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Cable Installation for
Deep Wells

Cable Tension During
Installation

Operational Situations

Working Loads

Receiving & Handling

Installation & Spooling

Operating and Maintenance

Common Abuses

Damage Caused by
Excessive Tension

Wire Line Spooling

Installation Tension for
Well Logging Cables Chart

Cable Damage Due
to Drum Crush

Figures 1 - 5

Example for a 7H42 Cable

Example for a 7H47 Cable

Cable Installation
Tensions

Installation Tension
Graph

Manual Menu

 

 

 

 

 

CABLE INSTALLATION TENSIONS


To ensure against premature cable failure, the installation of electrical wirelines demands the attention and care of experienced personnel. Maintaining recommended oling tensions is a critical part of this operation. Ideally, these tensions -1 model the expected cable loads during service. This is particularly important when operating in deep holes where the loads can easily exceed the normal installation tensions Failure to maintain adequate tension can cause damage to the remaining line on the drum, resulting in a crushed cable and/or dielectric failure.

The following information is intended as a recommended guide while installing Rochester cable.

AVERAGE DEPT
(Depths to 15,000 feet)
1st bed layer - tension applied 15% to 20% of cable breaking strength
2nd bed layer - tension applied 20% to 25% of cable breaking strength
3rd bed layer - tension applied 25% to 30% of cable breaking strength

DEEP HOLES
(Over 15,000 feet)
1st bed layer - tension applied 20% to 25% of cable breaking strength
2nd bed layer - tension applied 25% to 35% of cable breaking strength
3rd bed layer - tension applied 35% to 45% of cable breaking strength
4th bed layer - tension applied 35% to 45% of cable breaking strength

Maintain final bed layer tension until the intended cable depth is reached (as measured from whip end). Tension is then reduced after each 1,000-ft interval

(using the approximate figures given in the chart below) until a minimum tension of 500 lbf is maintained on .250" and smaller cables, and 1,000 Ibf on .315" and  er cables.

.181" tension reduced by  50 lbf/kft

.203" tension reduced by  65 lbf/kft

.220" tension reduced by  80 lbf/kft

.250" tension reduced by  90 lbf/kft

.315" tension reduced by  150 lbf/kft

.348" tension reduced by  180 lbf/kft

.375" tension reduced by  210 lbf/kft

.422" tension reduced by  265 lbf/kft

.464" tension reduced by  275 lbf/kft

.520" tension reduced by  380 lbf/kft

In many cases the constructional strength of a drum is not equipped to handle the increased installation tension of deep-hole work. Districts that continually operate in deep wells should use the high tension profile recommended to reduce the opportunity of cable failure, but this may not be possible if not equipped with a high-strength drum. To ensure against damage as a result of drum failure, it is important to identify the type of drum before using these tensions.

 

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Camesa, Inc · 1615 Spur 529 · P.O. Box 1048 · Rosenberg, Texas 77471
Phone: (281) 342-4494 · Fax: (281) 342-0531