Bergan Field Kuwait. The Minagish Reservoir comprising oolite shoals, is aquifer pressure connected to other fields in the region which interact with each other.

1. SPE 163367
Modeling of Regional Aquifer System Allows Decision on Early Pressure
Support to be Made for the Burgan Minagish Reservoir, Kuwait
F.A. Al-Faresi, Kuwait Oil Company; J.T. Wang, W. Clark, M.L. Belobraydic, M. Yaser, F.O. Iwere, E. Gomez, O.M.
Gurpinar, Schlumberger; K. Datta, A. Mudavakkat, L. Hayat, G.A. Al-Sahlan, R. Husain, A. Prakash, S.J.
Crittenden, D.J. Bond, Kuwait Oil Company
Copyright 2012, Society of Petroleum Engineers
This paper was prepared for presentation at the SPE Kuwait International Petroleum Conference and Exhibition held in Kuwait City, Kuwait, 10–12 December 2012.
This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been
reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its
officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission to
reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright.
Abstract
The Burgan Minagish reservoir in the Greater Burgan Field is one of several reservoirs producing from the Minagish
formation in Kuwait and the Divided Zone. The reservoir has been produced intermittently since the 1960s under natural
depletion. A powered water-flood is currently being planned. The pressure performance of the reservoir has proved hard to
explain without invoking communication with other reservoirs. Such communication could be either with other reservoirs
through the regional aquifer of through faults to other reservoirs in the Greater Burgan field. Recent pressures are close to the
bubble point.
A coarse simulation model of the nearby fields and the regional aquifer was constructed based on data from the fields and
regional geological understanding. This model could be history matched to allow all regional pressure data to be broadly
matched, a result which supports the view that communication is through the regional aquifer. Using this model to predict
future pressure performance suggested that injecting at rates that exceeded voidage replacement by about 50 Mbd could keep
reservoir pressure above bubble point. It was recognized that the process of history matching performance was non-unique.
This is a particular concern in the context of this study because the model inputs that were varied in the history matching
process included aquifer data that was very poorly constrained. To address this problem multiple history matched models were
created using an assisted history matching tool. Using prediction results from the range of models has increased our confidence
that a modest degree of over-injection can help maintain reservoir pressure.
This paper demonstrates the utility of computer assisted history match tools in allowing an assessment of uncertainty in a
case where non-uniqueness was a particular problem. It also emphasizes the importance of understanding aquifer
communication when relatively closely spaced fields are being developed.
Introduction
The Minagish Reservoir in the Burgan Field was discovered in the 1960’s. It has been producing intermittently since then.
Production was shut down for a period (2005 - 2009) due to concerns about the H2S content of the produced fluids. Since 2005
there has been limited production to a gathering center in West Kuwait. It is planned to increase production significantly and to
produce this to a newly built “sour service” gathering center. The reservoir pressure is determined to be currently at or slightly
below bubble point of the fluid. It has been recognized that water injection would be needed maintain pressure and to support
the increased off take.
The pressure behavior of the reservoir over recent years was studied and was hard to explain. In particular there was
pressure decline during periods with little or no production. Possible explanations for this included communication with
nearby fields and cross-flow through the wells due to mechanical problems. The pressure has recently reached or dropped
below the bubble point of the reservoir fluid. This gives the added urgency in the implementation of a pressure maintenance
scheme.
Early work focused on evaluating the scope for the pressure behavior being explained by cross flow. This involved
determining the cross-flow volumes that would be required and reviewing the well data for indications of cross flow. After
careful analyses, it was determined that cross-flow at the wells was not sufficient to account for the observed pressure trends.
This prompted the need the work described here and the scope for aquifer communication was then evaluated. This was done
in stages. Firstly, the information on the Minagish regional aquifer was reviewed. Special attention was given to the expected

