DescriptionThe Drill String Acceleration Tool (DSA), developed entirelyat BRG-LDEO, has been used on numerous ODP projects.Its primary purpose is to measure and record the drill bitacceleration and vibration signals during drilling. The DSAtool contains a single-axis high sensitivity accelerometer forheave measurements, a three-axial high frequencyaccelerometer for drill bit variations and a high resolutionpressure sensor. For ease of deployment, the DSA has beendesigned as a removable extension of the APC/XCB/RCBcore barrels. Using standard threaded connections, the DSAis attached to the top of a selected core barrel prior to corebarrel deployment. Except during connection anddisconnection of the DSA, coring activities are not affectedby its presence. Upon DSA/core barrel retrieval, the DSA isdisconnected and the data are downloaded to the third partydata acquisition system in the Downhole Measurements Lab(DHML) 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 quickconnection on the other, the DSA is designed for routine andrapid deployment with all standard ODP core barrels.

Specifications

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

Drill StringAcceleration Tool

DSA data depicting the vertical displacement of the bottomhole assembly compared to the heave motion of the ship.The DSA measurements provide crucial data from thedownhole environment while drilling.

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