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 rotary drilling rig is conveyed from the rig to the device via a drain in a manner known per se. The drilling mud contains water and solids, particularly drill cuttings. The drilling mud passes through several separation stages in which solids of varying particle sizes are removed, leaving behind water that contains fewer and, in particular, smaller solids after each stage. The drilling mud conveyed from the rotary drilling rig to the device initially contains relatively large solids, which are separated from the drilling mud in the first separation stage of the device. The remaining mixture of water and smaller solids can, for example, be referred to as wastewater.After one or more further separation stages and the corresponding removal of increasingly larger and smaller solids from the water, the remaining water can be called drilling fluid. This fluid is conveyed from the device to the drilling rig via a line called the inlet and can thus be reused as drilling fluid. The solids separated from the drilling mud can be collected either together or separately according to particle size fractions.

[0004] The device of this type features a flushing fluid reservoir tank divided into different compartments by a partition. These compartments serve to collect the respective water, along with any remaining solids, after various separation stages. While the partition, with one or more openings, is fundamentally functional in retaining the larger solids in a first compartment, thus separating it from a second, it also allows for a connection between the compartments. Ultimately, the various water streams must be combined to produce the total volume of flushing fluid that is to be pumped from the reservoir tank and returned to the drilling rig via a line referred to as the inlet.

[0005] The device of this type has proven its worth in practice, as it offers excellent drilling mud processing with a comparatively simple design and compact dimensions, thus enabling very good reuse of the drilling fluid, which is largely free of solids. Due to its compact design, the device can be mounted on the platform of a light truck or on a trailer and therefore used as a mobile drilling mud processing plant.

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

[0007] This problem is solved by a device according to claim 1. Advantageous embodiments are described in the dependent claims.

[0008] The invention relates to a device for processing drilling mud, comprising a first screen as a 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, wherein the second minimum grain size is smaller than the first minimum grain size, and a connection through which the drilling mud freed from the first and second solids can be discharged from the device, wherein the drilling mud freed from the second solids can be supplied 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 fundamentally separated from each other by means of a partition, the partition, however, having an opening which connects the two chambers.and wherein the device comprises a wastewater pump which is configured to pump wastewater out of the flushing liquid storage tank, wherein a circulation pump is arranged in the flushing liquid storage tank which is configured to circulate the water contained in the flushing liquid storage tank within the flushing 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 made possible by this device as shown in DE 10 2021 000 568 A1, so that the device does not need to be explained again in detail here, but rather the differences that constitute the further development compared to the generic design of the device will be explained.

[0010] In the drilling fluid storage tank, solids settle to the bottom. The wastewater, in particular, which enters the first compartment of the storage tank after the first separation stage, still contains a comparatively high proportion of solids, especially relatively large solids, since only the largest solids were removed from the drilling mud in the first separation stage. The sedimentation rate of these relatively large solids is comparatively high because they are difficult to keep suspended in the water. A wastewater pump transfers the wastewater from the first compartment of the storage tank to a second separation stage.

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

[0012] The solids that settle in the first compartment of the flushing fluid reservoir are kept in motion by the circulating water flow and thus conveyed to the wastewater pump. This automatically prevents the solids in the first compartment from accumulating to an undesirably thick layer, so that regular maintenance work, which would otherwise be required to remove the solids from the first compartment, can either be completely eliminated or at least only needs to be carried out at significantly longer intervals. Surprisingly, despite the additional technical component, the system ultimately becomes simpler and requires less maintenance.

[0013] According to one embodiment, the circulation pump can be arranged in the second room.

[0014] The circulation pump can be located in the first chamber of the rinsing fluid reservoir, thus generating the desired circulating flow within this first chamber. However, in one embodiment, the circulation pump is located in the second chamber. This simplifies the operation of the circulation pump, as it practically prevents the pump from drawing in larger solids, such as those found in the first chamber. Furthermore, it also ensures flow through the second chamber, thus preventing unwanted sedimentation and either eliminating the need for maintenance work to remove sediment or reducing its frequency to advantageously long intervals.

[0015] For further development, it may be provided that the opening in the partition wall connects to the bottom of the flushing fluid storage tank.

[0016] The opening in the partition wall, which creates the desired connection between the first and a second chamber within the flushing fluid reservoir tank, can be designed as a circular bore, completely enclosed by the partition wall material. In one embodiment, however, the opening abuts the bottom of the flushing fluid reservoir tank, so that sediments lying on the bottom can be picked up by the water flow and no flow-related shadowing can occur below the opening where sediments could accumulate undesirably.

[0017] According to one embodiment, the opening can be designed as a rectangular cutout in 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. Especially if the opening abuts the edge of the partition wall on two of its four sides, it can be created with just two straight cuts.

[0019] It may be particularly advantageous to arrange the circulation pump near a first end of the partition wall, and the opening near a second, opposite end of the partition wall.

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

[0021] It may be advantageous to arrange the wastewater pump in the first room and also near the first end of the partition wall.

[0022] In one embodiment of the device, with the circulation pump and the opening arranged in this way, the wastewater pump is also positioned near the end of the partition opposite the opening. However, the wastewater pump is located in the other chamber, namely the first chamber, while the circulation pump is located in the second chamber. This achieves an approximately U-shaped flow pattern through the flushing fluid reservoir, with the flow passing through both chambers along virtually their entire length on both sides of the partition. This ensures particularly effective transport of settled solids to the wastewater pump.

