Geology in Petroleum Production: A primer in production geology

248 Pages·1985·7.044 MB·ii-xiii, 1-239\248

by  A.J. Dikkers (Eds.)

DEVELOPMENTS IN PETROLEUM SCIENCE
Advisory Editor: G.V. Chilingarian
1 A.G. COLLINS
GEOCHEMISTRY OF OILFIELD WATERS
2. W.H. FERTL
ABNORMAL FORMATION PRESSURES
3. A.P. SZILAS
PRODUCTION AND TRANSPORT OF OIL AND GAS
C.E.B. CONYBEARE
4.
GEOMORPHOLOGY OF OIL AND GAS FIELDS IN SANDSTONE BODIES
5. T.F. YEN and G.V.CHILINGARIAN (Editors)
OIL SHALE
6. D.W. PEACEMAN
FUNDAMENTALS OF NUMERICAL RESERVOIR SIMULATION
7. G.V. CHILINGARIAN and T.F. YEN (Editors)
BITUMENS, ASPHALTS AND TAR SANDS
8. L.P. DAKE
FUNDAMENTALS OF RESERVOIR ENGINEERING
9. K.MAGARA
COMPACTION AND FLUID MIGRATION
10. M.T. SILVIA and E.A. ROBINSON
DECONVOLUTION OF GEOPHYSICAL TIME SERIES IN THE EXPLORATION
FOR OIL AND NATURAL GAS
11. G.V. CHILINGARIAN and P. VORABUTR
DRILLING AND DRILLING FLUIDS
12. T.D. VAN GOLF-RACHT
FUNDAMENTALS OF FRACTURED RESERVOIR ENGINEERING
13. J. FAYERS (Editor)
ENHANCED OIL RECOVERY
14. G. MOZES (Editor)
PARAFFIN PRODUCTS
15A O.SERRA
FUNDAMENTALS OF WELL-LOG INTERPRETATION, 1
THE ACQUISITION OF LOGGING DATA
16. R.E. CHAPMAN
PETROLEUM GEOLOGY
17A E.C. DONALDSON, G.V. CHILINGARIAN and T.F. YEN
ENHANCED OIL RECOVERY, I
Fundamentals and Analyses
18A A.P. SZILAS
PRODUCTION AND TRANSPORT OF OIL AND GAS
19A G.V. CHILINGARIAN (Editor)
SURFACE OPERATIONS IN PETROLEUM SCIENCE, I
Developments in Petroleum Science, 20
cleolosv in metroleurn
u -- - - I I
Droduction
I-- - ---- - -
a primer in production geology
A.J. DIKKERS
Van Soutelandelaan 45, 2597 EW The Hague, The Netherlands
ELSEVIER - Amsterdam - Oxford - New York - Tokyo 1985
ELSEVIER SCIENCE PUBLISHERS B.V.
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ISBN 0-444-42450-4 (Vol. 20)
ISBN 0-444.41625-0 (Series)
0 Elsevier Science Publishers B.V.. 1985
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Printed in The Netherlands
V
To Nans, who kept me going.
vii
PREFACE
This book, like so many of its kind, grew out of course notes; courses in applied
oilfield geology, run over many years for varied audiences. At the end of a recent
course, in the course review, one of the participants gave as his view: ‘All this is no
news, any geologist knows this’. Well, maybe so, but I have frequently, before and
since, met geologists who, although having experience in the oil industry, proved to
be unacquainted with at least some of the more common techniques applied in prac-
tical oilfield geology. Thus, finally, I came to the decision that it might be useful
to put together - in what I hoped would be a convenient manner - those elementa-
ry but effective methods with which I was familiar during some thirty years of
operational work.
I wish to emphasize that the resulting book is indeed intended as no more than
a primer, as a basic introduction for the use of geologists, geophysicists, petroleum
engineers and, perhaps, others involved in oilfield work. It makes no pretence to
any degree of sophistication. Accordingly, no attempt is made to go to any depth
into subjects closely related, such as log evaluation, seismic methods, sedimen-
tology, computerization, etc.; excellent textbooks on such subjects are readily
available.
The second part of the book’s title may require some justification. During a leng-
thy career my job title has variously been: works-geologist, subsurface geologist,
subsurface engineer, production geologist, geological engineer, development geolo-
gist. In my view the specialist under consideration is primarily a geologist; unlike
most geologists in the oil industry he does not work ‘on the exploration side’ but
‘on the production side’. Thus it would seem that the man is most unequivocally
described as a production geologist and his discipline as ‘Production Geology’.
‘A true geologist speaks in pictures’: the Professor of my undergraduate years,
B.G. Exher*, is gratefully remembered by his students for the magnificent drawings
- maps, sections, crystal shapes - that he used to make on the blackboard. From
that tradition stems the ‘comic strip’ style of this book. Critics may object to my
frequent use of fictional examples, rather than portrayals of actual geological condi-
tions found in nature. Apart from the administrative and legal difficulties involved
