Unconventional gas reservoirs : evaluation, appraisal, and development

622 Pages·2014·39.17 MB·English

by  M Rafiqul Islam

UNCONVENTIONAL
GAS RESERVOIRS
Evaluation, Appraisal,
and Development
M. RAFIQUL ISLAM
Trans Canada Training
London, Ontario, Canada
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AUTHOR BIOGRAPHY
Professor M.R. Islam is a worldwide
consultant on environment and energy-
relatedissues.HeiscurrentlydirectorofOil
andGasatTransCanadaTraining.DrIslam
is known as one of the most published
engineers in the world. He is credited to
have coined terms, such as “green petro-
leum” and “sustainable petroleum devel-
opment” at a time when “sustainable
petroleum” was considered to be an oxy-
moron. His work has created a paradigm
shift in a wide range of applications, spanning through various disciplines.
Dr Islam’s most notable contribution is in the areas of sustainability,
environmental integrity, and knowledge modeling, on which topic he has
written dozens of books and over 700 research papers. His latest work is
captured in his book: Unconventional Gas Reservoirs published by
Elsevier, 2014. Dr Islam’s current projects include: “greening of chemical
industries,” a “virtual research university,” and “knowledge-based model-
ing.”Spanninga professionalcareerfor morethan 30years, Professor Islam
has held faculty positions with seven different universities and supervised
over150researchstudentsandpostdoctoralfellows.Hereceived30million
US dollars in research funding from various government and industrial
entities.His research spun off a numberof technology transfer projectsthat
ledtothedevelopmentofthreecompanies.Oneofthemnowhasbecome
one of the most innovative oil spill remediation technology development
companies.
During 2000–2005, Dr Islam held the Killam Research Chair Professor
inOilandGas,whichwastheonlyPetroleumEngineeringResearchChair
in Canada. Prior to this, Dr Islam was the first NRCan (Natural Resources
Canada) Professor of Engineering at the University of Regina, where he
wastheProgramLeaderofPetroleumEngineering.Hewasinstrumentalin
establishing the Petroleum Technology Research Center (PTRC) and the
Greenhouse Gas Technology Center (GTC) in Regina. Dr Islam has
written over 700 research articles on various modeling-, management-,
energy-, environmental-, and communication-related topics. During the
vii
viii AuthorBiography
same period, he received more than 20million US dollars in institutional
and over 10million US dollars in individual research grants, and employed
over 150 postdoctoral fellows, graduate and undergraduate research stu-
dents. In recognition of his research and teaching excellence, he has
received a number of international awards, including the Einstein Gold
Medal of Honor and the Crown and Eagle Gold Medal for both of which
Dr Islam is the first recipient in Canada. He taught 30 different academic
courses and several industry professional development workshops around
the world. He gives numerous invited and guest speeches in multiple
countries.
CHAPTER 1
Introduction
1.1 SUMMARY
Only recently it has become evident that natural gas provides one with
great value with minimum impact on the environment. With the ongoing
“gas crisis” in Europe and steep energy needs of China and India, the
importance of natural gas is increasing tremendously in the global market.
Unconventionalgasreservoirsareresponsibleforaboutone-thirdofannual
US natural gas production. In the global scale, unconventional gas reserves
canadd60–250%totheprovengasreserves.Thisbookexploresthescience
behind unconventional gas and provides one with a basis that the realistic
estimate of total available gas could easily exceed all estimates of the past.
With newfound gas and technologies that harness it with environmental
integrity, the world could easily see another 100years of crisis-free energy
outlook. This book paints a rosy picture that is supportedby scientific basis
and guides the readership to be able to discern between hype and hysteria
involving petroleum resource management.
The potential of unconventional gas reserves is far greater than any
enhanced oil recovery scheme designed to date. However, when the two
are combined and added to that is scientific basis for revised assessment of
worldgasreserve,theenergyoutlookbecomesverybright.Thepurposeof
thisbookistoprovideonewithpracticalinsightsandtoolsthatcanbeused
to efficiently identify, appraise, and develop these types of reservoirs.
Initially, the readership is be familiarized with both engineering and
marketing aspects of natural gas. The mechanisms of gas production and
reservoir engineering are discussed. Presented are the origin and mecha-
nisms of gas production, along with the various techniques used to analyze
reservoirparametersandperformance,andunderstandhowthesehavebeen
applied to numerous projects. Specific features of unconventional gas re-
serves and the means of capitalizing on these features in order to maximize
long-term benefit are discussed. Scientific characterization of gas reserves
included discussion of the history of gas as well as the rock. This “bottom-
up” analysis helped develop truly scientific basis for unconventional gas
analysis. Thorough geological characterization was presented for US
UnconventionalGasReservoirs
ISBN978-0-12-800390-9 ©2015ElsevierInc.
http://dx.doi.org/10.1016/B978-0-12-800390-9.00001-3 Allrightsreserved. 1
2 UnconventionalGasReservoirs
reservoirsinordertoconnectwithpotentialsourcesofunconventionalgas.
