As you drive into Lytham St Annes along Queensway or across the Moss, you can’t help but notice the white drilling rig at Anna’s Road, standing out against the green fields of rural Fylde. At night the site blazes like a beacon. Well not any more. The rig has gone and the lights are all but turned off. Many people have been contacting RAFF to ask if that’s it – have Cuadrilla finished and moved away. No such luck I’m afraid. Rather, they have decided to discontinue drilling their current well and are now preparing to drill another about 10 feet away from the original. (In the drilling industry this is known as re-spudding).
Cuadrilla says that it drilled down to about 2,000 feet, which is about a third of the way down to the top of the shale formations they are exploring. Apparently, these shale formations (the Bowland and the Hodder) start at roughly 5,000 feet. and end at 11,500 feet. At 2,000 feet Cuadrilla say that they stopped to cement the top casing, the first of four in this well. Once the cement hardened, Cuadrilla say that they ran a CBL- a Cement Bond Log, (an acoustic probe that assesses the integrity of the cement work) between the casing and the rock wall of the well.
Apparently, the CBL showed the possibility of channelling (ie, the cement had not adhered evenly to the casing) near the bottom, well below the aquifer. To be absolutely certain of their cementing, Cuadrilla say that they perforated the casing at that point and attempted to pump drilling fluid through. The company claims this test apparently indicated that no fluid could pass through. At the same time, a packer (a tool which is used during testing for well integrity) temporarily installed at the bottom of the well, became trapped inside the well by the pressure of the testing. Cuadrilla says that it is not possible to drill through the packer, and drilling around it would be difficult should they get permission to drill horizontally at a later date. So they have abandoned the well and started a new one a few feet away.
.This is the second of Cuadrilla’s four North West wells to fail – the other being at Preece Hall, after it was damaged by the earthquakes. We are slightly surprised that they conducted a Cement Bond Log in the surface case stage. They are expensive and time consuming to undertake ,and the lack of adequate onshore regulations means that they are not required. Readers will be aware that RAFF’s Technical Adviser Mike Hill has highlighted how crucial these bond logs are to ensure the aquifer and surrounding land are not polluted. The Health & Safety Executive have been particularly inept by stating that they are not necessary. Certainly, Cuadrilla haven’t carried out any CBLs at any of their other three wells. We know this to be true because we have a Freedom of Information document saying so.
So are Cuadrilla to be congratulated for doing something over and above what was required of them? We’re not so sure. It certainly gives them some good PR – but where’s the proof that they actually carried it out? No one has seen the CBL because no body is checking. Cuadrilla can say they are collecting all the data in the world but unless it is being verified by an independent body, is means absolutely nothing.
Also why did they carry out a CBL at the surface case stage? Even the experts say it is ‘odd’. We suspect that there is more to this than meets the eye and will report back when we have further evidence.