Геологія видобутку нафти і газу (oil & gas production geology)

Oil & Gas Production Geology – 01 Overview

Геологія видобутку нафти і газу – 01 короткий опис

Вольфганг Нахтманн

Wolfgang Nachtmann � RAG � Wien

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Oil & Gas Production Geology – 01 Overview | 2011 | 2

Content of Lecture

Зміст лекції

Oil & Gas Reservoirs – from uncontrolled eruptions to an optimum production strategy – geological and reservoir-relevant parameters and methods to develop oil & gas fields


Petroleum – a Basic Element Sine Qua Non

Нафта – обов‘язкові вимоги

In the twentieth century, oil, supplemented by natural gas, toppled King Coal from his throne as the power source for the industrial world.

Oil also became the basis of the great postwar suburbanization movement that transformed both the contemporary landscape and our modern way of life. Today, we are so dependent on oil, and oil is so embedded in our daily doings, that we hardly stop to comprehend its pervasive significance. It is oil that makes possible where we live, how we live, how we commute to work, how we travel—even where we conduct our courtships. It is the lifeblood of suburban communities.

Oil (and natural gas) are the essential components in the fertilizer on which world agriculture depends; oil makes it possible to transport food to the totally non-self-sufficient megacities of the world.

Oil also provides the plastics and chemicals that are the bricks and mortar of contemporary civilization, a civilization that would collapse if the world's oil wells suddenly went dry.

Prologue to The Prize by Daniel Yergin, 1991


What is Petroleum

Що таке нафта і газ

PETROLEUM A generic name for hydrocarbons, including crude oil, natural gas liquids, natural gas and their products.

Glossary of Petroleum Industry Common Terms & Symbols

Petroleum is crude oil, a naturally occurring liquid that can be distilled or refined to make fuels, lubricating oils, asphalt, and other valuable products. Used in a broad sense, petroleum also refers to natural gas and solid asphalt, …


The Value Chain of Petroleum Industry – Three Legs

Ланцюг вартості у нафтогазовій індустрії – три етапи

The oil industry can be divided into three major components: upstream, midstream and downstream.

The upstream industry includes exploration and production activities, hence is also referred as the exploration and production (E&P) sector.

The midstream industry processes, stores, markets and transports commodities including crude oil, natural gas, natural gas liquids (NGLs) like ethane propane and butane and sulphur.

The downstream industry includes oil refineries, petrochemical plants, petroleum products distributors, retail outlets and natural gas distribution companies.

In general, both, internationally and domestically, the oil and gas sector is characterized by the existence of "integrated" companies, which are present in all these three sectors.


Upstream: Exploration and Produktion (E & P)

Апстрім: Розвідка та видобуток (E & P)

Upstream sector, the first part of the oil and gas industry, deals with exploration and production of oil and gas. Oil exploration takes place at oil wells in four stages:

• the first stage is drilling, act of boring a hole through which oil or gas may beproduced if encountered in commercial quantities.

• the second stage is completion, process in which the well is enabled to produceoil or gas.

• the third stage is production, production time of oil and gas.• the final stage is abandonment, where the well no longer produces or produces

so poorly that it is a liability to its owner and is abandoned.

An oil field is a region with an abundance of oil wells extracting petroleum (oil) from below ground. Because the oil reservoirs typically extend over large(r) areas, full exploitation entails multiple wells scattered across the area. There are more than 40,000 oil and gas fields of all sizes in the world (BP statistical Review,2006) and the largest discovered conventional oil field is the Ghawar Field (75-83 billion bbl) in Saudi Arabia.

In tandem with the stagnated reserves, the production of oil has also been sluggish over the last decade, as a matter of fact during the last ten years oil production has increased by only 1.6%.