This serves as a template for a new analysis that starts off with conventional
reservoircharacterization.Itisshownthatthetruereservepotentialofgasis
much higher than the one estimated using conventional approach. Latest
information on emerging technologies in typical enhanced oil recovery are
presented with lucid discussion of key features of reservoir characterization
anddevelopmentinordertohelpreadershipidentifytechniquesthatcanbe
used in “enhanced gas recovery” of unconventional gas. It is shown that
contrary to popular belief, such techniques are economically attractive and
environmentally sustainable. This unlocking of emerging technologies,
coupled with a novel technique for characterization of unconventional gas
reserves for which conventional techniques fail to yield sound results,
creates a true paradigm shift in gas reservoir analysis.
Thescienceofbothfluidandrockisdiscussedusingdelinearizedhistory
analysis. The discussion of coal bed methane and gas hydrate is carried out
with the focus on improving production rate under various production
strategies. Criteria for selecting candidates for hydraulic fracturing as well
as horizontal wells are discussed. For every case encountered specific
suggestion is made that is custom designed for the particular application.
Aguidelineisprovidedforoptimizationofrecoveryschemesundervarious
production and enhanced gas recovery strategies.
Finally, numerical modeling approaches are discussed and challenges in
modeling unconventional gas reservoirs are presented. A number of case
studies involving technological application as well as numerical modeling
are presented. Overall, new opportunities are highlighted and previously
held beliefs and myths deconstructed.
1.2 UNCONVENTIONAL TO MAINSTREAM:
A NECESSARY PARADIGM SHIFT
Newton did not know what the term “Newtonian” meant in any disci-
pline.ScientiststhatfollowedNewton’s“laws”andtheorieswithdogmatic
fervor did not know what the term non-Newtonian stood for. At present,
scholarly works on “Non-Newtonian” outnumber “Newtonian” by a big
margin. Over 50years ago, US government started to invest in research in
coal bed methane, shale gas, shale oil, along with other areas of petroleum
development. Decades later, the term “unconventional” was coined. Even
somemoredecadeslatercamethesuccessstoryofunconventionalgas.This
success would come only after Europe had been under the grip of a “gas
Introduction 3
Figure1.1 Location mapforBarnett shale.FromEIA, 2011.
crisis.”Withinyears,“unconventional”becamethebiggeststory inU.S.in
termsofenergyindependence.Anewtypeofrevolutionbegan.Figure1.1
shows graphical representation of wells in the shale gas plays of just one
basin in Texas. If 10,860 horizontal gas wells are called “unconventional”
one must wonder what would the term “conventional” represent.
Chapter 2 discusses the role of unconventional gas in the big picture of
petroleum.Itdeconstructsmanymythsthathaveperplexedmodernsociety
that has grown accustomed to vilifying carbondthe essence of life.
It unravels the mysteries of “resource triangle” that is based on the false
premise that natural is more expensive than artificial (Figure 1.2). It places
unconventionalgasinitscorrectpositionwithinprovengasandoilreserves
and shows that this “unconventional” is anything but unconventional in
conventional sense. It is the mainstream of the future.
Thechapteralsopresentsadelinearized historyofenergydevelopments
in relation to petroleum production, particularly as it relates to natural gas.
4 UnconventionalGasReservoirs
N
RACTION EW TECH
XT Conventional HI NO
E Reservoirs G L
OF HE OG
“Risky” venturIeNCsREASING COST NeTwig UhTtne GRccaheoMssnnC SoeovBarselMvontndlog,ytsiiy,ro sSNnhaealeledsedR QUALITY RYE SOORU IRMCPEROVED APPLI
C
A
TI
Includes gas hydrates and the O
N
poorest quality resources
Figure1.2 Conventional perceptionofresourcetriangle.
It shows that energy needs of the future can only be met if we excel in
accessing unconventional gas. It creates the need for a paradigm shift in
nomenclature as well as scientific description of unconventional reservoirs.
In simple terms, it delivers the message that the science of unconventional
gas cannot be understood with the conventional routines.