2. 2 SPE 163367
reservoir properties between Burgan Minagish and nearby fields and on the scope for there being fault barriers between the
fields. Based on this work, communication between the fields could not be ruled out. Secondly a model of the aquifer system
was constructed to demonstrate that it was possible, very broadly, to simultaneously account for the pressure behaviors of the
Burgan Minagish reservoir and nearby reservoirs with a model with “reasonable” aquifer properties. This involved calibrating
the simulation model to the pressure data (history matching). It was recognized that the aquifer properties, and also the
properties of possible tar mats, were not well defined by this process. Thirdly a series of matches to the data were produced.
These were used to investigate the range of future pressure performance that would be expected and to help investigate the
range of water injection rates that may be needed to support the planned production.
Inception of the study
The Burgan Minagish reservoir pressure data were examined in 2010 for historical trends. The reservoir pressure in the last
decade showed a significant decline, even when production from the reservoir was shut in for several prolonged periods of
time. The pressure is approaching the bubble point and any further significant pressure decline was considered undesirable.
Figure-1 gives a plot of pressure data (derived mainly from SIBHP surveys) and production.
A team was established within KOC to investigate the reasons for such an abnormal decline. This comprised members of
the concerned production assets and staff from KOC’s exploration department. Two possible causes were investigated. Firstly
cross flow to other reservoirs, and secondly, a reduction of aquifer support. Both reasons had to be investigated thoroughly to
provide an effective diagnosis, in order for correct actions to take place.
Investigation of possible cross-flow
As noted above, the pressure decline appeared to be inconsistent with the reported production. Additional productions, such as
those caused by the flow behind pipe to other reservoirs, could help explain the anomaly. This was investigated first by
estimating the level of such additional production that would be needed and then by assessing whether such cross-flow could
be taking place in the wells.
The first task was approached by building a simple material balance model. The model was incorporated with average rock
and fluid properties, a “deterministic” STOIIP and best estimates of blowout volumes (from the period immediately after the
liberation of Kuwait in 1990). The model was calibrated to reservoir pressures up to 1990. This avoided periods of high
production from nearby Minagish reservoirs and also the blow-out period. The results of this “tank” model can be found in
Figure-2. This Figure shows historical and calculated average reservoir pressures and historical production up to the present
time. We note an increasing gap between calculated and historical pressures starting from around year 2002. The discrepancy
eventually builds up to approximately 150 psi.
A possible explanation of this discrepancy is cross-flow. The material balance model was re-run incorporating additional
productions attributed to cross flow and the level of such production was adjusted to improve the match with pressure data. A
good match was achieved by assuming 25 Mbd of cross-flow since 2002. The results of this model are shown in Figure-3.
The scope for cross flow in wells drilled to the Minagish or deeper horizons was reviewed. There was no evidence of cross
flow from temperature surveys of the wells. The Minagish oil is distinct from the oil in the shallower producing horizons.
There was no evidence of cross-flow to these horizons based on geochemical analyses of the oil produced from the shallower
horizons.
Investigation of communication through the aquifer
The other possible scenario to explain the rapid decline in reservoir pressure is offset production from other reservoirs in a
common aquifer. A series of geological and geophysical tasks were carried out to determine whether this was plausible. These
included:
(i) A review of scope for major faults disrupting flow at Minagish level.
(ii) A review of major faults providing a means of inter-connection between the Minagish aquifer and other aquifer.
(iii) Preparation of some simple maps of the most likely views of the Minagish reservoir thickness, porosity and
permeability based on the data from KOC producing fields and regional data.
(iv) Evaluation of the uncertainty in the views of the regional aquifer. Based on these tasks between several fields through
a common aquifer seemed to be plausible.
Engineering data from the Burgan Minagish and nearby Minagish formation reservoirs were reviewed. A review of initial
pressures from these fields was consistent with the view that they could be in communication. These data were, however,
inaccurate; pressures were from mechanical pressure gauges. The pressure and production data from the various fields were
also compared. These data were highly suggestive of communication through the aquifer. Figure-4 shows the production and
pressure data from the Burgan Minagish reservoir and from a nearly reservoir, the Um Gadir Minagish. These data would
suggest that the anomalous decrease in Burgan Minagish pressure could be related to the increase in Um Gadir Minagish
production in 2002. A “proof of principle” simulation model, using single cells to model the Burgan and Minagish reservoir
and a uniform rectangular aquifer, gave increased confidence that this explanation was the correct one.
Based on the finding, a decision was made to embark on a more comprehensive and realistic study of pressure

