Vaca Muerta Formation - Subsecretaría de Energía, Minería e

Vaca Muerta - The Leading Shale Play
in Latin America
2-4 December | Buenos Aires, Argentina
InterContinental Hotel
Assessment of Vaca Muerta
Formation Shale Oil
Production Decline-Curve
Analysis
Anticlinal Picún Leufú
Nicolás Gutierrez Schmidt, Julio C. Alonso y Adolfo Giusiano
Dirección de Estudios
www.energianeuquen.gov.ar
December, 2012
ngutierrez@neuquen.gov.ar
jcalonso@neuquen.gov.ar
agiusiano@neuquen.gov.ar
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Outline
• Introduction to Neuquén Basin
Source Rocks of Neuquén Basin
Vaca Muerta Formation: Ro, TOC, Tickness, Area
• Oil production of Neuquén province
Production of Conventional and unconventional Oil
Bajada del Palo a-7 well
• Production decline-curve analysis
Analysis of Decline models
Forecast of Vaca Muerta Shale Oil production
• Discussions
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Neuquén Basin
Cuenca
Neuquina
Neuquén
Bahía
Blanca
Buenos
Aires
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Source Rocks of Neuquén Basin
Vaca Muerta
Upper Agrio
Lower Agrio
Los Molles
Lower
Quintuco
Vaca Muerta
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Vaca Muerta Formation
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Vaca Muerta Formation
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Vaca Muerta Formation
Vaca Muerta Formation
Area with potential for oil
and gas exploration
DRY GAS
WET GAS
OIL
• Area: 3,508,900 acres
(14,200 km2)
• Tickness: to 984 ft (300 m)
• Ro: 0.6 to 1.2 % (oil)
• TOC: 2 to 8 %
Conventional and Unconventional Oil
Production
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Conventional and Unconventional Oil Production
Oil and Condensate production in the
Neuquén province was 115.5 Mbbl/d
(18,386m3/d) in July, 2012.
• Main fields:
– El Trapial-Curamched
(Chevron Argentina S.R.L)
– Puesto Hernández
(Petrobras Energía S.A)
– Chihuido de la Sierra Negra
(YPF S.A.)
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Bajada del Palo a-7 well
• Target: Evaluation of
Vaca Muerta (1983)
• Depth: 9,160 ft
(2.792 mbbp)
• Ro=0,6 (oil window)
Vaca Muerta Top
• TOC=4%.
• Thickness: 410ft (125m)
Perforations
Tordillos Top
Shale Thickness
(Passey et.al 1990)
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Bajada del Palo a-7 well
August 2012
Fracture
Fracture ?
Plus Oil: 63Mbbl
• State: In effective production.
• Art. Lift: Beam Pump.
• Oil Prod. = 54.7 bblpd
(8.7 m3/d)
• Oil. Cum = 752.3 Mbbl
(119.6 Mm3)
• Prod. time: 27 years.
Hyperbolic Match
Di:0.024 A.n
b: 1.5
Dmin: 6%/yr
EUR @ 2030: 875.4 Mbbl
Production forecasting – Decline analysis
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Declination models
• To take into account:
– Very-low permeability reservoirs
– Wells with hydraulic fracture stimulation
– Flow transient for long time
– Drainage area is not necessarily circular
– What type should be used?
– Minimum production time for reliable forecast?
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Declination models
• ARPS – Hyperbolic
• Stretched Exponential Model
• Duong Model
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
ARPS – Hyperbolic Curve
where:
t: time (months)
q(t): rate to time t (m3/d or bblpd)
qi: initial rate (m3/d or bblpd) to t=0
b: Arps parameters
Di: Initial decline
qi, Di y b
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
ARPS – Hyperbolic Curve
50
THEORETICAL BASIS FOR
ARPS’ DECLINE EQUATION:
To “Di” and
“qi” constants
• Well or reservoir in boundarydominated flow (BDF)
• Constant radius drainage
5
• No transient flow data
b= 1.8
b= 1.5
month
288
264
240
216
192
168
120
96
72
48
24
0.5
144
b= 1
b= 0.5
0
bblpd
• Production at constant BHP
• Solution for 0<b<1
• In 24 months’ time there are no
significant differences between in
the curves with b from 1.5 to 1.8.
• Special attention on b estimation
on short production periods.
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
ARPS – Hyperbolic Curve
35000
30000
32%
20000
47%
15000
10000
5000
0
0
12
24
36
48
60
72
84
96
108
120
132
144
156
168
180
192
204
216
228
240
252
264
276
288
300
Cumulative (m3)
25000
Month
For a period of 25 years,
keeping constants ‘Qi’ and
‘Di’, there is a difference of
EUR of 32% between b=1.5
and b=1.8. Comparing the
first ‘b’ value with b=1, the
difference is 47% less.
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Modified Hyperbolic Model
VERY LOW PERMEABILITY RESERVOIRS:
MODIFIED HYPERBOLIC MODEL
• Best-fit ‘b’ values almost always > 1
• In many cases EUR are over-estimated.
• Flow transient for large time periods.
100
m3/d
10
Dmin
1
Meses
384
336
288
240
192
144
96
48
0
0.1
Combination with exponential curve
(minimum terminal decline rate,
Dmin) makes the model applicable,
giving a reasonable reserves to finite
time.
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Bakken Shale – Horizontal Well
Example: North Dakota Bakken
EUR @ 30 years
546Mbbl (86.000m3)
Fracture stages: 28 to 32.
Lateral length: 9,186 ft (2,800 mts)
ARPS parameters:
qi = 459 bbl/d (73 m3/d)
b= 1.4
Di= 0.197
Source: J. Mason – Oil Production Potential of the North of
Dakota Bakken (February, 2012)
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Production decline-curve analysis
Methodology
• Estimation of ‘b’ and ‘Di’ parameters by fitting of production data with the
mathematical model and by minimizing squared error (MS Solver Excel).
