir, where tool with large flowing area and circumferential flow shows its superiority, thus improving operator's reservoir evaluation. Downhole positions of both tools against formation features, such as vugs, porous spots and anhydrite inclusions, were reconstructed on microimager log.

Novel/Additive information
This case study describes and compares the approaches and methodologies to acquire and perform complex interpretation of critical formation pressure data in heterogeneous carbonate reservoir. The learnings from this successful acquisition and interpretation can substantially improve the reservoir characterization of similar fields worldwide.
Determination of Reservoir Properties and Heterogeneity through Pressure Transient Analysis for a Clastic Gas Reservoir
Authors: Guizada Pablo , Al-Harbi Abdulaziz 
Published: October 2016

Abstract
A clastic gas reservoir, have been characterized of being unconsolidated in nature, as well as its complexity and heterogeneity. Regarding to the ability to transmit fluids, this reservoir is predominantly tight with a wide variation in the permeability range, which confirms its heterogeneity. The depositional environment interpretation suggests the presence of channels running from West to East direction with kind of limited lateral extension. In terms of well completion strategy, most of the wells have been proppant fractured to produce at sustainable rates.
Pressure transient analysis (PTA) has been applied extensively to better characterize and understand the reservoir behavior, well performance and to obtain significant properties of the reservoir. The challenges of this work consisted of performing a critical review of the existing PTA to identify some common behaviors or general trends in the pressure response. Considering the PTA have assessed the same reservoir and that several wells have been completed with similar completion techniques was expected finding similar pressure response behaviors.
This paper presents different cases that have been analyzed through PTA, summarizing common trends, in terms of reservoir behavior and well response that have been observed during the study. The outputs of this study were used as inputs for the simulation reservoir models to narrow the uncertainty in some reservoir and wellbore properties and as inputs for the static model construction to better understand or confirm geological assumptions. The results of the PTA interpretation also helped to successfully drill newer wells away from any geological complexity and achieved the planned target of gas rates.
Wireline Formation Tester Data for Reserves Classification: The Russian Methodology and Experience.
Authors: Khoshtariya V. N. , Martyn A.A. A , Kurdin S. A. , Dmitriev S. E. , Abdrakhmanova L.G. G , Blinov V. A. , Weinheber P. , Ivashin M. D. , Novikov S. V. , Krupeev V. A. , Svikhnushin N. M. , Khaziev M. I. 
Published: October 2016

Abstract
The Russian Federation mandates a Russia-specific reserves reporting and classification system for all operating companies in the country. One of the key classifications thresholds within this system is from C2 to C1. According to the existing definitions moving reserves to C1 category requires 'industrial production' and this has traditionally meant an openhole DST. After much work with operating companies and the regulatory authorities this definition has been expanded to include wireline formation testers. In this paper we discuss some of the recent history behind the efforts that have led to this outcome.
A Methodology for the Refinement of Well Locations During Operational Drilling in Presence of Geological Uncertainty
Authors: Babin V. M. , Vashevnik A. M. , Ushmaev O. S. , Gruzdev A. P. , Pozdneev A. V. , Semenikhin A. S. , Quinones M. Paredes , Flach B. da , Ciaurri D. Echeverría 
Published: October 2016

Abstract
In this paper we present a methodology of automated optimal (in terms of NPV maximization) greenfield development strategy construction that takes into account geological uncertainties of the reservoir. The algorithm is based on ensemble of hydrodynamic models and uses the theory of probabilistic graphical models. The proposed methodology allows making dynamic (in the process of field development) decisions about well grid pattern change on the basis of information obtained from the studies on the oil reservoir carried out with the help of the appraisal wells: appraisal boreholes of the development wells and pre-drilling wells (drilling from current pad to the next one for refining geological targets). The decision of the wells pattern option change does not require any additional calculations.
The proposed methodology was applied for creating optimal development strategy for one of the new assets (on production stage) of JSC "Gazprom neft". The reservoir development is complicated by the set of uncertain parameters related to the complex heterogeneous structure of the collector. The parameters have very high influence on the optimal decision choice. As result expected NPV is increased by 15%.
Palaeozoic Reservoirs Geology Prediction and Exploitation Monitoring Features: Case Study of Tomsk Region Fields, Russia
Authors: Gritchina Vladlena , Kaeshkov Ilya , Nizamov Eduard 
Published: October 2016

