Every so often, a production well will need modification and repair – this is known as ’workover drilling’. The term ‘workover’ refers to any kind of well intervention relating to the pulling and replacing of a completion or plug. This may occur in the instance where production tubing is damaged, where downhole safety valves or electronic equipment (such as submersible pumps) need servicing or fail, or when the current well conditions no longer support the production equipment being used.
When production tubing is damaged, it is critically important to repair or replace the offending part(s). Production tubing sits inside the cemented casing (using a series of expandable packing devices) and is used to carry production fluids to the surface. It’s main purpose, aside from carrying production fluid, is to protect the casing string from damaging substances extracted during production. When the integrity of the production tubing is compromised, it must be fixed in order to prevent the leakage of corrosive, damaging compounds, opening up the risk of damaging the casing string.
In severe cases, it may be necessary to repair or replace the casing string as well. This is an incredibly expensive and difficult operation to perform, as the casing is cemented into the ground through the whole length of the well. Only for the most productive and valuable wells will casing workover be considered – as in most cases it’s economically prohibitive to do in any other case.
Even with the absolute best in engineering and design, machines and devices fail or need repair/servicing. This reigns true in the production drilling industry as well. So when downhole equipment is in need of service or replacement, workover drilling is employed to gain access to the necessary components. With safety being paramount in the industry, ensuring downhole safety valves are in prime working order is essential – these are often only accessible by workover drilling. Further, downhole production pumps occasionally need modification or replacement to ensure optimal operation – another area workover drilling is employed. Clearly, workover drilling is essential to operating a safe, successful production well.
Generally, a production well will be drilled to best exploit the prevailing conditions of the geology. Over time, however, the well’s characteristics can change – leading to the need to change the production tubing or other similar parameters. For instance, suppose a well was producing with 5” tubing. After a period of extracting the resource, well pressures and flow rates change to a point where 5” tubing no longer provides stable flow – in which case a smaller diameter tubing would replace it, to stabilize flow and production.
It’s quite evident that workover drilling is an essential part of the production well process. Whether it be damaged production tubing, downhole equipment needing service, or changing well dynamics, workover drilling is the only solution to many of this industry’s challenges. Here at Kanadian Bit Supplies, we offer a full range of workover drill bits to ensure your well is in prime production condition!