Oilfield Engineering

Modern modeling along with a reservoir potential reproduction, focuses on the system control process: the reservoir − the underground completion − the well − the on-surface infrastructure. The most significant and actual use of integrated modeling tools in offshore oil and gas fields is achieved with a significant increase in the resource base. This factor is accompanied by a high level of manufacturability and automation as well as accumulation of situational and complex integrated analysis.

To solve such problems in Yu. Korchagin and V. Filanovsky fields created and already uses integrated models, that include a set of interrelated mathematical and engineering models of wells, reservoirs, on-surface system of oil gathering, preparation and transportation with account of the best foreign experience in this field.

This set of models helps to solve the problems of operative control over oil production volumes, preparation of wells detailed, good-founded technological regimes, assessment of the gathering system potential, monitoring and evaluation of the risks of oil and gas production and modeling of intellectual wells production processes.

Keywords: oil and gas fields; complex modeling; integrated analysis; operational control.

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UDC 622.276.1/.4+622.276.43

MODELING OF OIL RESERVOIRS WATER-FLOODING
USING THE DIFFERENCE SCHEME "HOPSCOTCH" WITH ACCOUNT
OF CAPILLARY AND GRAVITATIONAL FORCES (p. 15)

Ivan Vladimirovich Afanaskin,

Alexander Vasilievich Korolev,

Petr Vladimirovich Yalov,

Dmitry Vladimirovich Solopov,

Andrey Yurievich Sorokin

Federal Scientific Center "Research Institute for System Studies of the Russian Acad emy of Sciences" (FGU FNC NIISI RAN)

36, bld. 1, Nakhimovsky prosp., Moscow, 117218, Russian Federation,

e-mail: ivan@afanaskin.ru

A new approach to the numerical solution of the equations system of oil and water two-phase flow with account of gravity and capillarity forces is proposed. The approach is to apply a differential equation to approximate the pressure of the "hopscotch" difference scheme. The similar scheme is used twice − for the flow in the horizontal plane and for the inflows between the layers. This allows calculation without salvation of linear algebraic equations in future. Comparative testing proved enough accuracy of the approach for practical purposes.

Keywords: two-phase flow; water-flooding modeling; "hopscotch" difference scheme; accounting of capillary and gravitational forces.

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UDC 622.276.66.001.57+622.276.2.001.57

DYNAMICS OF THE FLUID INFLOW TO A HORIZONTAL WELL
WITH MULTI-ZONE HYDRAULIC FRACTURING OF A FORMATION
UNDER ELASTIC DRIVE CONDITIONS (p. 23)

S.V. Elkin, A.A. Aleroev, N.A. Veremko, M.V. Chertenkov

LLC "LUKOIL−Engineering"

3, bld. 1, Pokrovskiy boulevard, Moscow, 109028, Russian Federation,

e-mail: Sergey.Elkin@lukoil.com, Aslanbek.Aleroev@lukoil.com, Nikolaj.Veremko@lukoil.com, Mikhail.Chertenkov@lukoil.com

The paper presents formulas to calculate the dependence of a horizontal well production rate with multi-zone hydraulic fracturing on the time under drainage elastic drive conditions. It became possible to obtain the approximate analytical solution by dividing the process into three stages, assuming that the pressure distributes among the fractures like a linear function slowly varying over time. The plotted production rate diagrams are well aligned with the actual wells’ production curves.

Keywords: multi-zone hydraulic fracturing of a formation; plane-parallel flow; boundary of the drainage area; mutual interaction of fractures; intermediate pressure; flow dynamics; inter-fracture space; cumulative oil flow rate.

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UDC 550.832.4

THE RELIABILITY OF THE PREDICTION OF THIN FORMATIONS
EFFECTIVE THICKNESS ACCORDING TO 3D SEISMIC SURVEY IN THE 2000's
(ON THE EXAMPLE OF THE DEPOSIT IN OF KhMAO – YuGRA REGION) (p. 32)

A.N. Yanin

LLC "Term "Project Office"

