[0001] The present invention relates to methods and apparatus having application in the
field of well construction, completion, monitoring and control. In particular, the
invention provides methods and apparatus that are particularly useful in oil or gas
wells situated in weakly consolidated or unconsolidated formations requiring screen
completions.
[0002] Traditional methods of completing hydrocarbon wells involve cementing a casing or
liner (typically made of steel) into the well and then forming perforations at locations
in the well believed to be situated in producing formations extending through the
casing and cement into the formation to provide paths along which fluids can flow
into the well. These flow paths can often be improved by fracturing or other stimulation
methods well known in the industry. Once the well has been completed, it is relatively
easy to re-enter the well with measurement tools and make measurements near the regions
in which there are perforations to determine the nature and characteristics of the
fluids flowing into the well from the formation at that point.
Also, it is possible to seal off the perforations if it is discovered that undesirable
fluids flow is encountered, for example high volume fractions or flow rates of water
entering the well at that point. All of these are generally possible because the perforations
constitute a relatively small extent of the well and the presence of the otherwise
solid casing allows portions of the well to be sealed while well treatments are taking
place.
[0003] However, there are certain, well-known situations in which this traditional approach
to well completion cannot be used, in particular when the producing formation is weakly
consolidated or unconsolidated, such as sand, or where the producing section of the
well has been drilled in a long reach horizontal section. In the first case, the formation
is too weak to allow casing to be installed, or for permanent perforations tunnels
into the formation to be formed. The only effective manner to allow fluids to pass
into the well is to provide a highly perforated or apertured liner, often called a
"screen" or "sand screen" or "gravel pack" to be placed in the well in the formation
of interest. In the past, such wells have often been left without any form of liner,
sometimes called "barefoot completion" or have had slotted liners or screens inserted
into the well but not secured by cement, similar to the approach to that used in unconsolidated
formations as described above.
[0004] One known form of screen useful in unconsolidated formations or long reach horizontal
wells is shown in Figures 1 and 2. The screen is formed in sections having a base
tube 12 which is provided with holes 14 along its length and around its circumference.
The screen itself is formed by a triangular section wire 16 (base outermost) that
is wound around the outside of the base tube 12 between small collar sections 18 provided
at each end of the base tube 12 and separated from the outer surface of the base tube
by longitudinal splines 22 secured to the outer surface of the base tube so as to
define an axially segmented annular chamber 24 around the base tube 12. The wire screen
16 is wound in such a way that a small space is left between adjacent windings that
is small enough to prevent small particles such as sand entering the chamber 24 or
base tube 12 yet not so small as to inhibit the flow of fluids into the well. While
this construction allows flow in the radial direction (i.e. into the base tube, it
also allows axial flow inside and outside the screen with little or no restriction.
This can bring certain problems when it comes to monitoring the production in the
well or treating the well or formation with treatment fluids. In the case of monitoring
or measurement, since there can be flow into the well at almost any point and since
there can be flow outside the base tube in axial directions (i.e. in the chamber 24),
it is very difficult to relate a measurement made at any particular point in the well
to the behaviour of a specific region of the formation outside the well. In the case
of well treatment, pumping a fluid inside the base tube cannot guarantee placement
in a zone of interest since there is nothing to force the fluid into that zone. Even
the use of coiled tubing to deliver treatment fluids cannot guarantee proper placement
or treatment.
[0005] Various forms of screen-type completions are known. US 5,435,393 describes one particular
form in which the completion is divided into sections, each of which is provided with
a controllable restriction in a passage communicating between the annular chamber
and the inside of the base pipe. This restriction is used to control the pressure
difference between the formation and the inside of the base pipe so as to maintain
a given pressure drop along the completion.
[0006] Long horizontal producing sections are often found in offshore wells, either singly
or in multi-lateral completions. Offshore wells can be completed as subsea (i.e. the
wellhead is located on the sea bed) or platform (i.e. the wellhead is located on a
platform at the sea surface. Subsea wells are a significantly less expensive method
of developing oil and gas fields than using platforms, because the platform itself
is a significant portion of the total cost. However a disadvantage of subsea wellheads
is that it is very expensive to gain access to the well once it is completed. For
dry wellheads on land or on platforms, interventions are made to acquire data about
the reservoir and producing fluids, and about the completion itself. The data obtained
is new data not known at the time of the original well design, and can be used to
plan further interventions to modify the flow of fluids from the reservoir, for example
shutting zones which produce water. The huge expense and operational risk of performing
equivalent interventions in subsea wells means they are rarely done.
