bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solutions for Drilling Efficiency Improvment in Extreme Geological Conditions of Timano-Pechora Region
Authors: Kamatov Kamal A. , Buslaev Georgy V. 
Published: October 2015

Abstract
The main goal of this paper is conducting of comparative analysis of geological drilling environment and currently used downhole assemblies and tools performance for directional wells construction. Identification of problems while drilling, based on this analysis, should help operators and drilling companies within the region to plan drilling operations more properly, therefore improving drilling and economical efficiency of well constructing in hard geological conditions of Timano-Pechora oil and gas province.
Combination of available surface and downhole data allowed to identify main drilling performance limiter, that being ineffective bit-rock interaction during both rotating and sliding modes of drilling. In order to address this problem, several possible optimization techniques are highlighted, including introduction of new drill bits designs and drilling parameters adjustment, along with development of new downhole tool for better weight transfer from surface to bottomhole in both sliding and rotation modes.
The analysis includes geological description of rocks drilled based on wireline and mudlogging data; drill bits performance and dull grading review; borehole drag value estimation; physic-mathematical model of drilling BHA with weight-to-bit applying tool.
A Cross Link Polymer Sealant for Curing Severe Lost Circulation Events in Fractured Limestone Formations
Authors: Soliman Ahmed Hussein , Fathallah Mohamad Omar , Tobeh Samir M. , Al-Oqab Mohammad S. , Godara Vijay K. 
Published: October 2015

Abstract
Preventing and curing fluid losses in limestone formations is one of the most challenging loss situations to prevent and control. Loss zones are unpredictable, due to large vugular zones and extended and connected fracture structures. Often these limestone intervals are depleted reservoirs. Typically, calcium carbonate pills containing various size distributions are part of the lost circulation armory in reservoir sections. However, results are highly variable and not suitable for large-scale losses. This is distinguished for those situations with the most-severe lost circulation, where chemical sealants may be more applicable than treatments by plugging particles.
The paper discusses about use of a cross-linking polymer fluid treatment that enables operators to cure lost circulation zones in many different applications, providing distinct operational and economic advantages over conventional reactive and temperature activated methods.
The paper discusses the customization of the polymer fluid to have specific thickening or setting time so this loss circulation fluid can be pumped through the existing bottomhole assembly (bit nozzle size greater than 14/32nd) without losing rig time associated with tripping and mixing conventional loss circulation material treatments (LCM). The paper discusses the execution procedures and cautions to be followed to improve cross-link LCM plug placement as well as chances to arrest losses.
Due to biodegradable nature of organic cross-linking polymer plugs, it was used in sensitive reservoirs with minimal effect on the formation. The cross-linked plug or pill, with time and temperature, will break back to a fluid state and may be produced back and circulated from the wellbore.
The discussions in this paper will further reveal the workings and applicability of cross-link polymer fluid to lower costs for drilling fluids, cementing and casing design.
Increasing Productivity of Tight-Gas Wells by More Than 30% with Integrated Approach to Well Construction and Stimulation: Case Study
Authors: Zharikov M. G. , Yaskin I. A. , Ablaev A. , Yudin A. , Zaichenko D. , Tyutikov S. , Mikhaltseva I. , Dobrohleb P. , Sullagaev N. 
Published: October 2015