Abstract
Paleozoic deposits, characterized by complex geological structure, require a special approach to lateral properties variation prediction. Typical correlation associations and dependencies showed limited relevance of statistical methods and low predictive potential for seismic analysis. Comparable complex structured reservoirs can be confidently predicted by traditional approach of geological similarity.
Regardless of complications mentioned, Paleozoic reservoirs production is effective and close to planned values at the moment
After a logical move beyond slanted well to horizontal ones, it is planned to drill multilateral wells as a next step to reduce uncertainties influence on production and to increase oil production profitability.
Non-conventional informational capacity of exploitation monitoring complex for Paleozoic deposits is shown in the paper in addition. Some examples are introduced and well test data usage for porous and filtration media type selection is demonstrated aiming at hydrodinamic model enhancement.
New Rapid Modeling Technology to Select Optimal Waterflooding Options for Oil Fields
Authors: Rodionov S. P. , Pichugin O. N. , Kosyakov V. P. , Musakaev E. N. 
Published: October 2016

Abstract
The article describes a computational technology to optimize a reservoir development system with known well locations. It includes a number of algorithms for determining the optimal options of setting injection and production wells or well perforation intervals.
The proposed technology is based on a combination of the Lagrange-Pontryagin formalism, the analytical solutions of flow equations, and a "greedy" algorithm. Such an approach to the problem ensures a hugegain in computation time, even for fields with a large number of wells.
The best well perforation intervals were determined in terms of oil recovery or the development system economics, or well perforation intervals in symmetric elements of different well patterns with a nonuniform distribution of flow properties using real fields.
The computational efficiency of the proposed algorithms was studied and their benefits in comparison with existing analogues were demonstrated. It has been found that the algorithms allow to get one of the most favorable options of the development system or well perforation intervals in a practicable time.
4D Geomechnical Model Creation for Estimation of Field Development Effect on Hydraulic Fracture Geometry
Authors: Pavlov Valeriy , Korelskiy Evgeny , Butula Kreso Kurt , Kluybin Artem , Maximov Danil , Zinovyev Alexey , Zadvornov Dmitriy , Grachev Oleg 
Published: October 2016

Abstract
A 3D geomechanical model was constructed to estimate the influence of the initially placed propped fractures and the pressure variation with time in active field development on the stress-state redistribution.
The main task of paper was to research the different parameters influence on stress state condition and especially on possibility of stress reorientation due to field development. In addition, the main purpose of the paper is to fiend impact of acting processes on hydraulic fracturing propagation.
A finite element method was applied to calculate the stress state in a target sector of the oil field. All available seismic data and pertinent well logging data were used to update the geological and hydrodynamic models, and data from hydraulic fracturing, 1D geomechanical modeling, and drilling history were used for verification of the modeling results. In the following paper the reservoir parameters which can be useful for other fields of West Siberia were used.
The 3D geomechanical model was created and used for the stress-state redistribution forecast, taking into account the field development history. The model was built by coupling the geomechanical finite element and compositional numerical reservoir simulator result at two time steps –the initial, virgin state and the current state of the field development.
It has been shown that the change in reservoir pressure has a significant influence on the value of the horizontal stress in the area of interest, whereas the change in stress orientation depends on the reservoir height, layout of wells, field development stage, and mechanical properties of the rock. Near the initial fractures, the fractures themselves have a strong influence on the magnitude and orientation of the horizontal stress.
Plane-Strain Propagation of a Hydraulic Fracture in Porous Media
Authors: Ulkin D. A. , Khodos O. A. 
Published: October 2016

