ROCKLock™ Openhole Packer Back-up Ring

The additively manufactured design for the ROCKLock™ Openhole Packer assembly has enabled the isolation of zones in well profiles that were previously unachievable with existing packer systems.

The ROCKLock™ Packer can now be used in wells with temperatures between 150–350°F and is not limited by higher angle build rates with ledges or obstructions in the borehole. Rotation is not restricted with this packer system, and flows above 10 barrels per minute do not cause damage to the packer assembly. Additionally, movement in the assembly during stimulation of the open hole does not dislodge the packer, thanks to the design of the backup ring, which allows for 15,000 psi differential pressure at a 6.125” hole washout and 10,000 psi in a 6.5” inner diameter hole.

As the setting sequence of the packer initiates and the lower gauge ring moves upwards against a fixed upper gauge ring, the outer rings expand climbing over the intermediate spacers. As the applied force increases, the 3-piece element system is gradually forced outwards while the metal back-up rings simultaneously petal open, and arc along with the element, conforming to the openhole ID. The fully set elements are supported on both ends with metal Backup rings. These Backup rings are supported by intermediate spacers and outer rings which are in turn supported by the gauge rings, eliminating extrusion forces to the element.

Existing Design

Setting a packer in an open-hole environment has traditionally been a multi-step process. Existing designs have been limited to wells with lower angled build rates, restricted the rotation of the packer string, and often prematurely set when encountering ledges or obstructions in the borehole. Additionally, borehole circulation was limited to no more than 10 barrels per minute. Previous packer systems required cementing the liner for the lateral section to minimize the borehole and were unsuitable for applications with high washout formations. Build rate angles above 4° per 100 feet often prevented the packer system from achieving the target, frequently resulting in the packer becoming stuck on ledges or obstructions in the borehole.

Validated Technology

A successful deployment proved the technology at a customer wellsite, with the goal of setting five stages of the packer. The success criteria required a 60% success rate (3 out of 5 stages). The ROCKLock™ Packer successfully achieved isolation in 4 out of 5 zones. The fifth zone was not isolated due to a loose formation, rather than any issue with the packer isolator.

Challenges

• Higher Pressure applications above 17,500 psi
• Challenged with 5 staged settings above 10,000 psi differential pressure.
• Small injection checks before and after stages are set and opened.
• Max flow rate above 35 bpm

Results

• 4 of 5 stages successful
• Maximum Borehole Pressure 17,964 psi
• Maximum Borehole isolation pressure 15,255 psi
• Maximum flow rate 20.4 bpm

ROCKLock™ Back-up Ring

• Packer Seal above 15,000 psi: 17,500 psi achieved
• Packer Sleeve in a high dogleg: 5.6°/100’ achieved
• Borehole flow rate >10 bpm: Achieved 51 bpm flow rate