in collecting such evidence, it is rare that Mother Nature presents us with examples
* Brother of the well-known graphic artist M.C. Escher.
viii
which illustrate with satisfactory clarity the phenomenon that one wants to de-
monstrate. I can only hope that my pictures, although artificial, will help to achieve
the objective of this book: to present to colleague-oilmen a ready-made set of tricks
of the trade for their use in production geological work.
1 gratefully acknowledge my indebtedness to the many teachers, colleagues and
friends who, over many years, helped me to learn my job and to thoroughly enjoy
doing it.
x1
LEGEND
LITHOLOGY
clay - shale
sandy clay
finer
sand
coarser
coarse sand - gravel
carbonate rock
impermeable (‘tight ’) rock
igneous - metamorphic
RESERVOIR CONTENT
4 1-
gas
.. . . . . . .
oil
water
tar
Note: the same symbols are used on some maps.
xii
FAULTS
fault in general
overthrust fault
ticks and triangles point to
downthrown block.
WELL SYMBOLS
on field development maps
8 oilwell, productive
8 well with oil indications
gaswell
wet well
injection well
abandoned well
0 location on programme
0 grid location
on illustrative maps
0 well in general
...
Xlll
ABBREVIATIONS AND SYMBOLS
A.H. along hole (depth) OIP oil-in-place
API American Petr. Inst. (gravity) OWC oiliwater contact
Bo Formation Volume Factor (oil) p, P pressure
BDF below derrick floor Pcap capillary pressure
BHP bottom hole pressure Po oil pressure
C.0. cut-out (of fault) Pw water pressure
D.F.EI. derrick floor elevation P probability
DST drillstem test PED Petroleum engineering Dep’t.
EOC equivalent oil column proj projected
E&P Exploration & Production PVT pressure-volume-temperature
GOC gas/oil contact 0 porosity
GOR gasioil ratio Q,s production rate
G.R. Gamma Ray (log) Res. Resistivity (log)
so oil saturation
H high value
HCH hydrocarbon column height Sor residual oil saturation
k permeability sw water saturation
K.B. kelly bushing swc irreducible water content
L low value S.G. specific gravity
M medium (most likely) value Sb subsea (depth)
mD milli-darcy STOI I P stock-tank oil initially in-place
sws sidewall samples
MSL mean sea level
P viscosity TD total depth (final depth of well)
NiG net over gross ratio TVD true vertical depth
NGS net gas sand V volume
NOS net oilsand Vgr gross volume
N.P. not present Vn net volume
N.K. not reached V.S. vertical separation (of fault)
OCH oil column height WUT water-up-to
ODT oil-down-to
1
Chapter A
INTRODUCTION
A.1 ORGANIZATIONAL FRAMEWORK
vMANAGEMENT
EXPLORATION P E TRO L EUM DRILLING PRODUCT ION FIELD
ENGINEERING ENGIN EERl NG
In the Preface it was pointed out that the production geologist does not work for
the exploration department of his company, as do most of his fellow-geologists, but
‘on the production side’. It is hoped that this book will show that this fact has a
profound influence on his objectives, his working methods and his relationships to
other members of his organization. Before starting on the description of the work
of the production geologist, it may be useful to examine the position he occupies
on the organization chart and to sketch the part he plays in the activities of his
organization.
Companies engaged in exploration for and production of oil and gas - collo-
quially referred to as E-P or E&P companies - tend to be quite similar in their
organizational structure, for obvious reasons.
Roughly speaking one can distinguish the technical/operationaI wing of the
organization from the service and administration wing. Within the technical wing,
sketched above, the various departments have their specific functions:
Exploration Department carries out the search for accumulations of oil and gas.
~
- Petroleum Engineering Department is charged with the planning and functional
supervision of - but generally not the line responsibility for - all operations
required for the commercial production of hydrocarbons.
- Drilling Department is responsible for the drilling of the wells, in accordance
with the general plans developed by the petroleum engineering department.
- Production Department carries out all operations to ensure the flow of the
hydrocarbons from the reservoir through the well bore to the surface facilities.
- Field Engineering Department constructs and operates the surface facilities: drill-
ing sites, roads, tanks, pipelines, pump stations, etc.