The World Consumes one Cubicmile of Oil per Year

Світ споживає одну кубічну милю нафти на рік

1 cubic mile of oil contains as much energy as we would get from 52 new nuclear power plants working for the next 50 years


Development of Worldwide Oil & Gas Reserves

Світова розробка резервів нафти і газу

Distribution of proved oil & gas reserves in 1988, 1998 and 2008Percentage

BP Statistical Review of World Energy 2009

Öl

Gas


Oil Reserves-to-Production (R/P) Ratios

Співвідношення резервів нафти до видобутку (R/P)

BP Statistical Review of World Energy 2010 BP Statistical Review of World Energy 2010


R/P Model

Модель R/P

0

5

10

15

20

25

30

2007 2017 2027 2037 2047 2057 2067 2077 2087 2097

Wor

ld A

nnua

l Oil

Pro

duct

ion

(bln

bbl

s)

Data base:� 2007 Reserves 1283 Mrd bbl� 2007 Production 29,8 Mrd bbl / a� R/P 41,6 years

R/P Model-Assumption:� stable production on 2007 level until

complete exhaustion of reserves


R/P Model Versus More Realistic Expectations

R/P модель у порівнянні з більш реалістичними очікуваннями

0

5

10

15

20

25

30

2007 2017 2027 2037 2047 2057 2067 2077 2087 2097

Wor

ld A

nnua

l Oil

Pro

duct

ion

(bln

bbl

s)

Assumption ignores that:� production from known fields won‘t

stay stable – an annual decline of 3% appears realistic

� New reserves will be added from exploration and field developments

Data base:� 2007 Reserves 1283 Mrd bbl� 2007 Production 29,8 Mrd bbl / a� R/P 41,6 years

R/P Model-Assumption:� stable production on 2007 level until

complete exhaustion of reserves


Reserves Additions: New Discoveries versus Existing Fields

Доповнення резервів: нові поклади у порівнянні з існуючими родовищами


Reservoir Management – Key to More Production from Old Fields

Менеджмент пластів – методи збільшення видобутку з нафтових родовищ


The Production Geologist – Member of a Multidiscipline Work Force

Геолог з видобутку – представник багатопрофільної робочої сили

A production geologist, in general, • works in a subsurface team • is responsible for understanding thegeological framework of the reservoir

• supports to understand how geologyinfluences fluid flow within a producing reservoir and creates „dead end pockets”that could eventually trap hydrocarbons (thebigger ones of these pockets may be worthtargeting with new wells)

• takes a leading role in planning such wells• typically uses computer software for a good part of his work


The Subsurface Team

Надра, команда


Reservoir Description – Data (Sources)

Опис пласта – дані (джерела)

Reservoir description is the base for a most effective and efficient reservoir management. Here, the production geologist plays a key role and will use a variety of data (sources), including:

• mud logging data• core data• sedimentology and petrography reports, studies• outcrop analogs / modern depositional environments• a broad spectrum of wireline log and logging-while-drilling (LWD) data• production log data• well test data• fluid samples• production data

• seismic data

Production Geologist � Static Model of Reservoir

Reservoir Engineer � Dynamic Model + Simulation of Flows

Common Target: maximization of production from an oil or gas field


Subsurface Techniques Over Time

Техніки розробки надр, основні етапи


Terminology Used in Appraising Oil & Gas Pools

Термінологія, що використовується при аналізі нафтогазових покладів


Continue with Chapter 02 – HC Basic Principles

Oil & Gas Production Geology – 02 Basic Principles

Геологія видобутку нафти і газу – 02 основні принципи



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Oil & Gas Production Geology – 02 Basic Principles | 2011 | 2

GEOLOGICALSITUATION

MIGRATIONRESERVOIR

TRAPSEAL

MIGRATIONPATHS

TRAPOVERTIME

SOURCEROCK

MATURITYOF SOURCE

ROCK

Petroleum System Puzzle

Паззл нафтогазової системи


The Petroleum System – Elements and Processes

Нафтогазова система – елементи та процеси


Petroleum System Definition

Визначення нафтогазової системи

The essential elements and processes and all genetically-related hydrocarbons that occur in petroleum shows, and accumulations whose provenance is a single pod of active source rock.

