1.0 Scope
Consideration for handling pressure and temperature conditions should be made at all times when working with slickline. Additional planning and special consid-eration should be made when handling high surface pressures of 10,000psi and above and for wellbore temperatures in excess of 265oF.
2.0 General Information
There is more potential for encountering a hazardous situation when performing slickline services on wells with pressures approaching 10,000 psi and above.
While working on high pressure/temperature jobs, it is recommended that a supervisor accompany the job. High pressure is defined as pressure or equal to or greater than 10,000 lb. High temperature involves temperatures above 265oF.
It is recommended to keep 1,500-2,000 lb above wellhead pressure on the grease seal lines. Use fresh/clean “honey-oil.” Care must be taken in handling high pres-sure equipment. High prespres-sure equipment is considerably heavy. Three people, at least, should be used for rig up.
High pressure work is dangerous and must be handled with experienced work-ers. Also, it is recommended that an experienced supervisor accompany the wire-line crew.
When testing the tree and lubricator upon rigging up, maintain pressure on the actuator if fusible plug is used. Best practices would be to use grease the injection stuffing box for 11,000+psi jobs.
3.0 Procedure
1. High Pressure
a. Make sure all equipment is current, as for as pressure, magnetic flux, and stress-crack testing.
b. Pressure-test the wireline valve as an extra safety precaution before going out on a job. Also, visually inspect lubricators and flanges to be used.
c. Have on hand a redress kit for the wireline valve, lubricator, and stuffing box. Also, extra autoclave valves and flange gaskets are recommended.
d. Upon arriving on location, examine the wellhead/tree. Also, note the work-ing pressure on the tree. Next, determine if you have the proper equipment to handle the job.
e. Hold a safety meeting with all people involved in performing the job. This includes the operator, service assistants, company representative and covers all matters related to the job.
Slickline Operations Manual SL 2.35 High Pressure/Temperature Operations
h. Change all o-rings in the lubricator and assemble the necessary lubricator sections.
i. Install two autoclave valves per lubricator valve port/hole. The second valve per hole acts as a backup.
j. The proper installation of the autoclave has the lower bleed hole on the auto-clave and valve nearest the lubricator.
k. Do not apply teflon tape to the autoclave valve threads. The threads are not designed to hold pressure.
l. During operations the outer autoclave valve is closed and used as a pres-sure-bleeding device. The inner autoclave serves as a safety backup and remains open at all times.
m. It is necessary to remove and place all glands and packing within the stuff-ing box.
n. The recommended packing stack from top to bottom includes, 91T136 (hard black), 2 soft 91M2467, 1 91T120 (red), 1 soft 91M2467 (soft), 1 91T120 (red), and as many soft black as necessary.
o. Installing a new lower blowout preventer within the stuffing box is neces-sary. Pack the void in the stuffing box with appropriate grease.
p. A hydraulic stuffing box is recommended in high-pressure conditions.
q. Check the bleed allen screw valve within the stuffing box. Make sure the valve is closed.
r. Screw in the adjustment nut on the stuffing box until tension is noticed, then back off a quarter turn.
Note For wells containing high CO2 concentrations, back the adjustment nut off one-half to one complete turn. CO2 tends to make the packing expand and tighten.
s. When running wire in the hole, apply a mixture of STP and oil to the wire.
t. When rigging down do not leave the wireline valve on the wellhead over-night. This may allow damage to occur to the elastomers in the wireline valve due to explosive decompression of gases trapped within.
u. Pressure test the lubricator stack to working and/or customer requirements with glycol, if applicable.
Note Do not use glycol where there are zinc or calcium products present. Glycol turns zinc into a salt deposit and calcium into a “peanut butter” type substance. If glycol is used, then it should be removed/drained from the tree.
v. Purge air out of the lubricator section by pressuring up to 1,000 lb and then bleeding off. This prevents spontaneous combustion of products within the lubricator.
Note This step necessary only on the first run into the wellbore.
Slickline Operations Manual SL 2.35 High Pressure/Temperature Operations
w. Use a liquid chamber to inject corrosive inhibitor grease. This protects the wireline and increases stuffing box life.
x. Install the liquid chamber immediately below the stuffing box.
y. When using exotic wire (mp35, stainless steel,.108,.125) or per customer request, employ a grease seal with flow tubes. Three to five flow tube sec-tions may be run.
Note The maximum line speed should be 200 ft/min. into and out of the well-bore.
z. Inject grease sealant at a point one flow tube above the lubricator.
aa. Install a return line below the stuffing box to capture used grease. At this point the stuffing acts as a wiper section or pressure backup device.
ab. Standard braided line should not be used when pressures exceed 3,000-4,000 lb. form is recommended for pressure above 3,000-3,000-4,000 psi. Dia-form is easier to seal and is a stronger braided wire.
ac. Use more weight/stem bar if braided line is employed on high pressure wells. Lead, tungsten, or spent uranium stem is recommended to shorten the tool string.
ad. When using braided line employ a double ram to accommodate the larger OD.
Note If the seal is lost, it is necessary to close the double rams on your lines and pump grease between the rams when closing the wireline valve.
ae. Fresh water should never be used on high-pressure gas wells.
2. High Temperature
af. Special packing and seals are needed when temperatures exceed 260oF.
ag. Use riton teflon and peak packing when working with high temperature/
pressures.
ah. Q-V o-rings can also be used.
Slickline Operations Manual SL 2.36: Downhole Power Unit Operations