eastranch p2 final - kansas geological survey · seismic isochron map clearly shows several...
TRANSCRIPT
SE
ISM
IC H
OR
IZO
NA
NA
LY
SIS
AN
D R
ES
ER
VO
IR C
HA
RA
CT
ER
IZA
TIO
N
Cro
ss
plo
t of is
op
ac
h v
s. s
eis
mic
iso
ch
ron
for th
e b
as
eo
f ka
rst to
x m
ark
er in
terv
al. T
he
co
rrela
tion
is g
en
era
llyg
oo
d. T
he
two
ou
tliers
circ
led
in re
d a
t the
top
of th
ep
lot a
re lo
ca
tion
s w
he
re th
e“x
”m
ark
er p
ick
s in
the
we
lls a
re q
ue
stio
na
ble
an
d m
ay
ne
ed
to b
e a
dju
ste
d.
Se
ism
ic is
oc
hro
n m
ap
(in tw
o-w
ay
trav
el tim
e) o
f the
inte
rva
l from
the
ba
se
of k
ars
t to th
e“x
”m
ark
er w
ith to
p o
f Sa
nA
nd
res
su
bs
ea
de
pth
co
nto
urs
su
pe
rimp
os
ed
.
SE
ISM
IC T
IED
TO
FO
RM
AT
ION
TO
PS
Fo
rma
tion
top
s w
ere
tied
to s
eis
mic
ho
rizons u
sin
g s
ynth
etic
se
ism
og
ram
s. S
ynth
etic
seis
mo
gra
ms w
ere
constru
cte
d fo
r11
we
lls in
the s
tudy a
rea w
ith b
oth
son
ic a
nd
density
logs
an
d a
n a
dd
itiona
l 51 w
ells
with
sonic
logs o
nly.
Th
e s
yn
the
tic s
eis
mogra
ms s
ho
w th
at th
ere
is n
ot a
sig
nific
an
t imp
ed
ance c
ontra
st a
t the to
p o
f the S
an
Andre
sF
orm
atio
n in
the s
tudy a
rea, a
nd th
ere
fore
, this
stra
tigra
phic
bo
un
da
ry d
oes n
ot c
orre
spond to
a s
eis
mic
refle
ctio
n.T
here
is a
n im
pe
da
nce c
ontra
st a
t the
base o
f the k
ars
t zon
eb
etw
ee
n n
on
-poro
us a
nh
ydrite
and p
oro
us re
serv
oir,
ho
we
ve
r. Sim
ilarly, th
ere
is a
po
sitiv
e im
pedan
ce c
on
trast a
tth
e“x
”m
ark
er, a
lthough
it does n
ot c
orre
spon
d to
a c
lear
se
ism
ic p
ea
k.
Lo
ca
tion
s o
f we
lls in
the
Wa
dd
ell F
ield
stu
dy
are
a w
ith s
on
iclo
gs
(blu
e) a
nd
bo
th s
on
ic a
nd
de
ns
ity lo
gs
(red
).
12
61
1,5
00
ft
Sy
nth
etic
se
ism
og
ram
for w
ell #
12
61
sh
ow
ing
tie w
ith s
eis
mic
da
ta. L
ab
ele
d to
ps
are
: top
Gra
yb
urg
(GR
BG
; da
rk g
ree
n), to
pS
an
An
dre
s (S
AD
R; c
ya
n), b
as
e o
f an
hy
dritic
se
ctio
n b
en
ea
thth
e to
p o
f Sa
nA
nd
res
(B_
AN
HY
; ma
ge
nta
), ba
se
of tig
ht z
on
eb
en
ea
th to
p o
f Sa
nA
nd
res
(B_
PO
R; lig
ht g
ree
n),
“x
”m
ark
er
(X_
MK
R; b
lue
).
GR
BG
SA
DR
X_M
KR
B_P
OR
B_A
NH
Y
Ce
nte
r of g
rav
ity o
f po
ros
ity fo
r the
inte
rva
l from
the
ba
se
of k
ars
t to th
e“x
”m
ark
er m
ea
su
red
in fe
et
su
bs
ea
. Lo
we
r ce
nte
r of g
rav
ity (b
lue
) co
rres
po
nd
s to
hig
he
r me
an
po
ros
ity.
Ma
p o
f me
an
se
ism
ic im
pe
da
nc
e fo
r the
inte
rva
l from
the
ba
se
of k
ars
t to th
e“x
”m
ark
er. M
ea
n p
oro
sity
co
nto
urs
from
we
ll log
s a
re s
up
erim
po
se
d.
Cro
ss
plo
t of m
ea
n p
oro
sity
ve
rsu
s m
ea
n im
pe
da
nc
efro
m w
ell lo
gs
(red
) an
d fro
m s
eis
mic
da
ta (b
lue
) for th
ein
terv
al b
etw
ee
n th
e b
as
e o
f the
tigh
t (ka
rst) z
on
e a
nd
the
“x
”m
ark
er.