15, Dzerzhinsky str., Tyumen, 625000, Russian Federation,

tel.: (345) 263-15-64,

fax: (345) 263-15-48,

e-mail: term@term-pb.ru

The article considers real results of 3D seismic survey application in one of KhMAO – Yugra deposits to determine the oil-saturated thickness of a thin superficial AS₁₁ formation. The acceptable "each well" accuracy (±20 %) of the predicted effective thickness by 3D seismic survey was achieved only for five new wells out of 18 drilled ones. The accuracy of the thickness prediction for the rest of the wells was unsatisfactory. Significant estimation error (up to 55 %) of h_ef., according to 3D seismic survey data is observed even in the interval of raised (more than 6,5 m) predicted thicknesses. The maximum error when predicting effective thickness of AS₁₁ formation according to 3D seismic survey data reaches 140…180 %. It is typical for areas with minimum (2,5…3,0 m) predicted thicknesses. The reliability of the prediction of a thin formation effective thickness during the historical period under consideration, according to 3D seismic survey data, proved insufficient to justify the location of the faces of specific design production wells.

Keywords: 3D seismic survey; KhMAO – Yugra region; oil saturated thickness; error of determination; thin formation; real results.

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UDC 622.276.1/.4.04

PECULIARITIES OF RISK MANAGEMENT IN CASE OF STRATEGIC DEVELOPMENT
OF OFFSHORE OIL AND GAS ASSETS OF THE NORTHERN CASPIAN SEA (p. 38)

Alexey Viktorovich Shevchenko

LLC "LUKOIL−Nizhnevolzhskneft"

1, bld. 2, Admiralteiskaya str., Astrakhan, 414000, Russian Federation

Alexander Nikolaevich Lesnoy,

Danis Ravilevich Maganov,

Dmitry Ivanovich Polukeev

PJSC "LUKOIL"

e-mail: Aleksandr.Lesnoy@lukoil.com

Denis Vladimirovich Korneev,

Artem Vladimirovich Nekrasov,

Maria Igorevna Pimenova

LLC "LUKOIL−Engineering"

3, bld. 1, Pokrovskiy boulevard, Moscow, 109028, Russian Federation,

tel.: (495) 983-24-11,

fax: (495) 983-21-41,

е-mail: LUKOIL-Engin@lukoil.com

Risk assessment is a necessary component of scientific and technical support of projects. The main tasks that are aimed at solving risk management problems are identification, assessment of existing risks and development of management actions to minimize them. Based on the work done, a risk register has been formed for further analysis.

Keywords: concept; risks; processes prioritizing; pre-project examination; target architecture.

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UDC 622.276.652

INFLUENCE OF A WORKING AGENT TEMPERATURE
ON THE COEFFICIENT OF HIGH-VISCOUS OIL DISPLACEMENT (p. 43)

M.K. Mustafaev

JSC "KazNIPImunaygas"

2, the 6^th micro-district, Aktau, 130000, Mangistau region, Republic of Kazakhstan,

е-mail: Turkpenbaeva_B@kaznipi.kz

E.K. Kaiyrzhan

JSC "Karazhanbasmunay"

8, the15^th micro-district, Aktau, 130000, Mangistau region, Republic of Kazakhstan

The article describes laboratory-experimental studies of the effect of the working agent temperature on the coefficient of high-viscous oil displacement in Karazhanbas field conditions.

The results of the studies, conducted by the laboratory center of JSC "KazNIPIMunaigas", make it evident that an increase of the working agent temperature contributes to an oil displacement increase. The increase of the oil displacement coefficient is observed for all lithotypes of rocks.

The displacement coefficient dynamics increases sharply as the temperature of the injected water rises from 50 °C and more. This is achieved due to a sharp decrease of oil viscosity (three times) and its mobility increase. It is confirmed by PVT-studies results of oil deep samples performed obtained from four wells.

Evaluation of the mineralization effect on clay rocks showed that its reduction negatively affects the reservoir characteristics. Permeability significant decrease, caused by the decrease of the injected water mineralization till its complete desalination, occurs due to the composition of clays (illites and smectites), which are highly prone to swelling.

Based on the results of laboratory-experimental studies, to provide effective oil replacement it is recommended to use hot water of 50…90 °C temperature and pilot-industrial testing.

Keywords: temperature of working agent; displacement of oil; PVT-studying of oil deep samples.

