Fiber optic monitoring of sand control equipment via tubing string

摘要

The progress and quality of the sand control process in a wellbore 10 is monitored by optical fibres 16 that are wrapped around sand control devices 14 in various patterns at a density dependent upon the measurement resolution required. The fibre pattern may be a zig-zag, spiral, or longitudinal array or may be located in a conduit at 0 an 180 degrees around its circumference. The character of the light travelling along the fibre is used to determine downhole conditions such as pressure, temperature, strain, vibration, or acoustic recognition and employs techniques such as microbending, Raman backscatter, and optical time domain reflectometry. Integrated sensors for interferometry, grating, fluorescence, or photoelasticity may additionally be used with the fibres and an optical demodulator 18 is located at the well head. The fibre may be protectively housed in a circumferential or axial groove in the sand control equipment or alternatively the fibre may be wound to lie between raised portions on the surface (see figure 7).