is GOM a more complex geology than other location in the world 1

[jfduroch]

hello,
I have been told that drilling in the Gulf of Mexico may be more challenging than other locations in the world. I would like to have professional opinion on such a statement. Can someone point me out towards the reasons (briefly) why the Gulf of mexico geological structure would be more complex than the North Sea (for instance) or the gulf of guinea.
Maybe it is due to the depth of the reservoirs, their dispersion, the stability of the structures... I really don t know and would like to have a feel whether it is really the case. I have browsed the internet to find out more about this area geology but was unfortunate with reference to this "drilling difficulty" aspect. Could someone direct me ? thanks

 

[zdas04]

The most challenging location in the world is .... the next one you have to develop. Statements like "the GOM is the most complex ..." are just rationalization for doing a bad job. Leave the stupid rationalizations to the folks at Guinness Book of Records and get on with developing the field you're assigned.

Are you looking for bragging rights? Good luck with that. The folks that took 25 years of active drilling to bring in the Overthrust Belt in the Northern U.S. might say that that faulted, folded, messed up geology was the toughest in the world, but so what?

As you might be able to tell, I really hate this sort of discussion. It is all hard. I read today that Obama is planning on instituting a Windfall Profits Tax on the "obscene profits" of the industry if he wins. Fear of that nonsense being reapplied has pretty much stopped the industry from taking risks and new fields are not being discovered fast enough. Is it because we've decided that "it's too hard" to find new oil and gas in the GOM, North Slope, or Gulf of Guinea? Probably.

David

 

[JLSeagull]

The shallow water GoM was developed long ago. Each year the "deep water" projects get deeper. Perhaps different views apply when the drill travels 8000-foot under water before the hiting the mud.

 

[jfduroch]

zdas,
I would like to clarify slightly my point. I am not a driller, I am not a geologist but I am a mechanical engineer with more than 10 years experience in the offshore construction field and I did a bit of reservoir engineering. My question was certainly naive but had no political implications. I am convinced it is not difficulties or tax issues that are going to prevent investment in drilling activities. In anycase, oil need to be produced and will be produced regarless of polical aspects and location. I was interested into understanding why some people state that the geology may be more complex somewhere than somewhere else and what is the geological impact on drilling completion. Can someone give a professional and sound scientific/experienced opinion or simply direct me.

 

[Xtal2012]

"Fear of that nonsense being reapplied has pretty much stopped the industry from taking risks and new fields are not being discovered fast enough. Is it because we've decided that "it's too hard" to find new oil and gas in the GOM, North Slope, or Gulf of Guinea? Probably."

Oil prices are now at record highs, so the financial incentive for exploration is stronger than ever. I suspect the reason we are not discovering enough new oil is that all the large oilfields have long since been discovered and exploited. Many of the "large finds" in recent years have been relatively small fields that soon enter decline. For example the Arctic National Wildlife Reserve is estimated to contain 10 billion recoverable barrels - enough to satisfy only 1.4 years of US consumption. We are having to explore at an ever increasing rate just to maintain current production levels.

People tend to blame corporations, politicians and environmentalists for high oil prices but the truth is that we are reaching the geological limits of production.

 

[BigInch]

True, but I wouldn't say too "hard". The financial incentive may be high, but is not enough by itself, as exploration cannot be a function of price alone. I'd say we're starting to get into the twilight zone of the high investment vs. low expected rewards curve, but for now its just a matter of seeing how much punishment the USD can take until demand for oil and other foreign goods equalize with the economic effects of still relatively constant supply of oil. Since oil price today is still a bit lower in constant 1978 USD, there's still a lot more upside to this, but the combined probability of rewards vs price increases of late makes be doubt that we will ever see the true limits of what the geologist can do to pump it out. I think we're on top of that curve from now on out.

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain

 

[DrillerNic]

I'm with zdas on this: drilling through the salt in the GoM is tricky, but the weak Balder/ Sele formations in the North Sea can be a bitch and the reservoir Thamamma formation in the Persian Gulf (the geology of which is poorly understood) can be so highly fractured that your mud just vanishes. And I've heard that Iran & Iraq have terrifying overpressures....

 

[jfduroch]

Thank you DrillerNic. You provide some technical insight with regards to Salt formation in the GOM and I understand reading in between the line that although tricky it is no more tricky that in other regions. That is a valuable answer.
Apparently I progressed a bit on my side on this investigation. It appears that the would be difficulty in the gulf of mexico is due to geotechnical reasons with soft soil formations. An incident occured a few years ago in this region where the tightness between the casing and the geological formation was not properly achieved. As a consequence the well went out of control from gas eruption with gas migrating outside of the casing,causing significant drillrig loss. Control of Well underwriters have concluded that the tightness is difficult to achieve making drilling "more difficult" in the GOM and then willing to apply a cost differentiation on "geological reasons". Can anyone confirm that or has heard about this story. I believe that maybe the concrete mixture may simply not have been well adapted when that occured. In that case the insurance conclusion is a bit too quick

 

[DrillerNic]

I don't know of that story, but underground blowouts which you describe aren't unknown around teh world.

What is true is that the geology of the deep & ultra deep areas of the world make for very hard drilling: the window between the rock's pore pressure (ie the pressure of the fluids in the rock- you must be above this to stop getting a kick or a blowout) and the rock's fracture pressure (the pressure at which the rock fails- you need to stay below this to stop loosing all your mud and then getting a blowout) is very very small, especailly in the shallow sediments. Now the deep & ultra deep areas are GoM, bits of West Africa and Brazil, so drilling offshore GoM, Brazil and bits of West Africa can be very challenging.