[0023] As an advantageous additional effect, in one embodiment of the device, the circulation pump can also be used to pump so-called flushing water onto one or more screens that serve as separation stages within the device. For this purpose, the circulation pump can have a flushing port through which the flushing water is pumped out of the pump. The flushing water is the liquid pumped by the circulation pump, for example, the liquid that is particularly free of solids and is located in the second compartment of the flushing fluid reservoir, and which is already intended as flushing fluid for the drilling rig. The flushing water can assist in removing the solids from the respective screen and prevent clogging of the screen mesh.

[0024] The invention is explained in more detail below with reference to the purely schematic representation. This shows Fig. 1 a top view of an upwardly open flushing fluid reservoir of a device for processing drilling mud.

[0025] In Fig. 1 A device 1 is shown which is essentially identical 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 reservoir 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 positioned at an angle within the rinsing liquid reservoir 2.

[0026] Above the two chambers 21 and 22, two sieves with different mesh sizes are arranged, though these are not visible in the drawing. 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 is conveyed from a rotary drilling rig to the device 1 via a line designated as outlet 11. Outlet 11 terminates above the first screen and thus above the first chamber 21. Initial, particularly large solids remain on the first screen, which is vibrated by a vibration drive and is inclined so that these particularly large solids are discharged from the first screen. Depending on the design of the device 1, the initial solids falling from the first screen can be collected in a receiving container or fall into a trough or onto a conveying device 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 entered the first chamber 21 is referred to as wastewater. This wastewater contains, according to the mesh size of the first screen, second, still comparatively large solids, which, however, are smaller than the aforementioned particularly large first solids. A wastewater pump 41 draws the wastewater from the first chamber 21 and conveys it to a second separation stage of the device 1, which is 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, which have been separated from the wastewater in this second separation stage, are either directed into the collection container mentioned above or collected separately from the particularly large solids as a separate fraction.

[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, proceeds to a third separation stage in the form of a relatively fine-mesh screen, which is located above the second chamber 22. This screen is also designed as a vibrating screen, so that any third solids retained on it are removed by this second screen and can either be directed into the single collection container mentioned above or collected separately from the particularly large solids as a separate fraction.

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

[0031] A circulation pump 45 is arranged in the second chamber 22, which pumps the rinsing fluid located in the second chamber 22 along the partition 20 through the second chamber. The circulation pump 45 is located near a first end of the partition 20, which is on the left in the drawing. The partition 20 has an opening 23 in the form of a rectangular cutout at its opposite, right end. This opening 23 extends to a base 46 of the rinsing fluid reservoir 2, thus creating a fluid flow across the base 46 in the rinsing fluid reservoir 2. This flow then travels in the opposite direction along the partition 20 on the other side of the partition 20, namely in the first chamber 21, where the water flow is indicated by arrows in the drawing.

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

[0033] In the illustrated embodiment, the circulation pump 45 has a flushing port 47 to which a flushing line can be connected. Flushing water can be directed via the flushing line onto the two screens to assist in the removal of the solids located on them and to prevent clogging of the screen mesh.

[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 drawing, including design details, spatial arrangements and process steps, can be essential to the invention both individually and in various combinations. Reference symbol:

[0036] 1 Device 2 Flushing fluid reservoir tank 10 Connection to inlet 11 Outlet 20 Partition wall 21 First room 22 Second room 23 Opening 41 Wastewater pump 45 Circulation pump 46 Bottom of flushing fluid reservoir tank 47 Flushing connection

Claims

1. Device (1) for treating drill sludge, • having a first screen as first separation stage for separating first solids with a first minimum particle size from the drill sludge, • having a further separation stage for separating second solids with a second minimum particle size from the remaining drill sludge, wherein the second minimum particle size is smaller than the first minimum particle size, • and having a connector (10') by way of which the drill sludge relieved of the first and second solids is able to be directed out of the device (1), • wherein the drill sludge relieved of the second solids is able to be supplied as flushing liquid to a flushing liquid receiving tank (2), • the flushing liquid receiving tank (2) has a first space (21) and a second space (22), • the two spaces (21, 22) are fundamentally separated from one another by way of a partition wall (20), • the partition wall (20) however has an opening (23) which connects the two spaces (21, 22) to one another, • and wherein the device (1) has an effluent pump (41) which is specified to convey effluent out of the flushing liquid receiving tank (2), characterized in that disposed in the flushing liquid receiving tank (2) is a circulation pump (45) which is specified to convey the water located in the flushing liquid receiving tank (2) so as to circulate within the flushing liquid receiving tank (2).

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

3. Device (1) according to Claim 1 or 2, characterized in that the opening (23) in the partition wall (20) adjoins a base (46) of the flushing liquid receiving tank (2).

4. Device (1) according to one of the preceding claims, characterized in that the opening (23) is configured as a rectangular cut-out of the partition wall (20).

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

6. Device (1) according to Claim 2 and 5, characterized in that the effluent pump (41) is disposed in the first space (21) and likewise close to the first end of the partition wall (20).

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