TECHNICAL INFORMATION

Ramco Oil Services LtdIn today's oil and gas industry, intensified attention is being paid towards safety and environmental issues, together with an inevitable link to equipment and procedural quality.

With this in mind, it was thought appropriate to issue this summary report on these topics as they affect the preparation and care of well tubulars.

The Ramco Oil Services Ltdmessage is clear-untreated well tubulars threaten well integrity, as will be illustrated. The threat to well integrity is also a threat to human life and to the environment.

Recent history in the Middle East has once more reminded us of the awesome reserves of destructive power contained in oil and gas wells.

In some areas, many of the major oil companies have their well tubulars cleaned to some degree, but up until now there has been no real effort to quantify the reasons for cleaning.

Ramco Oil Services LtdRamco Tubular Services, together with the expertise of Robert Gordon's Institute of Technology ran tests on a number of tubular samples in order to analyse the quantity of millscale present in, and on, ex-mill well tubulars.

The results were quite astonishing, especially when appropriately multiplied to represent casing and tubing schemes installed in wells.

Take, for example, a typical North Sea completion of, say, a modest 10,000 ft depth, comprising of 9 5/8" production casing and a 5 1/2" production string.

The Ramco Oil Services Ltdtally of millscale on the internal surfaces of the 9 5/8" and internal/external surfaces of 5 1/2" amounts to Over One ton!

This millscale will progressively flake off during the early life of the well; it is, however particularly resistant to removal by mechanical means, except abrasive blast cleaning.

In this paper the main safety requirements of typical North Sea wells are summarised, followed by the origins and effects of millscale.

In conclusion, recommendations are made as regards standards of well tubular finishing and protection.