Source: JMA 2000

Source RockSource RockMigration RouteMigration RouteReservoir RockReservoir RockSeal RockSeal RockTrapTrap

ElementsElements

МатеринськаМатеринська породапорода

ШляхШлях міграціїміграції

ПластоваПластова породапорода

НепроникливаНепрониклива породапорода

ПасткаПастка

ЕлементиЕлементи

GenerationGenerationMigrationMigrationAccumulationAccumulationPreservationPreservation

ProcessesProcesses

ФормуванняФормування

МіграціяМіграція

НакопиченняНакопичення

ЗбереженняЗбереження

ПроцесиПроцеси


Schematic Cross Section through a Petroleum System

Схематична поперечна секція через нафтогазову систему

Predicting the location, type, and quality of hydrocarbon systems is critical to successful oil and gas development. Technology, such as seismic imaging and computer modeling, has improved the process in recent decades.

http://www.learner.org/courses/envsci/unit/text.php?unit=10&secNum=4


Trap Type 1 – Anticlinale

Тип пастки 1 - антикліналь

http://www3.uakron.edu/geology/Foos/Energy/poil3.html


Trap Type 2 – Fault

Тип пастки 2 – структурна пастка


Trap Type 3 – Pinch Out

Тип пастки 3 – пастка виклинювання


Trap Type 4 – StratigraphicТип пастки 4 - стратиграфічна


HC-Trap Types in the Vienna Basin 1

Типи пастки вуглеводнів у Віденському басейні 1


HC-Trap Types in the Vienna Basin 2

Типи пастки вуглеводнів у Віденському басейні 2


View at a Petroleum System

Вигляд на нафтогазову систему

Source and Seal

ReservoirMonterey Fmt. – Gaviota Beach, Ca.


E & P Cycle

Цикл розвідки та вибодутку (Р та В)

Discovery

Appraisal& Planning

Prospect-Definition

Field-Development

Reservoir

Management

Basin-Analysis,(Play) Concept(s)

Regional Geology,Data (Expl. History),

Analogies

E & P Cycle

EXPLORATION

PRODUKTION

Seismic,Gravimetry


E & P Cycle

Цикл розвідки та вибодутку (Р та В)

Відкриття

Аналіз & планування

Визначення

перспективи

Розробка

родовища

Пласт

Менеджмент

Аналіз басейну,(комплексу) концепція(ї)

Регіональна геологія,дані (іст. розвідка),

аналогії

E & P Цикл

РОЗВІДКА

ВИДОБУТОК

Сейсміка,гравіметрія


Continue with Chapter 03 – Reservoir Description



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Oil & Gas Production Geology – 03 Reservoir Description

Геологія видобутку нафти і газу – 03 опис пласта

Oil & Gas Production Geology – 03 Reservoir Description | 2011 | 2

Sedimentary Rocks

Осадові породи

Practically, all rock-elements of a petroleum system are

sediments. So do, of course, almost all reservoir rocks.

� Clastic (siliciclastic) rocks (80-85% of the stratigraphicrecord)

� Carbonate sediments and rocks (10-15% of the stratigraphic record)

� Organic (carbonaceous) sediments and rocks

� Evaporites

� Volcaniclastic sediments and rocks


Integrated Study (Scale/Disciplines) – Micro- to Basin Scale

Інтегроване дослідження (масштаб/алгоритм) – масштаб від мікро- до басейну

Courtesy: Uli Bieg, RAG


Environments of Clastic Deposition

Середовище теригенних відкладів


Preliminary depositional model

Початкова літологічна модель

„River“ dominated delta



Log correlation – Digitalization of available data and storage in Petrel

Кореляція каротажу – електроний вигляд наявних даних та записів у Петрель



Idealized Succession – Flood-dominated river delta

Ідеалізований варіант – дельта річки, с переважанням течії

Outburst of ephemeral sediment laden floods

Trigger mechanism

Mouthbar

Con

fined

flo

w

River mouth

Un-

conf

ined

flo

w

Masterbeddingplanes



Synthetic Deposition model

Синтетична модель залягання


jet flow


A model of Subaqueous Slope Channel and Deep-Water Fan

Модель підводного похилого каналу та глибоководний конус виносу


(SCHOLLNBERGER et al 1974)

Deep water Fan Shapes

Глибоководні конусні виноси


Appraisal and Development of a Reservoir

Аналіз та розробка пласта

A sheet-like turbidite reservoir will need only a few wells to appraise and develop it.

Channelized turbidite reservoirs will require several wells for appraisal and development – due to this fact they may be less profitable.


