HERE - Spwla-houston.org

2014 SPWLA Houston Chapter Spring Topical Conference
April 30th – Chevron Auditorium
Petrophysics Meets Geophysics: A Multi-Disciplinary Approach to Reservoir
Challenges
Agenda
7:15 – 8:00 a.m. Registration
8:00 – 8:05 a.m. Welcome and Introductory Remarks - Matt Blyth (SPWLA)
8:15 - 9:00 a.m. “It’s About Time! Seismic Petrophysics as the Bridge to Cross the Chasm”– Mark
G. Kittridge (HESS Corporation).
9:00 – 9:45am. “Anisotropic Bounds and the Rock Physics of Unconventional Reservoirs” – Colin
Sayers (Schlumberger) 2010 SEG/EAGE Distinguished Instructor Short Course.
9:45 – 10:00am Break
10:00 – 10:45am. “Petrophysics for Rock Physics” - Mosab Nasser (Maersk Oil America)
10:45 – 11:30am. “A Multi-Disciplinary Integrated Study of the Haynesville Shale” - Jennifer
Lucas (BP)
11:30 – 12:30 p.m. Lunch
12:30 – 1:15pm. “Untangling Sonic Anisotropy” - Jennifer Market (Weatherford) SPWLA
Distinguished Lecturer 2008/2009 & 2011/2012
1:15 – 2:00pm. “QI Rock Property Models for Reservoir Characterization – A Velocity-Porosity
Example” - Stephan Gelinsky (Shell International E&P)
2:00 – 2:15 p.m. Break
2:15 – 3:00pm. “Advanced Rock Physics Diagnostics to Define the Link Between Petrophysics
and Geophysics” - Zakir Hossain (Rock Solid Images) –
3:00 p.m. – 4:00 p.m. Panel Discussion with Speakers and Wrap Up
It’s About Time! Seismic Petrophysics as the Bridge to Cross the Chasm
Mark G. Kittridge (HESS Corporation)
Abstract
Petrophysicists are recognized as the source for quantitative reservoir characterization results:
porosity, net-to-gross, mineral volumes, porosity, and (water) saturation. Core-log calibration
provides descriptive and analytical ground-truth and a platform for collaboration at the staticdynamic modeling interface. The metrics and language for communication with the geologist
and reservoir engineer are clear and well understood.
Communication with our Geophysical
colleagues seems more difficult and
less common; differences in reference
system, units, and vertical resolution
frequently challenge even the casual
conversation. And the unfortunate
reality is that Petrophysicists are the
primary
source
of
acquisition
decisions
that
affect
critical
geophysical data (density, Vp, and Vs),
uniquely positioned to quantify fluid
properties
and
their
vertical
distribution, and equipped to
characterize the near wellbore and
the radial distribution of fluids that
directly influence density and velocity.
In this presentation, we will explore key areas where the Petrophysicist can effectively interact
and deliver value and interpretive insight(s) to the Geophysicist, and positively impact a variety
of geophysical workflows. Using an iterative Seismic Petrophysics workflow, and pertinent
public-domain analog data, we examine details of key workflow elements, including reservoir
Petrophysics, shear log estimation, fluid replacement, and dry-rock modulus diagnostics, using
both siliciclastic and carbonate examples. The discussion will equip the Petrophysicist for a
more informed and productive dialogue with the Geophysicist and ensure the full realization of
Rock Physics in the interpretation of seismic data.
Biography
Mark G. Kittridge is a Petroleum Engineer with more than 25 years’ experience in Petrophysics,
including well operations, integrated reservoir studies, enhanced oil recovery, and rock
physics. Core competencies include deterministic Petrophysics, rock and fluid physics for QI,
shaly sand evaluation, pressure interpretation, core-log integration, and carbonate reservoir
evaluation. Mark is currently Geophysics Manager – Physics of Rocks for HESS
Corporation. Previously, he was Regional Discipline Lead (Petrophysics) and global Principal
Technical Expert (QI Petrophysics) at Shell International EP Inc. Additional roles included
Manager – Petrophysics and Rock Physics (ConocoPhillips) and VP Technology (Ikon
Science). He earned a MSc. in Petroleum Engineering from The University of Texas at Austin
(1988) and both BSc. and Professional degrees in Geological Engineering from The Colorado
School of Mines (1986). He has chaired and co-organized multi-disciplinary research
workshops and topical conferences for both SEG and SPWLA. Mark is the co-inventor of one
US patent for the characterization of logging tool performance.
Anisotropic Bounds and the Rock Physics of Unconventional Reservoirs
Colin Sayers (Schlumberger)
Abstract
Petrophysics seeks to determine rock properties such as porosity, lithology, saturation, etc.,
using a multi-tool inversion of well logs such as density, neutron porosity, gamma-ray, etc.
