Intro Petroleum System

7/29/2019 Intro Petroleum System

http://slidepdf.com/reader/full/intro-petroleum-system 1/33

PETROLEUM SYSTEM – AN OVERVIEW

Saloma Yomdo, Oil India Limited



AGENDA



Fish Fossil

Plant fossil

WHAT IS OIL ?

•CRUDE OIL, OR PETROLEUM, IS AN

ORGANIC SUBSTANCE DERIVED FROM

THE REMAINS OF PREHISTORIC PLANT

AND ANIMAL MATTER.

•IT IS A MIXTURE OF HYDROCARBONS,

I.E. MOLECULES CONTAINING

HYDROGEN AND CARBON, WHICHEXIST SOMETIMES IN LIQUID FORM

(CRUDE OIL) AND SOMETIMES AS A

VAPOUR (NATURAL GAS).

http://thumbpicked%282%29/

http://thumbpicked%282%29/



SOME PEOPLE THINK THAT OIL IS IN BIG POOLS

UNDERGROUND.

ACTUALLY, MOST OIL IS TRAPPED IN THE TINY PORE SPACES

BETWEEN GRAINS OF ROCK OR SAND. MOST OF THESE

PORES ARE TOO SMALL TO BE SEEN WITH THE NAKED EYE.



ORIGIN OF OIL

OIL IS FORMED FROM ORGANIC MATTER

(REMAINS OF TINY PLANTS AND ORGANISMS).

ORGANISIMS MUST ACCUMULATED, BURIED AND PRESERVED BY

FINE SEDIMENTS

PRESSURE, TEMPERATURE AND BACTERIAL ACTION CONVERT

THEM TO HYDROCARBON

ANAEROBIC BACTERIA REMOVE OXYGEN, NITROGEN,

PHOSPHORUS AND SULFUR AND CONVERT THEM TO PETROLEUM

IN FAVOURABLE TEMPERATURE AND PRESSURE CONDITIONS



ORIGIN OF OIL

Inorganic Theory :

According to the inorganic theory, hydrogenand carbon reacted together under immense

pressure and temperature far below the earth

surface and formed Oil and Gas. These

hydrocarbon then migrated through porous

rocks to collect in various subsurface traps.

Organic Theory :

The more widely accepted organic theory

states that the hydrocarbons were generated

from organic matter (land and sea plants andanimals) under the influence of pressure and

temperature over geologic time.

Organic Theory



CLEAN SANDSTONE

Clean Sandstone

• Well rounded grains

• Effective porosity

• Permeability

Clean Sandstone



PETROLEUM SYSTEM

Accumulation

Source Rock

r

120° F120° F

350° F350° FGenerationGeneration

MigrationMigration

Seal RockSeal RockReservoir RockReservoirRock

OilOil

WaterWater

Gas CapGasCap

EntrapmentEntrapment



MIGRATION OF HYDROCARBON

o DUE TO OVERBURDEN PRESSURE OIL IS SQUEEZED OUT OF THE SOURCE

ROCK AND MOVES /MIGRATES TO THE RESERVOIR ROCK. THIS PROCESS

IS CALLED MIGRATION.

Trap

GASOIL

Primary

Migration

Secondary

Migration

PRIMARY MIGRATION - SOURCE ROCKS TO RESERVOIR

SECONDARY AND TERTIARY MIGRATION - WITHIN RESERVOIR



Surface Trap

Sub - Surface Trap

Petroleum Traps



How Do We Find Oil?

• Oil reservoirs are located bymapping the subsurface

geology by seismic

acquisition

•

To do this, dynamites aredetonated on the surface,

and the resulting signals are

processed

• The processed data is then

analyzed and interpreted to

produce subsurface maps,

on which prospects can be

located.



Reaching The Oil

• Oil wells are drilled bydedicated drilling rigs that work24x7 to reach their targetdepth.

• Wells are drilled throughnarrow holes (varying from 30”to 6” in diameter)

• Drilling involves a lot of risks asit is very difficult to predictwhat layer of rock we mightencounter, what pressures and

temperatures might bepresent.

• Once drilling is over, aproduction setup is installed atthe wellhead.



Producing the Oil

• Oil wells are produced via a

production setup, called a

Christmas tree. It is an

assembly of valves and helps

to distribute the flow of oilinto the surface pipelines.

• When the production

declines, artificial lifting

mechanisms are installed,like Gas Lift, Sucker Rods, or

submersible pumps.



