Device for treating drilling mud

Abstract

In a device for processing drilling mud, comprising a first screen as the first separation stage, a further separation stage, wherein a second minimum grain size of the further separation stage is smaller than a first minimum grain size of the first separation stage, and a connection via which the drilling mud freed from the first and second solids can be led out of the device, wherein the drilling mud freed from the second solids can be fed as flushing fluid to a flushing fluid storage tank, the flushing fluid storage tank having a first chamber and a second chamber, the two chambers being essentially separated from one another by a partition wall, but the partition wall having an opening connecting the two chambers, and wherein the device has a dirty water pump configured to pump dirty water out of the flushing fluid storage tank, it is proposed thatthat a circulation pump is arranged in the rinsing liquid storage tank, which is designed to circulate the water contained in the rinsing liquid storage tank within the rinsing liquid storage tank.,

Description

[0001] The invention relates to a device for processing drilling mud according to the preamble of claim 1.

[0002] A device of this type is known from DE 10 2021 000 568 A1.

[0003] The drilling mud produced during the operation of a directional drilling rig is conveyed in a conventional manner through a drain from the directional drilling rig to the device. The drilling mud contains water on the one hand and solids, particularly in the form of drilling cuttings, on the other. The drilling mud passes through several separation stages in which solids of different grain sizes are separated from the drilling mud, leaving behind water which, after each separation stage, contains fewer, particularly smaller, solids. The drilling mud conveyed from the directional drilling rig to the device initially contains comparatively large solids, which are separated from the drilling mud in the device's first separation stage. The remaining mixture of water and smaller solids can be referred to, for example, as dirty water.After one or more additional separation stages and the corresponding separation of increasingly larger and smaller solids from the water, the remaining water can be referred to as drilling fluid, which is pumped from the device to the drilling rig via a line called the inlet and can thus be reused as drilling fluid during drilling. The solids separated from the drilling mud can be collected either together or separately according to particle size fractions.

[0004] The generic device comprises a drilling fluid storage tank divided into different compartments by a partition wall. The different compartments serve to collect the water and the remaining solids after various separation stages. By means of one or more openings, the partition wall is fundamentally functional for retaining the coarser solids in a first compartment and thus separating the first from a second compartment. However, it also simultaneously enables a connection between the compartments. Ultimately, the multiple partial water streams must be combined to produce the total amount of drilling fluid that is to be pumped out of the drilling fluid storage tank and fed back to the drilling rig via a line known as the inlet.

[0005] This device has proven itself in practice, offering excellent drilling mud treatment despite its relatively simple design and compact dimensions, thus ensuring excellent reusability of the drilling fluid, which has been largely freed of solids. Due to its compact design, this device can be mounted on the platform of a light truck or on a trailer, making it suitable for use as a mobile drilling mud treatment plant.

[0006] The invention is based on the object of improving a generic device in such a way that it enables low-maintenance operation with long maintenance intervals.

[0007] This object is achieved by a device according to claim 1. Advantageous embodiments are described in the subclaims.

[0008] The invention relates to a device for processing drilling mud, comprising a first screen as the first separation stage for separating first solids with a first minimum grain size from the drilling mud, a further separation stage for separating second solids with a second minimum grain size from the remaining drilling mud, the second minimum grain size being smaller than the first minimum grain size, and a connection via which the drilling mud freed from the first and second solids can be led out of the device, the drilling mud freed from the second solids being feedable as flushing fluid to a flushing fluid storage tank, the flushing fluid storage tank comprising a first chamber and a second chamber, the two chambers being essentially separated from one another by a partition wall, but the partition wall comprising an opening connecting the two chambers,and wherein the device comprises a dirty water pump which is configured to pump dirty water out of the rinsing liquid storage tank, wherein a circulation pump is arranged in the rinsing liquid storage tank, which is configured to circulate the water contained in the rinsing liquid storage tank within the rinsing liquid storage tank.

[0009] In other words, the invention proposes a further development of the generic device. Therefore, reference is made to the description of the device and the processing method enabled by this device as shown in DE 10 2021 000 568 A1, so that the device need not be explained in detail again at this point. Instead, the differences from the generic design of the device that constitute the further development will be explained in particular.

[0010] In the drilling fluid storage tank, solids settle to the bottom of the drilling fluid storage tank. In particular, the dirty water that enters the first chamber of the drilling fluid storage tank after the first separation stage still contains a comparatively high proportion of solids, especially relatively large solids, since only the first, largest solids were separated from the drilling mud in the first separation stage. The sedimentation rate of these relatively large solids is comparatively high, since these solids can hardly be kept suspended in the water. A dirty water pump pumps the dirty water from the first chamber of the drilling fluid storage tank to a second separation stage.

[0011] To prevent the solids within the first chamber from growing to an undesirably thick layer outside the suction area of the dirty water pump, according to the invention a circulation pump is arranged within the flushing liquid storage tank, so that the water is circulated within the flushing liquid storage tank. In this context, a circuit does not necessarily refer to a closed circuit that returns the water to the circulation pump. Rather, a circuit in this context refers to a water flow that causes a practically complete flow through the flushing liquid storage tank, so that not only an O-shaped flow of a closed circuit, but also a U-shaped flow can represent a circuit within the meaning of the present proposal.