[0007] There are alternative methods of changing the flow of fluids from a reservoir without
a physical intervention. Chemical treatments can be injected along the subsea flowline
down the well, or along permanently installed subsea chemical injection lines. This
utilizes the flowline linking the hydrocarbon gathering point and the reservoir. However,
the absence of data on the reservoir identifying the specific zones needing treatment
means reservoir treatments in subsea wells are also rarely done. It is also difficult
to position a chemical treatment accurately in any particular zone. This limits most
subsea chemical treatments to fluids which have a preference for any zone producing
a specific unwanted fluid, however such indiscriminate chemical treatments risk reducing
the productivity of all zones. Other chemical treatments are intended to treat the
entire completion, for example scale treatments. However it is not currently possible
to verify whether these chemical treatments have reached the entire completion. The
lack of interventions to log, and the difficulty in verifying the placement of chemical
treatments in subsea wells results in a much lower ultimate recovery than a comparable
field developed from a platform.
[0008] One recent development in the field of monitoring wells after completion and during
production is that of permanent monitoring using sensors foxed at locations in the
well to provide continuous or repeated measurements. However, if it is desired to
obtain accurate information about the contribution of each part of the completion
to the overall production from the well, it is currently necessary to provide multiple
measurements in each part of the well to allow accurate determination of which part
of the well is responsible for significant changes in its production, which can be
expensive and difficult to achieve given the power and space constraints of the downhole
environment.
[0009] The present invention attempts to provide solutions for some or all of the problems
identified above in relation to the construction, installation and monitoring of completions
and the conducting of well treatment operations.
[0010] In accordance with a first aspect of the invention, there is provided a method of
monitoring fluid production in a well, comprising:
- measuring over time local parameters at a series of locations along the well, each
local measurement being responsive to changes in the parameters in the region in which
it is made;
- measuring fluid properties in the well over time downstream from the series of locations;
and
- determining changes in the local measurements and in the measured fluid properties;
and
- identifying locations of the formation contributing to the changes in the measured
fluid properties by determining corresponding changes in the local measurements.
[0011] By combining a distributed measurement made within the formation and a measurement
of the fluids in the well downstream of the producing formation, it is possible to
identify the location in the well at which a change has occurred in the produced fluids.
[0012] It is preferred that each local measurement corresponds to a discrete location at
which formation fluids enter the well.
[0013] The local parameter measurement can be any parameter that is affected by changes
in the fluids flowing between the formation and the well at this location. For example,
resistivity, conductance, temperature, pressure or chemical composition parameters
might be measured. The sampling rate of the local measurements is preferably relatively
high, particularly with respect to the flow rate of fluids in the well, such that
the time at which a change is measured at a specific location can be identified relative
to corresponding measurements at other locations.
[0014] The fluids properties measured downstream of the local measurements are typically
flow rates, preferably volumetric flow rates. The flow rates measured at the downstream
location are used to quantify change of flow into the well whose particular location
has been identified by the local measurement. Also, by determining the physical location
of a local sensor and determining the time between a change being measured at the
local sensor and a measured at the downstream location, the flow rate determined at
the downstream location can be confirmed or calibrated.
[0015] In accordance with a second aspect of the invention, there is provided apparatus
for completing a well, comprising:
- an base pipe; and
- an permeable screen surrounding the base pipe and defining a chamber outside the base
pipe and inside the screen;
wherein the base pipe is provided with an apertured portion of limited axial extent
providing fluid communication between the chamber and the inside of the base pipe
such that fluid entering the chamber through the permeable screen passes into the
base pipe only via the apertured portion; and, in use, the screen and apertured portion
cause a relatively low pressure drop between the outside of the apparatus and the
inside of the base pipe.
