Core Barrel – Retrievable Memory Module (CB-RMM)


CB-RMM_schematicThe Core Barrel – Retrievable Memory Module (CB-RMM) may be deployed routinely with all standard IODP core barrels. It has been designed to capture incoming weight-on-bit, torque-on-bit, and pressure data from the Drilling Sensor Sub via a wireless inductive link. The data are transmitted between two coils, one mounted in the DSS and the other mounted on the CB-RMM antenna. The DSS transmits the data continuously even when the CB-RMM is not present. When the CB-RMM is present, it recognizes the incoming data and stores them in the onboard memory. In addition to storing data from the DSS, the CB-RMM makes its own pressure and acceleration measurements, which are stored with the DSS data.


• Heave compensated evaluation
• Core barrel performance evaluation
• Sediment compaction
• Fluid pressure

Tool Specifications

Temperature rating: 185° F (85° C)
Pressure rating: 10 kpsi (69 MPa)
Diameter: 3.625 in (9.2 cm)
Length: 155.38-184.25 in (3.94-4.68 m)
Weight: 250 lbs (113.6 kg)
Memory: 8 Mb
Acceleration sampling rate (x and z axis): 50 Hz
Power source: 24 “C” and 6 “AA” alkaline batteries
Battery life: about 16 hrs
Top connection: ODP GS fishing cup
Bottom connection: Interchangeable core barrel-specific adapters

Measurement Specifications

Acceleration measurement range (HSA channel):
    Option 1: ±4 g
    Option 2: ±25 g
Pressure measurement range: 0-10 kpsi (6.9 MPa)
Pressure resolution: 1 psi (6.9 kPa)