[0012] The solids that settle in the first chamber of the flushing liquid storage tank are thus kept in motion by the circulating water flow and thus fed to the dirty water pump. The growth of solids in the first chamber of the flushing liquid storage tank to an undesirably thick layer is thus automatically prevented, so that regular maintenance work, which would otherwise be required to remove solids from the first chamber of the flushing liquid storage tank, can either be completely eliminated or at least be performed at significantly longer maintenance intervals. Surprisingly, despite the additional technical component installed, the device is ultimately simpler, requiring less maintenance.

[0013] According to one embodiment, it can be provided that the circulation pump is arranged in the second space.

[0014] The circulation pump can be arranged in the first chamber of the flushing fluid storage tank, so that the desired circulating flow is generated within this first chamber. In one embodiment, however, the circulation pump is arranged in the second chamber. On the one hand, this facilitates the operation of the circulation pump, as it can be practically prevented that the circulation pump sucks in larger solids such as those found in the first chamber. Furthermore, a flow through the second chamber is also achieved, so that undesirable sedimentation can be avoided here as well, and maintenance work to remove the sediment can either be eliminated or only required at advantageously long intervals.

[0015] For further development, it can be provided that the opening in the partition wall connects to a bottom of the rinsing liquid storage tank.

[0016] The opening in the partition wall, which creates the desired connection between the first and a second space within the flushing fluid storage tank, can be designed as a circular bore surrounded by the material of the partition wall. In one embodiment, however, the opening connects to a bottom of the flushing fluid storage tank, so that sediments lying on the bottom can be captured by the water flow and no flow-related shadowing can occur below the opening, in which sediments could undesirably accumulate.

[0017] According to one embodiment, it can be provided that the opening is designed as a rectangular section of the partition wall.

[0018] The opening within the partition wall can be created particularly cost-effectively by designing it as a rectangular cutout in the partition wall. Especially if the opening adjoins the edge of the partition wall on two of its four sides, the opening can be created with just two straight cuts.

[0019] It can be particularly expedient to provide that the circulation pump is arranged near a first end of the partition wall and the opening is arranged near a second, opposite end of the partition wall.

[0020] To achieve the most complete flow possible through the flushing liquid storage tank or at least the space within the flushing liquid storage tank in which the circulation pump is arranged, the circulation pump is arranged in one embodiment near a first end of the partition wall, while the opening is preferably arranged remotely therefrom, near a second, opposite end of the partition wall. In this way, the water pumped by the circulation pump flows through the space practically along the entire length of the partition wall before the water flow can then pass through the opening in the partition wall into the adjacent space.

[0021] Advantageously, it can be provided that the dirty water pump is arranged in the first space and also near the first end of the partition wall.

[0022] With such an arrangement of the circulation pump and the opening, in one embodiment of the device, the dirty water pump is also arranged near the end of the partition wall opposite the opening, although the dirty water pump is arranged in the other chamber, namely the first chamber, while the circulation pump is located in the second chamber. In this way, an overall approximately U-shaped flow through the flushing liquid storage tank is achieved, with flow passing through both chambers on both sides of the partition wall over practically their entire length, so that the transport of settling solids to the dirty water pump can be achieved particularly effectively.

[0023] As an additional advantageous effect, the circulation pump in one embodiment of the device can also be used to pump so-called flushing water onto one or more screens that serve as separation stages of the device. For this purpose, the circulation pump can have a flushing connection through which the flushing water is pumped out of the circulation pump. The flushing water is the liquid that is pumped by the circulation pump, for example, the liquid that is particularly largely free of solids and that is located in the second chamber of the flushing fluid storage tank and is already intended as flushing fluid for the flushing drilling rig. The flushing water can assist in the removal of the solids located on the respective screen and counteract clogging of the screen meshes.

[0024] The invention is explained in more detail below using a purely schematic representation. Fig. 1 a plan view of an upwardly open flushing fluid storage tank of a device for processing drilling mud.

[0025] In Fig. 1 A device 1 is shown which basically corresponds to the device known from DE 10 2021 000 568 A1. Therefore, the same reference numerals are used for comparable components. The device 1 has a rinsing liquid storage tank 2, which is divided by a partition 20 into a first chamber 21 and a second chamber 22. The partition 20 consists of a flat plate placed at an angle in the rinsing liquid storage tank 2.

[0026] Two sieves with different mesh sizes (not visible in the drawing) are arranged above the two chambers 21 and 22. Above the first chamber 21 is a first sieve with a first mesh size, and above the second chamber 22 is a second sieve with a second mesh size that is smaller than the first mesh size of the first sieve.

[0027] Drilling mud containing water and solids flows from a directional drilling rig to the device 1 via a line designated as the outlet 11. The outlet 11 ends above the first screen and thus above the first chamber 21. The first, particularly large solids remain on the first screen, which is set into vibration by a vibration drive and is tilted so that these particularly large first solids are removed from the first screen. Depending on the design of the device 1, the first solids falling from the first screen can be collected in a collecting container or fall into a chute or onto a conveyor element so that they can be transported to a more distant location.