Abstract
E&P operating companies starting develop deeper production intervals with poorer formation properties due to depletion of the upper productive layers. This is a global trend worldwide. In connection with this it is very critical to optimize well construction and at the same time increase productivity of wells.
Purpose to this work was to increase the productivity of six deviated gas condensate wells drilled for the achimov tight-gas deposits of the Urengoy gas condensate field. Integrated approach to well construction, completion and two-stage stimulation as well as the other technologies were used In order to achieve high production objectives.
Because of the complex geological conditions of the achimov formation associated with the presence of abnormal pressure, narrow driling window, construction and completion of wells was associated with the risk of complications and emergencies.
The paper describes an integrated project approach to planning, construction and the stimulation of the six wells in low permeable gas-condensate formation.
The following technologies had been used during the wells construction: improved design of well completion (retrievable packer, the use of "floating" of the sealing arrangement, the use of the landing nipple below the packer to be able to cut off the producing formation, the use of premium gastight connections). Expanded set of logging (standard logging, NMR (Nuclear Magnetic Resonance), cross-dipole acoustic measurements), a special thee component cement slurry, fracturing technology with high conductive channels, coil tubing service and drilling pipes make up.
Due to integrated approach and new technology involved in well construction and completion of the six-deviated wells, construction time reduced and wells productivity increased by 30%.
Characterisation of Formation Damage Systems from Laboratory Coreflood Pressure Measurements
Authors: Vaz Alexandre Servulo , Maffra Daniel , Carageorgos Themis , Bedrikovetsky Pavel 
Published: October 2015

Abstract
During reactive flows in porous media with precipitation of a solid chemical reaction product, the permeability reduction occurs. The mathematical model for reactive flow in porous media formulated contains two empirical parameters – the kinetics rate coefficient, determining the reaction rate along with reagent's concentrations, and the formation damage coefficient, reflecting the permeability reduction due to the solid precipitation. These parameters are determined from the laboratory coreflood tests with commingled injection of reacting fluids. A routine laboratory method determines the kinetics rate coefficient from expensive and cumbersome reagent concentration at the core effluent; then, the formation damage coefficient is calculated from inexpensive and simple pressure drop measurements. In the current paper, a laboratory method for determining both coefficients from pressure measurements only is developed. The method utilises pressure measurements at the core inlet, effluent and some intermediate core port during commingled quasi steady state flow of incompatible fluids. The data treatment is based on the analytical model for one-dimensional commingled flow of reacting fluids. The formulae for determining the model coefficients from pressure measurements are derived. The intervals for inverse solution existence, uniqueness and stability are established. Good agreement between the model constants as determined by the routine and three-point-pressure methods validates the proposed method.
Uranium Wells: The Proper Selection of Drilling Mud and Completion Fluid Has Changed All the Rules of the Game
Authors: Arthur Gumarov , Akhat Kenjebayev , Denis Verte , Andrey Kharitonov 
Published: October 2015

Abstract
In Southern Kazakhstan, uranium ore is produced by the in-situ leaching (ISL) method. One of the uranium companies, which is producing in this manner experienced difficulties in attempting to increase yield when using bentonite-polymer mud and sodium hypochlorite for removing the filter cake. The company had additional objectives that included increased production cycle time and optimization of drilling technology to reduce well construction time.
The design of a typical well is represented by a vertical shaft 215.9 mm in diameter and up to 500 m deep. The well is cased by plastic pipes with a filter lining in the pay zone interval. Bottomhole temperature is in the 25–28°C range.
A three-stage concept has been proposed to complete these tasks: the use of inhibiting polyacrylamide (PAA)-based mud on the upper nonproductive intervals and a specialized mud system designed for completion of productive horizons, which includes only acid-soluble and biodegradable components. The final stage involves treating the reservoir with a filter cake removal system. Instead of sodium hypochlorite, an organic product has been proposed for the removal of the filter cake, exhibiting many advantages, such as increasing the reaction time for acid formation, deep penetration into the near-wellbore region, and guaranteed treatment of the entire interval, unlike conventional acids, which react instantaneously and are; therefore, inefficient in horizontal intervals.
These technologies were successfully applied and have provided a number of benefits to the customer, including an increase in well productivity by 20% as compared to the adjacent wells and up to a 10-fold yield increase in wells with depleted reservoirs. Time to reaching the design yield decreased on average by 30% while reducing the total well commissioning time by an average of 10%.
This article introduces some aspects of these technologies and the results of their application.
Fracturing Considerations in Mid Permeability Gas Condensate Formations
Authors: Butula K. K. , Yudin A. , Magdeyev I. , Chernyak V. , Samoilov M. 
Published: October 2015

