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)KSEPL::KS082 8-MAV-1990 11 14:13.56PROFS'SNIVM01(U27RS45)STEWARTR,KS082PATENT IDEA

Ton,Thanks for sending me a copy of the SEM EP patent application.

On the subject of patents I have for some time been thinking of a newdrilling mud system that might address some of the current issues beingraised re. SEM and oil based muds

The problem with OBMs and to a certain extent SEM is that theymake use of a water immiscible phase ( emulsified with water) to coatout onto borehole/cutting surfaces and reduce the unwanted shale/waterreactions that cause instability.Moves are underway to ensure that thecoating phase which ends up on the cuttings ( ego as a pile on thesea-bed floor in offshore operations ), has minimal toxicity to freeliving organisms - hence our move to put esters into SEM instead of oil

However even the least toxic components can still cause massivedamage to the ecosystem via their organic enrichment in for instancea cuttings pi le.Through bacterial growth on the residual organic materialattached to the cuttings the whole environment can become anaerobic andnoxious under and around the cuttings dump.

My idea is to use a water soluble non-ionic compound ( eg like theShell Oxilubes which are alcohol alkoxylates or perhaps somethingmore biodegradable) which has a distinct cloud point at say 25 deg. C.in place of the normal oil or ester phase. This product would then precipitateout of solution at > 25 deg C. ( ie downhole ) and coat the borehole/cuttingssurface witha water impermeable layer.However, when the cuttings are broughtto the surface and cooled prior to dumping the non-ionic becomes watersoluble again and can be recovered from the water phase leaving uncontaminatedcuttings which can be easily dumped.If preferreddischarged straight into the cold sea-water and the nonionic would leachout immediately into the water column thus avoiding organic enrichmenton the sea bed.

The concept seems ( to me at least emminently patentable. The questionis how much experimental evidence do I need to " prove" that the conceptcould work in practice? Can we file a quick priority patent on the conceptalone? I think we will need to move fairly quiCkly on this one if we areto avoid being pipped to the post

Kind regards,John DownsKSEPL LRP/12

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