A brief summary of Oil and Gas Upstream. PPT includes basic Chemistry, Basic Geology, Oil formation, Migration of Petroleum, Reservoir, porosity, permeability, Geological structures for petroleum entrapment, Exploration methods, Geological methods, Geophysical methods, geophysical methods, seismic methods, seismic methods, gravity methods, magnetic methods, well drilling, preparation to drill, setting the rig, drilling, enhanced oil recovery, EOR, primary oil recovery, secondary oil recovery, thermal recovery, gas injection and chemical injection

1. Oil and Gas:
Upstream
Rohit Bisht
(MBA Oil and Gas Management Graduate)

2. Chemistry
Crude oil, commonly known as petroleum,
is a liquid found within the Earth comprised
of hydrocarbons, organic compounds and
small amounts of metal. While
hydrocarbons are usually the primary
component of crude oil, their composition
can vary from 50%-97% depending on the
type of crude oil and how it is extracted.
Organic compounds like nitrogen, oxygen,
and sulfur typically make-up between 6%-
10% of crude oil while metals such as
copper, nickel, vanadium and iron account
for less than 1% of the total composition.
Crude Oil
Rohit Bisht

3. Basic Geology
Types of Rocks
o Igneous Rocks
o Sedimentary Rocks
o Metamorphic Rocks
Geologic Time Scale
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4. Oil Formation
Conditions for Oil and Gas Formation
There are four requirements necessary to form an oil deposit:
o There must be a source rock
o There must be a heating event
o There must be a reservoir rock
o There must be a trapping mechanism
Oil Maturity
Organic matter is first changed by the
increase in temperature into kerogen,
which is a solid form of hydrocarbon
Around 90°C, it is changed into a liquid
state, called Oil.
Around 150°C, Oil generation dies oil and
only Methane and Hydrogen are produced.Rohit Bisht

5. Migration of Petroleum
The movement of hydrocarbons from their source into reservoir rocks.
The movement of newly generated hydrocarbons out of their source
rock is primary migration also called expulsion. The further
movement of the hydrocarbons into reservoir rock in a hydrocarbon
trap or other area of accumulation is secondary migration
Migration typically occurs from a structurally low area to a higher area
because of the relative buoyancy of hydrocarbons in comparison to the
surrounding rock.
Being lighter than water, petroleum will displace groundwater and flow
upwards and will seep to the surface via faults and porous overburden
unless confined under special circumstances to became trapped and to
form economic petroleum deposits.
Rohit Bisht

6. Reservoir
A petroleum reservoir is a subsurface pool of hydrocarbons contained
in porous or fractured rock formations.
A suitable reservoir rock must be porous, permeable and contain
enough hydrocarbon to make it economically feasible fro the operating
company to drill for and produce them.
Porosity: Porosity of rock is a measure of its ability to hold a fluid.
Porosity = Pore volume/total rock volume x 100%
Permeability: Permeability is a measure of the amount of flow of a
liquid through a rock.
Q = KAD/uL
Rohit Bisht

7. Geological structures for
petroleum entrapment
TRAP: A trap consists of an impervious stratum that overlies the
reservoir rock thereby prohibiting hydrocarbons from escaping upward
and laterally. This impervious stratum is called a roof rock; it
intervenes to collect and hold hydrocarbons underground. The roof
forms a seal, or a barrier, which creates the needed conditions for a
pool.
Classification of Traps:
o Structural Traps
• Anticline Trap
• Fault Trap
o Stratigraphic Traps
• Pinchout
• Truncated
Rohit Bisht

8. Exploration Methods
Preliminary Studies
Surveying marks the elementary phase for oil and gas exploration. In
the first stage of the search for hydrocarbon-bearing rock formations,
geological maps and satellite data are reviewed to identify major
sedimentary basins. Remote sensing and aerial photography may then
be used to identify promising landscape formations such as faults, or
anticlines.
Geological Methods:
o Oil Seeps
The second important point in geological method for surface
exploratory methods includes:
o Preparation of geologic maps of the area
o Preparation of cross section geological formations
Rohit Bisht

9. Geophysical Methods :
Seismic Methods
It is a method of exploration geophysics that uses the principles of seismology to
estimate the properties of the Earth's subsurface from reflected seismic waves. The
method requires a seismic acoustic energy as a source, such as explosives (dynamite)
and vibrators for land surveys or air guns for marine surveys. The reflected signals are
output onto a storage medium, which is usually a magnetic tape. Once the data is
recorded on the tape, it can then be processed using specialist software which will
result in processed seismic profiles being produced.
On land, the typical seismometer used in a reflection experiment is a small, portable
instrument known as a geophone, which converts ground motion into an analog
electrical signal. In water, hydrophones, which convert pressure changes into electrical
signals, are used.
Seismic field acquisition involves three basic elements:
I. a source of acoustic energy
II. seismic receivers - geophones / hydrophones
III. a seismograph or recorder to collect and store the data
Rohit Bisht