3. SPE 163367 3
communication through the Minagish aquifer to help support the development planning work of the Burgan Minagish
reservoir. In particular there was a desire to evaluate the requirements for water injection and to determine if water injection
would be needed prior to the availability of the planned new production facilities The remainder of this paper describe the an
outsourced study carried out to address these issues.
Static model
A static model covering an area of approximately 100 km x 100 km (see Figure-5) was prepared for this purpose. The
structural grid was assembled from multiple sources of data to create a realistic combined aquifer model for the Burgan, Umm
Gudair (UG), Minagish (MN), and Wafra (WF) fields. The top Ahmadi structure (Carmen, 1996), was utilized as a trend
surface set to the elevation of the Umm Gudair and Burgan fields for the north part of the study area and the Ratawi structure
(Nelson, 1968) for the southern part of the study area (Figure 6). The final grid is 1000x1000 m, with 100 cells N-S and 100
cells E-W for a total coverage of 10,000 km2
as the model area. The structure of the top horizon, MN100, was used as the
main structural horizon and the grid was completed with the available isochores of the subsequent layers. By including fifteen
Minagish horizons, a final structural grid of 140,000 cells was created (Figure 77). Five facies are carried in the model:
mudstone-marl, bioturbated mudstone-wackestone, pelletal packstone, oolitic grainstone, and pelletal mixed grainstone. These
form the framework of the petrophysical model.
Regional Aquifer Dynamic Model
The regional aquifer model was primarily calibrated by historical observed static pressures with the use of a computer assisted
history matching (CAHM) application. To this end, the properties of the oil in the individual fields are made consistent with
the latest information related to the PVT data of the individual fields. On the other hand, matching historical fluid ratios (water
cut and GOR) is of secondary importance as only pseudo wells were used to carry entire historical productions of individual
fields. These wells are essentially long horizontal production and injection wells (Figure 88). In addition, significant tar mat
layers have been observed from petrophysical logs acquired in BG and MN fields. These may act as significant barriers to
reservoir fluid flows. In the model, partial flow barriers immediately beneath the oil zones of BG and MN fields were added to
the model to mimic their effects. These represent the tar mats observed in these fields and due to the uncertainties involved, the
extents to which they impeded flows are used as parameters for calibrating the model to production data. These parameters are
in the form of transmissibility multipliers.
Although the model grid covers quite a large area (100 km x 100 km), pressure declines along its boundary are still
inevitable throughout the simulated period of 64 years. An external analytical (Carter Tracy) aquifer was attached to the model
as a way of approximating the extensive aquifer system. The way it was connected to the model was made a parameter during
the history matching process and Figure 88 shows its final configuration in the base reservoir realization.
The model covers a vast area and many of the properties are subject to high level of uncertainty due to the very limited
number of control points. Some of these quantities (e.g. aquifer rock properties between field areas) may never be measured
and their values chosen for use in the simulation work are likely to be incorrect. The static model provides estimates of how
these properties are distributed throughout the area. These are adjusted when the model is calibrated by using the historical
production data as additional constraints.
During this process, multipliers of the two rock properties, namely, porosity and permeability, in the static model are
adjusted separately within and outside each field area. In other words, porosity and permeability in the eight regions (Figure
99) were used as parameters. Porosity multipliers in the regions (1 to 4) covering field areas typically vary between 0.5 and 1.5
during the process whereas permeability multipliers vary between 0.2 and 5.0. The full list of parameters that have been
adjusted within the range of uncertainty to calibrate the dynamic model:
 Porosity multipliers
 Permeability multipliers
 Initial datum pressures in UG and MN to compensate for the structural uncertainties. Due to the lack of information,
the area around the WF field shares the same PVT data and datum pressure as BG.
 Oil-water contact depths in UG, MN and WF to compensate for the formation thickness and structural uncertainties
 Reservoir radius for adjusting the influx constant of the analytical aquifer
 Aquifer permeability for adjusting the time constant of the analytical aquifer
 Average MN production rate during the early 90s
Once the model was deemed satisfactorily matching field data (Figure 10), it was interrogated for information that is of
interest. Figure 1111 shows pressure distributions at four specific times in the past. This Figure allows the general aquifer flow
directions during the development of the fields to be inferred. It also shows pressure declines along the model boundary.
One of the primary objectives in the fast loop phase was to estimate the historical aquifer flow among the Minagish
reservoirs in these fields. This will be an invaluable piece of information for the work in the Slow Loop phase. The
interference each field imposed on neighboring fields was very much the result of their individual development activities.
These activities (production, injection and the abnormal flow during the early 90s) led to fluctuations in the estimated aquifer
flows. The exact magnitudes of these aquifer flows are also very much dependent on the locations of the boundaries for
quantifying them. By setting two arbitrary boundaries, one midway between BG and UG and another one between BG and

