Seismic Risk Assessment for Production Scenario “Basispad Kabinet” for the Groningen field - June 2018
20
Figure 2-5
Production regions as defined in the Expectation Letter
Start-up Priority
Region
Clusters
1
North
BIR (constant rate)
2
Eemskanaal
EKL (constant rate, winter only)
3
South-East
ZPD/SZW/EKR
4
East-Central (1)
OWG/SCB
5
South-West (1)
ZVN/SPI
6
East-Central (2)
AMR/TJM/SDB
7
South-West (2)
SAP/TUS
8
South-West (3)
KPD/SLO/FRB
Table 2-2:
Production start-up list for achieving total required field production. Starting from the top of this list, groups
of clusters are sequentially opened-up by the surface network model until the total required production can be
achieved. The sequence was derived based on insights from the production optimisation study (see Fig. 2-4)
The second parameter to control volume off-take per region (spatial distribution) is the Load Factor. The Load Factor
is the ratio of cluster production to its maximum capacity. It is calculated for each individual cluster at every timestep
and a maximum value can be set as a constraint. A high maximum load factor will maximize volume withdrawal from
clusters high in the start-up sequence, but at the same time also increase production fluctuations from clusters low
in the start-up sequence (due to fluctuating demand).
Seismic Risk Assessment for Production Scenario “Basispad Kabinet” for the Groningen field - June 2018
21
It should be noted that, based on historic performance, the achieved load factor range is between 70% and 80%. A
pre-set maximum load factor of 70% was found to be a good compromise between optimising production distribution
while minimizing regional fluctuations. A maximum load factor of 90% was also tested and found to only give marginal
improvements in seismic hazard and risk metrics.
Seismic Risk Assessment for Production Scenario “Basispad Kabinet” for the Groningen field - June 2018
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2.5
References
1
Induced Seismicity in Groningen Assessment of Hazard, Building Damage and Risk – November 2017, NAM (Jan
van Elk and Dirk Doornhof), November 2017.
2
Vertrouwen in de toekomst, Regeerakkoord 2017 – 2021 VVD, CDA, D66 en ChristenUnie, Section 3.3 Gaswinning,
10
th
October 2017.
3
Advies Groningen-gasveld n.a.v. aardbeving Zeerijp van 8 januari 2018, Staatstoezicht op de Mijnen, 1
st
February
2018.
4
Optimisation of the distribution of production over the Groningen field to reduce Seismicity, Leendert Geurtsen
and Per Valvatne, December 2017.
5
Letter “Verwachtingenbrief aanvulling winningsplan Groningenveld 2016” to NAM, 2
nd
May 2018, Minister of
Economic Affairs and Climate Policy.
6
Advies GTS leveringszekerheid middels scenario analyse, 27/3/2018, Gasunie Transport Services
7
Bouwstenen voor Operationele Strategie Groningenveld 2018/2019, NAM (with contributions from Gasterra and
GTS transport Services, 2018.
Seismic Risk Assessment for Production Scenario “Basispad Kabinet” for the Groningen field - June 2018
23
3
Production scenario results
The production scenarios defined in Chapter 2 were simulated with the Groningen dynamic reservoir model (Ref. 1,
2 and 4). As described in Chapter 2, a proportional distribution of production per region is not a pre-described model
constraint, but rather a result of the demand for Groningen gas that is a function of time and temperature profile.
For every monthly timestep the model meets the demand through the use of the cluster start-up list (Table 2-2).
3.1
“Basispad Kabinet” – Average Temperature
Gas Production
The resulting production profile “Basispad Kabinet” for the average temperature outlook is given in Figure 3.1, split
by production region
3
. Eemskanaal serves as a capacity provider, represented by continuous offtake of 2 mln m
3
/d
from 1 October till 31 March, and subsequently shut-in from October 2022. Bierum is assumed the be on continuous
production of 6 mln m
3
/d for gas-years 2018/19 and 2019/20, subsequently reduced to 4 mln m
3
/d for 2020/21 and
2021/22, and shut-in from October 2022).
Between the various groups on the start-up list, South-East contributes the highest production share, some 30-40%
prior to October 2022, and subsequently increasing to almost fully covering field production. The larger part of
production demand is provided by the first four start-up groups (SE, CE1-2, SW1). The clusters close to Appingedam
(CE2) are mainly required for the first 2 years only, and the clusters close to the city of Groningen (SW2-3) are required
for capacity only.
3
Production regions as defined in the Verwachtingenbrief, see Figure 2-5 of this report