MXPA00004072A - An apparatus for the removal of sand in an underwater well and use of a jet pump (ejector) in connection with such sand removal - Google Patents

Abstract

It has been given an account of a sand removing apparatus (2) for use in the lower area of underwater wells (1). The apparatus (2) which is intended to be suspended from the end of a pipe string, comprises, as known per se, a container (6) having a closeable inlet (12) for allowing a flow of liquid accompanied by sand (3) thereinto. It has been an object to increase the sand container's (6) degree of filling and, thus, capacity. To this end, the container (6) has a separate outlet (11) assigned the suction side of a pump (5) constituting the drive device for the apparatus (2). The drive device is kept going until the degree of filling of the container (6) has been achieved. Between a separate inlet (12) provided with a one-way valve (13, 14) and said separate outlet (11), a filter (15) is disposed, counteracting that sand sucked into the container leaves the same again through a circulating flow together with the carrier liquid. A special use for a liquid-driven jet pump (ejector) (5) is as drive device for such a sand removing apparatus (2).

Description

TIN APPARATUS FOR THE REMOVAL OF SAND IN A WELL - SUBMARINO AND USE OF A JET BOMB (EYECTOR) WITH RESPECT TO THAT REMOVAL OF SAND FIELD OF THE INVENTION • The invention relates to an apparatus for the removal of sand, especially in the lower area of the well, with respect to the extraction of oil or gas, the The apparatus comprises a displaceable container that receives sand, which has a lockable inlet for the sand flowing into the container, and an outlet for removing the sand from the container, subsequent to its displacement, to a suitable location. In the same way, the invention concerns the use of a jet pump (ejector) with respect to that sand removal.

BACKGROUND OF THE INVENTION In the production of oil and gas, a problem that constantly arises is that the sand breaks off and comes off the formation, accompanying the oil and / or gas inside the well. The sand that follows the flow of oil or gas, called sand produced, can cause great damage to production team, both inside and outside the well. The amount of sand produced increases as the flow rate increases, and an important measure against sand production is, therefore, to reduce the flow velocity. Measurement equipment has been developed to detect the sand produced, so that measures can be taken to reduce the amount of sand, before the production equipment has been damaged to such an extent that it has to be repaired. Additionally, it is common to reinforce the formations that easily release sand, for example by injecting sand to which a binder has been added, for example sand / gravel mixed with an adhesive agent of the type referred to as "adhesive gravel". Well-known filters of a plurality of types can also be installed in the well in order to prevent loose sand from accompanying the flow up and through the well. After some time in use, the bottom of the well is filled with loose sand, and it becomes increasingly difficult to maintain an acceptable flow velocity. In the maintenance of a well it is, therefore, usual to try to remove the loose sand accumulated at the bottom of the well. The loose sand can also result from drilling or other work that is done inside the well, and it is about removing that sand before production begins. A common way of removing sand is to circulate liquid inside the well. The liquid pumped down to the bottom of the well, through a set of coupled tubes, transports sand to the surface when returning through an annulus that is between the set of coupled tubes and the wall of the well. It is known to add a gas, for example nitrogen, to the liquid to increase the effect, but it has been found that it is difficult to remove sand satisfactorily in this manner. Also, it is known to collect sand by means of a container that has been lowered into the well to be filled with sand before it is raised up the well. The container is closed at the level of the surface (before it is lowered), so that it will contain air or other gas when it reaches the lower area of the well, where it will be carried out when the sand is removed. At the bottom of the well the container opens. This may result, for example, in that an actuator means included in the release mechanism for the closure body of the container inlet, which may be assigned to a return device towards the closed position, collides against the bottom surface of the well, thus opening the entrance for a flow of liquid through it, bringing sand with it. The pressure in the well, which is substantially greater than the pressure inside the vessel, causes an intense but brief flow of sandy liquid into the vessel. When the container is removed from the well and the actuating means of the releasing mechanism no longer rests against the bottom surface of the well, the entrance closes and the sand is transported upwards, to the surface, stored inside the container. The disadvantage of this known apparatus and the method of filling the container, is that the degree of filling is small and that the removal of sand, therefore, takes a long time. When the vessel partially filled with sand has reached the level of the surface, where the sand is going to be discharged, the discharge takes place through the entrance of this known apparatus, and in this way the inlet acts as an outlet in this phase of process.

