HL Deb 23 October 1973 vol 345 cc509-11

2.42 p.m.

THE EARL OF LAUDERDALE

My Lords, I beg leave to ask the Question which stands in my name on the Order Paper.

The Question was as follows:

To ask Her Majesty's Government how many miles of seismic survey of the North Sea have been shot to date, what is the proportion shot before 1968, how many more miles of survey are believed to be necessary for building up a complete picture of the North Sea-bed geology.

THE MINISTER WITHOUT PORTFOLIO (LORD DRUMALBYN)

My Lords, the total amount of seismic surveys shot in the whole of the North Sea between 1962 and now is about 700,000 miles of which about 380,000 miles is in the United Kingdom sector. About 40 per cent. of this was shot before 1968. This has been sufficient to provide a broad picture of the geology of the North Sea as a whole with considerable detail in some areas of particular interest. It is impossible to judge how much more seismic work will be needed to complete the survey of all the structures of interest, particularly as techniques are being continually improved and many areas are being re-shot.

THE EARL OF LAUDERDALE

My Lords, I thank my noble friend for that very informative reply—more informative than replies sometimes are. May I ask whether he can say what proportion of this 380,000 miles shot in the United Kingdom sector has been shot in areas that have been licensed for production?

LORD DRUMALBYN

My Lords, I do not think I am able to give my noble friend that information. In fact, as I have said, it often happens that areas are re-shot. The reason for this is that the original shooting is on a broad grid basis and then, before the tenders go in for the licences, more careful examination is made on a very much smaller grid.

LORD SLATER

My Lords, when the noble Lord, Lord Drumalbyn, talks about "shot", may I, as an old miner, take it that he is talking about borings taking place in the North Sea? If so, why not say so?

LORD DRUMALBYN

No, my Lords; that is not quite the case. The current way of doing seismic surveys is by the use of sound waves. Previously it was done by the use of explosives. This is done in order to locate the kind of geological structure which might contain oil or gas. It is not done to prove the existence of gas or oil or to evaluate the quantity.

THE EARL OF LAUDERDALE

My Lords, may I ask this further question? When my noble friend says that the seismic shots so far shot are sufficient to give a fair picture of the geology of the North Sea, does that include areas that have not been licensed? Would he not agree that there is need for further seismic work on the unlicensed areas to explore not only the structures to which he referred but also the stratographic formations which may be of greater interest in the future?

LORD DRUMALBYN

Yes, my Lords. This work is going on all the time. There are about five vessels in full-time use on the United Kingdom Shelf and at times this number may be considerably exceeded. This is not something which is done once over an area as a whole and that is all. As I have explained, surveys are carried out in more detail and in more than one place.

THE EARL OF LAUDERDALE

My Lords, could my noble friend say whether there is not an obvious need for concentrating some new effort in the areas not yet licensed or offered for licence?

LORD DRUMALBYN

My Lords, I think it true to say that on the broad grid basis the whole area has been covered. Where there are indications of the possible existence of gas or oil obviously work will be done more intensively, and this is done with a view to people applying for licences as and when the licences are accorded.