[0016] In accordance with a third aspect of the invention, there is provided a method of
completing a well, comprising:
- installing a series of tubular members in the well connected in an end-to-end arrangement,
each tubular member comprising an elongate base pipe and an elongate screen surrounding
the base pipe and provided with multiple apertures distributed along its length, the
screen and the base pipe together defining an annular chamber between them,
wherein the base pipe is provided with an apertured portion of limited axial extent
providing fluid communication between the chamber and the inside of the base pipe
such that fluid entering the chamber through the permeable screen passes into the
base pipe only via the apertured portion.
[0017] Preferably, the base pipe has a series of longitudinal splines formed around its
outer surface, the splines acting to segment the chamber into a series of axial segments.
These splines can be formed by wires fixed to the outer surface of the base pipe,
for example.
[0018] It is particularly preferred that a collar section is provided on the base pipe near
to the apertured portion, the collar defining a manifold that communicates with the
annular chamber and the apertured portion such that fluid flowing from the annular
chamber into the base pipe flows through the manifold. In one embodiment, the collar
is located at one end of the base pipe and a simple collar is located at the other
end, the two collars defining the ends of the permeable screen and annular chamber.
[0019] The collar can also include a sensor system and/or a sealing system for closing off
flow through the apertured portion. The sensor system and/or sealing system can be
provided with connections for a data and power network.
[0020] In on particular embodiment, the apertured portion of the base pipe is located in
a part connecting two screen sections, the collar is located at the end of one of
the two screens and is connected to the connecting part by the manifold.
[0021] The collar can be provided with ports between the annular chamber and the manifold
and the base pipe provided with one or more apertures connecting to the manifold.
[0022] In accordance with a fourth aspect of the invention, there is provided a method of
treating a well that has been completed as described above, comprising pumping a treatment
fluid from the surface into the well while measuring local parameters in each tubular
member; detecting the arrival of the treatment fluid from the measurement of local
parameters; and ceasing pumping so as to leave the treatment fluid in a region of
the well to be treated.
[0023] In accordance with a fifth aspect of the invention, there is provided a completion
system, comprising:
- a tubular member for location in a well, the member including at least on opening
allowing communication between the interior and exterior of the member; and
- a closure system located adjacent the or each opening and including a source of stored
energy which, on activation, operates to close the or each opening.
[0024] It is preferred that the openings in the tubular member are confined to a region
of limited axial extent. It is particularly preferred that the openings are near a
collar on the outside of the tubular member. In one such arrangement, the closure
system can be located in or on a manifold.
[0025] The closure system can comprise a reservoir of expandable fluid and an activator.
On operation, the activator ruptures the reservoir and allows the fluid to enter the
manifold where it expands to prevent fluid flowing therethrough. Alternatively, the
closure system can comprise a heating system for activating a sealing fluid pumped
into the manifold from the surface.
[0026] It is particularly preferred that the closure system is reversible to allow reopening.
[0027] The present application will now be described by way of example, with reference to
the accompanying drawings, in which:
Figure 1 shows a prior art sand screen;
Figure 2 shows a detail of the screen shown in Figure 1;
Figure 3 shows a sand screen incorporating embodiments of the invention;
Figures 4 a - c show cross sections of the screen of Figure 3;
Figure 5 shows a schematic view of a well completed using the sand screen shown in
Figure 3;
Figure 6 shows an alternative form of well completion to that shown in Figure 5;
Figure 7 shows plots of measurements made over time for a well completed as shown
in Figure 5;
Figure 8 shows schematically a method of well treatment according to an embodiment
of the invention; and
Figure 9 shows a sealing system according to an embodiment of the invention.
[0028] Referring now to the drawings, the sand screen shown in part in Figure 3 is similar
to that of Figures 1 and 2 and corresponding parts are given corresponding reference
numbers in the 100 series. The screen 110 shown in Figure 3 is also formed in two
sections: a base pipe 112 and a wire screen 116 extending between collar sections
118 on the outside of the base pipe 112 defining a chamber 124 (Figure 4a). The collar
section 118' is formed on a connector section 112' of the base pipe 112 and is provided
with an end plate 130 having ports 132 which connect the chamber 124 to a manifold
134 within the collar (Figure 4b). The ports 132 are provided between the wires or
splines 122 supporting the screen 116. The other end of the screen 116 is connected
to a simple end plate (not shown).
