We experimentally demonstrate a high pressure sensor based on a polarization-maintaining photonic crystal fiber (PMPCF) with Sagnac loop configuration for downhole application. The pressure sensitivity of the proposed sensor is 4.21 nm/MPa and 3.27 nm/MPa at ~1320 nm and ~1550 nm respectively. High pressure measurement up to 20 MPa has been achieved in our experiment. The sensor also shows redu...

Hydraulic fracturing treatments are often monitored by strings of geophones deployed in boreholes. Instead of picking discrete events only, we here use time-frequency representations of continuous recordings to identify resonances in two case studies. This paper outlines an interpretational procedure to identify their cause using a subdivision into source, path, and receiver-side effects. For t...

The shear swirling flow vibration cementing (SSFVC) technique rotates the downhole eccentric cascade by circulating cementing fluid. It makes the casing eccentrically revolve at high speed around the borehole axis. It produces strong agitation action to the annulus fluid, makes it in the state of shear turbulent flow, and results in the formation of pulse pressure which affects the surrounding ...

The holistic inversion approach for frequency domain airborne electromagnetic data has previously been employed to simultaneously calibrate, process and invert raw frequency-domain data where prior information was available. Analternative formulation has beendeveloped,which is suitable in the casewhere explicit prior information is not available. It incorporates: a multi-layer vertically-smooth...

The gamma-ray attenuation porosity evaluator (GRAPE) component of the multisensor track (MST) unit on board the JOIDES Resolution measures the saturated bulk density of sediments by relating the attenuation of gamma rays in a core sample to that of a standard with known density (aluminum). After reaching thermal equilibrium, unsplit core sections are routinely run through the MST system. The sa...