16.3 Installation in Wellbores

The location of the source of the backscattered light is determined in terms of its distance along the fiber by the two-way transmission time and the velocity of light in the transmitting medium. It is therefore necessary to know how length along the fiber correlates to measured depth along the wellbore in which the fiber is installed. The foregoing information includes knowledge of the positions in the well and along the fiber where connections through casing shoes, packers and other features occur. All these can be assumed to remain constant between initial installation and mechanical interventions in the wellbore.

There are several fiber configurations deployed in wellbores, illustrated in Figure 16.3-1 which enable various calibrations to be made to the temperature data.

Figure 16.3-1 DTS fiber configuration patterns.