Introduction – Deep-Water Depositional Models

Вступ – глибоководні літологічні моделі

Wedge-Top Basins

Foredeep Basin

Inner Axial Outer

Basinal TurbiditeSystem

modified from Mutti et al., 2003

Submarine Transport and Depositional Processes

Courtesy: Anne Bernhardt, SPODDS

Fold-Thrust-Belt


Submarine Depositional Processes – Turbidity currents and debris flows

Підводні літологічні процеси – турбідитний та уламковий потік

Courtesy: Anne Bernhardt, SPODDS

Sediment gravity flows: Subaqueous flows that are driven down slope by gravity acting on particles

Debris Flow Deposit Turbidite

Ta

Tb

Tc


Lithofacies – Debris Flow Deposits

Літофації – відклади уламкових потоків


Lithofacies – Debris Flow Deposits

Літофації – відклади уламкових потоків

2 cm2 cm 2 cm


Lithofacies – Turbidity current deposits

Літофації – відклади турбідитних потоків


Core of a Good Quality Reservoir Rock

Керн породи якісного пласту


Pore space filled with CalcitePore space filled with Calcite--cementcement

= no room for oil/gas= no room for oil/gas

Sandstone Reservoir – No Porosity

Пласт пісковика – ніякої пористості


� Carbonate sand usually consists either of (fragmented) skeletal remains or non-skeletal grains (e.g., molluscs,

corals, forams, algae, bacteria, and many others)

� Most organisms initially form unconsolidated carbonate sediments

� Coral reefs and microbial mats (e.g., stromatolites) are examples of more solid carbonate structures

� Carbonate mud (micrite) is commonly the product either of chemical precipitation or algal/bacterial activity (e.g., ooids, onkoids, pisoids)

� Dunham classification of carbonate rocks:

� Texturally-based subdivision (cf. clastics): mudstone, wackestone, packstone, grainstone, rudstone

� Organically bound framework during formation: boundstone

Carbonate Rocks

Карбонатні породи


Tropical Carbonate Platforms: Facies Belts

Тропічні карбонатні платформи: фаціальні зони


Franconian Jurassic – Examples for Porosities in Carbonates

Франконський ярус, Юра – приклади пористості у карбонатах

Kalk-Stbr.-Ittling Dolomit-Stbr.-Bernhof

Courtesy: Roman Koch, GZ Nordbayern


Fractured Carbonate Rock

Роздроблена карбонатна порода


Continue with Chapter 04 – Reservoir Parameters

Oil & Gas Production Geology – 04 Reservoir Parameters

Геологія видобутку нафти і газу – 04 параметри пласта



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Oil & Gas Production Geology – 04 Reservoir Parameters | 2011 | 2

Key Reservoir Description Needs

Основні характеристики пласта


Example of a Structure Map

Приклад структурної карти


Reservoir Distribution

Розповсюдження пласта


Trap – a Matter of Reservoir Discontinuity Reasons

Пастка – через уривчастість пласта

Source: McMoRan, 2010


Reservoir Thickness and Barriers

Потужність пласта та ізоляція

Gross paytotal thickness of the reservoir unit

Net paythe fraction of the reservoir that has porosity above a minimum threshold (this is the sum of the productive zones)

Reservoir barriersReservoirs are heterogeneous in both vertical and horizontal dimension at all scales. This is due to Stratigraphic facies changes, faults, variation in diagenetic features such as cementation or dissolution, etc. A huge body of data is needed to adequately characterize most reservoirs. Most often reservoir barriers are revealed by the pressure history of neighboring wells.


Definitions: from Reservoir to Net Pay

Визначення: від пласта до ефективної нафтонасиченої потужності


Field Development after a Discovery Well

Розробка родовища після свердловини, що відкрила родовище


Initial Field Evaluation

Початкова оцінка родовища


Full Field Development

Повна розробка родовища


Terminology of Reservoir Related Parameters 1/2

Визначення параметрів, стосовно пласта 1/2


Terminology of Reservoir Related Parameters 2/2

Визначення параметрів, стосовно пласта 2/2


Terminology of Fluid Contacts in Reservoirs

Визначення контактів флюідів у пласті


Pressure Gradients while Drilling through Different Media

Градієнти тиску під час буріння при різних умовах

Pressure gradients encountered while drilling depend on the penetrated media


Hydrocarbon Column

Висота покладу вуглеводнів


Reserves Estimation in a Field Over Time

Оцінка резервів родовища упродовж часу


Effect of Fluid Contacts on Volumetric Maps

Вплив контакту флюідів на волюметричні карти

Typical isopach maps of reservoirs when the fluid contact is above the sand base


Isopach Maps – Inner and Outer OWC

Карта рівної товщини – внутрішній та зовнішній водонафтовий контакт

Isopachs when the fluid contact is below the sand base


Anticlinal Traps and Spill Point

Антиклинальні пастки та точка максимальної насиченості пласта

Where are spill points of these structures?

