Two properties are required for fluid movement of Reservoir rocks and Source rocks: permeability and porosity. It consist voids or pores, ability to contain fluid (known as porosity) and the pores are interconnected (permeability) in order to allow flow to occur. Hydrocarbons can be termed as reservoir fluid. The volume of hydrocarbons stored in a reservoir depends upon the porosity of the reservoir rock. The rate and volume at which hydrocarbons are withdrawn depends upon the permeability of the reservoir rock. Almost complete pore space of the superior several kilometres of earth’s crust contains water. Therefore in this water environment hydrocarbons exist with amalgamation of oil, gas and water occurring in different proportions.
The two dominant physical properties of oil and gas that enhance their movement through subsurface substance are their relative immiscibility in water and their lower density than water which causes their buoyancy. Buoyancy of the hydrocarbons occurs because of differences in densities of respective fluids while transcend via the oil and gas reservoir is a stimuli which creates differential pressures that exist in a reservoir bed.
The basic properties of rocks can be classified as the following:
Skeletal
The "skeleton" structures of the rocks of reservoir are affected by the depositional surrounding and numerous earth processes after deposition.
Dynamic
This is related to the blending of the fluids and rocks of the reservoir. Skeletal properties of interest to reservoir engineers include porosity, pore size distribution, compressibility, and absolute permeability of the rod. Interaction or dynamic properties of reservoir rocks are affected by the nature and by its interaction with present fluids, as...
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...a producing well is significantly lower than at other areas where no well is drilled. The driving force could be either natural or created by engineering design involving fluid injection through certain wells placed optimally to achieve the best results. Experimental data suggests that reservoir rocks are abundantly permeable in both vertical and horizontal directions. Among a myriad of factors related to geological and geochemical processes, the permeability of a rock is influenced by the slit, shape, configuration, and connectivity or a porous network.
Darcy Equation and its Application
Darcy’s law provides an accurate description of the flow of ground water in almost all hydrogeological environments. Henri Darcy established empirically that the flux of water through a permeable formation is proportional to the distance between top and bottom of the soil column.
Gas in shale formations are“low in permeability,” making it very tedious to extract, but with the increase in technological knowledge in fracking and horizontally drilling into shale beds, the vast reserves of natural gas resource could be extracted (4). Fracking is a large industrial operation that boost the “productivity of a oil or gas well” (5). It is a process by which, under very high pressure, a mixture of water, chemicals, and sand, are pumped into shale formations that causes fractures in the rocks to open wider or create new fractures that would allow otherwise trapped oil and gas to flow into the wells (6).
Offshore oil drilling refers to a mechanical process in which a wellbore is drilled through the seabed in search for petroleum that lies in rock formations. In 1891, the first oil wells were submerged in the Grand Lake St. Marys in Ohio. Since that day they have expanded their range of oil drilling, and our ecosystems are now paying the price for it. I think that offshore oil drilling should be banned because it is ruining the environment, hurting marine wildlife, and even has a negative affect on us humans.
...luence on migration, aggregation and forming reservoir. There have two aspects. On the one hand, the development of cracks in the shale can greatly improve the permeability of the reservoir; it also can increase the aggregate amount of free gas; and it can promote the migration of shale gas as a drainage system.
Throughout the past three decades, energy has been a perennial issue in United States politics, economics, and media. The main concern surrounding this topic is the idea of energy independence and how the United States should proceed into the future. Energy independence relates to the goal of reducing United States dependence on importing foreign oil and other foreign energy sources. This desire aims to maintain energy dependence domestically so the United States can avoid reliance on any unstable countries and be detached from global energy supply distribution. It is currently being speculated that the United States might not be too far off from this goal. America’s dependence on foreign oil has gone down every single year since 2007. In 2010, the U.S. imported less than 50 percent of the oil the country consumed -- the first time that’s happened in 13 years -- and the trend continued in 2011 (Zhang.) Experts credit new technology as the reason the United States is within several years of again becoming the biggest oil producer in the world, and perhaps two decades away from full energy independence. Hydraulic fracturing, fracking, is the “lead” technology in this technological revolution. Fracking is an economically more feasible way of drilling for oil or gas in harder to reach geological formation. Within the past decade or so, combining hydraulic fracturing with horizontal drilling has opened up shale deposits across the country. It has brought large-scale natural gas drilling to new regions that may not have had accessible deposits in the past. These areas have greatly benefited from the addition of this industry to their local economies. Certain are...