10. 2D - When exploring a new area where little is known of the subsurface geology, a 2D
survey is usually performed. It gives an idea about the lithology of the field and the
presence of any geological formations where petroleum can be trapped.
3D - In areas where the larger and more obvious traps are mapped, petroleum explorers
are increasingly using 3D surveys to obtain greater definition. By placing survey lines
much closer together, a more detailed three-dimensional picture can be built.
4D - 3D survey that is carried out at regular intervals to plan the development of the
field. Hence the fourth dimension becomes time.
Gravity methods
Gravity surveys involve taking reading about a kilometer apart throughout the region
with a device called gravimeter. The gravimeter measures the gravitational field and
this reading correlates with the density of the region. By studying the differences in the
density, one can predict which areas of the region might contain oil.
Rohit Bisht

11. Magnetic methods
By measuring the magnetic field, one can tell where there is
likely to be oil because the rocks that may contain oil have very
low magnetic readings. The magnetic field can be measured with
an instrument called magnetometer which can be flown over an
area or used on the ground. Magnetic surveys are usually made
with magnetometers borne by aircraft flying in parallel lines
spaced two to four kilometers apart at an elevation of about 500
meters when exploring for petroleum deposits. Ground surveys
are conducted to follow up magnetic anomaly discoveries made
from the air. Such surveys may involve stations spaced only 50
meters apart
Rohit Bisht

12. Well Drilling
Preparation to Drill
Setting the Rig
Drilling
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13. Preparing to drill
Once the land has been prepared, several holes must be dug to
make way for the rig and the main hole. A rectangular pit, called
a cellar, is dug around the location of the actual drilling hole. The
cellar provides a work space around the hole, for the workers and
drilling accessories. The crew then begins drilling the main hole,
often with a small drill truck rather than the main rig. The first
part of the hole is larger and shallower than the main portion, and
is lined with a large-diameter conductor pipe. Additional holes
are dug off to the side to temporarily store equipment -- when
these holes are finished, the rig equipment can be brought in and
set up.
Rohit Bisht

14. Setting the Rig
Depending upon the remoteness of the drill site and its access,
equipment may be transported to the site by truck, helicopter or
barge. Some rigs are built on ships or barges for work on inland
water where there is no foundation to support a rig (as in marshes
or lakes).
Rohit Bisht

15. Drilling
There are five basic steps to drilling the surface hole:
i. Place the drill bit, collar and drill pipe in the hole.
ii. Attach the kelly and turntable and begin drilling.
iii. As drilling progresses, circulate mud through the pipe and
out of the bit to float the rock cuttings out of the hole.
iv. Add new sections (joints) of drill pipes as the hole gets
deeper.
v. Remove (trip out) the drill pipe, collar and bit when the pre-
set depth (anywhere from a few hundred to a couple-
thousand feet) is reached.
Rohit Bisht

16. Once the final depth is reached, the well to allows il to flow into
the casing in a controlled manner. First, they perforating gun is
lowered a into the well to the production depth. The gun has
explosive charges to create holes in the casing through which oil
can flow. After the casing has been perforated, small-diameter
pipe (tubing) is put into the hole as a conduit for oil and gas to
flow up the well. A device called a packer is run down the outside
of the tubing. When the packer is set at the production level, it is
expanded to form a seal around the outside of the tubing. Finally,
they connect a multi-valved structure called a Christmas tree to
the top of the tubing and cement it to the op of the casing. The
Christmas tree allows them to control the flow of oil from the
well.
Rohit Bisht

17. EOR
Primary Oil Recovery Secondary Oil Recovery Enhanced Oil Recovery
Primary oil recovery refers
to the process of extracting
oil either via the natural
rise of hydrocarbons to the
surface of the earth or via
pump jacks and other
artificial lift devices.
This method involves the
injection of gas or water,
which will displace the oil,
force it to move from its
resting place and bring it to
the surface
Rather than simply trying
to force the oil out of the
ground, as did the previous
two methods, enhanced oil
recovery seeks to alter its
properties to make it more
conducive to extraction.
There are three main types
of enhanced oil recovery:
• Thermal Recovery
• Gas Injection
• Chemical Injection
Rohit Bisht

18. Thermal Recovery. This is the most prevalent type of EOR in the USA
and works by heating the oil to reduce its viscosity and allowing easier
flow to the surface. This is most commonly achieved by introducing
steam into the reservoir, which will work to heat the oil. Less
commonplace is the practice of burning part of the oil in order to heat
the rest (fire flooding or in-situ burning).
Gas Injection. Either natural gas, nitrogen or carbon dioxide
(increasingly the most popular option) are injected into the reservoir to
mix with the oil, making it more viscous, whilst simultaneously
pushing the oil to the surface (similar to secondary oil recovery).
Chemical Injection. The least common method of EOR, chemical
injection works by freeing trapped oil in the well. This is done by
lowering surface tension and increasing the efficiency of water-
flooding.
Rohit Bisht