Is any of the structures filled?

Are there not yet drilled prospects on this map?

What is the faults‘ role?


Porosity

Пористість

Porosity


Porosity



Total versus Effective Porosity

Повна та ефективна пористість


Types of Porosity

Типи пористості


Methods of Measuring Porosity

Методи виміру пористості


Porosity Measurement from Core

Вимір пористості з керну


Porosity from Logs

Пористість з каротажу


Characteristics of Logs

Параметри каротажу


Rock Types and Their Porosities

Типи пород та їх пористість


Reservoir Rock versus Trap Rock

Пластова порода та пасткова порода

www.priweb.org/.../reservoir/reservoir.html


Characteristics of Porosity

Параметри пористості

Effective porosity vs. total porosity Types:

Primary porositySecondary porosityPorosity in Clastic rocks vs Carbonate rocksRelationship between porosity and permeability

Depositional aspects:CompositionSortingRoundingGrain sizePacking

Diagenesis:DewateringCompactionCementation

What is good porosity?

0-5% - Negligible 5-10% - Poor 10-15% - Fair 15-20% - Good >20% - Very good

Practical cut off for oil Sandstone ~8% Limestone ~5% For gas the cut off is lower


Porosity in Carbonates

Пористість у карбонатах

http://strata.geol.sc.edu/thinsections/diagenesis.html

Depositional porosity is a function of rock texture, grain sorting and shape. Sorting and shape in turn are related to bottom agitation at the depositional site. Where currents and waves are particularly active, lime mud is winnowed from carbonate sands. In contrast, lime muds tend to collect in less agitated environments or where trapped by organisms, and after the sediment dewaters little or no porosity is retained. Many of the world's larger carbonate reservoirs have porosities that are largely depositional in origin.


Relationship Between Carbonate Diagenesis and Porosity

Відношення між карбонатним диагенезом та пористістю

The relationship between porosity and diagenesis is complex and variable. The major diagenetic processes affecting porosity are dissolution, cementation and dolomitization.

Each process requires a permeable host rock and a mechanism to flush chemically active waters through the rock. The water movement is controlled regionally by the hydrostatic head, structure and rock fabric.

Dissolution creates and enhances porosity. Commonly, however, dissolution of carbonate grains is accompanied by calcite cementation in adjacent primary pores. The end product in such a case is tightly cemented carbonate sand with well-developed moldic porosity and low associated permeability.

Cementation is an extremely important diagenetic process because it reduces porosity. The degree of cementation varies from thin cement coatings around the grains that partially fill the pores and alter permeability patterns to calcite spar that completely fill the pores.


Permeability

Проникливість

Permeability

“Permeable” is “Porous,” but “Porous” May Not Be “Permeable”


Permeability



Permeability


This is the key parameter in determining reservoir quality. Many rocks (e.g. shales, chalk) have high porosity, but very low permeability. Determined from Darcy's law.

Main controls on permeability are:

• Grain size (determines the size of the pore throats) • Pore connectivity

Effective permeability: When multiple fluids are present they interfere with each other. So that the effective permeability of the moving fluid is much lower than if a single fluid is present. In a typical reservoir at least water and oil are present, frequently water, oil, and gas share the pore space.

What is good permeability?

<1 millidarcy - Poor 1-10 md - Fair 10-100 md - Good 100-1000 md - Very good


Permeability is a Function of:

Проникливість є функією:


Porosity – Permeability Correlation

Кореляція пористості та проникливості


Increase/Reduction of Porosities and Permeabilities

Підвищення/зменшення пористості та проникливості

Processes that reduce porosity and permeability:

• Compaction • Cementation • Heavy hydrocarbon residue

Processes that enhance porosity and permeability:

• Dissolution • Fracturing • Dolomitization

Carbonate rocks are often subjected to early cementation, so reservoir quality depends very strongly on dissolution, fracturing and dolomitization. Most carbonate reservoirs are due to secondary porosity. Reefs sometimes preserve primary porosity.