Currently, there is great interest in resource shale plays such as the Bakken, Barnett, Eagle Ford,
Fayetteville, Haynesville, Marcellus and Woodford shales. Resource shales are usually
anisotropic, and an understanding of the anisotropy of shales is important, for example, in fluid
and lithology determination using AVO (Amplitude Versus Offset) data, in stress and fracture
characterization using AVAz (Amplitude Versus Azimuth) data, in hydraulic fracture design, and
in determining the variation in stress due to production. Traditionally, volume fractions
obtained from Petrophysical analysis are used as input into rock physics models. However
applications of rock physics for unconventional reservoirs require quantification of the
anisotropic rock fabric. While scalar properties such as density, neutron porosity, gamma-ray
and spectroscopy only provide information on the composition of the rock, tensorial properties
such as sonic velocity, resistivity, and dielectric properties are sensitive to both composition
and texture. In this talk the quantification of anisotropic rock fabric using orientation
distribution functions, fabric tensors and anisotropic correlation functions is described, and the
use of such information in rock physics models is discussed. Unless the fabric of the rock is very
simple, as, for example, a 1-D layered medium, it is extremely difficult to calculate the effective
properties exactly. Ponte Castaneda & Willis (1995) presented a simple prescription, based on
the Hashin–Shtrikman variational structure in the form developed by Willis (1977, 1978), for
the effective properties of anisotropic media consisting of a matrix containing one or more
populations of inclusions. The application of this method to unconventional reservoirs is
described and compared with the results of laboratory measurements.
Biography
Colin Sayers is a Scientific Advisor in the Schlumberger Seismic for Unconventionals Group in
Houston. He entered the oil industry to join Shell's Exploration and Production Laboratory in
Rijswijk, The Netherlands in 1986, and moved to Schlumberger in 1991.
His technical interests include rock physics, exploration seismology, reservoir geomechanics,
seismic reservoir characterization, unconventional and fractured reservoirs, seismic anisotropy,
borehole/seismic integration, stress-dependent acoustics, and advanced sonic logging.
He is a member of the AGU, EAGE, GSH, SEG, SPE, and SPWLA, a member of the Research
Committee of the SEG, and a member of the editorial board of the International Journal of Rock
Mechanics and Mining Science and Geophysical Prospecting. He has a B.A. in Physics from the
University of Lancaster, U. K., a D.I.C. in Mathematical Physics and a Ph.D. in Physics from
Imperial College, London, U. K. In 2010 he presented the SEG/EAGE Distinguished Instructor
Short Course "Geophysics under stress: Geomechanical applications of seismic and borehole
acoustic waves", and was chair of the editorial board of The Leading Edge. In 2013 he was
awarded Honorary Membership of the Geophysical Society of Houston "In Recognition and
Appreciation of Distinguished Contributions to the Geophysical Profession".
Petrophysics for Rock Physics
Mosab Nasser, Igor Escobar
& Gary Ostroff (Maersk Oil America)
Abstract
Petrophysical evaluations are very critical for rock physics diagnostics and studies. However,
most of them follow a one-size-fits-all approach producing a standard set of logs given a set of
typical and standard industry workflows. For example shale volume (VSH) is always a standard
product which is good but not sufficient for many rock physics studies, especially when dealing
with complex lithology systems. Multi-mineral evaluations and shale distribution (laminar,
dispersed and structural) are not usual deliverables, generated mostly upon request and often
leading into a thought-provoking discussion about their validity. Moreover, compressional sonic
logs are not typically used as part of the petrophysical evaluations and even less are shear logs.
Rock physics models could be empirical, theoretical or a mix of the two, requiring either a
lithological or a mineralogical breakdown of the composite material defining the framework, in
addition to porosity and the properties of the pore-filling fluid. This could simply mean sand
and shale in the clastic world as an example or in more complex lithology environments a
breakdown into their corresponding mineral composition, pore structure and fluid type.
Moreover, Gassmann fluid substitution is at the heart of rock physics which has proved to be
critical in the world of oil and gas exploration. However, wrong application of Gassmann could
lead into wrong predictions and in turn resulting in the drilling of dry wells or leaving
hydrocarbons behind. This is especially the case when dealing with finely laminated sand-shale
environments such as deepwater turbidites. In such environments, using VSH alone or VSH
combined with mineral logs could also lead to wrong prediction when applying Gassmann’s
method. What is needed is a reasonable estimation of the volume of laminar, dispersed and
structural shale (such as produced using a Thomas-Steiber model) in the system in addition to
VSH and mineral logs if possible. Last but not least is integrating sonic logs into the standard
petrophysical evaluations and workflows and should not be treated as a side product. Sonic logs
do respond to the framework composition and could be used in combination with other logs
and appropriate rock physics models to invert for lithologies or mineral composition.
