Abstract
The downhole tool comprises: (i) a housing connected with a collection chamber for receiving debris, the housing having an opening for collecting the debris from the petroleum well, the opening in fluid communication with the collection chamber through the housing; (ii) a rotatable shaft with transport blades arranged within the housing and extending from the opening to the collection chamber, the rotatable shaft configured for transporting debris from the opening to the collection chamber in operational use; (iii) an annular area defined between the rotatable shaft and an inner wall of the housing and (iv) a valve configured for keeping debris in the collection chamber. The valve is located within the housing between the opening and the collection chamber. The valve comprises a seal member with a movable part mounted in the annular area and around the rotatable shaft. The valve is opened when the movable part moves in direction of the collection chamber and is configured such that the movable part of the seal member is only movable in the direction towards the collection chamber when closed. The downhole tool provides a valve, which is easily opened, requiring a very small force, while providing a very good sealing effect when the seal member is closed.
Claims
1. A downhole tool (100) for collecting debris in a petroleum well, the downhole tool (100) comprising: a housing (120) connected with a collection chamber (130-1, 130-2) for receiving debris, the housing (120) having an opening (105) for collecting the debris from the petroleum well, the opening (105) being in fluid communication with the collection chamber (130-1, 130-2) through the housing (120); a rotatable shaft (110b) with transport blades (119) arranged within the housing (120) and extending from the opening (105) to the collection chamber (130-1, 130-2), the rotatable shaft (110b) being configured for transporting the debris from the opening (105) to the collection chamber (130-1, 130-2) in operational use; an annular area (121) defined between the rotatable shaft (110b) and an inner wall of the housing (120), and a valve (125) configured for keeping the debris in the collection chamber (130-1, 130-2), characterised in that the valve (125) is located within the housing (120) between the opening (105) and the collection chamber (130-1, 130-2), wherein the valve (125) further comprises a seal member (125s) with a movable part (125sm) being mounted in the annular area (121) and around the rotatable shaft (110b), wherein the valve (125) is opened when the movable part (125sm) moves in direction of the collection chamber (130-1, 130-2), wherein the valve (125) is configured such that the movable part (125sm) of the seal member (125s) is only movable in the direction towards the collection chamber (130-1, 130-2) when closed, the valve comprises a contact surface (125cs) for the movable part (125sm) to seal against when closed; the inner wall of the housing (120) comprises a further edge (125e2) for forming the contact surface (125cs); wherein the seal member (125s) comprises a ring-shaped inner mounting ring (125r) for being mounted to the rotatable shaft (110b), wherein the movable part (125sm) is connected with the ring-shaped inner mounting ring (125r).
2. The downhole tool (100) as claimed in claim 1, wherein the seal member (125s) is configured for being substantially static either with respect to the rotatable shaft (110b) or with respect to the housing (120) when valve (125) is closed while the rotatable shaft (110b) is rotating in operational use of the downhole tool (100).
3. The downhole tool (100) as claimed in claim 2, wherein the seal member (125s) is mounted around and fixed to the rotatable shaft (110b) such that it rotates together with the rotatable shaft (110b) and relative to the housing (120) in operational use of the downhole tool (100).
4. The downhole tool (100) as claimed in claim 2, wherein the seal member (125s) is mounted around the rotatable shaft (110b) such that it may rotate relative to the rotatable shaft (110b) while being substantially static with respect to the housing (120) even when the rotatable shaft (110b) is rotating in operational use of the downhole tool (100).
5. The downhole tool (100) as claimed in claim 1, wherein the rotatable shaft (110b) comprises an edge (125e1) for forming the contact surface (125cs).
6. The downhole tool (100) as claimed in claim 1, wherein the movable part of the sealing member is configured as a pivotably mounted or bendable curved flap (125sm), which extends within the annular area (121) along at least part of the circumference of the seal member (125s).
7. The downhole tool (100) as claimed in claim 1, wherein the movable part of the sealing member is configured as a ring-shaped bendable disk (125smr) substantially covering the annular area (121).
8. The downhole tool (100) as claimed in claim 1, wherein the seal member (125s, 125s) has been made from flexible material, such as rubber, plastic, or other elastic or woven materials.
9. The downhole tool (100) as claimed in claim 1, wherein the seal member (125s) comprises a plurality of further movable parts (125sm) similar to the movable part (125sm), wherein said plurality of further movable parts (125sm) is distributed along a circumference of the seal member (125s).
10. The downhole tool (100) as claimed in claim 1, wherein the valve (125) further comprises a further housing comprising a further seal member similar to the housing (120) and the seal member (125s) and being displaced from the seal member (125s) and being mounted in the annular area (121) and around the rotatable shaft (110b) within the further housing.
