What is Archie equation?
Sw = [ (a / Fm)*(Rw / Rt) ](1/n) Sw: water saturation. F: porosity. Rw: formation water resistivity.
What does tortuosity of the thoracic aorta mean?
Tortuosity of the thoracic aorta on chest radiographs is characteristic of atherosclerotic disease. Aging and hypertension are associated with the tortuosity, but little is known about the influence of other atherosclerotic risk factors on this abnormality.
What is mild tortuosity descending thoracic aorta?
A tortuous aorta may be characterized as a twisted, curved, enlarged or narrowed blood vessel of the heart. An underlying cause of the distorted shape may be due to a build up of fatty tissue that collects on the walls of the vessels or, it may be a finding from birth.
What do you mean by Archies law define properly with the help of equations?
Reformulated for the electrical resistivity (R), the inverse of the electrical conductivity , the equation reads. with for the total fluid saturated rock resistivity, and. for the resistivity of the fluid itself (w meaning water or an aqueous solution containing dissolved salts with ions bearing electricity in solution …
What is saturation exponent?
1. n. [Formation Evaluation] The exponent, n, in the relation of water saturation, Sw, to resistivity index, I (I = Sw-n) for a sample of rock. It expresses the effect on the resistivity of desaturating the sample, or replacing water with a non-conductive fluid.
What is cementation factor?
The cementation factor, sometimes referred as cementation exponent or porosity exponent, has been accepted as a measurement of the degree of cement and consolidation of the rock, as well as it is a measure of the tortuosity of the pore geometry of current flow.
What is the treatment for a tortuous aorta?
Surgical Treatment of Tortuous Vessels While many mild tortuous arteries are left untreated, severely tortuous arteries with clinical symptoms can be treated with reconstructive surgery [61]. Severely tortuous or kinking carotid arteries have often been treated by surgical shortening reconstruction [9, 113, 114].
What are the symptoms of tortuous thoracic aorta?
Shortness of breath and chest pains may also present due to the physical changes in the spine or chest wall. Muscle fatigue and blockages in the blood flow due to the narrowing of the aorta passages can also be observed.
How do you fix a tortuous aorta?
Many treatments are available in the medicinal world to combat the problem of tortuous aorta: This may include: Bypass graft repair. This technique involves bypassing the narrowed area by inserting a plastic tube called a graft between the portions of the aorta. Resection with end-to-end anastomosis.
How common are tortuous arteries?
In one of the largest angiographic studies conducted by Weibel and Fields [1], internal carotid artery tortuosity and angulation, respectively, were observed in 35 and 5% of 1,438 consecutive patients. Tortuous vertebral, subclavian and lingual arteries have also been reported [13, 14, 15].
What is Archie’s law and its application in water saturation measurement?
Archie’s law relates the formation factor F, which is the ra- tio of the resistivity of a fully saturated rock ρo(Ro) to the. resistivity of the fluid occupying its pores ρf (Rw), to the. rock porosity φ and a parameter he called the cementation.
What is the typical range of cementation factor?
At the initial saturation (≈30–39%), the cementation factor is −3.93 on average, but this changes to a positive value at approximately 90–100% saturation.
How is the tortuosity of the aorta related to age?
The tortuosity of the proximal descending aorta was moderately associated with age (r =0.38; P =0.004) and increased from a mean DM of 1.07 (at age 20 years) to 1.21 (at age 80 years). 25 The association of arterial tortuosity with age has also been studied for the aortic branches.
How is Archie’s law related to brine saturation?
In petrophysics, Archie’s law relates the in-situ electrical conductivity of a sedimentary rock to its porosity and brine saturation: Here, denotes the porosity, the electrical conductivity of the fluid saturated rock, represents the electrical conductivity of the brine, is the brine saturation,…
How is Archie’s Law used in hydrogeology?
Because the d’ exponent method is only relating drilling performance with pore pressures some other analysis is required to understand changes in formation water, porosity and lithology. Using Archie’s law to find Formation Water Resistivity seems like a simplistic approach to hydrogeology.
Which is model tries to correct for Archie’s Law?
The Waxman–Smits equation is one model that tries to correct for this. Archie, G.E. (1942). “The electrical resistivity log as an aid in determining some reservoir characteristics”.