Well-collision avoidance has gained greater importance as fields become more crowded and well paths increasingly complex. The safety and financial implications of shutting in production wells on platforms or repairing damaged wells have established a need for the industry to evaluate the potential for collision with a producing well.
When planning a drilling operation, evaluating the Risk is a main activity. Usually a collision into a producing well is one of the risk considered.
This paper / presentation elaborates how ClampOn has met this challenge by developing a real time monitoring system for detection of a drill bit in the proximity for existing wells. The ClampOn DSP Well Collision Detector developed, provides the operator with an advanced real time collision monitoring system with minimal equipment and personnel requirements. We will present the technology and field cases demonstrating the results.
The detectors provide drilling operators with real time data during the operation, thus supplementing collision risk analysis calculations and other available means for determining the bit's proximity to existing wells. A drill bit in operation generates strong vibration and also high frequency acoustic noise. When the drill bit approaches an existing well, this noise penetrates into the well structure, and propagates over long distances within the well.
Any change in the acoustic conditions on the well heads is readily available for scrutiny as the operation commences and may provide early warning of the drill bit approaching an existing well. Upon observations of strongly increasing ultrasonic signal levels, drilling can be halted and data from available sources analysed. Depending on the analysis, the drill string may be diverted or drilling can resume with confidence that a collision has been avoided or that predictive calculations have been confirmed.
ClampOn's passive acoustic sensors are used for many different applications; most common are sand monitoring, pig detection, leak detection, but also crack detection, and "well collision detection" (WCM). Common to all are acoustic emission, our instruments samples acoustic emission, and process the data specifically for the application. I.e. Sand impacting the steel of the flow line generate quite high frequent ultrasound, whilst a passing pig/scraper generate ultrasound in the lower frequency area. When a drill bit grinds its way through the rock formation, it generate acoustic emission. When the drill bit gets close to casings of existing wells, the acoustic emission will be transported through the rock, into the casing and up to the passive acoustic sensor attached at the wellhead.
