ClampOn’s unique Well Collision Detector offers real-time monitoring when drilling close to existing wells. “Our drive is to make tools to perform jobs that were previously impossible,” says Lars Ramstad, Drilling Service Manager.
Directional drilling close to other wells, or in areas where maps are inaccurate or non-existing, is challenging. In the best of cases, a well collision only has an economic impact; in the worst-case scenario, it can create a major incident with severe environmental consequences and loss of life.
ClampOn’s Well Collision Detector aims to minimise the risk during directional drilling operations. While gyro tools measure where the drill string is located, ClampOn’s system uses existing wells to pinpoint the drill string’s location in relation to these. Intrinsically safe and non-intrusive sensors with spectrum analysers digitise the ultrasonic signals from these wells. This provides operators with real-time data, which supplements risk analysis calculations for extra safety when drilling.
The idea for a well collision detector surfaced during a regular ClampOn sand-testing job in the Gulf of Mexico. As engineers performed the test, drilling for a new well took place nearby. “Our sensor, which was installed on an existing well, picked up signals from the drill as it came in close proximity to the well we were monitoring,” says Ramstad.
Multiple internal tests later, ClampOn performed two jobs for the same company, using the new Well Collision Detector technology. The first job yielded meagre results, with only a faint suggestion of a sound from the drill bit. On the second job, however, the sensor picked up a strong signal as the drill approached an existing well. The operators stopped the drill string, pulled it back, and redirected it, avoiding a collision.
“The first version of our Well Collision Detector used high frequency signals which provided a high resolution. We could pick up the ultrasonic signal from approximately three metres distance, and it increased as the drill string came closer. However, our customers requested a longer range, and after analysing many data, we have developed the equipment to include a low frequency sensor with longer range. Used in combination, we are able to pick up the signal from drill strings at a greater distance, while simultaneously using the high frequency, high resolution signal as an alarm function at shorter distances,” says Ramstad.
In 2013 and 2014, the number of ClampOn’s well collision jobs picked up significantly, with good results. Data from these jobs help improve the technology. Given enough data, Ramstad estimates that it may take two years to develop the sensors to the point where readings are accurate enough to gain access to resources in areas that are unavailable today.
“There are areas where no one dares drill because no maps exist. In time, our technology can make it possible to drill in a spaghetti of old wells where you have no idea what is below the surface.”