Wireline Unit on drill floor (Drilling)

[Mechh007]

Hi,
I want to know why wire line unit is being used in drilling rigs? I saw a wire line unit spec, as per that the wire dia. is 0.103" and length is 23,000 ft. My question is, on what basis the dia. and length have been fixed? Is there any calculation or thumb rule?

Thanks,
BN

 

[bimr]

Strength selection requirements are probably based on experience. The length is based on the well depth.

 

[DubMac]

It is a survey unit, most likely. Used to send a "Totco" unit downhole; mostly used to survey the inclination of the wellbore at any depth.

 

[venividivici]

I ran a wireline truck for a few years before getting out of the field. There's a list of reasons why wireline (WL) would be on a drilling site, these are the most common: 1) Drill pipe is stuck - they'll use WL to run either a backoff shot (they'll use an acoustic tool to find where the pipe is stuck, run in with det cord wrapped around their tool to the stuck point, the rig will put counter torque into the pipe, and WL will detonate the cord freeing (hopefully) the drill pipe) or a chemical cutter (locate the stuck point as mentioned and run in with a tool that uses a fluid to chemically cut the drill pipe). 2) Casing has been installed and cemented in place, and the customer wants to evaluate the cement (WL will run an acoustic tool that will produce a log that can show how well the cement bonded to the casing and possibly formation depending on the tool - this will also give a correlation log for the customer to use bc WL will zero off of the Kelly or drill floor and log the casing collars which will typically include a short joint). 3) Casing has been installed, and the customer wants to perforate a zone (this would most likely be for a low pressure vertical well). This could be done 1 of 2 ways - a) the customer has an open-hole log with a gamma curve, WL runs a tool with a collar locator and gamma detector, locates the zone of interest, pulls out of hole and tubing conveyed perforating (TCP) runs their shots in and mechanically detonates them perforating the zone. b) WL runs a gamma perforator tool with a collar locator and a gun string on the bottom, and locates and fires. If they had a casing plug and looked like they were mixing red cement - then that's a whooooole other ball game.

Wireline trucks getting the spool replaced every so often. I would bet that they were running 5/32" line (that's thinned out to 0.103" due to stretch from repeated use), and 23,000' just happened to be what was on their spool. Usually you purchase 25,30,35,or 40,000' at a time, and replace it as it becomes brittle or gets too much cut off that it can't catch any work.