Abstract
Hydraulic fracturing can be widely used for stimulation of gas condensate reservoirs not only in order to improve the Productivity Index (PI) of the well, but also to minimize the condensate banking effect and maximize recovery, therefore ultimate impact the economic success of the production enhancement operations.
Understanding the parameters affecting adequate propped fracture geometry is critical to the process. While none or limited influence can be exercised on the hydraulic fracture geometry from the reservoir side, the fracturing materials and the pumping technology at large, now on the disposition to the frac design engineer have ever been improving and will define the level of achievement.
The general statement valid for mid perm reservoirs of high pore pressure and relatively high reservoir temperature, that it is very important to create a fairly long and clean, conductive propped fractures is not sufficient, in reservoirs where condensate banking represent a potentially important pressure loss.
To counter the effects caused by pressure depletion below dew point that are resulting in multiphase flow and condensate bank creation in the reservoir, maximum conductivity fractures are designed. Further, depending on the drawdown and induced flow rate to the wellbore, non-Darcy effects, flow convergence and proppant damage can be potentially encountered; hence, fractures designed under the concept of "maximizing conductivity" will additionally decrease the well productivity decline.
The analysis presented in the paper was based on a combination of data obtained from field measurements, analytical calculation and numerical simulations, modeling in all details the key processes defining the productivity gas condensate reservoir. The first results obtained indicate that the placement of extremely conductive fractures has a definite advantage in both productivity as well as in recovery of liquid hydrocarbons.
To conclude – it can not be overemphasized that ensuring good conductive fractures that will ensure minimum pressure drop from multiphase, or non-Darcy flow is critical. Excellent wellbore connectivity by wide and conductive near wellbore fracture paths and maximizing inflow area and minimizing convergence flow effect is not to be underestimated too. The fracture design has to ensure this environment in the initial production phase as well as in years to come when reservoir pressure drop is expected and higher effective stress, proppant crush, fines migration and embedment, are placing additional strain on maintaining the fracture conductivity.
Unified Method for the Gas Condensate Field Model History Matching and Prognosis Calculations
Authors: Filippova J , Turbina T 
Published: October 2015

Abstract
The conversion technique for fluids produced on gas condensate field and passed through the gas treatment unit is proposed.
By proposed recalculation it is possible to transform data of produced gas volume and condensate mass to data of daily production both in volume and in mass.
Fluid model data transmission is proposed with the separation to the invariant groups of "dry gas" and "∑ C5+". With the help of data obtained from supervisory composition determination it is possible to track alteration in the "dry components" contribution supplied by the gas and condensate, as well as similar ratio of the ∑C5+ components group.
Taking the designed methodology into consideration it is possible to determine the daily volumes of "dry gas" and "∑C5+" in the gas treatment unit. Finally, according to the obtained results, produced fluids data can be matched with the data obtained from the simulation model adaptation.
Tight Gas Achimov Formation Evaluation and Sampling with Wireline Logging Tools: Advanced Approaches and Technologies
Authors: Novikov S. , Weinheber P. , Charupa M. , Ezersky D. , Rudenko D. , Mikhaltseva I. , Danilova D. , Mukminov I. , Snokhin A. , Tikhomirov I. 
Published: October 2015