PO
RO
SIT
YA
ND
SE
ISM
IC IM
PE
DA
NC
E
To
evalu
ate
the p
ote
ntia
l usefu
lness o
f usin
g s
eis
mic
impedance to
pre
dic
t poro
sity, w
e firs
t com
pute
d w
ell lo
g im
pedance fo
rall w
ells
conta
inin
g s
onic
and d
ensity
logs. F
rom
this
log im
pedance, w
e c
alc
ula
ted th
e m
ean im
pedance fo
r the b
ase o
f kars
tto
“x”
mark
er in
terv
al.
Acro
ss p
lot o
f the m
ean lo
g im
pedance v
ers
us th
e m
ean p
oro
sity
for th
e s
am
e in
terv
al s
how
s th
at th
etw
o m
easure
s a
re w
ell c
orre
late
d.
Me
an im
pedance
was a
lso g
enera
ted fro
m th
e s
eis
mic
data
for th
e in
terv
al b
etw
een th
e b
ase o
f kars
t and
“x”
mark
er
ho
rizons.T
his
mean s
eis
mic
impedan
ce is
als
o c
ross p
lotte
d a
gain
st m
ean p
oro
sity
at th
e w
ell lo
catio
ns.A
lthough th
ere
ism
ore
scatte
r tha
n fo
r the
log d
ata
, the
seis
mic
data
show
the s
am
e tre
nd o
f decre
asin
g p
oro
sity
with
incre
asin
g im
pedance.
Th
is c
orre
latio
n b
etw
een im
pedance a
nd p
oro
sity
allo
ws u
s to
use a
map o
f mean s
eis
mic
impe
dance fro
m th
e b
ase o
f kars
tto
“x”
mark
er to
appro
xim
ate
the d
istrib
utio
n o
f mean p
oro
sity
in a
reas w
ith p
oor w
ell c
ontro
l.
Th
e m
ean im
ped
ance s
how
s b
ands o
f north
-north
east-tre
ndin
g h
ighs a
nd lo
ws th
at a
re o
bliq
ue to
the m
ain
stru
ctu
re in
the
are
a.T
he h
igh im
pedan
ce a
reas m
ay c
orre
spond to
the lo
catio
ns o
f poro
us S
an
Andre
s s
hoals
.
HO
RIZ
ON
INT
ER
PR
ETA
TIO
NS
US
ING
SE
ISM
IC IM
PE
DA
NC
E V
OL
UM
E
In o
rder to
imp
rove o
ur in
terp
reta
tion
s o
f the
ba
se
of k
ars
t and
“x”
mark
er h
oriz
on
s, w
e h
ave g
en
era
ted
a m
od
el-b
ase
d im
pedan
ce in
vers
ion o
f the s
eis
mic
am
plitu
de v
olu
me in
the
“hig
h v
olu
me a
rea
”. Our s
tartin
gm
ode
l wa
s b
ase
d o
n th
e 1
1 w
ells
in th
e a
rea
with
so
nic
and d
ensity
logs.
The b
ase o
f ka
rst a
nd
“x”
ma
rker a
re m
uch
bette
r defin
ed in
the re
su
lting im
pedance v
olu
me th
an
in th
e o
rigin
al a
mplitu
de v
olu
me.
Aho
rizon
co
rresp
on
din
g to
the
co
ntra
st b
etw
ee
n h
igh
er im
pedance
above
and lo
wer im
pedance
belo
w th
at c
orre
spon
ds to
the b
ase o
f kars
t has b
een in
terp
rete
d a
cro
ss th
e s
tudy a
rea.
Aho
rizon
co
rresp
on
din
g to
the
“x”-m
ark
er c
an
als
o b
e in
terp
rete
d o
n th
e im
pedan
ce v
olu
me.
Th
e“x
”m
ark
er a
ppears
to b
e tru
ncate
d b
y th
e b
ase o
f kars
t ho
rizon in
the s
outh
ern
portio
n o
f the s
tudy a
rea a
nd lo
cally
ino
ther a
rea
s. In
the
we
ste
rn p
art o
f the
stu
dy a
rea
, the
“x”
ma
rker a
ppears
to o
nla
p o
nto
a d
eepe
r horiz
on, in
terp
rete
d a
s th
e to
p o
f G4.
Ve
rtica
l se
ctio
ns
D-D
' (top
) an
d E
-E' (b
otto
m), fla
tten
ed
on
the
Gra
yb
urg
ho
rizo
n,
thro
ug
h th
e E
as
t Ra
nc
h a
co
us
tic im
pe
da
nc
e v
olu
me
. No
te th
at th
e“x
”m
ark
er h
oriz
on
is tru
nc
ate
d b
y th
e b
as
e o
f ka
rst h
oriz
on
at s
ev
era
l loc
atio
ns
an
d a
pp
ea
rs to
on
lap
the
G4
ho
rizo
n.
We
inte
rpre
ted
da
ta fro
m a
3D
se
ism
icvo
lum
e in
a 2
.5 m
i x 3
.4 m
i (4.1
x 5
.4km
) are
a s
urro
un
din
g th
e“h
igh
vo
lum
eare
a”
in W
ad
de
ll Fie
ld. O
ur g
oa
l wa
s to
map
the c
on
figu
ratio
n o
f ke
y h
oriz
on
sbe
twe
en w
ell c
on
trol a
nd
estim
ate
the
late
ral d
istrib
utio
n a
nd c
ontin
uity
of
pe
trophysic
al p
rope
rties.
