Page 217 - Introduction to Petroleum Engineering

204 WELL COMPLETIONS
10.9 The permeability of a propped fracture increases with size of the proppant.

10.10 A drilling AFE does not include costs for completion.

10.7.3 Exercises

10.1 Estimate the skin for a well if the damaged zone extends 4 in. beyond the
radius of the well, which is 3 in. The native formation permeability is 10 md,
and the permeability of the damaged zone is 3 md.
10.2 Find the productivity index for a well with the following properties: well
radius = 4 in. and r = 550 ft; formation thickness h = 20 ft; permeability
e
.
= 15 md; oil viscosity = 095 cp; formation volume factor B = 155 RB/STB;
.
o
and skin = 6.
10.3 Use the following values to find Brooks’ N : perforation penetration length
pd
.
L =20 in.; perforation tunnel diameter d = 03 in.; formation damage length
p
p
L = 4 in.; number of shots per foot n = 4/ft; the ratio of horizontal to vertical
d
/
permeability k k = 10; and the perforation tunnel skin s = 2.
p
h
v
10.4 For a particular perforation plan, Brooks’ N = 150. What should be done to
pd
improve the plan?
10.5 Find the McGuire–Sikora relative conductivity for a fracture in an 80‐acre
pattern. The formation permeability is 0.01 md, the fracture permeability is
50d, and the fracture width is 0.2 in.
10.6 Find the parameter R used in Figure 10.4 for a fracture in an 80‐acre pattern.
The length of the fracture from the wellbore is 220 ft.
10.7 Referring to Figure 10.4, if R is 0.3 and the relative conductivity is 50 000,
find the ratio of productivity indices J/J . The well drains a 40‐acre pattern
o
and the radius of the well is 4 in.
10.8 Estimate the permeability of a frack filled with 100 US mesh proppant. The
porosity is 36%.