Abstract
The Yamal region of Western Siberia holds enormous reserves of gas and condensate across many geologic layers including the Achimov deposits of the Late Jurassic and Early Cretaceous. The Achimov however, is among the most challenging layers in the Yamal area with deep bedding, very low permeability, thin laminations and abnormally high reservoir pressures that all greatly complicate the appraisal and production of hydrocarbons. In this regard, accurate formation evaluation is essential to ensure efficient and economically reasonable methods of production. Modern methods of openhole logging, including NMR, acoustic and wireline formation testers (WFT) provide advanced information about the formation and can aid in the most efficient development.
In this article we present the results of advanced methods of openhole logging that provides greater understanding of the characteristics of the Achimov reservoir. Special NMR measurements were used to estimate the residual fluid saturation which was confirmed with WFT tools designed for downhole fluid analysis and sampling. We also show how to overcome the negative impact of supercharging on measurements of formation pressure in the Achimov formations and the necessity of carrying out such measurements to validate the hydrodynamic reservoir model. To understand the validity of the samples acquired downhole a simulation was carried out further showing the range of possible variations of the basic PVT properties of hydrocarbons during the sampling.
The results of advanced acoustic logging allows to estimate the anisotropy of the mechanical properties of the Achimov layers. The use of the data allowed us to model the fractures resulting from hydraulic stimulation and showed significant differences in the geometric characteristics of the fracture between wells and explains why the lower section of the Achimov are often depleted with respect to the upper sections.
Current Results of Overlooked Targets Identification in the Fields of the Orenburg Region
Authors: Shakirov V. A. , Deryushev D. E. , Ivanov M. A. , Sereda I. A. 
Published: October 2015

Abstract
The Orenburg oil region is one of the oldest regions of the Volga-Ural oil and gas province. The story of the field discoveries in the Orenburg region starts from the end of 30s of the twentieth century. By now the explored stock of large and easy-to-recover deposits is nearly depleted. The production has gradually led to the depletion of the existing deposits, and the replacement of oil producer resource base has become necessary.
The Chernyshev Swell: Supertrap or Waste Zone?
Authors: Sobornov K. O. , Danilov V. N. 
Published: October 2015

Abstract
Several years ago the Chernyshev swell was regarded as one of the most promising areas for petroleum exploration in the Timan Pechora basin. This was mainly due to an outcome of drilling of a 1-Vorgamusur well which targeted a new exploration play related to a subthrust zone. The well encountered an oil zone which yielded an uncontrollable oil blowout. Consequently a serious interest of oil and gas companies aroused. They rushed to secure prospective acreage on the newly established trend. Since then significant exploration efforts, including new seismic acquisition and drilling of several wells, have failed to deliver commercial volumes of hydrocarbons. As a result, prospectivity of the area has been downgraded and much of the exploration acreage was relinquished. The failure was explained mainly with poor qualities of reservoirs and unfavorable preservation conditions related to intense faulting resulting in breaching of seals.
A critical review of G&G data suggest that the unsatisfactory outcome of the past exploration may to a large extent reflect shortcomings in the understanding of regional geology and inadequate technical solutions, rather than scarcity of oil and gas endowment of the Chernyshev swell. A reinterpretation of the regional structural geology provides vital clues for understanding the reasons of the past failures and permits the identification on new potentially high-impact opportunities.
An Optimization Algorithm for the Calculation of Phase Equilibrium for Thermo- and Hydrodynamic Modeling
Authors: Shevchenko A. V. , Tsybulin I. V. , Skalko Y. I. 
Published: October 2015

Abstract
Taking the possibilities of phase transition into consideration is necessary for numerical simulation of multicomponent mixtures flow. The problem of defining phase equilibrium of mixture with arbitrary amount of components, which are characteristic for hydrocarbons deposit (water, light and heavy oils, soluble gases) is viewed in this paper. It is considered that phase equilibrium conditions are set through constants of phase equilibrium. The modified problem of phase equilibrium is solved given values of molar concentration of all mixture components, its molar enthalpy and pressure. As a result, we define on what phases the mixture will segregate to, its molar fractions, compositions and temperature. The algorithm is based on minimization of Gibbs potential with usage of the ideas of logarithmic barriers method. The algorithm is verified and has been studied in detail.
Geological and Hydrodynamical Simulation with Formation Mechanical Properties Taken into Account
Authors: Bogachev K. Yu. , Eydinov D. A. , Korneva D. A. , Piskovskiy E. V. , Shaybakov A. L. 
Published: October 2015