Tim
e s
truc
ture
ma
p o
f the
ba
se
of k
ars
t ho
rizo
n b
elo
w th
e to
p o
f the
Sa
nA
nd
res
Fo
rma
tion
. Cro
ss
se
ctio
ns
D-D
' an
d E
-E' a
re lo
ca
ted
.
Ve
rtica
l se
ctio
n D
-D' th
rou
gh
the
se
ism
ic a
mp
litud
e v
olu
me
(top
) an
d a
na
co
us
tic im
pe
da
nc
e v
olu
me
(bo
ttom
) ge
ne
rate
d fro
m th
e s
eis
mic
am
plitu
de
da
ta u
sin
g m
od
el b
as
ed
inv
ers
ion
. Th
e to
p G
ray
bu
rg (g
ree
n) a
nd
ba
se
of tig
ht,
an
hy
dritic
ka
rst (c
ya
n) in
terp
rete
d fro
m w
ell d
ata
are
sh
ow
n c
on
ne
cte
d b
ys
traig
ht lin
es
. We
ll log
s d
isp
lay
ed
are
so
nic
(da
rk re
d) a
nd
de
ns
ity (d
ark
blu
e).
DD
'
DD
'
D
D'
E
E'
1 m
ile
DD
'
EE
'
Gra
yb
urg
Ba
se
Tig
ht Z
on
e
“X
”M
ark
er
G4
Gra
yb
urg
Ba
se
Tig
ht Z
on
e
G4
“X
”M
ark
er
ISO
CH
RO
N M
AP
PIN
G
Am
ap h
as b
een g
enera
ted o
f the is
ochro
n b
etw
een th
e b
ase o
f kars
tand
“x”
mark
er h
oriz
ons.A
cro
ss p
lot o
f this
isochro
n v
ers
us th
e is
opach
valu
es g
enera
ted fro
m w
ell to
ps h
as a
genera
lly g
ood c
orre
latio
n,
suggestin
g th
at th
e s
eis
mic
isochro
n c
an b
e u
sed to
appro
xim
ate
changes in
inte
rval th
ickness in
loca
tions w
ithout w
ell c
ontro
l.T
he
seis
mic
isochro
n m
ap c
learly
show
s s
evera
l appro
xim
ate
ly n
orth
-south
-tre
ndin
g th
icks a
nd th
ins in
the re
se
rvoir in
terv
al, w
hic
h a
ppear to
sw
ing
aro
und fro
m a
north
-north
east tre
nd
in th
e e
ast to
a n
orth
-north
west
trend in
the w
est.
The
isochro
n is
locally
thin
in th
e s
addle
are
a o
f the
south
east-tre
ndin
g a
ntic
line.T
he is
ochro
n m
ap a
lso s
how
s a
rea
s w
here
the x
mark
er h
as b
ee
n tru
ncate
d b
y th
e k
ars
t (white
are
as o
n th
e m
ap).
These a
reas a
re lo
ca
ted o
n th
e fla
nks, ra
ther th
an th
e to
p, o
f the
San
Andre
s s
tructu
re a
nd h
ave a
prim
arily
north
to n
orth
east o
rienta
tion. In
the s
outh
ern
part o
f the m
ap, h
ow
ever, th
e a
rea w
here
the
“x”
mark
er is
absent s
how
s b
oth
a n
orth
east tre
nd th
at lin
es u
p w
ith th
e s
addle
and a
north
west tre
nd th
at p
ara
llels
the m
ain
trend o
f the a
ntic
line.
When m
ean im
pedance is
com
pare
d to
the c
ente
r of g
ravity
of w
ell lo
gpo
rosity, w
hic
h s
pecifie
s th
e d
epth
of th
e p
oro
sity
develo
pm
ent in
the
inte
rval b
etw
een th
e b
ase o
f kars
t and th
e“x
”m
ark
er, it c
an
be s
een th
at
the e
aste
rnm
ost tre
nd o
f low
impedance (h
igh m
ean p
oro
sity
)co
rresponds c
losely
to a
low
cente
r of g
ravity, s
uggestin
g b
ette
rde
velo
ped p
oro
sity
in th
e lo
we
r portio
n o
f the re
serv
oir in
terv
al. In
co
ntra
st, th
e c
entra
l hig
h im
pe
dance (lo
w m
ean p
oro
sity
) trend
co
rresponds to
a s
imila
r trend o
f hig
her c
ente
r of g
ravity, s
uggestin
g th
at
the p
oro
sity
has s
hifte
d to
hig
her le
vels
in th
e in
terv
al a
nd is
of lo
wer
magnitu
de.T
he w
este
rnm
ost n
orth
-south
trend o
f low
impe
dance (h
igh
mean p
oro
sity
) corre
sponds c
losely
to a
low
cente
r of g
ravity, c
onfirm
ing
a g
enera
l rela
tionship
that p
oro
sity
that is
develo
ped lo
wer in
the in
terv
al
is g
reate
r in m
agnitu
de.