WaterWater

OIL OIL

GasGas

OIL + Gas

(Associated gas)

Associated Gas (Solution Gas ) Reservoir

Evolution of Solution Gas



Associated Gas (Gas Cap Gas ) Reservoir

OIL + Gas solution gasGas

Gas-cap-gas

OIL

Gas

OIL

Gas

Water Water

Expansion of the

Gas-Cap-Gas



Water Water

Gas Gas

Non-Associated Gas Reservoir

(Non-Associated gas)

Gas



Source: US Department of Energy, National Energy Technology Laboratory

OIL PRODUCTION



SURFACE SEPARATION OF

CRUDE OIL INTO OIL, GAS ANDWATER ON PRODUCTION

PLATFORMS

STORAGE OF CRUDE OIL IN

TANK FARMS

WELLS DRILLED INTO A

RESERVOIR – CRUDE OIL AND

NATURAL GAS PRODUCED



RESERVOIR LIFE PROCESS

EXPLORATION

DISCOVERY

DELINEATION

DEVELOPMENT

PRIMARY

SECONDARY

TERTIARY

ABANDONMENT



IOR Processes

Productionenhancement

• Optimizing

artificial lift• Increasing well

stimulation

• Re-activating idlewells

• De-bottleneckingfacilities

Drilling / wellintervention

methods

• Infill/step-out

drilling• Re-completion

• Workover

• Deepening

Secondary recovery

• Water flooding

• Gas flooding(immiscible)

Enhanced oilrecovery

• Gas flooding –

CO2

• Condensateflooding

• Microbial (MEOR)

• Surfactant(chemical)

• Polymer• Thermal



Field Size Distribution (FSD)

FSD in a basin Shows Lognormal distribution

•Very small fields - Few•Small fields - Many•Medium-size fields - Handful•Large fields - Very few

• FSD typically shifts towards smaller sizes as exploration matures

• Exploration and development opportunities diminish over time

in a mature basin



Peak Oil – not just jargon

According to the theory of peak oil, worldwide reservesof petroleum have reachedtheir maximum.

New discoveries will not push

reserve replenishment figuresto where it was in the past

Further discoveries of oilfieldswill only help stem thedecline in reserves

Going by the trend of

exploration and productionthe world over, the theory of peak oil has been provedbeyond doubt.



Reservoir Management Critical

Decreasing discovery trend

Insufficient production

Increasing consumption

Increasing exploration costs

Thrust to maximize recovery fromestablished reserves



The Concept of Reservoir Management

RESERVOIRMANAGEMENT

Productionengineering

Reservoirengineering

Gas andchemical

engineering

Environmentaland legal aspects

Economics andmanagement

Research andservice labs

Productionoperations

Drilling

Design andconstructionengineering

Geology andgeophysics

fl f d



Influence of Primary Producing

Mechanisms on Reservoir Pressure and

Recovery Efficiency

Recovery Efficiency, % OOIP

10 20 30 40 50 60

R e s e r v o i r

P r e s s u r e ,

% O

r i g i n a l P r e s s u r e

20

40

60

80

100Liquid and Rock Expansion

Solution Gas Drive

Gas Cap Expansion

Water Influx

Gravity Drainage

Through proper reservoir

management, it is aimed tokeep the graph following this

pattern, in order to maximize

recovery



INTEGRATION AND TEAMWORK

PEOPLE

MANAGEMENT

ENGINEERS

LAND/LEGAL

FIELD

FINANCIAL

DATA

GEOLOGICAL

GEOPHYSICAL

RESERVOIR

ENGINEERING

FINANCIAL

TOOLS

SEISMICINTERPRETATION

DATA ACQUISITION

LOGGING

CORING

FACILITIES

SIMULATORS

EOR

PRESSURE TRANSIENT

TECHNOLOGY

SEISMIC

GEOLOGIC

GEOSTATISTICS

ENGINEERING

DRILLING

COMPLETIONS

EOR

HSE

T I t ti



Team Integration

(G&G and Reservoir Engg.)

Flat spot recognised on seismic,implying presence of gas.

Secondary gas saturation from gas injection

observed in simulation model.

Model validated and loop closed.

Moran Field

New Approaches



New Approaches

(3D Static and Dynamic Modelling)3D geocellular modelling captures

the complex sand-body geometries



Virtual realization of the Geological model

KALPALOK

VIRTUAL REALIZATION CENTREOIL INDIA LIMITED, DULIAJAN

RESERVOIR



RESERVOIR

SIMULATIONHelps to view the effects of

production and injection plans

on the reservoir in the past, as

well as helps us forecast future

production trends

In simulation, the entire

reservoir is converted into a

cyber grid, and using

processed seismic, geologicaland petrophysical data, the

model is made to resemble the

reservoir as best as possible.



Category-I:

Proved petroliferous basins with

commercial production

Category-II:

Basins with known occurrence

of hydrocarbons but from which

no commercial production has

been yet obtained

Category-III:

Basins with no significanthydrocarbon shows but

assumed prospective on

geological considerations

Category-IV:

Frontier basins with uncertain

prospects. Deemed prospectiveon analogy with similar basins

worldwide

Category-V

Offshore basins

Deep Waters

Indian Petroleum Basins : An OverviewSedimentary Basins



“We usually find oil in new places with old ideas. Sometimes,

we also find oil in an old place with a new idea, - but seldom

we find much oil in an old place with an old idea. Severaltimes in the past, we have thought that we were running out

of oil, whereas we were actually running out of ideas.”

Parke Atherton Dickey



Documents

Intro Petroleum System