caw unit 5 - perforating version 1-2009 jmp

DELIVERING KNOWLEDGE. DEVELOPING COMPETENCE.

2009 Pitac Ltd, All Rights Reserved Pitac Ltd - Version 01/2009 2

Introduce the basic methods of perforating Stress the need and benefit for

efficient perforating Outline gun selection

recommendations Review impact on well performance Discuss problems associated with

perforating


The Deep Penetrating (DP) Charge


The Big Hole (BH) Charge


Big Hole & Deep Penetrating Charge - 34 gms


Berea Sandstone 3000psi stressed


Penetration as a function of Compressive Strength

ln Pf = ln Pt + 0.086 X (Ct - Cf)/1000 Ct is the compressive strength of test

material - usually Berea SS = 6500 psi Cf is the compressive strength of

material penetrated-- the formation Pt is the penetration acquired in the

API RP 43 test, inches Pf is the predicted penetration into the

selected formation,inches.


Hollow-Carrier type Capsule type


Tubing Conveyed Perforators

Ideal for perforating long intervals

Underbalanced or extreme overbalanced

Options:

Kill & pull Drop guns in rathole Leave in place Strip gun out from live well (deployed)

Relatively large holes & deep penetration

Wide selection of gun ODs, charge sizes,phasing,

density, etc.

Unlimited perforating length


Tubing Conveyed Perforator

System more complicated and normally takes more time to run guns - watch temperature!

Typically requires a correlation log for proper spacing after reaching TD

Firing options: Drop Bar Tubing pressure Annular pressure Electrical wet connect


Perforating Guideline : Consolidated Sandstone

Underbalanced in clean salt water

Hollow Steel Carrier, 20+ gram charge

Shot density of 8 SPF

Phase angle of at least 180 degrees

Hole Diameter > 0.4 (prefer > 0.5)

Max penetration (>10); goal of


Perforating Guideline : Carbonate Formations

Displace casing with clean salt water

Spot 10 % acetic acid across formation

Perforate with 100 to 300 psi

overbalance

Wireline Conveyed Hollow Steel

Carriers

Shot density of 2 to 4 SPF w/20+ gram

Phase angle of at least 180 degrees

Hole diameter of at least 3/8 inch


Perforating Guidelines: Gravel Packing

Underbalanced (500 psi) in clean SW

Phase angle < 90 degrees

Shot density 12 SPF

Hole diameter >0.7

Penetration 6 probably adequate

Minimize time before GP & avoid pills

Consider perf clean-up or stimulation

Pre-pack or Frac-pack


Perforating Guideline : Paraffin /Asphaltenes/ Scale

Perforate underbalanced in clean SW

Desired hole: Large, Smooth &

Uniform

Entrance hole > 0.5 (prefer 0.75)

Shot density: Normally 4 SPF

Leave 5 ft gaps if feasible

Re-perforate if necessary (up to 25

SPF)


for Oil Zones


Aged reusable port plug / screw port gun

Note sealing area around the threaded holes

Dents behind charge ports in this 120o phased gun are from repeated recoil of the charges over a series of uses

Walls of gun are about 0.5-0.75 (1.25 to 1.87 cm)

caw unit 5 - perforating version 1-2009 jmp

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