[0029] The manifold 134 is in the form of a shroud which encircles the base tube 112' (Figure
4 c) and directs the fluids into a delivery pipe 136 which is connected to an aperture
138 in the base pipe 112' such that the only fluid communication path between the
chamber 124 and the inside of the base pipe 112' is via the ports 132, manifold 134
and aperture 138.
[0030] The ports 132, manifold 134 and aperture 138 are dimensioned such that there is essentially
no restriction of flow of fluids from the screen 116 into the base pipe 112, i.e.
there is essentially no pressure drop between the screen 116 and the inside of the
pipe 112', the inner diameter of the base pipe 112 being the only significant restriction
to flow from the formation into the well.
[0031] The collar is also provided with a sensor package and associated electronics 140
which are connected to a power and data communication system 142 running along the
well from the surface. The sensor can be any one of a number of permanent or long
term sensors that can be installed in a well and which are responsive to fluid or
other environmental parameters such as pressure or temperature, chemical composition,
conductivity or dielectric, or electrodes responsive to resistivity or inductance
either in the formation itself or the fluids entering the screen.
[0032] The manifold 134 also includes a sealing system 144 that is connected to the same
data and power network 142 as the sensor system 140. The operation of the sealing
system 144 is described in more detail below.
[0033] Figure 5 shows an example of a well completed using screens of the type shown in
Figure 3. The well shown in Figure 5 is an offshore, subsea well (well head located
on sea bed). The well extends vertically downwardly 154 from the well head 150 and
the proceeds in a substantially horizontal section 156 through the producing reservoir
158. The vertical section of the well is completed in a conventional manner with steel
casing 160 cemented into the borehole. The horizontal section 158 is completed using
a series of screens 110 of the type described above connected in an end to end manner.
The sensors 140 and sealing systems 144 are connected to a network 148 running through
the well and connected to a power and data acquisition unit 162 at the well head 150.
The effect of installing the screens described above is to divide the well into a
series of finite producing elements as all of the fluids entering a given screen enter
the base pipe at a single location, that of the aperture connecting to the manifold.
Thus each screen has the effect of focussing the production in that region into a
specific point in the well.
[0034] A flow measurement device 164 is positioned in the well downstream of the horizontal
section 158. This device can be any suitable flow meter such as a venturi device,
spinner, electromagnetic device or combination of these. One particularly preferred
form of meter is the EWM Electric Watercut Meter of Schlumberger that comprises a
capacitive measurement system and an electromagnetic measurement system downstream
of a venturi. Such a meter can measure flow rates for mixtures of 0 - 100% water.
[0035] A similar completion with an alternative form of sensor system is shown in Figure
6. In this case, instead of the discrete sensors in each collar, the system comprises
a distributed continuous sensor 166, particularly a distributed fibre optic temperature
sensor which is installed in a U tube extending along the well. Such a system is available
from Sensa of UK and is operated from the well head without the need to be connected
to the data and power network 148 downhole. Such a system can be operated to give
discrete measurements at any given location in the well, in a similar manner to a
series of discrete sensors.
[0036] In use, the flow meter 164 measures the total flow rate of the fluids produced from
the well. Any changes in production are reflected in this flow rate measurement. However,
from this measurement alone, it is not possible to identify where the event causing
the change in production has taken place and so is not useful for identifying selective
treatment options if the change is an undesirable one, such as water breakthrough.
Clearly a change in production of fluids for a given screen or screens will be reflected
in the measurements made by the associated sensors 140 located in the collars (or
the associated discrete measurement is a distributed sensor is used) but in view of
the restrictions on space and power, it is typically not possible to provide a full
multiphase flow sensor in each collar and so it is essentially impossible to obtain
accurate quantitative measurements in each collar to identify the particular change
in production that is detected by the flow meter downstream. Most of the sensors that
can be installed in the screen are essentially non-quantitative in respect of flow,
or are of unreliable or unknown accuracy and therefore very difficult to interpret.