Abstract
Hydraulic fracturing (HF) in a plane-strain environment is addressed by using continuum mechanics. Fracture propagation is expected in quasi-stationary mode (i.e., not account for inertial effects and the fracture width is smaller than its length). Irwin's fracture criterion is used to govern the growth of fracture length. The internal problem of incompressible fluid motion in the fracture is described by Poiseuille's law. Fracture and fluid are propagated independently, so a fluid-free domain (lag) might exist near the fracture tip. The external problem of stress state in the unbounded medium with the fracture is addressed by the linear elastic law. The solutions to the internal and external problems are fully coupled (pressure in fluid is equal to normal stress on the fracture boundary; the half width of the fracture in the internal problem is equal to the displacement of the fracture boundary in the external problem). Fluid leakoff to the media through the boundary of the fracture is addressed by local Darcy's law. Under these assumptions, a system of integral-differential equations is built to address the problem. The equations of the system are analyzed by nondimensionalization and application of the method of similarity. Three modes of fracture propagation are examined, depending on the relative magnitude of the fluid leakoff to the media—no leaks, with predominant leaks, and general. The no leaks and predominant leaks modes are revealed to have asymptotically self-similar behavior to the solution in all physically meaningful cases. In a general case of nonzero in-situ stress, a new self-similar solution exists for the power law fluid injection rate with an exponent 1/3. Symmetry of the system of equations under the group of scaling transformations enables the time dependence of self-similar solutions in explicit form. An implicit conservative difference scheme is used to construct the effective algorithm for a numerical solution to fracturing in a complex plane-strain environment. Verification of obtained results is determined by a qualitative comparison with experimental data and known self-similar solutions.
Modified Approach to Incorporating Hydraulic Fracture Width Profile in Unified Fracture Design Model
Authors: Paderin G. V. 
Published: October 2016

Abstract
Hydraulic fracturing is one of the most effective ways to stimulate oil production. To this end, our study suggests an algorithm of calculating the optimal hydraulic fracturing design based on a modified approach to incorporating hydraulic fracture width profile in the context of unified fracture design (UFD) concept. Vertical propagation of fracture is controlled by the plane-strain problem of brittle fracture mechanics. To determine equilibrium height of hydraulic fracture, we suggest using the Irwin criterion, which implies that stress intensity factor equals the value of fracture toughness in a multi-layered structure. Fracture growth profile is calculated by solving a 2D elasticity problem in the context of three-layer approximation. Calculation of hydraulic fracture length is based on PKN model for power-law rheology fluid and specified proppant concentration schedule based on Nolte model. Injected volume, pumping time and fluid efficiency are determined by iterative solution of material balance equation. Hydraulic fracturing optimization involves selection of parameters of fracturing operation, including injection rate and rheology of fracturing fluid for maximization of dimensionless productivity index.
The proposed model was used to formulate a numerical algorithm for hydraulic fracturing design calculation and its optimization in the context of the above presumptions. This optimization approach further develops the unified fracture design concept and adds to it the advanced model of fracture width profile calculation. The presented algorithm of design calculation and optimization helped to significantly increase the accuracy of hydraulic fracture geometry and net pressure calculations, which is confirmed by comparison with commercial software.
Remaining Oil Characterization through Surveillance Data Analysis for a Mature Giant Sandstone Reservoir in Middle East
Authors: Yong Li , Lihui Xiong , Baozhu Li 
Published: October 2016

