Array acoustic logging tool while drilling (MAST)

MAST sends the signals by using a monopole transducer, and receive the signals by four arrays receiving transducers. Such tool could collect the monopole full wave signals of the formation in real time, and send the P-wave slowness to the ground in real time via downhole waveform real-time processing program. The measured waveform is saved in the memory of the instrument, which can be used for waveform data processing and analysis at later stage. Such instrument could measure the P-wave slowness of the formation in real time, and could also provide S-wave time slowness measurements in hard formation.

Applications

Lithology identification
Porosity calculation and rock mechanical parameters calculation
Borehole stability prediction, gas layer identification
Real-time formation pressure prediction
Synthetic seismogram for positioning on seismic map
Better real-time performance could reduce the drilling risks effectively.

Tool specifications

Max. body OD: 6.75″
Buckle type: 5-1/2 FH Box / 5-1/2 FH Box
Max. working temperature: 150℃
Max. working pressure: 20,000 psi
Flow rate: 225～650 gpm
Hole size range: 8.5～9.875″
Shock: ≤500g@1ms half sine

Measurement specifications

Detection system: 1 transmitter × 4 receiving (with spacing of 8 inches),
Isolator of drilling collar>30 dB
Transmitting transducer: monopole, bandwidth of 1.5～20 kHz
Receiving transducer: monopole, bandwidth of 500 Hz～23 kHz
Measuring range:　40～150 us/ft
Measurement accuracy: ±2 us/ft
Vertical resolution: 8″