11. The downhole tool (100) as claimed in claim 1, further comprising a plurality of collection modules (130-1, 130-2) for collecting debris.
Description
BRIEF INTRODUCTION OF THE DRAWINGS
(1) In the following is described examples of preferred embodiments illustrated in the accompanying drawings, wherein:
(2) FIG. 1a shows a downhole tool in accordance with a first embodiment of the invention;
(3) FIG. 1b shows an enlarged view of the downhole tool of FIG. 1a;
(4) FIG. 1c shows an enlarged view of FIG. 1b;
(5) FIG. 2a shows a part of a cross-sectional view of the downhole tool of FIG. 1a, wherein the valve is open;
(6) FIG. 2b shows a part of a cross-sectional view of the downhole tool of FIG. 1a, wherein the valve is closed;
(7) FIG. 3a shows a sealing element when in a closed position in accordance with an embodiment of the invention;
(8) FIG. 3b shows the sealing element of FIG. 3a when in an open position;
(9) FIGS. 4a-4d show different variant of the sealing element in accordance with other embodiments of the invention;
(10) FIG. 5 shows a downhole tool in accordance with another embodiment of the invention;
(11) FIG. 6a shows a part of a cross-sectional view of the downhole tool of FIG. 5, wherein the valve is open;
(12) FIG. 6b shows a part of a cross-sectional view of the downhole tool of FIG. 5, wherein the valve is closed, and
(13) FIG. 7 shows a sealing element in accordance with the downhole tool of FIG. 5.
DETAILED DESCRIPTION OF THE EMBODIMENTS
(14) The invention provides for a downhole tool for collecting debris having a valve, which does hardly need any force to open, while it ensures a good sealing when the tool is removed from a petroleum well. This will be further explained in the detailed description, which follows.
(15) FIG. 1a shows a downhole tool 100 in accordance with a first embodiment of the invention. The downhole tool 100 comprises a housing 120 with an opening 105 at the tip. In this embodiment the housing 120 forms a valve module 120 of the downhole tool 100, in series with a first collection module 130-1 and a second collection module 130-2, as illustrated. The first collection module 130-1 embodies a first collection chamber, and the second collection module 130-2 embodies a second collection chamber. From now on the collection modules 130-1, 130-2 will be referred to as collection chambers. The second collection module 130-2 may comprise a filter section as in this embodiment. In operational use of the downhole tool 100 the second collection module 130-2 may be connected to a rotation motor (not shown), which on its turn may be connected to a downhole tractor (not shown). A downhole tractor is generally used for bringing the downhole tool to its desired place, but also for providing push-and-pull power downhole and for providing anchoring function for the downhole tool 100. The rotation motor may be an electric motor. There may also be provided a damper unit (not shown) between the electric motor and the downhole tool 100 in order to achieve an increased tool performance. In alternative embodiments of the downhole tool 100 there may be more collection modules than shown in FIG. 1, all modules being connected in series and in fluid communication with each other. For more implementation aspects of the downhole tool, including its function and operation, reference is made to the patent application publication with number WO03/036020A1.
(16) FIG. 1b shows an enlarged view of the downhole tool of FIG. 1a. In this view the two collection chambers 130-1, 130-2 have been shortened for illustration purposes. This figure shows more clearly the tip of the tool. In the opening 105 there is provided an input screw 110a, which has a conical-shaped head 110ah for facilitating the collection of debris in the opening 105. It must be stressed that this input screw is just an example. Other types of input screws that look different may be used as well.
(17) FIG. 1c shows an enlarged view of FIG. 1b, wherein further details are more clearly visible. The figure shows that inside the housing 120 there is a transport screw 110b, which in this embodiment comprises of two parts 110b1, 110b2 having different lead or pitch. Around the transport screw 110b there is an annular volume 127 as illustrated. The transport screw 110b and the input screw 110a together effectively form the rotatable shaft 110 with transport blades. Between said two parts 110b1, 110b2 of the transport screw 110b there is provided a valve 125 in accordance with the invention. The annular volume is here defined as the volume after the valve 125 when seen from the opening 105. The use of an input screw 110a and a transport screw 110b is just an embodiment of the rotatable shaft with transport blades as mentioned in the claims. By no means is the invention limited to the use of screws for inputting or transporting the debris. The pitch (or lead) of the second part 110b2 of the transport screw 110b is preferably larger than of the first part (as shown), because this prevents accumulation of debris right after the valve, which facilitates the pushing of the debris through the valve 125.
