Geology formation in the oil fields - Essay Example

Geology formation in the oil fields. Geology is the branch of geography which studies rocks, which are building blocks of the Earth. How these rocks are formed, change and their properties are the subject matter of this subject. This field of study expands over to include hydrocarbons like oil for example. Inorganic minerals which are often found buried deep within the layers of the Earth’s crust. The arrangement of the rocks, the age of the rocks and even the distribution of these rocks are some of the interests for those who study this discipline. The geology formation is also important in the formation of oil. A large number of organic wastes from animals and plants that existed during a certain period on Earth died. These remains of the fossils were crushed, placed under pressure for a long time and the curves in the different status of rocks which lead to the formation of crude oil. Such makes the field of study on such subject matter part and parcel of geology. Fields of Geology include economic geology, mining geology, petroleum geology and engineering geology. Crude oil is a product of pressure, organic matter from ancient living creatures and certain formation of the rocks in the strata. The porous and permeable rock reservoirs are the collection point of the hydrocarbon fuels. This is possible due the accumulation of these liquid oil and gases such as methane and shale gas. There are however some important factors that ensure the conditions are right for the formation of the crude oil. These factors include the existence of what are referred to as source rocks, reservoir rocks, traps and oil and gas seals. Each of the named features should definitely be present in order for the conditions to be optimal and to allow the proper formation of crude oil. Oil and naturally occurring gas come from certain types of rocks. These rocks are sedimentary in type and were deposited in water during the changing phases of the transformation of the Earth. These rocks are known as source rocks (Hunt, 1979, p. 52). Mineral fragments, remains of organic substrates, and moisture. When this type of rocks experience a lot of pressure and heat from the compressing by other layers of rock. The term sedimentary comes from the characteristic of the rock to be formed from sediments, these include organic matter. The sedimentary rocks were usually deposited as soil or mud at the bottom of lakes and oceans. This excessive pressure forces the organic matter from the sedimentary rocks to start to be heated and when the right temperatures reach oil and gases are expelled from these rocks. This makes for the formation of oil and gas. It takes millions of years for this extraction of oil from the sedimentary source rocks to occur. For sufficient volumes of oil and gas to be found it means that even more additional millions of years for the oil collected to be substantial. Source rocks that contain only wood fragments lead to the formation of gas. There also exist rocks which are also necessary in the geology of oil production. One of these rocks is the rocks which are referred to as reservoir rocks (North, 1985, p.35-36). Interconnection of pores which are minute is one of the characteristic of this type of rock. After the oil and gas exit the source rocks, they enter into the tiny holes of the reservoir rock. Storing of the oil and gas that come from the source rocks is the function of the reservoir rock. Seals which are rocks that have no pores and are not permeable. These seals which are also rocks serve as the blocks for the oils and gases. Oil and gas traps refer to when the seals are arranged in such a way that it surrounds reservoir rocks in an arrangement which is known as oil and gas traps (Levorsen, 1967, p. 63). As the oil and gas accumulate up the reservoir rock it might hit an area where it cannot penetrate this is what we call traps. A trap can also be defined as a high point where oil and gas are highly concentrated. This sets the oil and gas in a stable container like setting. There are different types of these traps. The existence of this geological form makes it possible for the exploration of oil. A cap rock is another important feature in oil formation, it overlies the traps and prevents the oil and gases from spilling over the ground. Shale and inorganic salts are common types of this type of feature The two main types of traps are as follows: structural and stratigraphic (Levorsen, 1967, p.64; North, 1985, p. 50). Just as the name suggests the structural traps are formed when the sedimentary rock is deformed. Through volcanic activity, plate tectonics, faulting and folding, the sedimentary rock might be deformed into seals. Due to the difference in the densities, the natural gas will form a layer on top of the crude oil and the oil floats atop the water in the saturated points of the crude oil reservoir. The formation of stratigraphic traps, however involves no external force. Meaning that just as the rocks are originally stratified the different strata that exist means that the reservoir may be sandwiched between two layers of traps. When this happens often the pressure from the water, gas and oil in the reservoir level, creates pressure and thereby making the landscape to form an undulating form which show that there exists a reservoir. To access oil we therefore have to engage in drilling of wells. Exploratory techniques of trying to find if there are commercially viable oil deposits in a region. One of the methods is referred to as seismic exploration and it is utilized in the location of traps that are slightly below the surface. The use of an explosive and a measuring device is usually the method of this technique. An explosion set off at near the surface as the sound travels through the sedimentary layers it is recorded by detectors. Echoes are used to give a picture of the rock structure (Hyne, 2012, p. 21). The different but necessary geological formations that are required to be present before there are oil and gas deposits serve as good indicators. It is therefore necessary to acknowledge that these features are important and keen in understanding of the same will definitely provide insight into minerals especially valuable ones like oil and gas. This knowledge will serve in the long run if one does understand how to apply these same facts in the field and might lead to increased knowledge in this field. Bibliography Hunt, M. J. Petroleum geochemistry and geology. WH Freeman and Company, 1979. Print Hyne, Norman J. Nontechnical guide to petroleum geology, exploration, drilling, and production. PennWell Books, 2012. Print Levorsen, Arville Irving. Geology of petroleum. Ed. Frederick Almet Fulghum Berry. San Francisco: WH Freeman, 1967. Print North, F. K. Petroleum geology. Boston et al.: Allen and Unwin, 1985. Print Read More