The estimated number of truck journeys to Cuadrilla’s proposed fracking sites in Lancashire assumes that less than half the flowback fluid returns to the surface, the company’s technical director said today.
Andrew Quarles told an industry conference the volume of fluid that comes back up also affects whether a well is commercially successful.
“We have been estimating we will get back 40% of flowback and our estimates of truck traffic and recycling are based on that. If we get a lot of it back then it is unlikely that the project works”.
Traffic likely to be generated by Cuadrilla’s proposed wells at Roseacre Wood and Preston New Road has been a big concern of local residents. Increased traffic also led planners to recommend refusal of the application for Roseacre Wood.
Mr Quarle said shale tended to have very low amounts of water stored in it. The pores of other rocks at a similar depth would typically be 40-80% water. But in shale the proportion of water would be 20-30%.
Because of this, “Very little of the fracture fluid actually ever returns to the surface”, Mr Quarles said. “So when we inject the water in there most of it does not come back”.
He said: “There are lots of theories. No one know exactly what is going on or where the water goes or where the final resting place is”. The water could go into the fractures created by fracking or it could be absorbed into the shale formation, he said.
- Andrew Quarles was talking at the UK Shale Gas summit, orgaised by the Instituion of Mechanical Engineers. Our other reports from the summit: