2.2 Permeability Calculation
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.
The permeability of a reservoir can be measured in many ways including wire line log analysis
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In their model, they also included the porosity and cementation and tortuosity factor w (Eq. 2.18). The difficult point of this model was the determination of the parameter w.
K^0.5= C/W^4 (∅^2w/(Rw⁄Rt)) Equation (2.18)
Where, W is tortuosity factor; Rw,Rt water and true resistivity
Yao and Holditch (1993) introduced a method to calculate permeability using well log data in tight formations. The model involved porosity, deep and shallow resistivity, and GR (Eq. 2.19) and showed a moderate to strong correlation with core permeability, R2 > 0.7.
K=(∅^e1 (〖1-IGR)〗^e2 Rild^e3)/((〖Rild/Rsfl)〗^e4 ) Equation (2.19)
Where, IGR is gamma log index and Rild,Rsfl are deep ,shallow resistivity.
Saner et al. (1997) recognized an experimental estimator for permeability with water saturation and resistivity, which were determined by resistivity well log data. The study was done using carbonate samples. The resulted relation was between formation factor and permeability (Eq. 2.20). log〖(K)=7.04-4.19*〗 log〖(F) Equation (2.20) 〗
Where, F is formation
purpose we use this for is to drill wells into so that we may obtain the water that
In conclusion table 10-1 on page 292 list the three types of models. These models provide
The amount of water required and the different chemical additives used in the frac fluid is what poses a threat to the safety, health and welfare of the public. Hydraulic fracturing uses concoction of slush water, sand and chemicals combined with pressure to stimulate to either create or expand cracks in the shale. One of the main concerns is the large amount of fresh water used and lost in todays fracturing techniques. Certain fracturing techniques can use to 8 millions gallons of water, either freshwater or treated produced water. This freshwater makes up about 98% to 99% of the total volume of the slush (fracfocus.org). After the frac is done the w...
The rock coquina is originally a sedimentary rock. Sedimentary rocks are made up of sediments. The sediments are formed by the mechanical or chemical activities of the natural activities like running water, blowing wind, glaciers etc. this which causes disintegration and decomposition of the pre-existing rocks. The products of decay are transported to some depositional sites by the natural agencies, where they get deposited and with subsequent compaction form sedimentary rocks (Hefferan, O’Brien, 2010). . The sedimentary rocks usually accumulate under a great variety of conditions. This shows the variation in rock, chemical structure as well as in texture. Weathering is the most important process that operates in the formation of sedimentary rocks. Weathering takes place by three methods as: mechanical disintegration, rock decomposition, and biological weathering. Mechanical disintegration is due to frost action, thermal expansion and contraction, aided with gravitational forces. Due to mechanical disintegration, the reduction of size and desegregation of rocks takes place. Chemical weathering is the use of the chemical elements of the atmosphere such as moisture, carbon dioxide, and oxygen (Hefferan, O’Brien, 2010). . This depends on the composition of the rock and the size of the particles that make up them. Biological weathering is a form of weathering caused by growth of roots and burrowing of animals. The environment of a sedimentary rock can show the deposition the quality and quantity of the deposition is affected. Sedi¬mentary rocks differ from environment to environment. These environments include the continental environments such as estuarine, lacustrine (fresh and salt water), deltaic, glacial. Anothe...
(Mazzassa – Lea's science). Calcium silicate hydrate is the fundamental result of lime-pozzolan response. Calcium aluminous hydrate, hydrated gehlenite, calcium carboaluminate, ettringite and calcium aluminous monosulfate are a percentage of alternate items that outcome from the lime-pozzolan response notwithstanding calcium silicate hydrate. (Admixtures for cement T.erdogan). The hydration between slica of pozzolans and calcium hydroxide are given by mathematical statement.
A system of injection wells is used to place the carbon dioxide into the geologic formation. An injection well is like an oil well or a water well, except that instead of drawing oil or water out of the ground, carbon dioxide is injected into the well.
