Vibration Memory Sub (VMS)

The Vibration Memory Sub (VMS) is a stand-alone down-hole tool that measures, calculates and records axial, lateral and angular down-hole vibrations for retrieval and analysis at the surface. The VMS allows operators to assess the severity of downhole drilling shock and vibration, including stick-slip and whirl, and correlate the data to drilling events and equipment performance or failures. Measurements are stamped by date and time for correlation with other data. The VMS can be used to characterize downhole conditions for future BHA planning, post-well analysis of equipment failures or to provide evidence for use in warranty claim resolution.

The tool provides data in the form of ASCII text files which can analyzed by APS's Vibration Data Viewer software or your own analysis software.

The tool's 8 MB memory is capable of recording up to 310 hours of continuous data. Battery life is rated at 420 hours.

This hard-mounted, sonde-based tool is available in 6.75 in. and 4.75 in. drill collar sizes, with standard box and pin connections. The sonde-based design allows this tool to be scaled up or down easily for use with other drill collar sizes. Please inquire with your APS sales representative if you require a different collar size.

Operation Preparing the tool for recording vibration data is straightforward: • Ensure that a battery is installed with sufficient life for recording the desired bit run. • Set desired user programmable recording parameters through VMM/VMS interface software installed on a standard Windows-based (2000 or XP) PC. • Clear memory or ensure that there is sufficient memory remaining. • Install shorting plug in memory dump port to turn tool on. • Install all covers. Battery replacement is easily performed in a shop environment using basic hand tools.   Data Collection Vibration measurements are made using two ± 250 g accelerometers and one fluxgate magnetometer rotation sensor. Vibration data is acquired at a rate of 1,000 samples per second, averaged and stored every 4 seconds. Magnetometer data is acquired at a rate of up to 100 samples per second for stick-slip and whirl calculations.   Calculated Data Every four seconds, the microprocessor calculates and stores: • Maximum lateral acceleration – vector sum of x- and y-accelerometer measurements • RMS lateral acceleration • Maximum axial vibration – from z-accelerometer • RMS axial acceleration • Maximum and minimum angular speed (RPM) • Absolute date and time

Raw Data Snapshots
In addition to the maximum and average data, the tool stores seven "snapshots" of the raw accelerometer and magnetomer readings. 40-second sets of 1,000 sample/s raw readings are recorded. Raw data can be collected following several user-selectable events.
•	The user can select four different vibration conditions which will trigger raw data "snapshot" collection.
•	The user can select three different rotation conditions which will trigger raw data "snapshot" collection.
Retrieving Data
Data is easily retrieved by accessing the data dump port on the sub and connecting it through the VMS Interface Box to a PC. LabWindows™-based software on the PC converts the stored data to a text file with acceleration levels as a function of real time. The data can be erased when retrieved or left in memory after the download.

Download the TDS above to view detailed Product Specifications.

* Specifications subject to change without notice