What is Hydraulic Fracturing or as some refer to as Fracking? Hydraulic Fracturing or Fracking is a method of mining. The process of drilling and injecting fluid into the ground at high pressure in order to crack shale rocks and release trapped natural gas from the ground. Fracking was first used in 1947, at the Hugoton field in southwestern Kansas. Stanolind Oil (AMOCO) was the company that conducted the experimental fracking method. Floyd Farris, who works for AMOCO, is the person who preformed studies of the pressure of injecting water and certain chemicals into oil and gas wells; the process of fracking was introduced. Fracking can produce a lot of energy, but it also has the potential to harm the environment. One question that is asked is “Will Fracking affect our water that we drink and change our lifestyle?” America could become independent on energy if there is more fracking. Independence on gas and oil would help all of our country.
Once this natural gas forms, it depends on two very critical characteristics of the surrounding rock: porosity and permeability. POPOSITY is referred to as the amount of empty space there is within the grains of the rock. Highly porous rocks like sandstones, on a good day have porosities of 5% to 25%. this gives them a large amount of space to store fluids like oil, water, and gas. PERMEABILITY is a measure of the degree in which the pore spaces in a rock are interconnected. A rock with high permeability will let more gas and liquids to flow very easily through the rock.
Fracking is a procedure that uses high-pressure fluids to obtain shale gas through the drilling of underground rocks. According to Broderick et all (2011), shale gas1 is found trapped within the shale2 formations, it is a very flexible substance as it has a wide range of uses, such as automobile fuels, domestic use and power generation. Nowadays, the gas demand is increasing vastly. Shale gas is one of the main sources of energy for some countries, such as United States of America and United Kingdom (Broderick et al. 2011). The low permeability3 of the shale makes difficult the flow of the gas inside it, therefore, it makes inviable to extract the substance without the support of hydraulic fracturing. Higher the permeability of a rock, higher the flowing of the fluid on it (King 2012). In order to improve the shale gas extraction, a high pressure mixture of water, sand and other additives is injected in the rock to increase its fractures and facilitates the flowing of the gas and its capture (Howarth et al. 2011). The figure below illustrates the fracking process.
Hydrocarbon recovery forms the crux of the oil and gas energy. Ever since petroleum was established as a source of energy, the oil and industry has always persevered to improve and optimize conventional recovery techniques in an effort to boost production and profits. Nevertheless, the increased over- dependency on hydrocarbons has exhausted reserved from the most commercially viable wells/plays, which is to say that wells requiring standard exploration and production techniques are now on a decline. However, oil and gas deposits are very much available in many regions as shown in Figure 1.1. Most of them exist as unconventional resources usually treated as possible reserves.
As internal processes, mountain building and volcanic activity, elevate Earth’s surfaces, external processes, weathering and erosion, breakdown and move Earth’s surfaces down slope. It’s a continuous rock cycle, and water movement contributes greatly to Earth’s external weathering and erosion processes, sculpting earth’s surfaces throughout the course. As water evaporates from the ocean and precipitates over the mountains, river systems are established; and in their many shapes and forms, move eroded rock material from the surface towards the ocean, further disintegrating material along the way. River systems move Earth’s surface materials, while shaping its landscapes.
Every rock group has a different depositional environment. For example, the Kawr group represents the Oman Exotics and is composed of distal sediments (chert). Closer t...
Permeability is a measure of the ease of flow of a fluid through a porous solid. A rock may be extremely porous, but if the pores are not connected, it will have no permeability. Likewise, a rock may have a few continuous cracks which allow ease of fluid flow, but when porosity is calculated, the rock doesn't seem very porous.
Permeability is defined as the ability of porous medium to transmit fluids through it. Permeability controls how fluid can migrate through the reservoir. The permeability is a main parameter in reservoir development and management because it controls the production rate. Generally, the permeability increases with increasing porosity, increasing grain size and improved sorting (SeIley, 1998; Tagavi, 2005). In carbonates rocks connectivity between pores is the main control for the permeability. Heterogeneity arises in carbonate reservoirs as a result of variation in depositional environment and subsequence diagenetic processes.
My bachelor degree in Applied Geology led me to acquire a strong background of concepts such as structural Geology, Basics of Geophysics, Exploration Geophysics, Physics of the Earth and Petroleum geology. With extensive research and discussions with my professors and professionals linked with oil and gas industry, I chose Geophysics as my area of interest for my graduation.
Production changes, carried out during a transient well test, induce pressure disturbances in the wellbore and surrounding rock. This disturbances extend into the formation and are affected in various ways by the rock features. For example, a low permeable rock will restrict the pass of the pressure wave. Therefore, a record of the pressure response over time produces a curve whose shape is defined by the reservoir’s unique characteristics.