(18) FIG. 2a shows a part of a cross-sectional view of the downhole tool of FIG. 1a wherein the valve is open. FIG. 2b shows a part of a cross-sectional view of the downhole tool of FIG. 1a wherein the valve is closed. These figures show further details of the downhole tool of the invention. The input screw 110a is mounted in the downhole tool 100 via bearings (not shown). Further is shown the transport blades 119, which in this embodiment extend into the collection chamber 130-1, but that is not essential, yet preferred. The radius of the rotatable shaft 110 and the transport blades 119 is typically smaller within the collection chambers 130-1, 130-2. Furthermore, in the second half part of the last collection chamber 130-2 there is typically no transport blades on the rotatable shaft in order to prevent that the downhole tool 110 stops collecting debris before the collection chamber 130-1, 130-2 is full.
(19) FIG. 2b illustrates what is meant with the word annular area 121 as mentioned in the claims, which is defined as the area between the (rotatable) shaft of the transport screw 110b. The valve 125 of the invention comprises a seal member 125s, which covers the annular area 121 (at the location of the valve 125). The seal members 125s comprises a movable part 125sm, which in this embodiment takes a significant part of the area of the seal member 125s, such that it can move over a relative large distance. In this embodiment the valve 125 further comprises an edge 125e1 formed in the housing 120 (also referred to as valve module) for forming a contact surface 125cs for the movable part 125sm of the seal member 125s when in the closed position (FIG. 2b). The valve 125 further comprises a further edge 125e2 formed in the rotatable axis of the transport screw 110b for also forming the contact surface 125cs for the movable part 125sm of the seal member when in the closed position (FIG. 2b).
(20) The downhole tool 100 as illustrated in FIGS. 2a and 2b functions as follows. When the input screw 110a is collecting debris in a petroleum well the debris (not shown) is transported by the first part 110b1 of the transport screw 110b towards the valve 125. There the debris will hit the movable part 125sm of the sealing element 125s. The sealing element 125s has been fixed to the transport screw 110b and rotates together with it. Therefore the movable part 125sm of the sealing element 125s will easily move outward. In this embodiment the movable part 125sm will conveniently rest in its open position on the threads 119 of the second part 110b2 of the transport screw 110b. This position is illustrated in FIG. 2a. The interesting effect in this position is that the movable part 125sm will not form any significant hindrance for the debris to be transported further into the collection chamber 130-1. This means that all forces will be used for rotating the screw and no significant force is used for opening the valve 125. The movable element 125sm will stay in the position of FIG. 2a until transport screw 110b stops rotating. As soon as that happens will the debris press the movable element 125sm back to the position of FIG. 2b against the contact surface 125cs, which seals of the annular area 121. The displacement of the movable part 125sm of the seal member 125s is illustrated by the two arrows d1, d2.
(21) FIG. 3a shows a photo of a seal member 125s when in a closed position in accordance with an embodiment of the invention. FIG. 3b shows the sealing element 125s of FIG. 3a when in an open position. The seal member 125s in this embodiment is made of rubber, but other flexible materials are also possible. The number of variations of designing a seal member 125s is enormous. The example illustrated has a ring-shaped inner ring 125r. The hole in this ring has been intentionally designed non-round such that it will not easily rotate relative to the rotatable shaft when mounted. The movable part 125sm in this embodiment is effectively defined by cutting the seal member 125s. Such cutting may be conveniently done with a water-cutting technique. Furthermore, a mounting hole 126 has been formed, which is used to fix the seal member 125 to a transport blade of the transport screw with a small screw (not shown). Other ways to fix the seal member to the transport screw are also possible.
(22) FIGS. 4a-4d show different variant of the sealing element in accordance with other embodiments of the invention. FIG. 4a shows the embodiment of FIGS. 3a and 3b. The figure illustrate how the piece of flexible material forming the seal member 125s may be cut in accordance with a cutting line 99. By cutting according to this cutting line 99 the movable part 125sm is defined. Simultaneously, an unmovable part 125sf of the seal member 125s is defined. The figure further illustrates the locations of the contact surfaces 125cs formed in the rotatable shaft and the housing/valve module (defined by the edge 125e1 and the further edge 125e2) with respect to the seal member 125s and the movable part 125sm. The embodiment illustrated in FIG. 4a provides for a movable element 125sm having a larger displacement in the open position. This embodiment fits best when the transport screw 110b has a lead being equal to its pitch (which is true for all single-start thread-forms).
(23) FIG. 4b shows an alternative embodiment. In this embodiment an alternative cutting line 99 is made which is longer in that it follows the circumference longer. In this way a movable part 125sm is made having a larger displacement in the open position, which allows more debris to be transported through the valve.