However, each sensor will be sensitive to the fact that a change in production is
occurring and therefore the location(s) of the changing production can be identified
by correlating a detected change in the sensor(s) one or more screens with a measured
change in the production from the well as measured by the flow meter.
[0037] By simultaneously measuring the local parameters in the reservoir on the screens
and the fluid properties downstream, it is possible to use the qualitative local measurement
to identify the location of the change of fluid flow into the well.
[0038] Because it is possible to identify the location of the change in production to within
one or two screen lengths, it is possible to design well treatment actions that address
only this region rather than all regions as has been the case in the past. Where a
well includes multilateral completions from a main well, a flow meter can be installed
in each completion to provide the benefits outlined above.
[0039] In Figure 7, there is shown a plot of the reading from the downstream flow meter
in terms of % water (W%) in the flowing fluids vs. time (T). An array of instrumented
screens of the type described above (S
1 - S
14) is monitored over the same time period with respect to the resistivity measured
at each screen. What is monitored over time for the array is the change Δ in the measurement
rather than the absolute measurement itself. At time T
1, the flow meter shows an increase in water cut of the produced fluids. An examination
of the screen measurements for the same time period shows that the readings from screen
S
4 changed during that time period indicating that water influx started in the region
of screen S
4. At time T
2, the flow meter indicated an increase in water cut. In this case, the sensor at screen
S
7 showed a change, indicating the location of new water influx. A further change in
water cut occurred at time T3 and is indicated on screen sensor S
12. In each case, it is a change Δ in the measurement from a screen sensor that is needed
to identify the location of the event causing the change, not the absolute measurement
from that sensor. At all other times or other locations, the sensors have a substantially
constant reading suggesting that there has been no change in the fluids produced.
[0040] In the case described above, the increase in water cut after times T
1 and T
2 might still be sufficiently low that remedial action in the well is not justified,
but with the increase at T
3 might then increase the water cut to a degree that it will be worthwhile performing
a well treatment to shut off the water influxes and allow the well to continue at
low water cut production. Knowing the location of the water breakthrough allows a
treatment to be designed which only addresses these locations and allows the other
parts of the well to continue production unchanged.
[0041] While the example given above uses the example of increased water production as the
change detected, it could be any change in production, for example a change in the
type of oil produced at a given screen might also be detected. This can be important
in flow assurance, especially for wells with long subsea tie-backs.
[0042] The construction of the screens described above also allows treatments to be provided
at the level of each individual screen because flow into the base pipe is all focused
through the chamber. Thus it is possible to exercise effective control at the individual
screen level to modify flow from the formation into the well. For example, in the
case described above, water breakthrough only occurs at screens S
4, S
7 and S
12. Therefore, shutting off those screens will allow the well to continue producing
oil only (and hence avoid the need for separators or the like) while only reducing
the production from the well marginally. This can be repeated each time water breakthrough
occurs until the reduction in overall production is sufficient to justify installation
of separators and producing the well as a mixture of oil and water (often involving
opening the shut off screens as well).
[0043] The local sensors in each screen can also be used to monitor the progress of treatment
fluids pumped through the well. In a typical subsea completion, the only way previously
to ensure accurate placement of a well treatment has been to locate a vessel over
the well head and perform a well intervention using a coiled tubing deployed into
the reservoir. This is a very expensive and time consuming operation. Using a completion
of the type described above, it is possible to pump a well treatment fluid down the
well from the surface and monitor its progress in real time using the local sensors
in each screen. Figure 8 shows such a process in a schematic form. The well in question
is a subsea well having a well head 250 on the sea bed 252 which is connected to a
production platform 254 by means of a pipeline 256 running along the sea bed 252.
The well extends down from the well head 250 in to the producing reservoir 258 where
it runs in an essentially horizontal path and is completed with instrumented screens
260 as described above. Although only one well is shown here, there may be multiple
wells connected to a single well head which will have valves allowing individual wells
to be isolated from the others.
