Geology and the Petroleum Industry

The basic question which comes in mind when reading the headline or any article's heading is what it is all about. Same question comes in mind when someone read this article who does not know about geology. This is the reason I explain everything from basics to advance (technical) level in almost all of my articles.

Geology in very simple concept is just study about earth. Different scientists define geology in different ways but the theme of all the definitions is "study about earth". In addition geology has been revolutionized by introduction of "Theory of Plate Tectonics".


According to me geology can be completely defined as "The scientific study of the origin, history and structure of the earth".

Geology has many different fields but the fields which are mentioned below are essentials of petroleum industry.

• Petroleum Geology: It is the branch of economic geology that deals with occurrence and exploitation of oil and gas fields.

• Sedimentary and Stratigrapy Geology: Sedimentary geology is the study of sediments (small particles of sand, mud, clay) and its deposition. Sedimentology has strong relation with stratigraphy geology which is study of relationship between rock layers.

• Structural Geology: It is the study about structure of earth in order to learn about tectonic history, environments and events which are responsible for changes in earth's structure.

• Paleontology OR Palaeontology: It is the study about fossils (preserved remains of plants, animals and other organisms). The word fossil is derived from Latin word fossus.

• Biostratigraphy: It is an effort to figure out how old a certain layer of rock and sediment is. It is based on study of fossils to determine the age of rock layers.         

              

• Geophysics: It is the study of physical properties of earth such as earth's size and gravity using physics.

• Geochemistry: It involves the study of chemical composition of earth. With the help of chemical composition of different rocks and soil samples geologists can identify the presence of petroleum because of the presence of minerals and elements present in different types of rock and soil.

Importance of Geologists in Petroleum Industry

Geologist's role now days in petroleum industry has widely expanded because the price of oil and gas is touching sky these days. This is due to shortage of oil and gas. Petroleum industry is struggling hard to find and hire experienced geologists and they are paying good salaries to them.

 Importance of Geology in Petroleum Industry

Above discussion of importance of petroleum geologists and various fields of geology in petroleum industry gives crystal clear vision of its importance in petroleum industry.

"In short without scientific study of earth we are not able to discover oil and gas and this is the precious gift of geology that crude oil is fulfilling our energy requirements".  

Article by Eng Fahad

Hope you find this information helpful and do not forget to share your ideas!

Complete story of BLACK-GOLD (Oil and Gas)

CRUDE OIL (complex mixture) is commonly known as black gold. Today the war in this world is of black gold and future wars will be on energy sources. Sometime the question comes in mind when we purchase oil and gas from fuel stations for our vehicles or for any other usage that from where it came to us in this form of gasoline (petrol) or natural gas and what processes and people are involved behind the scene in the production of oil and gas from subsurface.
Story of oil and gas is as old as creation of our planet (Earth) which is 4.6 billion years ago. Many scientists and researchers propose different concepts and theories about the origin of petroleum but most commonly and widely accepted theories are only two

1. Organic
2. Inorganic

The scientists who support organic theory believe that oil and gas forms beneath the earth through different processes and mechanisms related to life (living things). According to these scientists oil and gas forms when living organisms (Plants and Animals) died millions of years ago and deposited at the bottom of ancient rivers and seas in the form of layers, the process known as sedimentation. After deposition of many layers, pressure of layers and heat inside the earth turned the animals and plants into viscous material known as kerogen (large complex organic molecular structure). Then due to temperature differences kerogen is converted into oil and gas. After these complex processes and mechanisms oil and gas migration begins and finally the oil and gas are going to accumulate into petroleum traps. Traps are just like container that are capable of holding something e.g. oil, gas, water or any thing. Died animals generate oil and died plants generate gas. This theory is widely accepted as compared to any other theory because the petroleum reserves of the world predicted from this theory are most accurate.

Inorganic theory first put forward in early 1800s. Inorganic theory is not common and the petroleum reserves predicted from this theory are greater in amount as compared to organic theory. The theme of inorganic theory is that the petroleum is left over from the formation of solar system or was formed later deep with in the earth. Due to presence of hydrogen and impurities in crude oil, scientists support this theory. Geologists that support inorganic theory also believe that it explains why petroleum taken from a large area is often chemically similar even though the formations where it was found are made of different type of rocks of different geological ages.

Conforming the presence of petroleum and extracting it from subsurface is not a job for every one. Mainly there are four departments involved

1. Geology
2. Reservoir
3. Drilling
4. Production

Geology is the study about earth. Geologists survey the earth and find the presence of hydrocarbons (oil and gas) through different techniques mainly seismic survey. Finally geologists indicate the point of drilling.

Reservoir is just like pool and an oil reservoir is just like pool or pond of oil. Reservoir engineers work in conjunction with Geologists and the main work of reservoir engineer is to estimate the amount of recoverable hydrocarbons from reservoir.

Drilling is the technique to make a hole. Drilling the oil and gas wells is the toughest job because the driller has to go hundreds of thousands of meters inside the earth where extreme temperatures and pressures are present which are most difficult to handle. Drilling engineers goal is to hit the target where oil and gas is present inside the earth and make clear path between the subsurface and surface for production of crude oil.