Abstract
M reservoir is a mature giant sandstone reservoir in Middle East with more than 60 years' production history, which has been developed via natural aquifer support followed by peripheral water injection of low salinity waters. Understanding of water flooding swept characteristics can significantly improve the understanding of remaining oil distribution. This paper presents a detailed study on remaining oil characterization mainly based on surveillance data.
Firstly, a workflow for remaining oil characterization mainly based on production logs and saturation logs are proposed. Then based on the surveillance data and the proposed method, lateral and spatial distribution of fluid saturation are gained by gridding surveillance data, and a series of predicted saturation maps by layer and by year are generated. And through comparison with saturation maps of different years, habitats of remaining oil are determined, and corresponding development strategies are proposed.
In this study, more than 300 wells with saturation logs and production logs were tested within 5 years for M giant multi-layered reservoir. Maps of every layer of each year between 2012 and 2015in M reservoir for remaining oil saturation and pure oil thickness were generated, and remaining oil spatial distribution are also generated for each year respectively. The remaining oil change of different years illustrate the variability of waterflooding patterns, swept characteristics and waterflooding drive mechanisms. And habitats of remaining oil were also determined, and corresponding development strategy are also proposed.
This study helps determine the locations of new wells and better development and adjustment strategy decision for mature multi-layered sandstone reservoir. Most importantly, the methodology presented can be adopted in other similar multi-layered sandstone fields.
A Novel Cost-Effective Approach for Enhancing Capillary Number while Stimulating Abu Dhabi Tight Carbonate Reservoirs
Authors: Ansari Arsalan , Haroun Mohammed , Rahman Mohamed Motiur , Chilingar George V. 
Published: October 2016

Abstract
Electrokinetic Low-concentration acidizing is one of the emerging technologies where the application of the Low-concentration acidizing is integrated with electrokinetic enhanced oil recovery (EK-EOR) as presented in previous studies [Ansari et al., 2014-2015]. This research focusses on analyzing the effectiveness of the EK LCA-IOR process in Abu Dhabi tight carbonate reservoirs by qualitatively analyzing the improvement in the capillary number and increase in depth of penetration.
Core-flood tests were conducted by saturating Abu Dhabi carbonate core-plugs with medium crude oil in a specially designed core-flood setup at reservoir conditions. After the waterflooding stage, EK LCA-IOR was applied under optimum conditions (1.2% HCl concentration, 1V/cm voltage gradient), where acid was injected and transported by EK to the target producer. Moreover, the capillary number change, Single Energy CT Scan (SECTS) and oil API gravity change results were analyzed in order to observe the effect on rock-fluid interaction to control rock adsorption capacity through interfacial tension and depth of penetration.
Several correlations at reservoir conditions related to acid concentration, displacement efficiency and permeability enhancement have shown that the application of waterflooding on the carbonate cores yields an additional 15-28% oil recovery beyond the waterflooding limit (58%), recording a maximum oil displacement efficiency of 88% and maximum permeability enhancement of 53%.EK LCA-IOR also improves the capillary number by 500% in Water-wet core plugs and 1500% in Oil-wet core plugs, mainly due to a decrease in interfacial tension, increase in crude oil API gravity by 20-40% with an increase in API gravity of about 10-18%. The use of SECT imaging confirmed wormhole orientation and propagation length across core-plugs, precisely delivering the acid front throughout the core-plug and also indicate the decrease in acid adsorption as acid is precisely transported to the targeted production well through the tortuous path.
EK LCA-IOR may offer a feasible option to augment the efficient unswept oil displacement allowing us to save on the OPEX by maintaining decreased power consumption while reducing the acid/water requirement upto 10 times as compared to currently applied conventional EOR methods. This study takes one step forward towards the development of EK LCA-IOR method feasible for complex tight carbonate reservoirs in UAE.
Restriction of Gas and Water Inflow to a Horizontal Oil Producing Well as the Case in the Field of a Name Yu. Korchagin
Authors: Mett D. A. , Suhodanova S. S. , Abraeva T. I. 
Published: October 2016

Abstract
Work is devoted to increase of efficiency of development of subgas oil deposits with the spreading water-saturated horizon. Increase of efficiency is observed due to decrease in volume of intake of gas and water in a production well at preservation enough big rates of selection of oil. The similar effect is reached by side track kickoff in a gas cap and a technology trunk in the water-saturated horizon.
On the basis of the created model, operating modes of the "constraining" trunks, and also an optimum depression in an oil-extracting well have been chosen. At the same time for preservation of equilibrium system the received and drained gas was pumped back in a gas cap, considerable volumes of in passing extracted water were dumped to the water-bearing area.