SUMMARY OF THE INVENTION The object of the invention is to provide a simple and efficient apparatus for removing sand from a well. The object is achieved through features such as those defined in the following description and claims. An apparatus according to the invention comprises a container having two separate openings. An opening forms a separate inlet and is assigned to a one-way valve, such that the sandy liquid can flow into the container but not back out of the container. Between the inlet and the other opening forming a separate outlet, a filter is placed to retain the sand carried along with the circulating liquid flowing into the container. Through the establishment of a suction effect inside the container with the possibility of spillage for the liquid without sand, the sandy liquid can, in this way, be made to flow into the container at the entrance thereof, and cause the filtered liquid to flow towards the outside of the container at the exit of the same and, from the same, towards outside and inside the well. The outlet is assigned to the suction side of a pump, preferably a jet pump or ejector, driven by a flow of liquid supplied thereto from another pump. The container is lowered into the well and pulled upwards through a set of coupled tubes, for example, a threaded pipe, coupled to the jet pump. By supplying the jet pump with a liquid that flows forcefully through the coupled tube assembly, it causes a low pressure to build up inside the vessel. The liquid inside the well or liquid that operates the jet pump in the event that the well is filled with gas, picks up sand and flows into the vessel through the inlet. The filter prevents the sand from accompanying the liquid through the outlet and into the pump. The jet pump may be stopped, based on experience, after a predetermined time has elapsed, or upon the occurrence of a signal from a sensor that sends the signal when the container has reached an acceptable degree of filling. When the container is removed from the well, the single-pass valve prevents sand from falling through the inlet.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, the invention is further described by an exemplary embodiment, with reference to the accompanying drawings, in which: Figure 1 is a side elevational view, schematic, simplified, partially in vertical section, showing a well and an apparatus placed therein for the removal of sand; Figure 2 shows an axial section of the apparatus, on a larger scale. DETAILED DESCRIPTION OF THE PREFERRED MODALITY In Figures 1 and 2, the reference number 1 denotes the lower part of a well into which an apparatus 2 has been lowered in order to remove sand 3. The apparatus 2 is attached to a set of coupled tubes 4, for example in the form of a threaded pipe, adapted to driving liquid to a jet pump (ejector) 5 assigned to a vessel 6 for receiving and removing sand 3. As is known, the jet pump 5 comprises a housing 7. In the upper part, inside the housing 7 of the pump, is located a nozzle 8. The nozzle 8 is adapted to create a jet of liquid and pass it with a high speed towards an end of a channel 9 which, through one or more side gates 10, passes out of the housing 7. The cross-sectional area of the channel 9 increases with the increase in the separation of the nozzle 8, the channel 9 is assigned to at least one of those gates 10 conducting liquid through the wall of the housing 7 of the pump and outwardly, towards the well 1. The housing 7 is in connection with the container 6, through an outlet orifice 11 of the container 6. At the lower end thereof, the container 6 is provided with an opening 12 that forms an inlet for sandy liquid. A cap 13 that is rotatably attached to the container 6 by a hinge 14 is adapted to act as a single-pass valve, preventing liquid and sand from flowing out of the container 6 into the inlet 12. The housing 7 and the container 6 is filled with a liquid which will normally be the same liquid as that found in the well 1. In a well 1 filled with gas, the liquid supplied to the pump 5 will gradually fill the lower part of the well 1, so that the container 6 and the housing 7 are filled with liquid. In the area between the nozzle 8 and the channel 9, the liquid flowing out of the nozzle 8 and into the channel 9, takes liquid with it into the housing 7. The liquid that is pumped out of the housing 7 in this manner, it is replaced by liquid coming from the container 6. The liquid that flows inside the container 6 at the inlet 12 takes with it. sand 3 of the well 1. A filter 15 prevents the sand 3 from being carried into the housing 7 by the liquid flowing through the container 6. 'Gradually, the container 6 is filled with sand 3, and the pumping is completed, the lid 13 is then rotated downwards, about the axis (hinge) 14, taking the closed position, thus closing the inlet 12. The set of coupled tubes 4 carrying the apparatus 2, is removed out of the well 1, and the container 6 is discharged, leaving the sand 3 at a desired location (at a location on the surface), after which the apparatus 2 is possibly lowered into the well 1 once again. In order to provide the filter 15 with a large surface area relative to the need for filter space, inside the container 6, at the outlet 11 thereof, the filter may have the shape of a hollow, three-dimensional, cone-shaped body or pyramid, having a shape with tapering down, Figure 2. It will be clear, without mentioning that, with respect to an apparatus whose mode of operation is based on the suction action of a pump 5, in the container 6, and the circulation of the liquid transporting sand, towards the inlet 12 of the container, through the container 6, out of the exit thereof, after filtering the sand 3 and outwards and through one or more side gates 10 of the pump jet 5 operated with liquid (arrow 16, Figure 1) - a degree of filling can be achieved with respect to the container 6, close to 100% if this is desirable. Consequently, through the invention a substantial technical progress has been obtained with respect to the most relevant technique, described in the introduction of the specification. In practice, the degree of filling achieved / desired can be based on the time and experiences of various sand removal situations, where the jet pump 5 has to stop after a predetermined time has elapsed. Alternatively, a sensor can be mounted, for example at a level corresponding to the desired maximum level, of a quantity of sand. The sensor is driven, for example, physically, through the growing layer of sand, and is adapted to provide a signal that passes to the jet pump 5 and, possibly, also to the cover 13 of the single-pass valve, to cause the jet pump 5 to stop and the cap 13 to rotate and close the inlet 12 of the container. It has been found that the jet pump 5 used to effect suction of liquid mixed with sand (driven liquid 16, often in a mixture with liquid produced) to the displaceable container 6 and for the sand housing, of the sand removal apparatus 2, of the invention, possesses a higher efficiency and reliability than the actuator device of the invention. apparatus 2, such that the water-driven jet pumps 5 appear to maintain a unique position in the present respect. In this way, the invention consists, in addition to the combination of the constructive characteristics of the apparatus for the removal of sand, in a use of a jet pump (ejector) as an actuator device for the apparatus.