Finally the production engineers are going to handle pressures of oil and gas which is coming from subsurface and production surface facility is installed. The main equipment of surface facility is X-mass tree (Assembly of valves). Pressure is handle through different assemblies of valves and chokes and finally crude oil is transported through pipe lines, bouzers etc to Refinery.

Refinery is the final stage of crude oil processing. As we know crude oil is complex mixture. In refinery crude oil is bifurcated into different products e.g. Diesel Oil, Gasoline (petrol), Natural Gas etc due to temperature differences. After bifurcation of crude oil the role of marketing begins and refinery sells crude oil products to industries, fuel stations, power plants etc.

Article written by Engineer Fahad.....

Purpose of this article is to give idea about crude oil production to non technical person

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How to "BUILD,HOLD and DROP" in DIRECTIONAL WELL

There are basically two types of directional well designs

1. Build and Hold
2. Build, Hold and Drop ( S-Type)

These two profiles are basic profiles. We can design our own profile that we need for our well that well is called as "DESIGNERS WELL".

Now the point is this how we can build angle then we have to hold (maintain angle) the angle and if the profile is S-type then we have also to drop.

These three main steps are mainly dependent on Bottom Hole Assemblies. For each purpose we have to use different bottom hole assembly.

Now First of all we have to build angle for building the angle we will use Fulcurm Assembly then after building the angle we have to maintain it then for maintaing anlge we will use Packed-Hole Bottom Hole Assembly and finally in the drop section in which the well is vertical we use common bottom hole assembly which we use to drill vertical wells known as Pendulum Assembly.

In all of these assemblies only the difference is of arranging drill collars,heavy weight drill pipes and stablizers mainly.

This is small article generated by me......

Hope you find this little information helpful

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DIRECTIONAL DRILLING AND APPLICATIONS OF DIRECTIONAL DRILLING

Definition of Directional Drilling

Directional drilling can generally be defined as the science of directing a
wellbore along a predetermined trajectory to intersect a designated subsurface
target.

Applications

Multiple wells from offshore structures

The most common application of directional drilling techniques is in
offshore drilling. Many oil and gas deposits are situated well beyond the
reach of land based rigs. Drilling a large number of vertical wells from
individual platforms is both impractical and uneconomical. The obvious
approach for a large oilfield is to install a fixed platform on the seabed,
from which many directional boreholes can be drilled. The bottomhole
locations of these wells are carefully spaced for optimum recovery.
In conventional development, wells cannot be drilled until the platform has
been constructed and installed. This can mean a delay of several years
before production begins. Such delay scan be considerably reduced by predrilling
some of the wells through a subsea template while the platform is
being constructed. These wells are directionally drilled from a semisubmersible
rig and tied back to the platform once it has been installed.

Relief Wells

Directional techniques are used to drill relief wells in order to “kill”
blowouts. Relief wells are deviated to pass as close as possible to the
uncontrolled well. Heavy mud is pumped into the reservoir to overcome
the pressure and bring the wild well under control.

Controlling Vertical Wells

Directional techniques are used to “straighten crooked holes”. When
deviation occurs in a well which is supposed to be vertical, various
techniques can be used to bring the well back to vertical. This was one of
the earliest applications of directional drilling.

Sidetracking

Sidetracking out of an existing wellbore is another application of
directional drilling. This is done to bypass an obstruction (“fish”) in the
original wellbore, to explore the extent of a producing zone in a certain
sector of a field, or to sidetrack a dry hole to a more promising target.
Wells are also sidetracked to access more reservoir by drilling a horizontal
hole section from the existing well bore.

Inaccessible locations

Directional wells are often drilled because the surface location directly
above the reservoir is inaccessible, either because of natural or man-made
obstacles.

Fault Drilling

Directional wells are also drilled to avoid drilling a vertical well through a
steeply inclined fault plane which could slip and shear the casing.

Salt Dome Drilling

Directional drilling programs are sometimes used to overcome the
problems of drilling near salt domes. Instead of drilling through the salt,
the well is drilled at one side of the dome and is then deviated around and
underneath the overhanging cap.

Shoreline Drilling

In the case where a reservoir lies offshore but quite close to land, the most
economical way to exploit the reservoir may be to drill directional wells
from a land rig on the coast.


These are only some of the many applications of directional drilling.
Although it is not a new concept, one type of directional drilling, horizontal
drilling, is the fastest growing branch of drilling, with major advances
occurring in tools and techniques. As with directional drilling, there are
numerous specific applications for horizontal drilling.



PLEASE COMMENT AND SHARE ANY KNOWLEDGE AND YOUR IDEAS  REGARDING DIRECTIONAL DRILLING!

Bismillah Arheman Arhim

Salam to every one this is the general petroleum and natural gas forum. Every one can share any valuable knowledge or any helpfull information or books download links or any thing related to petroleum and natural gas.

Regards

Eng Fahad Ahmed....