Capillary Pressure

Капілярний тиск


Fluid Distribution within a Reservoir

Розповсюдження флюідів всередині пласта


Reservoir Quality

Якість пласта


Capillary Pressure Curves

Криві капілярного тиску


Reservoir Engineering aspectsthe Production Geologist should

be aware of


Reservoir Engineering Tasks

Завдання технології розробки


Building a Reservoir Description

Структура опису пласта


Continue with Chapter 05 – Reservoir Fluids

Oil & Gas Production Geology – 04 Reservoir Fluids

Геологія видобутку нафти і газу – 04 пластові флюіди



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Oil & Gas Production Geology – 05 Reservoir Fluids | 2011 | 2

Hydrocarbon Content – Production Data

Об'єм ВВ – виробничі дані

Assessment and Adaption of volumetric reserves by production history

„dynamic methods“ for oil & gas reservoirs


Dynamics

Динаміка

Production (Exploitation) is governed by Reservoir Fluid(s) and their Drive Mechanism

The relations are provided by

Material BalanceSimulation


Calculation of Volumes

Розрахунок/параметри об‘єму

at standard conditions

Oil: 1,01325 [bar(a)] 15 [°C]

Gas: 1,01325 [bar(a)] 0 [°C]

Transformation from reservoir to surface via

„Formation Volume Faktor“ B ;

B = V Reservoir / V Standard conditions

Bo, Bg from PVT analysis in labs or from correlation


PVT Correlation for Oil

PVT кореляція для нафти

� Standing

� Lasater

� Vasquez and Beggs

� Petrosky

� Beggs and Robinson for oil-viskosity

Evaluated Data:

Bubble Point Pressure Pb [psia oder bara]

Solution GOR Rs [scf/STB oder Sm3/m3]

Formation Volume Factor Oil Bo [RB/STB oder Rm3/m3]

(saturated oil)

Oil-Viskosity µo [centiPoise]


Formation Volume Factor (FVF), B for Oil

Фактор формування об‘ємів, B для нафти

Two Phases:

• P > gas dissolution pressure P b

Bo increases with pressure reduction

Bo decreases with pressure reduction

PReservoir

Bo

1 Pb

2 Phases FVF, BT

• P < gas dissolution pressure P b


Formation Volume Factor (FVF), B for Gas

Фактор формування об‘ємів, B для газу

One Phase

The Volume develops disproportionalto the Pressure

Bg ~ 1 / PReservoir

Correction necessary since natural gas is not an „ideal“ gas


Gas Reservoir

Газовий пласт

Natural gas is a „real“ gas

Deviations from the ideal p.V/T = constant. Behavior described by the z-factor, „real gas favtor“

• gas composition (approximated via density ρρρρ)

• pressure

• temperature

Z-Factor depends on


Z – Real Gas Factor

Z – фактор реального газу

Gas reservoir:

0,7

0,8

0,9

1

1,1

1,2

0 100 200 300 400 500Pressure [bar]

z [-]110 [°C]90 [°C]70 [°C]50 [°C]30 [°C]10 [°C]

z-“real gas factor“ for natural gas, ρρρρ = 0.565 (Luft =1)


Dynamic Hydrocarbon Calculation

Динамічне визначення об‘єму ВВ

Oil volume (OIP), N

Gas volume (SGIP, GIP), G

Np Gp Wp

Method for „dynamic“HC-volume definition:

Aquifer

Winj

P

„Tank“ for MB, simulation cell


Untypical Oil-Water Contact Configurations

Нетипове розташування контакту води з нафтою


Drive Mechanisms in Reservoirs

Механізми імпульсу в пластах

� Expansion drive (Expansion of Fluids) � Volumetric gas reservoir

� Oil reservoir without gas cap

� Water drive� Natural water drive by aquifer expansion

� Compaction� Compaction of reservoir by overburden

� Water injection� Pressure maintenance in reservoir by water

injection

� Gas(Re)injection� Pressure maintenance in reservoir gas

injection


Example(s) for Oil Reservoirs

Приклад(и) нафтових пластів

Oil field

0

50

100

150

200

0 1000 2000 3000 4000 5000Oil Production [m³ or t]