4. 4 SPE 163367
WF, the model estimates history aquifer flow profiles as shown in
Figure 1212. The Figure shows a very significant outflow from the BG area considering the peak BG MN production
(excluding the early 90s) is approximately 45,000 b/d. In fact, the production activities of other fields account for most of the
pressure drop there.
The high level of uncertainty associated with a number of parameters (e.g. aquifer reservoir properties) makes the model
calibration process described above very non-unique indeed. In other words, it is very likely that multiple versions of the
model possibly with very different input parameters also match the same set production and pressure data to similar degrees.
The identification of these alternative realizations was achieved by continuing the calibration process with the CAHM
application. This time, the BG area (region 1) porosity multiplier has been excluded in order to maintain a constant fluid
volume there. Table 1 summarizes the parameters of the regional aquifer realizations identified following this process. The
‘Base’ case refers to the one described in the previous section. Using these combinations, Figure 1313 shows the pressures in
the model compared to historical data.
CASE NAME
Units Base E263 E276 E281 E287 E313 E346 E354 E358 E359 E365 E367 E373 E376 E379 Min Max Av
Region 2 porosity multiplier 0.85 0.75 0.75 0.77 0.78 0.75 0.95 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.95 0.77
Region 3 porosity multiplier 1.00 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.10 1.00 0.93 0.93 1.10 1.07
Region 4 porosity multiplier 1.20 1.40 1.00 1.01 1.00 1.00 1.40 1.00 1.00 1.00 1.31 1.00 1.31 1.13 1.38 1.00 1.40 1.14
Region 5 porosity multiplier 0.50 0.61 0.30 0.44 0.69 0.30 0.44 0.30 0.48 0.30 0.59 0.39 0.58 0.42 0.30 0.30 0.69 0.44
Region 6 porosity multiplier 0.50 0.33 0.30 0.54 0.30 0.32 0.30 0.30 0.53 0.40 0.54 0.50 0.30 0.70 0.30 0.30 0.70 0.41
Region 7 porosity multiplier 0.10 0.20 0.18 0.20 0.12 0.18 0.20 0.20 0.13 0.20 0.09 0.19 0.12 0.16 0.20 0.09 0.20 0.17
Region 8 porosity multiplier 1.00 0.87 1.04 1.20 1.20 0.84 1.20 0.80 0.90 0.80 1.20 1.18 1.20 1.19 0.92 0.80 1.20 1.04
Region 1 perm multiplier 3.00 5.00 3.56 3.71 5.00 4.62 5.00 4.82 2.82 2.90 2.42 1.58 3.35 4.05 2.43 1.58 5.00 3.62
Region 2 perm multiplier 2.50 5.00 2.00 3.32 5.00 2.87 5.00 5.00 2.00 2.00 4.32 3.75 5.00 5.00 2.00 2.00 5.00 3.65
Region 3 perm multiplier 1.20 1.67 1.73 1.47 0.50 0.50 0.57 1.55 0.50 0.75 0.50 1.07 2.00 0.50 1.99 0.50 2.00 1.10
Region 4 perm multiplier 1.68 3.46 1.76 1.70 2.48 1.70 3.50 1.70 3.50 1.70 2.37 1.70 2.69 3.50 2.34 1.68 3.50 2.39
Region 5 perm multiplier 2.00 3.00 2.23 3.00 1.61 2.90 1.31 1.91 3.00 3.00 1.68 2.26 2.31 3.00 2.66 1.31 3.00 2.39
Region 6 perm multiplier 1.80 0.80 1.97 0.94 1.05 1.36 0.83 1.10 2.43 1.53 1.01 1.27 0.78 0.63 1.37 0.63 2.43 1.26
Region 7 perm multiplier 1.20 0.82 1.50 1.25 0.82 1.30 1.32 0.30 1.21 1.50 1.50 0.30 1.41 1.21 1.50 0.30 1.50 1.14
Region 8 perm multiplier 0.06 0.09 0.07 0.05 0.09 0.05 0.05 0.05 0.07 0.05 0.04 0.04 0.06 0.05 0.04 0.04 0.09 0.06
MN tar mat trans multiplier 0.003 0.002 0.003 0.001 0.035 0.036 1.000 0.001 0.305 0.024 0.040 0.013 0.002 0.371 0.002 0.001 1.000 0.142
BG tar mat trans multiplier 0.006 0.063 0.040 0.027 0.073 0.072 0.005 0.032 0.024 1.000 0.020 0.001 0.026 0.049 0.019 0.001 1.000 0.137
UG datum pres psia 4125 4019 4004 4131 4200 4020 4123 4000 4022 4000 4116 4000 4200 4200 4064 4000 4200 4082
MN datum pres psia 4647 4600 4847 4847 4847 4847 4847 4847 4847 4647 4847 4847 4847 4843 4606 4600 4847 4788
UG OWC depth ftSS 8450 8440 8462 8444 8440 8443 8440 8440 8454 8458 8440 8440 8440 8440 8454 8440 8462 8446
MN OWC depth ftSS 9780 9756 9750 9750 9786 9779 9791 9758 9783 9764 9777 9761 9750 9827 9776 9750 9827 9773
WF OWC depth ftSS 6470 6457 6521 6491 6492 6498 6452 6492 6495 6498 6460 6492 6458 6461 6456 6452 6521 6480
Aquifer int. radius ft 2E+7 4E+5 1E+8 4E+5 1E+8 9E+5 1E+8 3E+6 1E+6 2E+6 2E+6 1E+8 1E+8 1E+8 8E+5 4E+5 1E+8 4E+7
Aquifer perm md 600 800 800 800 658 313 420 399 310 271 418 599 725 109 350 109 800 505
MN early 90s rate mbo/d 400 410 200 210 410 410 410 410 410 290 410 410 263 410 410 200 410 364
Table 1 – Model input parameters in alternative regional aquifer realizations
The average BG MN pressures predicted by the model with these 15 realizations are shown in Figure 144. In all these
cases, the pressure decline is predicted to continue for roughly another 10 years before beginning the flattening trend. As the
pressure drops, the rate at which fluid leaves the Burgan area is slowed gradually and this resulted in the flattening trend. The
Figure shows the estimated average BG MN pressure in 16 years to be estimated to be between 2,450 psi and 2,580 psi if the
productions at all fields were to be maintained at their rates in 2011.
Obviously, the low resolution of the model grid casts doubt on performance prediction results obtained from the model. In
this case, simple scenarios are simulated to determine the impact of implementation of water injection and the relative location
for the injection to take place. These cases (Table 2) are mostly for determining the effects of injection at a moderate rate (80
Mbwpd) and at a high rate (160 Mbwpd) on BG MN pressure.