[0044] In order to conduct well treatments, fluids are pumped into the well from the platform
254. This can be done from a treatment skid or the like located on the platform 254,
or, as is shown here, from a support boat 262 which connects to the pipeline 256 via
the platform 254. A slug of treatment fluid 264 is injected into the pipeline from
the boat 262 and is pumped down the well using a suitable fluid as is known in the
art. For example, the treatment in question can be an annular chemical packer which
includes a highly conductive chemical additive as a marker. As the slug 264 passes
each screen 260, a portion of the fluid enters the manifold 266 where its presence
causes a change in the reading from the sensor 268. Thus, by monitoring the measurements
from the screens 260, the progress of the slug 264 through the well can be determined.
This data can be represented in graphical form on a display unit 270 on the platform
254 or support boat 262 from which pumping is controlled. When the sensors 268 indicate
that the slug 264 has reached the screen identified in the previous monitoring step,
pumping can be stopped or the pump rate can be increased to shear the fluid so as
to decrease its viscosity and enable it to be pumped from the base pipe into the chamber
and screen. The fluid then sets and seal off production from the or each particular
screen.
[0045] An alternative form of control of flow through a screen can be obtained using the
sealing system installed in the chamber of each screen. One example of a sealing system
in accordance with an embodiment of the invention is shown in Figure 9. The sealing
system is located in the manifold 300 near to the point where the flow enters the
base pipe 302 and comprises a reservoir 304 containing a sealing fluid and a heating
coil 306 around the manifold 300 at that point that is connected to the data and power
network. In use, when it is desired to shut off a given screen, a signal is sent to
the relevant sealing system to cause an expandable sealing fluid to be released from
the reservoir 304. This can be done using a small detonator cap, electromagnetic device
or even by heating using the coil 306. This serves to rupture the reservoir which
releases the sealing fluid into the chamber where it expands. The heating coil 306
can then be used to set the fluid and prevent flow through the manifold 300. While
the objective is that the expanded sealing fluid should fill the chamber and prevent
fluid flow into the base pipe, it is often enough that the expanded fluid provide
sufficient flow restriction in the chamber that the pressure drop is too great for
fluid to flow. The pressure drop required for this is relatively small in many cases.
[0046] It is also possible to use the heating coil 306 to break the seal by raising the
temperature even higher provided that a suitable breakable sealing fluid is used.
This allows screens to be reopened in the future. Alternatively, a mechanical system
for reopening can be used.
1. A method of monitoring fluid production in a well, comprising:
- measuring over time local parameters at a series of locations along the well, each
local measurement being responsive to changes in the parameters in the region in which
it is made;
- measuring fluid properties in the well over time downstream from the series of locations;
and
- determining changes in the local measurements and in the measured fluid properties;
and
- identifying locations of the formation contributing to the changes in the measured
fluid properties by determining corresponding changes in the local measurements.
2. A method as claimed in claim 1, wherein each local measurement corresponds to a discrete
location at which formation fluids enter the well.
3. A method as claimed in claim 1 or 2, wherein the local parameter measurement is a
parameter that is affected by changes in the fluids flowing between the formation
and the well at this location.
4. A method as claimed in claim 3, wherein the local parameter measurement measures resistivity,
conductance, temperature, pressure or chemical composition.
5. A method as claimed in any preceding claim, wherein the sampling rate of the local
measurements is relatively high, particularly with respect to the flow rate of fluids
in the well, such that the time at which a change is measured at a specific location
can be identified relative to corresponding measurements at other locations.
6. A method as claimed in any preceding claim, wherein the fluid properties measured
downstream of the local measurements are flow rates
7. A method as claimed in claim 6, where the flow rates are volumetric flow rates.
8. A method as claimed in claim 6 or 7, wherein the flow rates measured at the downstream
location are used to quantify a change of flow into the well, the location of which
has been identified by the local measurement.
9. A method as claimed in claim 6, 7 or 8, comprising determining the physical location
of a local sensor which detects a change and determining the time between a change
being measured at the local sensor and a flow rate measured at the downstream location,
and confirming the flow rate measured downstream from these measured changes and time.