In this presentation we discuss the above topics in more details, giving examples for each of
them to illustrate the point. We also suggest some ideas and direction for the way forward and
how petrophysics and rock physics can work more closely together to achieve the desired
outcome.
Biography
Mosab Nasser is a geophysicist currently working as a rock physics specialist and advisor for
Maersk Oil, following 9 years with Shell International Exploration and Production. He also
serves as an adjunct professor at the Department of Earth and Atmospheric Sciences at The
University of Houston acting as an industry advisor on rock physics. Between 2006 and 2009 he
served as a Shell Subject Matter Expert on 4D seismic feasibility and interpretation. His areas of
specialty and expertise include Rock Physics, AVO, quantitative seismic interpretation, modelbased petro-elastic seismic inversion and 4D Seismic. He received a B.Sc. in Physics from the
Islamic University of Gaza, Palestine; M.Sc. in Physics from The International Centre for
Theoretical Physics in Italy; and a Ph.D. in Physics from The University of Tromso in Norway.
A Multi-Disciplinary Integrated Study of the Haynesville Shale
Jennifer Lucas (BP America)
Abstract
A case study is presented which combines and integrates analyses of microseismic data, openhole logs, production logs, hydraulic fracture treatments, and flow-back performance from four
horizontal wells in the Haynesville shale, east Texas. The laterals of the wells are approximately
5,000 ft. long, oriented N-S, and each stimulated with twelve stages. Three of the laterals were
geo-steered within an 18 ft. target window, whereas one was drilled transverse across a 131 ft.
window. The open-hole logs and production logs were run in the transverse lateral to identify
zones in the Haynesville that produced the most gas. The microseismic data were obtained
using a dense near-surface permanent array spanning ~30 square miles. Based on 1,229
microseismic events, inferred fracture half-lengths range between ~423 ft. and ~675 ft. About
half the lengths of most of these fractures are contained within the target reservoir interval.
Inferred fracture orientations range between ~13° and ~164°, consistent with regional SHmax,
thereby supporting our choice of well azimuths. Some of these fractures align with those
observed on 3-D seismic based coherency, implying that pre-existing fractures have been
activated. Stimulations of northward wells caused fewer microseismic events, but generated
more elongated fractures than southward wells. Additionally, the southward wells with higher
microseismic activity implying greater initiation and stimulation of fractures, correlate well with
gamma ray log values <~110 gAPI, compared to their northward counterparts, where gamma
ray log values in their laterals are predominantly ~110 gAPI, indicating a possible diagnostic of
fracture capability, consistent with lithology-based brittleness index. The completions strategy
involved pumping resin coated sand in one well, combining that with white sand in others, and
stimulating the shortest lateral with the same propant volume and stages as others. Open-hole
log modeling confirms that the transverse lateral is on the target. Open-hole log interpretation
and production log interpretation from the transverse lateral show that the base of the Upper
Haynesville, namely the “rabbit ears” zone, is most productive, followed by the top zone of the
Upper Haynesville. These two zones have the largest effective stimulated rock volumes. Overall,
the study provides multidisciplinary insights into design of future horizontals in the area.
Biography
Jennifer Lucas received a Bachelor’s in geology and a Master’s in Geoscience from the
University of Alabama. She is a senior geoscientist at BP America with experience working both
conventional and unconventional reservoirs in Wyoming, Louisiana, Texas, Gulf Coast and GOM
shelf. She has held positions as a geologist and a geophysicist in Appraisal, Development, and
Operations
Untangling Acoustic Anisotropy
Jennifer Market (Weatherford)
Abstract
Acoustic anisotropy analysis is used in a wide variety of applications, such as fracture detection,
wellbore stability, near- and far- wellbore stress variations, production enhancement, and
geosteering. However, the methods by which acoustic anisotropy are determined are not
always well understood, both by the end user and the data analyst. Azimuthal variations in
velocities may be due to stress variations, intrinsic anisotropy, bed boundaries, or some
combination thereof. Environmental effects such as hole inclination, centralization, hole
condition, and source/receiver matching affect the viability of the data and must be considered
in the interpretation. Untangling the various acoustic anisotropy factors is essential to
effectively using the results.
