Distributed Fibre Optic Sensing With Hydraulic Fracturing

Unlike conventional reservoir monitoring devices, in which the sensing element is a physical device usually placed at the end of a copper line, with distributed fiber optic sensing, the entire length of glass fiber is turned into thousands of sensing points.

A critical advance has been micro seismic monitoring,which provides an even better subsurface picture of fracture growth and effectiveness, but it still leaves operators with multiple possible interpretations of the results and performance inconsistencies from one stage to another, leading to such questions as: Why is there micro seismic overlap? Is there stage communication in the reservoir? Is a plug leaking or is there poor cement quality in that particular hole section? With distributed fiber optic sensing, by analyzing the laser light reflections from different spots in the fiber, the temperature and strain of the glass can be determined at any point in the well, and the fiber can be turned into a series of distributed microphones or hydrophones.

Whereas in the past, one may have been limited to a couple of sensing points per well, with distributed sensing, the operator effectively has thousands of measurement points covering the entire well bore.

For the large unconventional reservoirs that operators are now targeting, the real value of distributed fiber optic sensing comes in combining multiple subsurface diagnostic techniques with the surface hardware and fluid chemistry to get the most out of each fracturing treatment.

In a project where thousands of wells may be drilled, it is critical to get the well spacing and horizontal orientation correct. If the operator does not have it right, he is either drilling too few wells or stranding valuable reserves, or drilling too many wells spaced too closely together and wasting tens of millions of dollars on drilling and completing wells that are not required.

While distributed fiber optic systems are invaluable in monitoring hydraulic fracture treatments, they also provide value throughout the life of a well. After the frac job, the same distributed sensing fiber can be used to perform production logging or be used for long-term well bore integrity monitoring.

Note: Full Case Study on "Fiber Optics Sensors Creating New Possibilities For Optimizing Fracturing"  Will Be Updated Soon.