1 Dear members, and friends of the LPS, Our final One Day Seminar for the year will be held on 14th December, with the title ‘Everything Formation Testing’. We have a remarkable agenda lined up for next Thursday (see page 2), so this is definitely not one to miss! Registration forms have already been distributed, and are also available on our website. Following this Seminar will be our annual ‘President’s Evening’ at the King’s Head, kindly sponsored by Gaia, Schlumberger, and Baker Hughes. This is a free event with drinks and finger food provided, and partners are most welcome to join us for the Christmas cheer. See the official invitation on page 3. This month’s technical article is ‘Rock Typing in Carbonate Reservoirs’, authored by Jonathan Hall who has previously held the office of VP Technology in LPS (twice). It is an informative and authoritative work, starting on page 7. Thankyou to all who attended our Annual General Meeting on 21st November, and also to those who had mailed in their postal ballot to successfully update Article 13 in our Constitution. As we presented, our income from both One Day Seminars & Sponsorship has fallen significantly. So we have introduced a range of measures to stabilize our financial situation, among these are cancellation of the free New Technology seminar in January, and relocation of Evening meetings to the smaller ‘Council Room’ in the Geological Society. In addition I anticipate that income from the 2018 SPWLA Annual Symposium will replenish the coffers. I would like to thank out-going Executive Committee members Carole Reynaud and Negah Arjmandpour for their efforts. Next year we introduce Shyam Ramaswami as Officer of Sponsorship, and welcome back incoming President Mike Millar. Mike first joined the LPS in 2005, and was President in 2012/13, so I am confident of leaving the leadership of our Society in good hands. Thankyou for the journey over the last two years, and I wish you the best in our fascinating pursuit of both the scientific and technical aspects of formation evaluation. Best Regards, Michael O’Keefe Michael O’Keefe - LPS President London Petrophysical Society: Newsletter 2017-12 1 www.lps.org.uk Technology Dawn Houliston [email protected]Seminars Joanne Tudge [email protected]Membership Sharan Dhami [email protected]External Liason Brian Moss [email protected]Newsletter Jenny Rastogi [email protected]Publications Carole Reynaud [email protected]Website Anne Denoyer [email protected]
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Dear members, and friends of the LPS, Our final One Day Seminar for the year will be held on 14th December, with the title ‘Everything Formation Testing’. We have a remarkable agenda lined up for next Thursday (see page 2), so this is definitely not one to miss! Registration forms have already been distributed, and are also available on our website. Following this Seminar will be our annual ‘President’s Evening’ at the King’s Head, kindly sponsored by Gaia, Schlumberger, and Baker Hughes. This is a free event with drinks and finger food provided, and partners are most welcome to join us for the Christmas cheer. See the official invitation on page 3. This month’s technical article is ‘Rock Typing in Carbonate Reservoirs’, authored by Jonathan Hall who has previously held the office of VP Technology in LPS (twice). It is an informative and authoritative work, starting on page 7. Thankyou to all who attended our Annual General Meeting on 21st November, and also to those who had mailed in their postal ballot to successfully update Article 13 in our Constitution. As we presented, our income from both One Day Seminars & Sponsorship has fallen significantly. So we have introduced a range of measures to stabilize our financial situation, among these are cancellation of the free New Technology seminar in January, and relocation of Evening meetings to the smaller ‘Council Room’ in the Geological Society. In addition I anticipate that income from the 2018 SPWLA Annual Symposium will replenish the coffers. I would like to thank out-going Executive Committee members Carole Reynaud and Negah Arjmandpour for their efforts. Next year we introduce Shyam Ramaswami as Officer of Sponsorship, and welcome back incoming President Mike Millar. Mike first joined the LPS in 2005, and was President in 2012/13, so I am confident of leaving the leadership of our Society in good hands. Thankyou for the journey over the last two years, and I wish you the best in our fascinating pursuit of both the scientific and technical aspects of formation evaluation. Best Regards,
Michael O’Keefe
Michael O’Keefe - LPS President
London Petrophysical Society: Newsletter 2017-12 1 www.lps.org.uk
Early dolomitisation processes occurred at shallow depth by seepage of saline brines
associated with evaporite deposition. Burial
dolomitisation processes, such as
displacive dolomite veining, created
euhedral crystal-lined porous and
permeable 'zebra structures’ and dolomite breccias. Results of fluid inclusion studies
suggested that the timing of reservoir
hydrocarbons’ charge was after the late-
stage burial dolomitisation and involves
high temperature hydrothermal fluids.