1.3 THE PARADOX OF UNCONVENTIONAL GAS
Weliveinaninterestingépoque.Everythingsurroundingusseemstopoint
to contradictions. We made unprecedented progress in technology devel-
opment, only to hear from Nobel Laureate Chemists (e.g., Robert Curl)
that ours is a “technological disaster.” We claim to have progressed from
darkagesofsavageryandlackofempathytomodernenlightenmentonlyto
hear from some of the most ardent supporters of modern European mind-
set of Capitalism (e.g., Pope Francis) that unfair economic structures that
creates huge inequalities are actually an act of terrorism. As civilization
evolved, we claim to have become wiser and more efficient, only to
discoverourpercapitaenergyneedhasskyrocketedinthemodernera.We
areso sureaboutoursuperioritythatwecallhumansas thetopofthefood
chain and boast about our entitlement over other species, only to discover
that the greatest crisis is the population growth of humansdthe “best
creation” of nature. We have identified “greening” as the key to resolving
the environmental disaster that has befallen on us only to target carbon as
Introduction 5
theworstenemytoenvironmentalintegrity.Thisisthesamecarbonthatis
the essence of “greening.” We praise nature for its unique ability to turn
badintogood,foritstenacityandsustainability,onlytotargetpetroleumas
the number one enemy of the environment. Which petroleum? The one
that was perfected by naturedthe very nature we love to be in tune with.
Chapter 2 started the paradigm shift and Chapter 3 continues it in the
realm of unconventional technology development, its geological nature,
and the economics that can support its development and growth. It shows
conventionalengineeringanalysisisnottheonlyonethatdoesnotapplyto
unconventional reservoirs; conventional accounting theories as well as
energypricingmodelsdonotapplyalso.Itshowswithdetailswhyessential
features of unconventional gas are such that none of the conventional
techniques and principles should apply. This ranges from geology to
chemistrytoengineeringforcoalbedmethane,shalegas,tightgasaswellas
methane gas hydrate.
1.4 GREENING THE FUTURE OF UNCONVENTIONAL GAS
Humans seek status quo. Somehow, we have great difficulty in changing
our style of analysis. It starts with our inability to change the first premise.
Today’s first premise in energy sectors seems to be based on the miscon-
ception that global warming is because of petroleum production. This may
beillogicalcomingfromfallaciousarguments,butthemomentitbecomesa
political issue, humanity loses its ability to think from outside the box.
Evenatthepinnacleofunconventionalgasrecovery,wehavemanagedto
use only hydraulic fracturing and horizontal wells as the only technological
tooltoproducegas.Talksareallaboundhowtoincreasetheresourcebase,
wheretodrillnewwells,howtofracturemorewells,howtopenetratemore
difficult-to-access formations, but few talk about using numerous other
technologiesthatarereadilyavailabletoday.Chapter4introducesasection
“Lessons learned from Enhanced Oil Recovery” (EOR) and summarizes
successstoriesoflast50yearsofEOR.WhylearnfromEOR?Itisbecause
they are much easier to apply in gas reservoirs, particularly the ones that
containhugeamountofgasinshallowerformations.
The chapter demystifies the global warming debate and shows that
natural gas is the most environmentally appealing energy source known
today. Then, it shows how the unconventional resource base can be
expanded multifold by adopting EOR technologies that have been per-
fected by the same petroleum sector that produces unconventional gas.
6 UnconventionalGasReservoirs
These do not need any research investment for future development. They
only need careful custom designing for a particular application.
Addedtotheequationisthetremendousresourcelockedinmethanegas
hydrates.Techniquescapableofunlockingtheseformationsarediscussed.
The concept of using novel techniques for enhanced gas recovery is
introduced. This would add to the current estimates of unconventional
reserves. Discussion is carried out on reservoirs that are not commonly
characterized as “unconventional,” such as volcanic reservoirs.
1.5 PARADIGM SHIFT IN RESERVOIR CHARACTERIZATION
Recent years have brought a rapid expansion of activities around uncon-
ventional gas. The successes in unconventional gas exploitation have been
mainly attributed to advances in engineering. In particular, hydraulic
fracturing and horizontal wells are considered to be the game changer.
To date, geophysics and geology have yet to assume a major role in the
development of this important resource.
Islametal.(2012)recentlyarguedany“gamechanger”mustaccompany
realchange,whichmeanschangefromthefirstpremisetotheprocessitself.
If previous chapters established that unconventional gas reservoirs are
indeed uniquely different from conventional ones, why should we assume
the reservoir characterization tools and procedures of conventional reser-
voirs would apply to unconventional ones?
Chapter 5 introduces a new reservoir characterization technique that
uses paradigm shift in its real sense. The outcome is a refreshing new
approach that is practical and prepares one for in-depth understanding of
the mechanisms involved in unconventional gas reservoirs. The technique
relies heavily on whatever is available during the course of the reservoir
development and minimizes spending on expensive tools that have little
validity in unconventional reservoirs. At the end the chapter introduces a
screening toolto identifydifferent typesofformations so thatdevelopment
strategies can be chalked out.
1.6 THE SCIENCE OF UNCONVENTIONAL GAS
AlbertEinsteinfamouslysaid,“Anyintelligentfoolcanmakethingsbigger,
more complex, and more violent. It takes a touch of geniusdand a lot of
couragedto move inthe oppositedirection.” Sadly,this touchof genius is
missing from the New Science. The contradictions pointed out in earlier