The presentation will begin with a discussion of the types of acoustic anisotropy, followed by a
review of common industry methods for computing anisotropy from wireline and LWD
azimuthal tools. Next, examples of adverse environmental effects and their associated limits
will be discussed. Finally, a series of examples will be shown to illustrate how to untangle the
various acoustic anisotropy responses.
Biography
Jennifer Market is the borehole acoustics advisor for Weatherford. She has 15+years’
experience in borehole acoustics, working in service companies to develop acoustics tools and
applications and in a consulting/software company to deliver high quality acoustics and
petrophysics and answer products. She frequently publishes articles for both SPWLA and SPE
and was an SPWLA distinguished lecturer in 2008-2009 and 2011-2012.
QI Rock Property Models for Reservoir Characterization – A VelocityPorosity Example
Stephan Gelinsky(Shell International E&P)
Abstract
A common goal of quantitative seismic interpretation (QI) workflows is to derive the reservoir
properties we seek from the remote sensing data we can record. We describe the crucial role
QI rock property models play in establishing this link. To illustrate the connection we focus on
sandstones and describe in some detail how compressional and shear velocity information (VP
and VS) can be related to porosity and what controls those relationships. We discuss useful
velocity-porosity bounds which we utilize to constrain key model parameters and demonstrate
our clean sandstone endmember workflow with a real data example.
When building a velocity-porosity model for clean endmember sandstones we find it useful to
assemble reservoir-specific models that typically are dominated by local sorting changes related
to depositional processes that yield fairly flat velocity-porosity relationships. When not directly
pursuing data-driven empirical regressions but working with a rock physics model, we always
calibrate our model to fit both VP and VS versus porosity and find that many published heuristic
rock physics models are much more suited to describe VP(POR) than VS and typically severely
over predict VS unless fudged with a ‘shear reduction factor’. However, we typically succeed
matching modified HS+ Bounds to our data – only a sensible mineral end point and a range of
plausible critical porosities are required and once we get individual model lines to match both
VP and VS, zone by zone, we have a consistent model that constrains both sorting and
composition – which especially in the absence of core data is quite useful. The resulting
reservoir-specific models are only valid for similar compaction and cementation conditions – to
extrapolate deeper or shallower, the velocity-porosity change caused by the related difference
in diagenesis is provided by the HS+ Bounds.
Biography
Stephan is Shell's Principal Technical Expert for QI Petrophysics. He presently leads Shell's
Houston Quantitative Reservoir Characterization team. Stephan has filled a variety positions
within Shell and has before worked with Baker Atlas and Western Geophysical where he was
involved with borehole acoustic R&D and seismic pore pressure prediction. He has an MSc in
solid state physics and a PhD in Geophysics from Karlsruhe University, Germany.
Advanced Rock Physics Diagnostics to Define the Link Between
Petrophysics and Geophysics
Zakir Hossain(Rock Solid Images)
Abstract
Rock Physics is widely used to describe the functional relationship between Geophysics and
Petrophysics. However, many rock physics and petrophysics theories are not consistent with
local geology. The objective of this study is to establish the link between Geophysics and
Petrophysics using advanced Rock Physics Diagnostics (RPD). This RPD is consistent with local
geology to quantify characterizing diagenetic pore-filling cement, contact cements, dispersed
shale, and laminated shale. We present a method to quantify the amount of contact and porefilling cement using RPD analysis. This cement quantification method combines multiple rock
physics theories and is a physical based approach to quantify the amount of contact and porefilling cement. A depth-dependent Thomas-Stieber model is also presented in this study to
describe the effects of shale laminations and shale compactions. The depth-dependent
Thomas-Stieber model combines rock physics depth trends with the Thomas-Stieber model in
order to quantitatively characterize lithology as a function of depth. This study indicates that
quantitative cement substitution is as important as fluid substitution to understand the
difference between the hydrocarbon effect and the cementation effect from seismic data. This
study also demonstrates that the link between Petrophysics properties and seismic properties
is important for economical evaluation of a reservoir.
Biography
I have started working at RSI on February 1, 2012 as Rock Physicist. I have received my PhD in
Petroleum Geophysics (2011) and MSc in Petroleum Engineering (2007) from the Technical
University of Denmark. During my PhD study I have worked with the Rock physics modeling
and integration of NMR study to rock physics. In 2009 I have worked as a visiting research
scholar in Stanford University as a part of my PhD study under the supervision of Professor
Tapan Mukerji. During my MSc study I worked with the relationship between static and
dynamic properties of reservoir rocks. My research interest includes rock physics modeling,
AVO analysis, NMR studies to rock physics, pore fluids effect on reservoir properties including
CO2, 4D rock physics, integration of rock mechanics to rock physics, integration of Petrophysics
to rock physics, seismic and electrical anisotropy.

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