DescriptionThe Core Barrel - Drill String Acceleration Tool (CB-DSA), developed at BRG-LDEO, has been used on numerous ODP projects. Its primary purpose is to measure and record the drill bit acceleration and vibration signals during drilling. The tool contains a single-axis high sensitivity accelerometer for heave measurements, a three-axial high frequency ac-celerometer for drill bit variations and a high resolution pressure sensor. For ease of deployment, the CB-DSA has been designed as a removable extension of the APC/XCB/RCB core barrels. Using standard threaded connections, the CB-DSA is attached to the top of a selected core barrel prior to core barrel deployment. Except during connection and disconnection of the tool, coring activities are not affected by its presence. Upon DSA/core barrel retrieval, the DSA is disconnected and the data are downloaded to the third party data acquisition system in the Downhole Measurements Lab for immediate analysis.

Applications♦ Downhole heave measurement♦ Drill string vibration measurement♦ Fluid pressure measurement♦ Reconfigurable to suit

Utilizing a standard fishing neck on one end and a quick connection on the other, the CB-DSA is designed for routine and rapid deployment with all standard ODP core barrels.

Specifications

ODP Logging Services, Lamont-Doherty Earth Observatory, Rt. 9W, Palisades, NY 10964

Core Barrel - Drill StringAcceleration Tool

CB-DSA data depicting the vertical displacement of the bottom hole assembly compared to the heave motion of the ship. The DSA measurements provide crucial data from the downhole environment while drilling.

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Time (seconds)

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Heave Compensator stopsDrilling

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