5. SPE 163367 5
Case
BG Injection BG Prod
1 80 Mbd above tar mat from 1/1/2014 Continue at current rate
2 80 Mbd above tar mat from 1/1/2014 Shut down BG MN production till 2015
3 160 Mbd above tar mat from 1/1/2014 Continue at current rate
4 160 Mbd above tar mat from 1/1/2014 Shut down BG MN production till 2015
4a 160 Mbd below tar mat from 1/1/2014 Shut down BG MN production till 2015
Table 2 – Simple prediction scenarios
In addition, the non-uniqueness of the model calibration process as illustrated above prompts the need for estimating the
range of uncertainty associated with the predicted results in these cases. The one parameter that could potentially have a
significant impact on the effect of water injection in BG MN is the extent of its tar mat that was observed near or at the oil-
water contact at a number of wells. Given this, each of the development scenarios listed in Table 2 is tested with three model
realizations (see Table 1 for their input parameters) with very different reductions in flow transmissibility (or transmissibility
multiplier) across the tar mat
 No reduction (E359 case) – no tar mat transmissibility multiplier
 Moderate reduction (Base case) – tar mat transmissibility multiplier at 0.006
 Severe reduction (E367 case) – tar mat transmissibility multiplier at 0.001
It should be noted that the model is calibrated to the same set of observed historical pressure and production data in these
realizations. With these extreme transmissibility multiplier values, the other parameters are set to different values (listed in
Table 1) as a result of the calibration process for the model to match the same observed data in a similar fashion.
Results of these simulations with the nine development scenarios are presented in Figure 155 to Figure 188. In each of
these Figures, results of two of these cases are compared to those in the case in which all voidage production and injection
rates are assumed to be maintained at their levels in September, 2011 (“do nothing” case). Figure 155 and Figure 166 show
how the predicted average BG MN datum pressure in these cases and based on the three realizations described above. The
following observations can be made from this Figure:
1. The effect of suspending BG production (until 2015) on the long term predicted pressure is relatively insignificant.
This is because production activities in other neighboring fields have a more pronounced effect on BG MN reservoir
pressure than even its own production.
2. As expected, the average BG MN pressure is very sensitive to the transmissibility across the tar mat when injecting
water inside the tar mat
Table 3 shows a snapshot of predicted pressure values in 2024 in these cases. The estimated pressure increase values at that
time are also presented in Figure 177. Given this, the reservoir pressure should be closely monitored in any future water
injection operations. This would be useful for reducing the uncertainty on how the tar mat affects the way the BG MN
reservoir interacts with the surrounding aquifer. Figure 188 shows how the placement of the water injection well (inside or
outside the tar mat) impacts the predicted average pressure in BG MN. As expected, the contrast is more prominent if the tar
mat is relatively impervious to flow across it.
Scenario
Realization
No Tar Mat Mult = 0.006 Mult = 0.001
Average
Pressure,
psia
Do nothing 2614 2597 2587
Injecting at 80 Mbwd 2722 2756 2970
Injecting at 160 Mbwd 2829 2892 3414
Increase,
psi
Injecting at 80 Mbwd 107 159 383
Injecting at 160 Mbwd 214 296 827
Table 3 – Predicted average BG MN pressures and pressure increases in 2024

