Pressure Testing – Slickline Equipment
A typical test consists of pressuring up the lubricator against the closed tree swab valve to the working pressure of the lowest pressure rated item of equipment in the rig up or 110% of anticipated surface pressure.
Make sure the surface equipment is purged of air to obtain a satisfactory pressure trace on the chart recorder.
Water or other suitable liquid should be used (a fluid that does not contain solids) – nitrogen is also a suitable test fluid.
Subsequent trips in the hole require that the surface pressure be tested. This can be easily accomplished using the Quick Test Sub as this is usually the only connection that’s broken.
Install a gauge on the lubricator to detect any pressure build-up which would indicate a leaking ram element.
Close the rams and pull the rope socket up to the ram block. Apply test pressure either from a pump or the well could be slowly opened. Monitor the lubricator gauge for pressure build-up.
After testing the ram, open the equalizing valve on the BOP which will pressure up the lubricator. Check the quick unions and stuffing box for leaks.
Shut-in the well, bleed pressure off the lubricator, open the rams, and remove the wire. Close the rams and apply pressure below the closed rams to test the rams against the open hole.
Install a gauge in the lubricator to monitor pressure.
Close the lower set of rams, pull the rope sock up to the closed rams and apply test pressure. Monitor gauge for pressure build-up.
Close the upper rams, open the equalizing valve on the lower rams which will pressure up the cavity between the two sets of rams, and then open the lower rams. Monitor the lubricator gauge for pressure build-up.
Open the equalizing valve on the upper rams to pressure up the lubricator.
The surface pressure control equipment commonly found on electric/braided wireline units are as follows:
Wireline Control Head - used in braided and electric line operations and serves the same purpose as a slickline stuffing box – available in working pressures up to 15,000 psi.
Grease Control Head - found on braided and electric line operations and serving the same purpose as the two above – utilizes grease or very viscous oil to effect a seal around the wire as opposed to rubber packing elements – available in working pressures up to 15,000 psi.
Swabbing Stuffing Box - serving the same purpose as the stuffing box or grease control head but used with braided line in low pressure operations.
Lubricator - sections of pipe equipped with unions on either end – serve to house the tool string prior to entering the well and after the tool string has been retrieved from the well – commonly in lengths of 8 feet – available in working pressures up to 15,000 psi.
Wireline Valve - wireline blowout preventer – available in manual and hydraulically operated models – both for slickline and multi-strand wireline – available in single and dual configurations – working pressures as high as 15,000 psi.
Tree Connection - several styles available: flanged connections (usually for high pressure work), 8-round pin x hammer union, and 8-round pin x quick union are the most common – working pressures as high as 15,000 psi.
Electric/Braided Line Stack Configuration
Braided/Electric line wireline is generally used when the strength of slickline is insufficient for the task or when services are required which are specific to electric line.
Pack-Off Liner Wiper – wipes the line free of grease or oil as it is pulled from the hole
Grease Head – a device comprised of a low pressure and high pressure section – seals around the wire – braided line equivalent to the slickline stuffing box
Head Catcher - uses internal dogs to latch the rope socket when the tool string is pulled from the hole; designed to prevent the wire from being pulled out of the rope socket