Claims (10)

NOVELTY OF THE INVENTION Having described the above invention, it is considered as a novelty, and therefore, the content of the following is claimed as property: CLAIMS

1. An apparatus for removing sand from a well, used with respect to the extraction of oil or gas, the apparatus comprises a displaceable container which accommodates sand and which has a lockable inlet, to allow a flow of sand to the container , together with a carrier fluid in the form of a liquid, an outlet connected to the suction side of a pump, a filter between the outlet and the inlet, and an outlet for the discharge of sand after recovery of the well apparatus, characterized in that the pump is a jet pump (ejector) driven by a carrier fluid flowing through a nozzle, into a channel through the suction area of the pump, then out of the pump through the gates; and because the channel is closer to the container than the nozzle.

2. An apparatus according to claim 1, characterized in that the separate inlet is provided with a one-way valve.

3. An apparatus according to claim 2, characterized in that the one-way valve is a butterfly valve. An apparatus according to claim 3, characterized in that the butterfly valve, which substantially has a rectangular circumferential shape, is pivotally positioned on an edge on an edge portion of the container defining one side of a rectangular valve opening which in addition corresponds to it. An apparatus according to any one of claims 1 to 4, characterized in that the separate inlet and the separated outlet are placed in two opposite side walls, for example a bottom wall and an upper wall in reference to the position of use, and because the filter is placed immediately adjacent to the outlet, its circumference extends radially outside the circumference of the outlet and is attached, in a hermetic manner to the sand, to the wall of the container in which it is located. departure. 6. An apparatus according to any of the preceding claims, characterized in that the filter, in order to provide a large surface area relative to the need for space thereof within the container has the form of a conical or pyramidal hollow body that is ahusa in a direction that moves away from the exit. 7. An apparatus according to any of the preceding claims, characterized in that the drive device of the apparatus in the pump form is assigned to a synchronized equipment unit which stops the pump and, therefore, cuts off the circulation of the liquid after a predetermined time has elapsed and corresponds to that which empirically represents a satisfactory degree of filling of the container. 8. An apparatus according to any one of claims 1 to 6, characterized in that the container is assigned to a sensor adapted to react to an increasing amount of sand inside the container, so that, when an amount is enclosed of sand corresponding to the desired degree of filling, generating a signal transferred to at least the pump or to the actuator means thereof, to stop the pump and put the apparatus out of operation. 9. The use of a jet pump (ejector) as a driving means for an apparatus for removing sand from an underwater well, wherein the sand removal apparatus assigned to the jet pump is adapted to be able to be connected to the free end of a set of tubes coupled, for example, in the form of a threaded pipe. 10. The use of a jet pump in the form of a liquid-driven pump the pressure side thereof is in liquid communication with the surroundings in a well through one or more side gates through the wall of the jet pump housing.