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UDC 622.276.66.001.57:622.276.346

EVALUATION OF A HORIZONTAL WELL FLOW-RATE
AFTER A MULTI-STAGE HYDRAULIC FRACTURING OF A FORMATION
AND ANALYSIS OF A "SUPER-WELL" PARAMETERS INFLUENCE
ON ITS PRODUCTIVITY (p. 48)

Zhou Xiaofeng,

Anatoly Borisovich Zolotukhin

Gubkin Russian State University of Oil and Gas (National Research University)

65, Leninsky prosp., Moscow, 119991, Russian Federation,

e-mail: gubkin.cup@yandex.ru, anatoly.zolotukhin@gmail.com

The authors of the article introduce a new concept of a "super-well" that characterizes a horizontal well completion zone formed after conducting of a multi-stage hydraulic fracturing of a reservoir that covers both the horizontal well itself with a network of fractures and porous medium with changed reservoir characteristics. The presented concept allows a new view on the fluids flow in the super-well completion zone to get a new simplified model of fluid inflow towards a horizontal well with a system of hydraulic fractures. The model allows a simple analytical solution for a steady-state fluid flow to the "super-well" and to evaluate the fractures influence on its production. The proposed "super-well" model is considered an equivalent model for describing the fluid inflow to a horizontal well with uniformly changed properties in the zone of the formation hydraulic fracturing. It should be noted here that this approach allows to obtain an analytical dependence of the average weighted permeability of the zone on the total number of fractures and their length after conducting of a formation hydraulic fracturing, that is formed in a “super-well” natural-fractured collectors. The proposed model makes it possible to simulate a spatial fracture network and to use it for optimization of designing of a formation hydraulic fracturing.

Keywords: "super-well"; production evaluation; multi-stage hydraulic fracturing of a formation; analysis of parameters effect on a well productivity.

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UDC 622.276.031.011.433:550.822.3+622.276.7

SELECTION OF THE MOST EFFICIENT FLUIDS OF WELLS KILLING
FOR RESERVOIR-ROCKS OF PERM REGION DEPOSITS AND ASSESSMENT
OF THEIR IMPACT DURING CORE LABORATORY SIMULATION (p. 53)

Igor Anatolievich Shilov,

Anton Igorevich Nevolin

"PermNIPIneft", a branch of LLC "LUKOIL−Engineering" in the city of Perm

29, Sovetskaya Armiya str., Perm, 614066, Russian Federation,

tel.: (342) 717-01-54,

e-mail: Igor.Shilov@pnn.lukoil.com, Anton. Nevolin@pnn. lukoil.com

The article describes the major complications, arising from the wrong selection of wells killing fluids in Perm region fields. The methodology for assessing killing fluids impact on the filtration parameters of models’ core components is developed. Killing fluids of different formulations and manufacturers on core material and the "free volume" in order to justify their application efficiency at different development sites are studied.

Keywords: killing fluids; methodology’ research on core.

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UDC 622.276.53.054

CALCULATION METHOD TO OBTAIN OPERATIONAL CHARACTERISTICS
OF A ROTARY CENTRIFUGAL GAS-SEPARATOR (p. 57)

M.G. Volkov

LLC "RN–UfaNIPIneft"

3/1, Bekhterev str., Ufa, 450103, Republic of Bashkortostan, Russian Federation,

e-mail: m_volkov@ufanipi.ru

Numerical modeling of the hydrodynamic structure of the well fluid flow inside the centrifuge inter-blade channel has shown that its significant influence on the flow structure is paid by its transverse twisting inside the inter-blade channel of the gas separator, caused by the liquid inertial properties. In the cross-section of the gas-separator inter-blade channel, the pressure gradient is directed from the line passing through the masses center toward the periphery and the root part of the blade. Small bubbles of gas, falling into the centrifugal field, are squeezed out both towards the surface of the blade drum hub and to its periphery. Large bubbles of gas are pressed out only to the surface of the hub. This distribution of gas bubbles in the inter-blade channel of the blade centrifuge explains the high separation factor during gas separators operation, in particular GSA5-1, in a coarse-dispersed water-air mixture, and the low one in case of its operation on a fine-dispersed water-surfactant- air mixture.

The developed analytical technique method allowed to carry out a numerical analysis of the influence of β_in. input gas content on K_c separation coefficient and gas bubbles d_p diameter in the gas-liquid mixture on β_ost. residual gas content. It is revealed that the separation coefficient of the centrifugal gas separator increases along with the growth of the gas bubbles diameter. The calculations showed that in case of "GSA5-1" gas separator use an increase of gas bubbles diameter in gas-liquid mixture from 10 to 120 μm leads to the gas separation coefficient increase from 0,459 to 1,0.

