S07 ORME 5 2021 Well Intervention_Layout 1 27/07/2021 14:50 Page 24
Technology
Delivering an effective wellbore
clean-up solution Saleh Al Saeed, Coretrax, describes how a ‘single trip’ clean-up and cement removal solution delivered rig-time and sustainability savings in Saudi Arabia. ELLBORE CLEAN-UP IS a vital process as discarded debris and residue can result in reduced productivity or even significant non-productive time (NPT). Ensuring this is performed as efficiently and as sustainably as possible not only enables faster access to first hydrocarbons, but also greatly reduces cost, risk and carbon footprint. During a recent drilling project in the MENA region, a major Saudi operator tasked Coretrax, the global well integrity and production optimisation leader, to create an innovative, one-trip wellbore clean-up assembly solution. For the first time, the company combined its CX-LTTT (Liner Top Test Tool) multi-packer tool with the CXBumper Sub to perform clean-up, inflow testing and casing pickle operations, without compromising the lower completion that had already been deployed. Pickling the casing prior to an acid job removes mud and cement debris, mill scale, mineral scale and corrosion by-products. Circulating chemicals and removing remains around the hole protects the well and minimises the number of workovers or the need to reopen wells to counter the potential of leaking or corrosion in the future.
Two technologies – one trip Unlike conventional clean-up activity, the operator required a 7” landing sub to locate itself precisely on top of a 4 ½” TOL at a 66° inclination to stop the mule shoe hitting and causing damage to the ceramic disk: a physical barrier used to provide well control in temporary wellbore isolation applications. A second 9 5/8” landing sub was also required to land on top of a 7” TOL. This dual operation would safeguard the integrity of the lower completion, ensuring there was no potential for leakage, while at the same time, casing pickling would safely and effectively remove suspended solids and debris without damaging the disk and potentially causing a major well control issue. As a multi-set packer with three separate elements, the CX-LTTT (Liner Top Test Tool) combines cement drill out, wellbore clean-up, 24
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Issue 5 2021
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Saleh Al Saeed, Coretrax.
displacement and isolated positive or negative inflow testing on liner tops and casing shoes, in a single trip. This eliminates the need for a dedicated drill out run (Figure 1). Along with non-rotating scrapers, brushes, magnets and circulating tools, the device works by setting down weight to compress and extrude the elements. It can be used during both drilling operations and the displacement process. The large bypass area under the packer element enables quick running speeds when running to depth and a generous flow area past the tool to achieve high flow rates. This is essential for the
The device works by setting down weight to compress and extrude the elements.”
efficient and accurate recovery of debris out of hole and thereby, minimising risk of damage to the packer. It can also work across different metallurgies in the shoe track. The packer is designed with customisable shear value torque through capabilities to ensure it is suited to a range of applications, including HPHT, extended reach drilling and multi-lateral projects, as well as being able to run in one trip. The tool is essentially a purpose-built packer added to the wellbore clean-up assembly to allow inflow testing to be performed concurrently in the harsh operating environments in the Middle East. This includes being successfully set at 17,500 ft with a well inclination of around 74 degrees. Capable of combining the clean-up, displacement and inflow test operations in the same run, the heavy-duty and robust device is a proven and reliable inflow test packer. To enable the CX-LTTT to land at two separate points with the same string in one run, it was deployed alongside the CX-