10. Apparatus for completing a well, comprising:
- an base pipe; and
- an permeable screen surrounding the base pipe and defining a chamber outside the
base pipe and inside the screen;
wherein the base pipe is provided with an apertured portion of limited axial extent
providing fluid communication between the chamber and the inside of the base pipe
such that fluid entering the chamber through the permeable screen passes into the
base pipe only via the apertured portion; and, in use, the screen and apertured portion
cause a relatively low pressure drop between the outside of the apparatus and the
inside of the base pipe.
11. Apparatus as claimed in claim 10, wherein the base pipe has a series of longitudinal
splines formed around its outer surface, the splines acting to support the screen
on the base pipe.
12. Apparatus as claimed in claim 11, wherein the splines are formed by wires fixed to
the outer surface of the base pipe.
13. Apparatus as claimed in claim 10, 11 or 12, comprising a collar section provided on
the base pipe near to the apertured portion, the collar defining a manifold that communicates
with the annular chamber and the apertured portion such that fluid flowing from the
annular chamber into the base pipe flows through the manifold.
14. Apparatus as claimed in claim 13, wherein the collar is located at one end of the
base pipe and a simple collar is located at the other end, the two collars defining
the ends of the permeable screen and annular chamber.
15. Apparatus as claimed in claim 13 or 14, wherein the collar includes a sensor system.
16. Apparatus as claimed in claim 13, 14 or 15, wherein the collar includes a sealing
system for closing off flow through the apertured portion.
17. Apparatus as claimed in claim 15 or 16, wherein the sensor system and/or sealing system
are provided with connections for a data and power network running through the well.
18. Apparatus as claimed in any of claims 13 - 17, wherein the apertured portion of the
base pipe is located in a part connecting two screen sections, the collar is located
at the end of one of the two screens and is connected to the connecting part by the
manifold.
19. Apparatus as claimed in any of claims 13 - 18, wherein the collar is provided with
ports between the annular chamber and the manifold and the base pipe provided with
one or more apertures connecting to the manifold.
20. A method of completing a well, comprising:
- installing a series of tubular members in the well connected in an end-to-end arrangement,
each tubular member comprising an elongate base pipe and an elongate screen surrounding
the base pipe and provided with multiple apertures distributed along its length, the
screen and the base pipe together defining an annular chamber between them,
wherein the base pipe is provided with an apertured portion of limited axial extent
providing fluid communication between the chamber and the inside of the base pipe
such that fluid entering the chamber through the permeable screen passes into the
base pipe only via the apertured portion.
21. A method of treating a well that has been completed by installing a series of tubular
members in the well connected in an end-to-end arrangement, each tubular member comprising
an elongate base pipe and an elongate screen surrounding the base pipe and provided
with multiple apertures distributed along its length, the screen and the base pipe
together defining an annular chamber between them, the base pipe being provided with
an apertured portion of limited axial extent providing fluid communication between
the chamber and the inside of the base pipe such that fluid entering the chamber through
the permeable screen passes into the base pipe only via the apertured portion, the
method comprising pumping a treatment fluid from the surface into the well while measuring
local parameters in each tubular member; detecting the arrival of the treatment fluid
from the measurement of local parameters; and ceasing pumping so as to leave the treatment
fluid in a region of the well to be treated.
22. A completion system, comprising:
- a tubular member for location in a well, the member including at least one opening
allowing communication between the interior and exterior of the member; and
- a closure system located adjacent the or each opening and including a source of
stored energy which, on activation, operates to close the or each opening.
23. A completion system as claimed in claim 22, wherein the openings in the tubular member
are confined to a region of limited axial extent.
24. A completion system as claimed in claim 23, wherein the openings are near a collar
on the outside of the tubular member.
25. A completion system as claimed in claim 22, 23 or 24, wherein the closure system can
be located in or on a manifold.
26. A completion system as claimed in claim 25, wherein the closure system comprises a
reservoir of expandable fluid and an activator.
27. A completion system as claimed in claim 26, wherein on operation, the activator ruptures
the reservoir and allows the fluid to enter the manifold where it expands to prevent
fluid flowing therethrough.
28. A completion system as claimed in claim 26, wherein the closure system comprises a
heating system for activating a sealing fluid pumped into the manifold from the surface.
29. A closure system as claimed in any of claims 22 - 28, wherein the closure system is
reversible to allow reopening.