[0028] The portion of the drilling mud that has passed through the first screen and reached the first chamber 21 is referred to as dirty water. Depending on the mesh size of the first screen, this contains second, still comparatively large solids, which are, however, smaller than the aforementioned particularly large first solids. A dirty water pump 41 sucks the dirty water from the first chamber 21 and conveys it to a second separation stage of the device 1, not shown in the drawing. For example, this second separation stage can be formed by one or more cyclones, as described in DE 10 2021 000 568 A1. The second solids separated from the dirty water in this second separation stage are either fed into the above-mentioned collecting tank or collected as a separate fraction from the particularly large solids.

[0029] The portion of the drilling mud that has passed through the first two separation stages and has been freed from both the particularly large first solids and the aforementioned second, still comparatively large solids, reaches a third separation stage in the form of the comparatively fine-mesh screen, which is arranged above the second chamber 22. This screen is also designed as a vibrating screen, so that third solids retained on it are removed by this second screen and can either also be fed into the aforementioned single collecting container or collected as a separate fraction separate from the particularly large solids.

[0030] The portion of the drilling mud that has passed the third separation stage in the form of the second screen enters the second chamber 22 and contains only such small solid particles that it can be conveyed to the flushing drilling rig via a connection 10' and a line, which is referred to as the inlet, and can be used there as flushing fluid.

[0031] A circulation pump 45 is arranged in the second chamber 22, which pumps the rinsing liquid located in the second chamber 22 along the dividing wall 20 through the second chamber. The circulation pump 45 is located near a first end of the dividing wall 20, which is on the left in the drawing. The dividing wall 20 has an opening 23 in the form of a rectangular cutout at the opposite, right-hand end. This opening 23 extends to a bottom 46 of the rinsing liquid storage tank 2, so that a liquid flow sweeping over the bottom 46 is caused in the rinsing liquid storage tank 2, which liquid flow flows on the other side of the dividing wall 20, namely in the first chamber 21, in the opposite direction along the dividing wall 20, with water flow being indicated by arrows in the drawing.

[0032] At the end of an almost circular flow, namely again at the left-hand end of the partition wall 20, but in the first chamber 21, the water flow reaches the suction area of the dirty water pump 41. All solids transported by the water flow from both chambers 21 and 22 are therefore captured by the dirty water pump 21 and conveyed to the aforementioned second separation stage.

[0033] In the illustrated embodiment, the circulation pump 45 has a flushing connection 47 to which a flushing line can be connected. Rinsing water can be directed to the two screens via the flushing line to assist in removing the solids present thereon and to prevent clogging of the screen meshes.

[0034] The invention is not limited to one of the embodiments described above, but can be modified in many ways.

[0035] All features and advantages arising from the claims, the description and the drawings, including design details, spatial arrangements and method steps, can be essential to the invention both individually and in a wide variety of combinations. Reference symbols:

[0036] 1Device 2Rinsing liquid storage tank 10'Connection to inlet 11Outlet 20Partition wall 21First chamber 22Second chamber 23Opening 41Waste water pump 45Circulation pump 46Bottom of the rinsing liquid storage tank 47Rinsing connection

Claims

1. Device (1) for processing drilling mud, • with a first screen as the first separation stage for separating first solids with a first minimum grain size from the drilling mud, • with a further separation stage for separating second solids with a second minimum grain size from the remaining drilling mud, wherein the second minimum grain size is smaller than the first minimum grain size, • and with a connection (10') via which the drilling mud freed from the first and second solids can be led out of the device (1), • wherein the drilling mud freed from the second solids can be fed as flushing fluid to a flushing fluid storage tank (2), • the flushing fluid storage tank (2) has a first space (21) and a second space (22), • the two spaces (21, 22) are basically separated from one another by a partition wall (20), • the partition wall (20) has an opening (23) which separates the two spaces (21,22) with each other, • and wherein the device (1) has a dirty water pump (41) which is designed to pump dirty water out of the rinsing liquid storage tank (2), , characterized by that a circulation pump (45) is arranged in the rinsing liquid storage tank (2), which circulation pump is designed to circulate the water contained in the rinsing liquid storage tank (2) within the rinsing liquid storage tank (2).

2. Device (1) according to claim 1, characterized by that the circulation pump (45) is arranged in the second space (22).

3. Device (1) according to claim 1 or 2, characterized by that the opening (23) in the partition wall (20) connects to a bottom (46) of the rinsing liquid storage tank (2).

4. Device (1) according to one of the preceding claims, characterized by that the opening (23) is designed as a rectangular section of the partition wall (20).

5. Device (1) according to one of the preceding claims, characterized by that the circulation pump (45) is arranged near a first end of the partition wall (20), and the opening (23) is arranged near a second, opposite end of the partition wall (20).

6. Device (1) according to claim 2 and 5, characterized by that the dirty water pump (41) is arranged in the first space (21) and also near the first end of the partition wall (20).

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