Page 167 - Origin and Prediction of Abnormal Formation Pressures

Original Shale Pressure 1946 (Short Normal)
Shale Pressure 1966 (Sigma Curve)
Ib/gal MW-Maximu
needed to redrill well
.- Kick off Point
10.2
-
x---x
Ib/gal)
= 0.53 0.2
(1
G
30 40 50 20 Formation Pressure, 1000 psi Sigma Shale, C,, Fig. 5-1 1. PNC log used in quantitative formation pressure evaluation. (After Fertl and Timko, 1970.) (A) Shale resistivity plot in Tepetate field well, Louisiana, 1966. (C) Original shale pressure from short normal log (1946) and
Original Mud Weight 9.7 Iblgal Ortego A I 12.8 lWgal 14.0 = Homeseeken A 14.3 Iblgal Homeseeken B I 14.8 lbigal = Homeseeken C Homeseeken 0 14.9 Iblgal - 17.3 Iblgal - Twedel 17.6 Iblgal 2.0 drilled in 1946. (B) Sigma shale plot in the same well (cased) based on PNC log run in depleted shale pressur
Iblgal

1946 I .I. 'a 1 .O Shale Resistivity, R,,

Tepetate, LA (A1 0.5

- - 0.3
7,000 8.000
t * , A 5: Y c t Q a, 13