(24) FIG. 4c shows yet an alternative embodiment. Instead of forming one large movable part a plurality (here two) of movable parts 125sm is made by cutting in accordance with further alternative cut lines 99 as shown. This embodiment also allows for more debris to be transported through the valve than in the embodiment of FIG. 4a. Furthermore, this embodiment is very suitable to be used when the transport screw has double-started threadform, i.e. two threads intertwined with each other (but that does not need to be the case).
(25) FIG. 4d shows yet a further alternative embodiment, wherein four movable parts 125sm are formed by using further alternative cutting lines 99. This embodiment is suitable to be used when the transport screw has a quadruple-started threadform (but that does not need to be the case).
(26) FIG. 5 shows a downhole tool in accordance with another embodiment of the invention. This embodiment will be discussed in as far as it differs from the embodiment of FIG. 1. The main difference resides in the design of the valve as will be further explained with reference to the following drawings.
(27) FIG. 6a shows a part of a cross-sectional view of the downhole tool of FIG. 5, wherein the valve is open. FIG. 6b shows a part of a cross-sectional view of the downhole tool of FIG. 5, wherein the valve is closed. These drawings will be only discussed in as far as they differ from FIGS. 2a and 2b. The main difference resides in the design of the seal member 125s of the valve. The seal member 125s comprises a ring-shaped inner mounting ring 125r mounted around the rotatable shaft 110b such that it can rotate around the shaft 110b. The mounting ring 125 may be made from metal for example. Around the mounting ring 125r, here within a circumferential recess on the ring, there is provided a ring-shaped bendable disk 125smr. The ring-shaped bendable disk 125smr may be made from flexible material such as rubber, just like the seal member in accordance with FIGS. 1 to 4. FIGS. 6a and 6b illustrate that how the bendable disk 125smr may bend to open and close the valve respectively. The shape of the bendable disk 125smr has been further optimized to facilitate bending in the direction of the collection chamber 130-1 when debris is being collected. The most important difference with FIGS. 2a and 2b is that the disk 125smr is one piece, i.e. it has no cuts. Also important to note that the disk 125smr is sealing against both the mounting ring 125r as well as the contact service 125cs of the housing (here the valve module 120) when the valve is closed (FIG. 6b).
(28) FIG. 7 shows a sealing element in accordance with the downhole tool of FIG. 5. The figure shows the shape of the seal member 125s in a bit more detail. The ring-shaped bendable disk 125smr may be mounted to the mounting ring 125r by means of a moulding process for example. Such moulding process provides for a firm attachment between said parts 125smr, 125r.
(29) The downhole tool in accordance with FIGS. 5 and 6 operates as follows. When the valve is closed (FIG. 6b) the bendable disk 125smr is in grip with the housing 120, such that when the rotatable shaft 110 starts to rotate the seal member 125r does not rotate. In other words, the seal member 125r remains static with regards to the housing 120, while the seal member 125r rotates relative to the rotatable shaft 110. The advantage of this is that the seal member 125r does not wear out so fast. When the downhole tool collects debris (not shown) the debris will hit the seal member 125r at a certain moment and bend the bendable disk 125smr thereof as illustrated in FIG. 6a. Herewith the valve 125 is opened and the debris will be pushed further into the collection chamber 130-1. When the downhole tool is finished with collecting debris the rotatable shaft 110 is stopped and the debris, which is already in the collection chamber 130-1 will push the bendable disk 125smr back in its closed position (FIG. 6b).
(30) The description of the embodiments clearly illustrates that the valve in accordance with the invention is particularly simple in design and small in size. The valve covers the whole inner diameter of the collection chamber, while it has a very low building height. The low building height minimizes the distance between the input screws. A smaller distance between these screws leads to less energy that is required for pushing the debris through and beyond the valve. Moreover, a consequence of that is that more energy is available for filling the collection chamber. The downhole tool in accordance with the invention is thus very energy effective.
(31) The valve in accordance with the invention is also very cost effective. This is a result of the construction, the manner the valve is mounted, the material choice, etc. Furthermore, the valve is also very robust and durable. Before each usage, a simple visual inspection will be required to see if the valve needs to be replaced.
(32) The thickness of the seal member may be chosen dependent on the diameter of the downhole tool. The larger the required diameter of the seal member the larger the required thickness in order to avoid valve distortion. In any case, the design of the downhole tool may remain the same independent of the size.
(33) The material of the seal member may be adapted to the well conditions under which the downhole tool has to be operated. High temperatures or environments with high concentrations of gasses may influence some rubber types. Nevertheless, this problem may be solved by simply changing the material to another material (i.e. replacing the seal member with another seal member), which is capable of handling these different conditions.
(34) It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb comprise and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article a or an preceding an element does not exclude the presence of a plurality of such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