Solubility is defined as the greatest amount of a solid, liquid or gaseous chemical substance that will dissolve in equilibrium in a specified volume of solid, liquid or gaseous solvent at a particular temperature or pressure to form a homogenous solution. Meanwhile, dissolution is a process whereby the solid chemical substance is dissolved in the solvent to form a solution.
They wanted to try to develop a water-based mud that would not have a strong effect on the Pierre shale and would be environmental friendly to dispose of the cuttings. They studied the PDC bits in order to help the drilling rates while drilling through this troublesome shale. They performed the project with two 8 1/2 –in PDC drill bits and nine different types of drilling fluids. Two of the drilling fluids were oil based while seven of the drilling fluids were water based. The different types of drilling fluids can be seen in figure two. The cores used for the experiment came from outcrops of the Pierre shale in Colorado and they were preserved in diesel oil in order to make the shale fully saturated during the experiment and this would model a soft formation where bit balling would be prevalent [5]. The two experimenters also used two types of PDC bits for the experiment; a steel-body ribbed PDC and a matrix-body bladed PDC bit. Hemphill and Clark ran many different tests changing the flow rate, weight on bit, drilling fluids, and the two different drill bits. They first concluded that the two different bits had different penetration rates for the Pierre shale. The matrix bodied bladed bit drilled faster than the steel body bladed bit in all of the mud samples
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.
In the United States today, one of the most controversial topics facing the country is the practice of fracking, or hydraulic fracturing. It is considered by many to be both an environmental issue and topic of intense political debate. However, despite the strong feelings that many people have on the subject, a small percentage of them actually understand the techniques that fracking utilizes. And it is easy to fear or avoid something that little is known about. To formulate an adequate opinion on the process of fracking, a person has to have a grasp of the science that goes into it and a bit of its history. Fracking is a process that increases the effective porosity, or permeability, of a rock’s subsurface. Porosity is a measure of the volume
One of the biggest natural resources used in fracking is water. On average, around one to eight million gallons of water are used on a fracture job. There are also around 500,000 active fracture sites around the world and each site can be fractured around 18 times. This means that roughly 72 trill...
Filters are the means of controlling and directing the flow of seepage water through dams for hundreds of years. Filters are used to prevent movement of soil particles from or between various zones and foundations of embankment dams. Such movement, if not controlled, can result in the development of concentrated leaks that can lead to serious consequences and, in extreme cases, failure of an embankment dam. In fact, approximately 50% of all dam failures are attributed to excess seepage. These sort of failures are progressive in nature and begi...
News: Long Valley Exploratory Well. Information Network: International Continental Scientific Drilling Program. GeoForschungsZentrum PotsdamDecember 5, 2003. <http://icdp.gfzpotsdam.de/sites/longvalley/news/news.html>
Vertical gauges are typically installed in pieces of 2.0 meter lengths; there should be enough length so that it surpasses the maximum flood level. The zero of the gauges should correspond with the lowest possible water level when dealing with water controlled by a weir. For naturally controlled stations, the zero must be lower than the lowest water level in rivers that are relatively constant year round and lower than the lowest bed level in rivers that do not maintain a water level year round...
Salt dilution method is used in mountain rivers with rough cross section, big boulders and turbulent flow. An electrical conductivity (EC) meter was used for discharge measurement. Salt dilution method is particularly used for measurement of flow in mountainous stream and any other sites where high degree of turbulence exists to ensure complete mixing of injected solution in the pre-determined length of the channel. Under such condition of flow, the conventional approach to flow gauging such as current meter or calibrated structure are not feasible. NaCl was used for discharge measurement with the salt dilution methods. The amount of salt to be injected depends on flow estimation flow (generally 5 g/l). The salt was dissolved properly in a bucket. Then this solution was injected at once in the stream water almost 100 m from point of measurement. Base level conductivity of water was noted. As the salt reached to the place of measurement, the conductivity value started changing. The conductivity values were noted with 5 second interval. This was done until the measured value reached the base level conductivity again (Hofer, 1998). The rate of flow in channel (Q) can then be calculated by: