1. A method for determining fluid flow rates in a cluster of fluid injection wells which are connected to a collective fluid supply header conduit assembly, the method comprising:
a) monitoring fluid flow, and optionally pressure, in the collective injection fluid supply header conduit assembly by means of a header flow meter, and optionally a header pressure gauge;
b) monitoring one or more injection well variables in or near each injection well by means of well variable monitoring equipment arranged in or near each injection well, including a tubing head pressure gauge in a fluid injection tubing in or near each injection well, and optionally a surface or downhole flow meter, an injection choke valve position indicator, a differential pressure gauge across a flow restriction, a wellhead flow line pressure gauge andor a downhole tubing pressure gauge;
c) sequentially testing each of the injection wells of the cluster by performing a dynamically disturbed injection well test on the tested well, during which test the well is first closed and is then gradually opened in a sequence of steps so that the injection rate to the tested well is varied over a range of flows whilst the fluid flow rate and optionally pressure in the header conduit assembly are monitored in accordance with step a and one or more injection well variables of the well under test and of the other wells in the cluster are monitored in accordance with step b, and controlling the other wells in the cluster such as to cause their tubing head pressures or flow meter readings to be substantially constant for the duration of the test;
d) deriving from step c a well injection estimation model for each tested well, which model provides a correlation between variations of the fluid flow rate attributable to the well under consideration, and optionally pressure, in the header conduit assembly measured in accordance with step a, and variations of one or more well variables monitored in accordance with step b during each dynamically disturbed injection well test;
e) injecting fluid through the header conduit assembly into the cluster of wells whilst a dynamic fluid flow pattern, and optionally a dynamic pressure pattern, in the header conduit assembly is monitored in accordance with step a and one or more well variables of each injection well are monitored in accordance with step b;
f) calculating an estimated injection rate at each well on the basis of the well variables monitored in accordance with step e and the well injection estimation model derived in accordance with step d; and wherein the method further includes a dynamic reconciliation process comprising the steps of:
g) calculating an estimated dynamic flow pattern in the supply header conduit assembly over a selected period of time by accumulating the estimated injection flows of each of the wells made in accordance with step f over the selected period of time;
h) iteratively adjusting for each injection well the well injection estimation model for that well until across the selected period of time the accumulated estimated dynamic flow pattern calculated in accordance with step g substantially matches with the monitored header dynamic fluid flow pattern monitored in accordance with step e; and
i) repeating steps g and h from time to time.
2. The method of claim 1, wherein the well variable monitoring equipment either does not comprise surface or downhole flow meters or comprises one or more defective or inaccurate surface or downhole flow meters, at one or more injection wells and wherein a virtual flow meter is generated in step f and then refined via the dynamic reconciliation process.
3. The method of claim 1 wherein at least one injection well is a multi-zone injection well with multiple zones andor branches that are each connected to a main wellbore at a zonal or branch connection point which is provided with an Inflow Control Valve (ICV), means for estimating the current position of the ICV, and one or more downhole pressure gauges located upstream andor downstream of the ICV for monitoring the fluid pressure upstream andor downstream of the ICV, and the method further comprises:
j) performing a deliberately disturbed zonal injection test during which the flow rate of the fluid injected into each zone of the tested multi-zone well is varied by sequentially changing the opening of each ICV;
k) monitoring during step j injection well variables including the surface flow rate and pressure of the fluid injected into the tested multi-zone well, the position of each ICV and the fluid pressure upstream andor downstream of each ICV;
l) deriving from steps j and k a zonal injection estimation model for each of the tested zones, which model provides a correlation between the monitored injection well variables and an associated fluid injection rate into each of the zones of the multi-zone well;
m) calculating an estimated injection rate at each zone on the basis of the surface and zonal variables monitored in accordance with step k and the zonal injection estimation model derived in accordance with step l; and
n) repeating steps j, k, l and m from time to time.
4. The method of claim 3, wherein the method further includes a dynamic reconciliation process comprising the steps of:
o) calculating an estimated dynamic flow pattern in the surface wellhead of any of the multi-zone wells over a selected period of time by accumulating the estimated injection flows of each of the well zones made in accordance with step m over the selected period of time; and
p) iteratively adjusting for each injection well zone the well injection estimation model for that well zone until across the selected period of time the accumulated estimated dynamic flow pattern calculated in accordance with step n substantially matches with a monitored surface wellhead dynamic fluid flow pattern; and
q) repeating steps o and p from time to time.
5. The method of claim 4, wherein step p is performed with an estimated surface wellhead fluid flow pattern computed from step e and reconciled with the monitored surface wellhead dynamic fluid flow pattern.
6. The method of claim 3 wherein:
r) an operational injection target is defined for each of the zones, consisting of a target to be optimized and various constraints on the zonal injection flows and well bore pressures or other variables measured in step k; and
s) from the estimates of step m or step p, adjustments to settings of zonal ICVs are made such that the optimization target of step r is approached.
