Background
In the last two decades there has been a major shift in well design, from vertical to horizontal. With these changes there has been a significant learning curve to optimize well design. In the past, it was standard to leave stage-to-stage spacing at greater lengths up to 300 ft (100 m) with fewer stages per well. With advancements in knowledge and technology, today operators are minimizing stage spacing while maximizing reservoir contact for increased production. As a result, there are thousands of wells previously completed with longer stage spacing that have unstimulated reservoir waiting to be exploited.
Technology Overview
The AccuStim® coiled tubing straddle packer was designed for efficient frac-down-coil operations to be completed with burst sleeves, pre-perforated wells or for refracturing applications. The system utilizes a multi-set packer which maximizes tool life, greatly improves screen out recovery and allows instantaneous equalization when moving tools stage-to-stage. The AccuStim’s upper assembly features a triple cup mandrel, hydromechanical disconnect and the Hydraulic Hold Down (HHD), which is unique to the industry. The proprietary HHD allows the tool to release from the set position post-frac with minimal overpull.
Results
An operator was not satisfied with the stimulation results on a 14-stage plug-and-perf completion. The operator decided to perforate in between each stage and called Interra Energy to refracture the entire wellbore. Interra deployed its AccuStim coiled tubing straddle packer assembly to complete the task, straddling and fracing each new perforation within an 18-hour window in a single trip. Satisfied with the results, the operator recompleted a second well with Interra and the AccuStim coiled tubing straddle packer.
The AccuStim coiled tubing straddle packer has been deployed in more than 750 wells from 15 – 50 stages as of March 2020.