Pressure [bar]

Oil expansion

Int. Gas, Gas cap Water drive


Graph for Gas Equation

Графік для газового рівняння

0

50

100

150

200

0 100 200 300 400 500Gp Mio [Nm³]

P/z [bar] Scheme for a graphic material balance

„depletion drive“

„displacement“

overpressuredreservoir G


Example of a Graphic Material Balance

Приклад графічного балансу матеріалів

0

50

100

150

200

0 100 200 300 400 500Gp Mio [Nm³]

P/z [bar]

Pi/zi

Well 2Well 3Well 4

Result:

„depletion drive“ without water, G = 490 Mio [Nm³]

G0


Scheme for Well Test

Схема випробування свердловини

HC prone Formation

Fluid (O, G, W)

Pressure

Rate (Volume, Time)


Well Test – 1. Flow Period

Випробування свердловини – 1. робоча фаза

Procedure for OHT and CHT:

Rate

Time

Time

1. Flow period

t1

Pressure


Well Test – 1. Pressure Build Up

Випробування свердловини – 1. зміна тиску

Time

Time

1. Pressure build up

∆∆∆∆t1

Rate

t1

Pressure



Well Test – 2. Flow Period

Випробування свердловини – 2. робоча фаза

Time

Time

2. Flow period

t2

Rate

t1 ∆∆∆∆t1

Pressure



Well Test – 2. Pressure Build Up

Випробування свердловини – 2. зміна тиску

Time

Time


t2 ∆∆∆∆t2

Rate

∆∆∆∆t1t1

Pressure



Well Test – Pressure Build Up Interpretation 1/7

Випробування свердловини – аналіз результатів зміни тиску 1/7

-0.5

0.5

1.5

2.5

-1.5 -0.5 0.5 1.5 2.5

Diagnostic - PlotLog p

Log t



-0.5

0.5

1.5

2.5

-1.5 -0.5 0.5 1.5 2.5

Diagnostic - PlotLog p 1. Pressure Build Up

derivative






-0.5

0.5

1.5

2.5

-1.5 -0.5 0.5 1.5 2.5

Diagnostic - PlotLog p 1. Pressure build up





100

120

140

160

0.0 0.2 0.4 0.6 0.8 1.0

Nach Horner:

pressure

(t+dt)/dt



-0.5

0.5

1.5

2.5

-1.5 -0.5 0.5 1.5 2.5




100

120

140

160

0.0 0.2 0.4 0.6 0.8 1.0

Nach Horner:

(t+dt)/dt



pressure




100

120

140

160

0.0 0.2 0.4 0.6 0.8 1.0

Nach Horner:

pressure

(t+dt)/dt

permeability, k 1

permeability, k 2

k1 ~ k2




100

120

140

160

0.0 0.2 0.4 0.6 0.8 1.0

Nach Horner:

pressureP* ... Reservoir pressure

Inclination 2m:1m ... Fault

m2m

(t+dt)/dt


Initial Saturation

Початкова насиченість

Capillary pressure measurement at core samples

via:

• porous Diaphragma

• centrifuge

• mercury capillary pressure measurement


Saturation Distribution 1/2

Розподілення насиченості 1/2

Result of capillary pressure measurement[bar]

Water saturation, Sw [%]

0

100

200

300

0 20 40 60 80 100

k = 2000 [mD]

k = 20 [mD]

Pc

equivalent to height of HC column

h = Pc /(ρρρρw - ρρρρo)g


Saturation Distribution 2/2

Розподілення насиченості 2/2

-10

0

10

20

30

40

0 20 40 60 80 100

k = 2000 [mD]

k = 20 [mD]

Water saturation, Sw [%]

h[m]

Free Water Table

capillary water

Irreducible water


Fluid Distribution within a Reservoir

Розподілення флюідів всередині пласта


Producing Behavior of an Oil Column

Робочій режим/характер нафтового стовпа


Value of Information

Отримання інформації

Value of Information

Tests:• influx (gas, oil, water and their ratios)

• pressure (initial, reduced; limited reservoir; tight)