A comparison of the calculated and experimental data on the discharge-pressure characteristics of the screw-type supercharger of Centrilift gas separators for water operation regimes proved a fairly good convergence of the results.

Keywords: oil; gas; pump; well; mixture; gas separator.

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UDC 622.276

ANALYSIS OF REPAIR-ISOLATION (SHUT OFF) WORKS
WITH THE USE OF ACTIVE CELLULOSE FLOUR IN THE PRODUCTIVE DEPOSITS
OF FIELDS LOCATED IN THE EASTERN MARGIN OF MELEKESSKY DEPRESSION
(p. 63)

F.A. Gubaidullin, P.V. Isaev

Kazan (Privolzhsky) Federal University

e-mail: fargub@mail.ru

M.A. Saifutdinov

PJSC "Tatneft"

75, Lenin str., Almetyevsk, 423450, Republic of Tatarstan, Russian Federation,

e-mail: tnr@tatneft.ru

The article analyzes technological and economic efficiency of pilot-industrial works on water shut off in fractured reservoirs using active cellulose flour reagent (ACF) is carried out in. The work was carried out in production wells of "Nurlatneft" Oil and Gas Production Department (PJSC "Tatneft") of Ashalchinsky, Bureikinsky, Vishnevo-Polyansky, Pionersky and Nurlatsky fields.

Keywords: field; productive horizon; water-flooding; production; development analysis; heterogeneity; repair and isolation (shut off) works; active cellulose flour.

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UDC 622.276.72

MAPPING OF SCALING ZONES, INFLUENCE
OF A PRODUCTIVE RESERVOIR DISSOLUTION ON THE DEVELOPMENT
OF YARAKTINSKY OIL-GAS-CONDENSATE DEPOSIT (p. 66)

Alexander Nikolaevich Cheremisin

LLC "Geomechanical Systems"

e-mail: acheremisinn@gmail.com

Alexey Anatolievich Gorlanov,

Diana Dmitrievna Romanova

LLC "Sibkor"

58a, Veterany truda str., Tyumen, 625031, Russian Federation,

e-mail: gorlanich@gmail.com, kusnerdd@gmail.com

Viktor Nikolaevich Shchetkin,

Irina Pavlovna Lebedeva,

Igor Valentinovich Sabanchin,

Anna Vladimirovna Evseenko

LLC "Irkutsk Oil Company"

4, Bolshoy Liteiny prosp., Irkutsk, 664000, Russian Federation,

tel.: (395) 221-13-52,

e-mail: shetkin_vn@irkutskoil.ru, lebedeva@irkutskoil.ru, isabanchin@irkutskoil.ru, evseenko_av@irkutskoil.ru

Alexander Iosifovich Voloshin

LLC "RN−UfaNIPIneft"

e-mail: Voloshinai3@mail.ru

Fluids passing from the bottom to the mouth of oil and gas wells brings the thermobaric conditions change, thus breaking the existing thermodynamic equilibrium in a reservoir system. So, the temperature and pressure drop are often the reasons for deposits formation, in particular, inorganic salts in the near-well zone, on the surface of deep-pump equipment, tubing as well as in the fields’ product gathering systems. Mineral deposits, being continuously formed in the process of field operation lead to wells productivity decrease, gradual reduction of a tubing column cross-section, submersible equipment failure, thus requiring maintenance and preventive measures. Their success depends on scaling prediction quality. Due to the facts mentioned, it seems important to determine the conditions of scaling in reservoir conditions, to predict the processes of dissolution of easily-soluble rock components and to change the injected water composition during its movement from injection wells to producing ones. The article gives general information on the scaling problem and the conditions contributing to salt formation at the Yaraktinsky oil and gas-condensate field (YaOGCF). The work included program modeling of mineral salts deposition, prediction of scaling risks for YaOGCF in reservoir conditions, in wells and surface equipment, development of scaling maps. The zones and wells of the fields that are most susceptible to different types of scaling are identified, the degree of various factors influence on the formation of salts in reservoir conditions is determined.

Keywords: scaling; gypsum; calcite; halite; de-scaling of a reservoir rock.

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JSC "ALL-RUSSIAN SCIENTIFIC-RESEARCH INSTITUTE OF ORGANIZATION, MANAGEMENT AND ECONOMICS OF OIL AND GAS INDUSTRY"

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