June 2007 Newsletter
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Message from the President
Firstly the committee would like to extend great thanks to Roger Samworth from Weatherford UK Ltd and to LPS's Adam Moss and Kirill Shmyglia for rescuing our May evening talk. His topic on "Why Calibrate Logs?" was very interesting and well attended, and provoked a great deal of discussion from the audience, which is always encouraging.
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Thanks also go to VP Membership Assia Belhaouas, who has not publicised the 2007 membership status lately but has instead been working quietly but efficiently in chasing up existing and prospective members. She must be pleased to announce that membership now stands at 113 members, which is an excellent head count for this time of year.
Coming up this month at the LPS Evening Meeting:
"Characterization of Multiple Fluids in a North Sea Gas Condensate Reservoir Using Magnetic Resonance Radial Profiling". from Jim White of Schlumberger in Aberdeen at our evening meeting on Monday the 18th of June. See below for an abstract of the talk.
On the subject of evening meetings, we are still looking for a presentation for the 16th of July. If you wish to present an interesting talk to your fellow members on this date please contact any member of the committee.
After the summer break we have, on 27th September, a Rock Physics/Rock Mechanics seminar. Again, please see below for further details of what we hope will be an enjoyable and worthwhile event on a subject that is getting more and more attention in the petrophysical world.
Finally I must recommend that you have a look around the growing (in content) LPS website (Thanks to Iain Hillier for spending quite some time on this).
Patrick Crossouard LPS President
LPS Evening Meeting - June 18th, 6 pm at Burlington House:
Characterization of Multiple Fluids in a North Sea Gas Condensate Reservoir Using Magnetic Resonance Radial Profiling
Jim White, Schlumberger
Gas condensate reservoirs sometimes contain two distinct hydrocarbon types, one essentially gas condensate and the other a light oil with high gas/oil ratio. Operators seek to correctly identify the volumes of these two fluids, as the economic value of the field is strongly influenced by the fluid type and contact depth. In reservoirs with good permeability, fluid density and contact can be determined conventionally by formation pressure plotted with true vertical depth. This approach breaks down in low-permeability reservoirs, where supercharging effects predominate, and in producing reservoirs, where formation pressure is not stable. In such situations the only remaining "standard" method for identifying fluid contacts between the two hydrocarbon types relies on the increased density-neutron separation seen in gas zones. This effect is not reliable in gas condensate / light oil reservoirs because any small change in curve separation at a fluid contact can be easily perturbed by invasion and clay content.
A continuous magnetic resonance (MR) method is now available that provides robust resolution of these two fluids even in the difficult situations outlined above. This method is demonstrated in a recent North Sea well, where diffusivity measurements logged across the whole reservoir correctly identified the presence of two different hydrocarbon fluids, and the contact between them. This information helped guide subsequent sampling depths using a formation tester. Here two distinct hydrocarbon types were seen with downhole fluid measurements and later confirmed by pressure/volume/temperature analysis of samples returned to the surface.
The latest methods of continuous fluid profiling using MR also investigate fluid saturations at three increasing depths in the formation, allowing a saturation profile away from the wellbore to be measured. These multiple radial measurements allow an estimation of hydrocarbon mobility, measuring the degree to which mud filtrate is able to move the reservoir fluids away from the wellbore. This North Sea example shows that the deepest reading measurements have the highest reservoir hydrocarbon saturation, confirming that the hydrocarbon is mobile over the whole interval. In addition, the measurement with the deepest reading is quite immune to occasional borehole rugosity that can affect the shallowest readings.
This demonstration was based on a light oil/gas condensate reservoir but similar measurements are being run in other reservoirs where hydrocarbon type and mobility is also of primary concern. For example, heavy oil reservoirs benefit from both continuous viscosity measurements provided by MR and an indication of recovery factors provided by the moved hydrocarbon volume using saturation profiling.
University of Leicester Festival of Postgraduate Research
LPS Members are warmly invited to attend the third, annual Festival of Postgraduate Research at the University of Leicester on 29th June 2007.
The Graduate School will stage the third annual Festival of Postgraduate Research, organised jointly by the Student Learning Centre and the Careers Service. Research postgraduates from across the University's academic disciplines are invited to present their research in a poster presentation format to an audience comprising academic staff, employers and the general public.
The University of Leicester is one of the UK's leading research institutions, and its Festival of Postgraduate Research showcases the latest research emerging from its postgraduate community. The event offers organisations, interested parties and the general public an opportunity to meet the next generation of innovators and cutting-edge researchers.
Please use this link (http://www.le.ac.uk/gradschool/festival/business.html) to find out more, including why you should attend the Festival, how else you could get involved (e.g. acting as a judge, hiring an exhibition stand or contributing sponsorship), and how to book to attend.
LPS sponsored student, Joanne Tudge, will be presenting a poster of her work.