Industry

Cuadrilla plans seismic testing near Preston New Road frack site

171207 seismic testing vibroseis machine Cuadrilla Resources

Vibroseis machine used for seismic testing. Photo: Cuadrilla Resources

The shale gas company, Cuadrilla, has announced plans to carry out seismic surveys in a field next to its Preston New Road site near Blackpool.

In an email to the site’s community liaison group, the company said the work would help to establish the best locations underground to drill the two planned horizontal wells.

It said the work was expected to be done late this month (December) or early in 2018 and would take two to three days.

Cuadrilla said it would use what’s known as an articulated hydrostatic vehicle, equipped with a seismic vibroseis unit (see picture above).

The vehicle creates sound waves underground. They are reflected back from different rock layers. The company said it could build up an accurate picture of the subsurface at the exploration site by measuring how long it took for the sound waves to be reflected back.

“This helps us in positioning the horizontal exploration wells some 2km underground. This is a standard practice used in seismic surveys across the country.”

Cuadrilla said the vibroseis unit would be positioned above the bottom of the pilot hole currently being drilled from the Preston New Road site (marked on the image below by Expected Well TD).

PNR 171207 seismic testing Cuadrilla Resources

Location and well head and seismic testing area. Image: Cuadrilla Resources

The email said:

“The information on the shale rock from this survey at this single point above the pilot hole will be matched with the wider data obtained from Cuadrilla’s seismic survey of the Fylde carried out in 2012.

“Together this combined information will be used to inform the optimum subsurface locations for drilling of two horizontal wells in the shale rock from the Preston New Road site.”

Cuadrilla said the work was not expected to exceed the noise limits set in the planning condition for Preston New Road.

  • Cuadrilla is hosting its third public webcast tour of Preston New Road tomorrow (Friday 8 December 2017) from 2pm-3pm. The tour can be viewed online at http://pnrlive.co.uk Details

36 replies »

  1. As a “pioneer front runner for UK shale” I would expect them to go slowly TW. Gold standard regulation adherence, and attention to detail should not be rushed-otherwise, could end up with a squished bird!

  2. The BLACKPOOL GAZETTE has done a spread on the risk posed by hydrogen sulphide by fracking in the Fylde:
    https://www.blackpoolgazette.co.uk/news/business/scientist-s-gas-fears-over-fylde-fracking-1-8896259
    The newspaper interviewed me regarding my H2S report – to see it, do a Google Search with this sentence “Geological concerns about fracking the Bowland shales of NW England. Briefing Note #4 :Major Hazards from Hydrogen Sulphide Gas” and click to download the PDF.
    In the BLACKPOOL GAZETTE, Cuadrilla gave their response which I have coded as CUAD#1 and CUAD#2 for future reference:
    CUADRILLA #1: “Mr Grayson’s assertions are not correct.” “The presence of significant levels of hydrogen sulphide in shallow gas reservoirs elsewhere in the region occurs due to changes in the gas composition as it migrated slowly upwards over time from the deep shale source to the shallower reservoir. We have established that the natural gas in the shale rock contains no hydrogen sulphide above trace levels.”
    CUADRILLA #2: “We will produce Lancashire’s natural gas directly from this shale source. Natural gas is monitored independently prior to connection into the grid.”

    Meantime, a Drill or Drop poster called ‘Ken has raised five points of concern of general interest:
    KEN#1: “Professor of Petroleum Geophysics Quentin Fisher was commenting on this yesterday. Apparently with the iron content of carboniferous shales, H2S would be converted into iron pyrites and so would not be an issue.”
    KEN#2: “Cuadrilla have extensive field knowledge of the area and I gather H2S is not an issue. By that I mean they have drilled through the formations and produced gas and there are no issues that I have heard of.”
    KEN#3: “All well data is made public anyway so I can see no logic in suspending any test.”
    KEN#4: “This is a question for experts, and they appear to have no concerns and they have access to the data.”
    KEN#5: “It looks like another fake news story designed to whip up hysteria about an issue that engineers deal with.”

    I will respond to KEN#1-5 and CUADRILLA#1-2 in the course of the next few days, along with any other points raised meantime. Cheers, Robin Grayson MSc

  3. Martyn, can you tell me where i can read these Gold Standard regulations to which you refer, oh I forget they don’t exist!!!

  4. Imagine if you produced a detailed map that showed where it would be suitable to build a new factory. You then build said factory in the highest risk flood zone on foundations that are quite unsuitable. At which point you say, ‘I really must produce a more detailed map, just to confirm I’ve built my factory in exactly the right place’. Do excuse my stupidity, but why are Cuadrilla doing 3D seismic surveying now? They’ve already decided on their location and drilled a well. Surely they haven’t put it in the wrong place…. or drilled through a fault line. Heaven forbid. Couldn’t that cause seismic activity?

    • Where does it say they are doing a 3D seismic survey? From the limited information, they seem to be planning to record a VSP. This will give velocity information to help depth control the planned wells.

  5. Save Lincs-no point you finding the Gold Standard regulations until you have mastered a certain basic! Gritting lorry just gone past my window-here comes that Arctic Blast. Wonder what the UK gas usage will be this weekend?

  6. I have Martin, I live near a potential fracking site, do you, and if you are going to be sarcastic please don’t use Gold Standard quote when even you know they don’t exist.

  7. You can’t put your sensors downhole until after you’ve drilled it. Quite common to get better data with a VSP by utilising the wellbore. As the pilot hole is going deeper than the horizontal sections it makes sense to do it this way.

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