7. The method of claim 3, wherein the step of monitoring injection variables further includes:
monitoring the position of one or more flow or pressure control valves andor the performance of one or more fluid injection pumps and an associated regulatory control mechanism at the earth surface;
monitoring the temperature, composition andor other physical properties of the injected fluid downhole or at the earth surface by other types of gauges such as a temperature gauge andor acoustic devices; andor
virtual metering of fluid injection into each zone by a virtual flow meter which monitors a pressure difference \u0394p across each ICV and calculates a fluid velocity v in a smallest cross-sectional flow area of each ICV using the formula \u0394p=\xbd\u03c1\xb7v2, wherein \u03c1 is the density of the injected fluid flowing through the ICV and v is the fluid velocity through the ICV, and which calculates the flow rate by multiplying the calculated fluid velocity by the smallest cross-sectional flow area of the ICV.
8. The method of claim 6, wherein
during each repetition of step m a well and zonal injection and pressure prediction model for the multi-zone well system is derived, which model provides a correlation between the position of each ICV and the surface pressure, and the associated fluid injection rate and pressures at each of the zones of the multi-zone well; and
ICV settings corresponding to the requirements of step s are computed using the well and zonal injection and pressure prediction model computed, and optionally, additionally on the basis of the surface and zonal variables monitored in accordance with step k, using a differenced form of the well and zonal injection and pressure prediction model.
9. The method of claim 1, wherein step c comprises testing sequentially one or more of the injection wells of the cluster by closing in all other injection wells, and performing a dynamically disturbed injection well test on the tested well, during which test the injection rate to the tested well is varied over a range of flows whilst the fluid flow rate and pressure in the header conduit assembly are monitored in accordance with step a and one or more injection well variables of the well under test are monitored in accordance with step b.
10. The method of claim 1, wherein the dynamic reconciliation process further comprises making reconciliation adjustments to the well injection estimation models, which adjustments are related further to the previous reconciliation adjustments to the well injection estimation models to reflect a balance between the information available in the previous reconciliation period and the current reconciliation period.
11. The method of claim 1 wherein the dynamic reconciliation process further comprises computing additive and multiplicative quantities applied to each of the well injection estimation models.
12. The method of claim 11, wherein the computation uses a least squares method, or optionally a recursive least squares method, or optionally generalizations thereof with additional auxiliary constraints and targets leading to solution via convex quadratic program.
13. The method of claim 1, wherein the injected fluid comprises any combination of the following: water, steam, carbon dioxide, nitrogen methane and chemical enhanced oil recovery compositions.
14. The method of claim 6, wherein the step of defining an operational injection target further includes reflecting in the operational injection target and constraints derived quantities such as preference of nearly equal pressures downstream of the ICVs for all zones and or maximum allowable pressure downstream of the ICVs.
15. The method of claim 6, wherein the step of computing from the model of step l, ICV settings to be adjusted further includes computing adjustments to settings of a surface flow or pressure control valve or pump such that the optimization target is approached.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1-15. (canceled)
16. A refrigeration device comprising:
a body having at least one inner chamber provided therein;
a first door and a second door that jointly close the inner chamber; and
an upright member pivotally mounted on the first door, the upright member having an inner side that extends between the first door and the second door when the first door and the second door are disposed to jointly close the inner chamber, the upright member being pivotable in connection with an opening movement of the first door and the upright member being adjustable in height relative to at least one of the body and the first door.
17. The refrigeration device according to claim 16, wherein the upright member is arranged so that it can be adjusted continuously in height to one of a plurality of different height mounting dispositions.
18. The refrigeration device according to claim 16, wherein the upright member is arranged so that it can be adjusted in height in steps.
19. The refrigeration device according to claim 16, wherein the first door bears the upright member by means of a suspension device having a vertical channel and a supporting bolt for the upright member that can be fixed at different heights in the channel.
20. The refrigeration device according to claim 19, wherein the channel is closed at one end and a removable locking element that defines the length of the channel is placed in the channel between the closed end and the supporting bolt.
21. The refrigeration device according to claim 20, wherein the locking element is disposable in the channel in at least two positions each of which blocks the channel at different widths.
22. The refrigeration device according to claim 20, wherein the channel has at least two vertically spaced receptacles in which the locking element can engage.
23. The refrigeration device according to claim 21, wherein the channel has at least one receptacle at which the locking element can engage in different orientations.
24. The refrigeration device according to claim 19, wherein the supporting bolt has a head that engages in an undercut of the channel.
25. The refrigeration device according to claim 19, wherein the supporting bolt and one wall of the channel define at least one wedge-shaped cavity in which a finger of a locking component engages.
26. The refrigeration device according to claim 25, wherein the locking component is held non-positively in the channel.
27. The refrigeration device according to claim 25, wherein the locking component is held positively in the channel.
28. The refrigeration device according to claim 25, wherein a locking notch and a locking projection which engages in the locking notch are provided, wherein one of the locking notch and the locking projection is formed on the finger and the other of the locking notch and the locking projection is formed on a wall of the channel defining the wedge-shaped cavity.
29. The refrigeration device according to claim 28, wherein the locking notch is a through opening in the wall of the channel.
30. The refrigeration device according to claim 28, wherein a plurality of locking notches are provided at different heights.