Abstract
Describing changes of stress-strain state during hydrodynamic simulation is currently a problem of great importance. In this paper we consider one of possible approaches to solve coupled hydrodynamic and geomechanical problem.
Geological Models for the Implementation of Adaptive Exploration and Fast-Tracking Field Development of Oil Pools in Imilor-Istochny License Aria
Authors: Kasatkin V. , Shalamova V. , Druchin V. 
Published: October 2015

Abstract
New conceptual geological models of oil pools of Imilor-Istochny subsurface area (West Siberia, Surgut oil- and gas-bearing region) are proposed, this is the basis of computer realization performed in options of permanent geological 2D and 3D models. Models were created under the assumption that the complex structure of the geological features of the area - are connected to a nonpositive regional structures, multifacies genesis of productive reservoirs, a clinoform-like structure of the main oil and gas complex, the presence of zones of anomalous section of the Bazhenov Formation.
The detailed correlation of perspective deposits is created taking into account the seismic CDP-2D and 3D, while used a clinoform-like model of the Neocomian deposits, landslide genesis of the formation of reservoirs in the anomalous "Bazhenov". Built consistent structural skeleton of the field with simultaneous using of all the reference horizons, with the specified boundary of the domain of productive strata. The boundaries of the spread of productive layers, line thinning, replacement of reservoirs. the effective thickness are of the preliminary determined due to the geological interpretation of seismic data.
To justify the reservoir properties of productive beds proposed approach from the standpoint of thin-layered media.
Built new geological 2-3D models of Imilor-Istochny subsurface area (the area of simulation approx 1500 km2) include 23 productive reservoirs in Upper Jurassic and Lower Cretaceous sediments, for the first time allocated 85 oil pools. These models are used to support exploration and the "local" field development, the basis for the calculation of reserves and the implementation of design and technological documents for the development of pools. To create the models used modern mathematical approaches based on variational principle and ideas of mathematical physics implemented in computer programs Isoline, GST, Roxar, Stratatool.
Experience of 3S-technology Application for Natural Gas Processing at Gas Facilities in Russia and China
Authors: Bagirov Lev A. , Imaev Salavat Z. 
Published: October 2015

Abstract
Over the last decade ENGO Engineering Ltd. successfully implements supersonic separation technology (3S-technology) for natural and associated gas processing at the gas producing facilities in Russia and China. This paper describes supersonic gas separation technology main physical principles and provides detailed information about the technology application at the facilities in operation.
New Approach to the Evaluation of the Structure of Initial Reserves in Ozhginskoe Gas-Oil Field
Authors: Podnebesnykh A. V. , Baryshnikov A. V. , Kuvaldin A. P. , Stukov S. P. , Enilin A. S. , Timokhovich Yu I. , Nurov R. S. 
Published: October 2015

Abstract
At the present time insufficient attention is given to reserves estimation of fields on exploration and operational stages. Estimation of reserves distribution, as a rule, is made by classical approach, based on tectonic geology and generation of average reservoir properties (Orlova L.A. and the others, 2010; Gutman I.С., 1985). Under this approach risks and uncertainties of geological factors analysis is lacking. Due to this approach it is possible to correct of reserves distribution during the development and in the end it can influence on strategy of field development.
Ozhgiskoe gas-oil field is on the first stage of development and has all specific parameters: progressive production, increasing well fund, low water-cut, high rate reservoir pressure decline. Three clusters are in operation (in central and west parts of the field).
For effective development monitoring and development strategy formulation geo-technical model was created. Further to integral history matching it failed to achieve good convergence: discrepancy of gas production history and current gas-oil ratio well after well, considerable discrepancy oil production in several good wells. Using all allowed methods of history matching, it failed to history repeating (Tatarinov I.А. and the others, 2012).
Therefore by the example of Ozhgiskoe gas-oil field ZAO «UNS» new procedure of IOIP estimation was realized with risks and uncertainties analysis. This procedure allows to take strategic decisions when placing new objects in operation. Results of work are interesting for specialists, which are concerned of uncertainties estimation and risks management during new fields development.