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Unformatted text preview: Kelly F =
In this case P and D are known, σ may be
calculated, and K i is determined graphically.
(i) First, determine the pore pressure gradient.
= 0.735 psi / ft
Fracture Gradients 1.11- 17 Example - Matthews and Kelly
(ii) Next, calculate the matrix stress. S=P+σ
σ =S-P = 1.00 * D - 0.735 * D
= 0.265 * D
= 0.265 * 11,000
σ = 2,915 psi
Fracture Gradients S = overburden, psi σ = matrix stress, psi P = pore pressure, psi D = depth , ft 1.11- 18 Example - Matthews and Kelly
(iii) Now determine the depth, D i , where,
under normally pressured conditions, the
rock matrix stress, σ would be 2,915 psi.
Sn = Pn + σ n n = “normal” 1.00 * Di =...
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This note was uploaded on 09/18/2012 for the course ENGINEERIN 102 taught by Professor Clyde during the Spring '12 term at A.T. Still University.
- Spring '12