TAG is always seeking new ways to increase production from already producing wells. We have been hard at work on Cheal E7 by perforating the wells in order to expose more of the reservoir to potentially increase production. If you are not familiar with perforation, a short explanation is that a perforation gun is entered into the well to punch a pattern of holes (perforations) in the casing of the well to connect the cased wellbore and the production reservoir.
Our main goal with perforation is to increase production, but with Cheal E7 it was double duty, and the geological and geophysical (G&G) team was also able to use the data to support E-site development with water flooding.
Our highly skilled subsurface G&G team in New Zealand starts the process by reviewing the well logs and identifying areas of bypassed pay (reservoir that was not perforated during the initial well completion) in the well bore.
For E7, the zone of bypassed pay was lower in the wellbore than the tubing was landed, and we were able to utilize thru tubing technology for adding perforations to the identified pay zone. Thru tubing means just that – through the well’s tubing so all the work can be completed without removing the completion. As the thru tubing equipment has to fit inside the tubing, it is quite small; the perforation guns that TAG used on E7 were only 2.125″ in diameter. Using thru tubing proves to be quite beneficial, saving a tremendous amount of time and money; the completion does not have to be removed from the well, thus avoiding rig work.
Once G&G and TAG production manager, Ryan Beierle, decides the area to be perforated, the team develops a program, completes purchasing, and submits regulatory notifications. Once regulatory obligations are met, a G&G rep and e-line engineer meet on site, proceeding to rig up on the well and correlate the guns to the desired depth using GR-CCL (gamma ray, casing collar long), which is run in tandem with the perforation guns. Once the guns are on-depth, the well is then perforated and put on test with gauges in the hole. Testing is used to tell the team if incremental production exists, as well as gauging any change in reservoir pressure.
There are two main ways to perforate a well: slick-line and e-line. Typically, slick-line is just wire without the ability to transfer data across it. TAG uses it for basic intervention (wax cutting, setting plugs, etc.) It’s more robust and cheaper than TAGs perforation method of choice for E7, electric line (e-line). With e-line, data is transferred up and down the wire in real time, and offers the ability to detonate charges for perforating. For E7, TAG first employed slick-line to prep the well for perforating, then transitioning to e-line for the actual perforation work.
TAG employs a highly skilled team of professionals in and outside of the field, who work together to consistently enhance TAG’s current assets – optimizing production and lowering per barrel production costs – all while simultaneously looking for new expansion opportunities.