The Through-Tubing Wireline Gravel-Pack System

We currently have a six minute video that describes this Procedure. To download the video: Click Here.

To view our patent: Click Here.

This procedure is performed with an electric wireline, and can be installed in damaged conventional gravel pack completions, zones that have been washed out, and newly perforated zones. Most importantly, it can all be done under pressure.

The process begins by going down through the tree with a non-vented plug, and setting it below the perforations or desired production zone. Next, utilizing wireline bailers, sand and cement are dumped to provide a base for the gravel-pack assembly. At this stage, the production zone is re-entered with a perforating gun, to create new and clean perforation tunnels.

Now the well is prepared to begin the gravel-pack procedure.

The assembly consists of a capped plug pinned in place with a brass pin. This plug will be removed after the gravel-pack installation is complete. An R. A. Tag is installed in the top section, for correlation purposes if needed. An eighteen inch (18") vent screen serves as a means of allowing movement of fluids and gasses to flow through the assembly during the installation. It also allows fluid, which is pumped into the well, to create a horizontal force on the gravel-pack slurry in the zone. In the event that the cap is not pulled, the well can be produced through this vent screen. An upper spacer section is added, which generally consists of two bow-spring centralizers and a ten to fifteen foot section of pipe. This spacer section allows room to top off the gravel pack sand and a four foot cement cap. Next is the gravel-pack screen, which is sized according to the inner diameter of the production tubing string and the length and condition of the perforated zone. The type and brand of screen used, will be determined by the customer’s needs. A lower spacer section is added, which consists of another bow-spring centralizer and a one inch, solid spacer bar, eight to ten feet long. This is adjusted on location, according to well conditions. The gravel-pack assembly is then lowered through the well-head, tubing, packer and into the casing. The assembly is then placed into position on the cement base. Utilizing gravity bailers, a fifteen pound gravel pack slurry is dumped around the assembly, up to the spacer blank, above the screen section. In situations where the casing is large enough, the bailer will move down, between the assembly and casing wall. This is done while maintaining a fluid over-balance on the well. This gravel pack slurry contains a Forty Sixty gravel-pack sand and H.E.C. polymer with a breaker, designed according to the bottom hole temperature of the well. The gravel-pack slurry is then allowed to break out over-night. A tag run is then made to the top of the gravel-pack sand, to assure that the pack is complete. At this point, salt-water is dumped at the top of the gravel pack sand to flush out any polymer residue that may exist. Cement is then dumped around the blank section of the assembly, to prevent any flow from occurring along the side of the gravel-pack assembly. The cap plug is then retrieved by using a centralized over-shot. The procedure is now complete, and the well is ready to flow.

Another application for this service is repairing a conventional gravel pack completion which has failed. This procedure involves setting a cast iron bridge plug in the base pipe. Then, setting a wireline gravel-pack assembly on the bridge plug. While pumping into the production zone, the necessary amount of gravel pack sand, in slurry form, is then dumped around the gravel-pack assembly up to the blank. The slurry is then allowed to break out over-night. A shot-rod is run along-side of the assembly to confirm a proper level of gravel-pack sand. At this point, the cap plug of the assembly is removed, And a slick-line type pack-off is set on top of the gravel pack assembly. The procedure is now complete, and the well is ready to flow.

By utilizing this procedure, the well can be back in production in less time not to mention the cost of a rig move, killing the well, and all the risks involved in a conventional work-over. The through-tubing gravel pack has been highly successful in its many applications. The ability to accurately position tools at these great depths, and complete in such a short timeframe, not only assures the quality of the work done, but compared to previously available methods, can be done for a fraction of the cost.