6. 6 SPE 163367
Conclusions
A detailed study has been carried out to address the extent of pressure communication between the Burgan Minagish reservoir
and other nearby reservoirs producing from the Minagish formation. This has shown that the pressure performance of the
Burgan Minagish reservoir can be explained by communication through the aquifer.
The properties of the aquifer are relatively poorly known, as are the properties of Tar mats in the producing reservoirs. A
range of models were conditioned to the available data. Although these all match the historical data they predicted future
pressure performance differs considerably. This range of models has been used to estimate the timing and volume of the
required water injection.
Acknowledgments
The authors thank Kuwait Oil Company and Schlumberger for their permission to publish this paper. We also wish to thank
KOC Manager West Kuwait, Mr. Hasan Bunain, and his staff for their support and advice.
References
1. Carman, G.J.: “Structural Elements of Onshore Kuwait”, presented at the 2nd
Middle East Geosciences Conf. and
Exhib., GEO96, Bahrain, 15-17 April 1996.
2. Nelson, P.H.: “Wafra Field Kuwait – Saudi Arabia Neutral Zone”, Presented at the Regional Technical Symposium,
Dhahran, Saudi Arabia, 27-29 March 1968.

7. SPE 163367 7
Figures
Figure 1 – Pressure and production performance of Burgan Minagish reservoir
Figure 2 – Material Balance model results

8. 8 SPE 163367
Figure 3 – Material Balance results assuming extrap efflux
Figure 4 – Relation of Burgan Minagish and Umm Gadir production and pressures

9. SPE 163367 9
Figure 5 – Study model area
Figure 6 – Adjusted Ahmadi (blue), Ratawi (pink), and MN100 structural contours (green) and MN100 tops (pink
dots).

10. 10 SPE 163367
Figure 7 – Final structural grid demonstrating the zones (10x exaggeration)
Figure 8 – Tar mat boundaries and external aquifer connections

11. SPE 163367 11
Figure 9 – Regions for porosity and permeability adjustments
Figure 10 – Pressure match of calibrated model

12. 12 SPE 163367
Figure 11 – Estimated historical regional aquifer pressure distributions
Figure 12 – Historical aquifer flow profiles estimated by the base case model

13. SPE 163367 13
Figure 13 – Regional aquifer model pressure match (15 realizations)
Figure 14 – Predicted BG MN pressures in the continuing current operation scenario

14. 14 SPE 163367
Figure 15 – Case 1, Case 2 and “Do-nothing” case predicted pressures
Figure 16 – Case 3, Case 4 and “Do-nothing” case predicted pressures

15. SPE 163367 15
Figure 17 – Predicted pressure increase (2024) in BG MN (w.r.t. do-nothing case)
with water injection inside tar mat
Figure 18 – Case 4, Case 4A and “Do-nothing” case predicted pressures