• rate (initial rates, production behavior; permeabilities)

Capillary pressure measurements:• saturations (control of volumetrics)

• permeabilities


Definition of Recovery Factor (RF)

Визначення фактору витягання з нафтового пласта

� the Recovery Factor RF is a product of:

� ED ….. Displacement Efficiency

� EV……. Vertical Sweep Efficiency

� EA ……. Areal Sweep Efficiency

RF = ED * EV * EA


Displacement Efficiency ED

Коефіціент витіснення ED

� depends on saturation ratios

� initially Soi (initial oil saturation), Swi (initial water saturation)

and

� at production end Sor (residual oil saturation)

� Soi = (1 – Swi)

� ED = (Soi - Sor) / Soi z.B.: Swi = 0.3 ( Soi = 0.7), Sor = 0.3

� ED = (0.7 – 0.3 ) / 0.3 = 0.571429


Sweep Patterns

Витіснення


Vertical Sweep Efficiency EV

Ефективність вертикального витіснення з пласта EV

� depends on:

� heterogeneity in the reservoir (permeability profile)

� dip of reservoir layer(s)

� mobility ratio of displaced fluid (oil) and displacing fluid (water or gas)

� Density difference between displaced (oil) and displacing fluid (water or gas)


Areal Sweep Efficiency EA

Ефективність витіснення за площею EA

� depends on:

� Heterogeneity of the reservoir

� Mobility ratio between displaced fluid (oil) and fluid to be displaced (water or gas)

� Pattern of production and injection wells


Factors Influencing why Oil is Left Behind in Oil Fields

Фактори впливу на залишки нафти позаду пласта


Attic Oil

Нафта продуктивного пласта над стовпом горизонтальної свердловини


When Drilling Becomes Uneconomic

Коли буріння стає нерентабельним


Maturity Pie Chart of an Oil Field

Секторна діаграма зрілості нафтового родовища


Continue with Chapter 06 – Reserves

Oil & Gas Production Geology – 06 Reserves Assessment

Геологія видобутку нафти і газу – 06 підрахунок запасів

Patos Marinza Heavy Oil Field, Albania



[email protected]

Oil & Gas Production Geology – 06 Reserves Assessment | 2011 | 2

Reserves versus Resources – the BIG Difference

Резерви та ресурси – ВЕЛИКА різниця

Resources are always much higher than Reserves.

In a classification of geological resources (mineral commodities, coal, oil, gas) we usually differentiate between reserves that can be produced economically today with existing technology and at given prices, and potential respectively prospective resources which can only be produced with improved technologies and at higher prices in the future.


Resources Classification System

Система класифікації ресурсів


Gas in Place (GIIP) and Ultimate Recovery (UR)

Геологічні запаси та максимальне витягання

GIIP = A x h x Ф x (1 – Sw) x Bgi

GIIP gas initially in place (m³)

A area (m²)h net pay (m)Ф porosity (%)Sw water saturation (%)Bgi formation volume factor

UR ultimate recovery (m³)

RF recovery factor (%)

UR = GIIP x RF

Reserves = UR - Production


Reserves Classification Terms

Умови класифікації резервів

� Proved

� „Very Likely“ – reserves exhibiting a low degree of uncertainty (~ 90 % confidence level)

� Probable

� „Likely“ – reserves exhibiting low to moderate degree of uncertainty

� Possible

� Potential – reserves exhibiting moderate to high degree of uncertainty


Why are Reserves Important?

Чому резерви важливі?

� Proved

� Generally only category reportable to regulatory agencies

� Generally only category used by lenders

� Probable

� Combined with proved, often the basis for field development plans and commitments (Business Planning!)

� Possible

� Identifies upside potential and areas for further investigation and data collection.


Evaluation Methods

Методи оцінки

� Volumetric Approach (Early Life, Performance Not

Indicative, Complex Reservoirs, Always an Essential Baseline)

� Map, Calculate OIP, Recovery Factor

� Analogy

� Reservoir Simulation

� Performance Approach ( More Mature Fields, Performance Trends

Established, Limited Additional Development, Volumetrics Still Informative)

� Decline Analysis

� Material Balance

� Reservoir Simulation

� Analogy

Геологія видобутку нафти і газу (oil & gas production geology)

Education