• The wells with more production history are used
• A maximum and minimum is considered for estimation of the type well.
(Source: SEN Cap. IV)
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Production decline-curve analysis – Study zone
Dry Gas
Lower
Quintuco
Wet Gas
Oil
Vaca Muerta
Zone of production wells.
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Production decline-curve analysis – Study zone
Vertical wells
• Fracture stages: 3
• h average: 330 ft (100 m)
Horizontal wells
• Lateral length: 3,281ft
(1,000 m)
• Fracture stages: 10
• xf: 130 ft (40 m)
• h average: 164 ft (50 m)
Analysed wells results
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Vertical Wells - Fm Vaca Muerta
16,000
100
Vertical-type well
Vaca Muerta
Max. well
12,000
10
10,000
8,000
6,000
1
4,000
Med. well
Min well
Nq.VMUT-2
Nq.VMUT-3
Nq.VMUT-4
Nq.VMUT-1
Cum. Max
2,000
Cum. Med
0
Cum. Min
24
12
0
0.1
Cumulative (m3)
Production rate (m3/d)
14,000
Months
Max. Well
Med. Well
Min. Well
qi
(m3/d)
54
32
28
b
1.69
1.81
1.30
Di
n.yr
0.45
0.46
0.40
Dmin
(%/yr)
6
6
6
t @ Dmin
(yrs)
9.75
9.11
12.66
q @25 yrs
(m3/d)
1.51
1.03
0.45
EUR @ 25 years:
176,120 bbl
(28,000 m3)
Range:
98 Mbbl – 620 Mbbl
Arps parameters:
qi= 200 bbl/d (32 m3/d)
Di=0.45
b= 1.8
Dmin= 6%/yr
EUR @ 25 yrs
(m3)
42,500
27,900
15,600
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Horizontal well - Fm Vaca Muerta
70,000
Only a well with
considerable
production period.
60,000
50,000
40,000
10
30,000
20,000
10,000
0
0
12
24
36
48
60
72
84
96
108
120
132
144
156
168
180
192
204
216
228
240
252
264
276
288
300
1
Months
Nq.VMUT-5(h)
Source: CAP IV SEN
Horizontal-typed well
Vaca Muerta
Horizontal well
Cum. Hor. Well
Cumulative (m3)
Production rate (m3/d)
100
EUR @ 25 years:
389,000 bbl
(61,800 m3)
Arps parameters:
qi= 336.5 bbl/d (53.5
m3/d)
Di=0.25
b= 1.8
Dmin= 6%/yr
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Vertical wells Vs. Horizontal well - Fm Vaca Muerta
70,000
100
389Mbbl
60,000
50,000
x 2.2
40,000
30,000
Vertical type well
Cumulative (m3)
10
176.1Mbbl
1
20,000
10,000
0
0.1
0
12
24
36
48
60
72
84
96
108
120
132
144
156
168
180
192
204
216
228
240
252
264
276
288
300
Production rate (m3/d)
Horizontal Well vs. Vertical Wells
Months
Nq.VMUT-2
Nq.VMUT-3
Nq.VMUT-4
Nq.VMUT-1
Horizontal well
Nq.VMUT-5(h)
Cum- Vert. Type well
Cum. Hor. Well
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Horizontal well – Lower Quintuco + Vaca Muerta
140,000
Only a well with
considerable
production period.
Horizontal well
Lower Quintuco + Vaca
Muerta
120,000
100,000
80,000
10
60,000
40,000
Cumulative (m3)
Production rate (m3/d)
100
EUR @ 300 meses:
812,416 bbl
(129,160 m3)
20,000
1
0
12
24
36
48
60
72
84
96
108
120
132
144
156
168
180
192
204
216
228
240
252
264
276
288
300
0
Months
Hor. Well QTUC+VMUT
Sourse: CAP IV SEN
Nq.QTUC-VMUT-1
Cum. QTUC+VM Hor. Well
Arps parameters:
qi= 500 bbl/d (80 m3/d)
Di=0.125
b= 1.8
Dmin= 6%/yr
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Lower Quintuco + Vaca Muerta Vs. Vaca Muerta
140,000
100
812Mbbl
120,000
80,000
447.8Mbbl
389Mbbl
60,000
1
40,000
x 2.2
176.1Mbbl
20,000
0.1
Months
300
288
276
264
252
240
228
216
204
192
180
168
156
144
132
120
108
96
84
72
60
48
36
24
12
0
Cumulative (m3)
100,000
10
0
Production rate (m3/d)
x 2.1
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Discussions
Based on the study is considered that:
• It can adjust with decline curves for the analyzed wells, obtaining values of EUR
that differentiate the performance between horizontal and vertical wells and different
producing intervals, besides giving results comparable to other shale plays.
• The approach taken in this study of rate production decline is comparable with that
adopted in others basins, such as Bakken Shale.
• It is indicative that there would be better performance in the horizontal wells in the
Vaca Muerta formation, increasing it by a factor of 2.2 from vertical wells, which are
also increased by a factor of 2.1 with the participation of lower Quintuco.
Assessment of Vaca Muerta Formation Shale Oil:
Production Decline-Curve Analysis
Discussions
• The Arps parameters have values in the order of other shale plays estimations
with a average value of ‘b’, for Vaca Muerta’s wells, of 1.8. The Di value can vary
from 0.45 to 0.25.
• Might be considered that a production period of at least two years can get
production forecasts with significant reliability.
• From the analyzed wells it would be indicator that the EUR is directly proportional
to the initial production rate, being it related to well completion (fracture design and
number of fracture stages).
Any questions?
Thanks for your
attention