Zebra fabric ‘rhythmites’ in Middle Kurrachine cored interval.
More textural information may be obtained
from borehole image logs, vertical
interference pressure testing, chemical
tracers and an interesting cased hole log application log, spectral noise logging,
yielding information about connectivity at
hydraulic unit scale and higher; being well-
suited to static and dynamic model builds.
Nuclear magnetic resonance logs, in continuous mode acquisition, may yield a
pore size distribution and, if T2 distribution
can be reliably set, and significant a priori knowledge is available, an irreducible water
saturation, Swir, value may be determined.
Both of these parameters may be useful
indicators in determining storage capacity,
but may yield ambiguous interpretation as
to connectivity or flow capacity unless, they can be independently, calibrated. NMR
offers pore size distribution functions to be
developed.
Pore size distribution modelling from an Aptian platform limestone, Abu Dhabi, SPE165150 2013
Other microstructure correlation functions
can be developed for n-dimensional two phase isotropic media and include: • n-point probability functions
• surface correlation functions • lineal-path function • chord-length density function • pore-size distribution functions • percolation and cluster functions
The Influence of Carbonate Microstructures Many carbonates exhibit random
heterogeneous structure, yet at microscopic
scale may demonstrate some isotropic
repeating structures. The field of study that
unifies, rigorously, both microstructures
and their macroscopic properties has been studied for many natural; biological,
12 London Petrophysical Society: Newsletter 2017-12 www.lps.org.uk
Tuesday 21st Nov
2017
6:30pm-730pm
”
Prof Ruth Morgan
UCL
Thursday 14th
Dec 2017
9:00 am –5:00pm
Macroscopic Effective Properties: Tortuosity Again
An illustration of the realities of these
physical bounds comes from work
published by Herrick and Kennedy (1996).
These authors measured resistivity index
on two composite core plugs comprising, in
one case, a parallel arrangement of three isotropic materials and, in the other case, a
series arrangement. The figure below
reflects their measurements. In electrical
transport property terms we used the
characteristic length concept, tortuosity, to
define the conductivity path of 100% brine saturated composite medium through the
Archie ‘m” term and another modifier,
Archie ‘n’ term desaturated (drainage) or
resaturated (imbibition) cycles.
Results of resistivity index measurements made by
Herrick and Kennedy, 1996, on series and parallel arrangements of matrix material with different formation factor values
Four classes of steady-state effective media problems, modified after Torquato, (2002) and pers. comm. (2017).
Tortuosity as a term used by
petrophysicists, reservoir engineers or
geologists is often used to describe transport processes in a composite porous
material. Values for electrical, diffusional
and hydraulic tortuosity differ. Electrical
tortuosity is defined in terms of
conductivity whereas hydraulic tortuosity is
usually defined geometrically, and diffusional tortuosity is derived from
temporal changes in concentration.
Tortuosity might be better defined in terms
of the underlying flux of material or
electrical current with respect to the forces, which drive this flow.
Torquato, (2002) recognizes 4 classes of
steady state effective media problems,
where and we recognise that most are commonly study in certain oilfield
applications.
In the figure above, modified after Torquato, 2002. Left: L and l represent the macroscopic and
microscopic length scales. Right When L is bigger than l, the heterogeneous material can be treated as a homogeneous material with effective property, Ke •
It is this characteristic length that defines tortuosity, which underpins the rigorous
relationships between transport processes
in rocks. In this way, for carbonates, the
macroscopic measurement of various
effective properties can be related specific microstructures, and thereby to rock type
