| Popis: |
Measurement of downhole dynamics while drilling has become commonplace. However, the use of sensors to measure downhole dynamics while coring has rarely been exploited. This paper will detail the use of compact dynamics sensors strategically placed within the coring assembly. A unique 4" (core diameter) jam mitigation device provides two jam protection, significantly improving core quality and reducing the total economics of obtaining whole core samples. At the occurrence of a core jam, two telescoping liners deploy within the aluminum inner barrel, allowing the ability to mitigate the core jam(s) and continue with coring operations. Compact downhole dynamics data recorders are strategically embedded in the core hanger (non-rotating) and near-bit stabilizer directly behind the core head (rotating). The data recorders are fitted with 3-axis vibration, 3-axis shock, 3-axis gyros and two temperature sensors. Measurements include shock, vibration, rotation speed (angular velocity in RPM), torsional oscillation, stick-slip and temperature. The sensors have been deployed on multiple coring applications throughout North America Land (NAL). The data recovered revealed formation related coring dynamics response while transitioning through interbedded intervals. Certain formations produced very high shock and vibration levels that could potentially cause damage to core quality and equipment. The onset of shock and vibration also revealed a significant temperature rise above bottom-hole temperature due to the coring dysfunctions. This paper will detail the coring dynamics data captured from the sensors. The dynamic response of a coring assembly is significantly different from that of a drilling assembly due to the assembly mechanical dimensions and rock recovery methods. Proprietary software was utilized to merge downhole dynamic recorder data and surface Electronic Drilling Recorder (EDR) data. The software provides a fast and efficient interface to view the merged data, allowing surface and downhole correlation of the information. |
