Casing Perforating Overview

Brad Hansen

Devon Energy Corporation
NYSE: DVN www.devonenergy.com page 2

Perforating Objective

• The primary objective of a perforating gun is to provide effective 

flow communication between a cased wellbore and a productive 

reservoir.

• To achieve this, the perforating gun “punches” a pattern of 

perforations through the casing and cement sheath and into the 

productive formation.
NYSE: DVN www.devonenergy.com page 3

First Bullet Perforating - 1932

Lane Wells Company, Unit #1 First Perforating Job
NYSE: DVN www.devonenergy.com page 4

Shaped Charge Components
NYSE: DVN www.devonenergy.com page 5

Typical Shaped Charge

HMX

Explosive

Steel

Case

Blended Powdered

Metal Liner
NYSE: DVN www.devonenergy.com page 6

Perforating Gun Components

• The Perforating Gun has four components

– A conveyance for the shaped charge

– The individual shaped charge

– Detonating cord

– Detonator
NYSE: DVN www.devonenergy.com page 7

Explosives Used for Shaped 

Charges and Detonator Cord

• RDX (Cyclotrimethylene Trinitramine) Good to 330 degrees F

• HMX (Cyclotetramethylene Trinitramine) Good to 400 degrees F

• HNS (Hexanitrosilbene) Good to 520 degrees F

• Each shaped charge will contain between 3 to 60 grams of explosives
NYSE: DVN www.devonenergy.com page 8

Shaped Charge Perforating

• When detonated, the perf guns go off instantaneously.

• The leading tip of the jet has a velocity of 25,000 to 30,000 ft/sec.

• The impact pressure is approximately 10 to 15 million psi. 

• This pressure overcomes casing and formation strength and forces 

material radially away from the jet axis. 
NYSE: DVN www.devonenergy.com page 9

Perforating Guns

• Most perforating guns punch holes from 0.23” to 0.72” in diameter.

• Typical perf guns have penetrations of 6” up to 48” in length.

• Most perforating guns shoot from 4 to 12 shots per foot.

• Perf guns come in different pressure and temperature ratings.
NYSE: DVN www.devonenergy.com page 10

Perforation Geometry
NYSE: DVN www.devonenergy.com page 11

API RP19B Section 1 Test

Casing

Gun

28 Day

Concrete

Target

Briquette

Test

Specimen

Water
NYSE: DVN www.devonenergy.com page 12

Example of Perf Charges from a 

3-3/8” Gun

From an API RP19B Section 

1 Test

25.5”

27.7”

38.5”
Example of one Company’s Perforating Gun Performance Chart
NYSE: DVN www.devonenergy.com page 14

Hollow Carrier Gun

•Charges are carried in a heavy wall tube.

•Charges are sealed from wellbore fluid and 

pressure.

•Most of the debris from the charge remains in 

the carrier.

•Detonation only slightly swells the gun but 

not enough to affect recovery from the well.
NYSE: DVN www.devonenergy.com page 15

Expendable Shaped Charge Gun

•Charges can be larger than the charges for 

the same diameter hollow carrier gun.

•Charges are individually sealed from the 

wellbore environment.

•The Detonator cord and detonator are 

exposed to wellbore fluids.

•Much of the debris is left in the well, falling 

into the rat hole on vertical wells. 
Typical Wireline-conveyed perforating setup

Typical Wireline 

conveyed 

perforating hookup
Wireline Pressure Control 

Equipment Configuration. 

The Pressure Control 

Equipment is commonly 

known as a Lubricator.
NYSE: DVN www.devonenergy.com page 18

Control Head

• Control Heads are the uppermost point of the lubricator string, 

where the wireline enters the lubricator system. Well pressure is 

controlled with packing, pack-off rubbers, grease injection or a 

combination of all. 
NYSE: DVN www.devonenergy.com page 19

Wireline Passing Through GreaseSeal Flow Tube
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Lubricator or Riser Section

The lubricator or riser section is used to 

allow the full wireline tool string to be 

raised above the wellhead before and after 

the operations.

The length of lubricator required is 

proportionate to the length of the wireline 

tool string.
NYSE: DVN www.devonenergy.com page 21

Depth Correlation

• A cased hole gamma ray / casing collar locator log are run for 

correlation purposes to assist in perforating depth control. 

• Short joints of casing are sometimes run to assist in the 

correlation.

• The distance from the top shot of the gun to the casing collar 

locator is measured before running the perforating system in the 

well to ensure the perforations are placed where they were 

intended. 
NYSE: DVN www.devonenergy.com page 22

Gamma Ray Logs

• A gamma ray log is a measure of the natural radioactivity of the 

formations.

• The gamma ray log can be recorded in open holes and cased wells 

making it an ideal log for correlating.

• Nearly all gamma radiation encountered in the earth is emitted by 

the radioactive potassium isotope atomic weight 40 and by the 

radioactive elements of the uranium and thorium series. 
NYSE: DVN www.devonenergy.com page 23

Port and Ball Drop System with 

Open Hole Packers for Isolation

Working interest: 60%

1st production: July 2007

To reach 50 MBOED gross in 2008
NYSE: DVN www.devonenergy.com page 24

Ball Drop Sliding Sleeve
Thank You.