EP3231983B1 - Process for the treatment and recycling of drilling mud - Google Patents

Description

The invention relates to a method for the preparation and at least partial recycling of drilling mud that occurs during an earth drilling.

When drilling earth bores (for example horizontal bores or vertical bores, such as bores for thermal probes), drilling fluids are used that are pumped into the borehole via the drill head. The drilling fluids are composed of various substances, the main component of which is usually water. Bentonite is usually used as an aggregate, which forms a suspension together with the water content. In addition, drilling fluids contain additional additives that are adapted to the subsoil to be drilled. The task of the drilling fluids is to cool and lubricate the drilling head, stabilize the drilling channel and remove the soil. To complete the borehole, the used drilling fluid is pumped out of the borehole again and then contains material from the borehole. The material from the borehole can also include pollutants such as heavy metals or leached contaminated sites.

So far, the drilling mud has been spread on agricultural land, or stored entirely in landfills, at great expense. Since the specific composition of the drilling mud is unknown, application to agricultural land is ultimately an incalculable risk.

Out DE 197 45 766 A1 a sludge processing station for a tunnel boring machine is known, the strut tip of which consists of sludge compacted by pressure.

U.S. 4,635,735 A discloses an oil drilling apparatus in which drilling mud is continuously examined for hydrocarbons by analyzing gas deposits from the drilling mud. The aim of this is to locate oil and gas when drilling.

US 2010/193249 A1 discloses a closed circuit of drilling fluid in the production of a well.

EP 2 530 237 A1 also describes a drilling process with a closed circuit in which drilling mud is recycled as far as possible at the drilling machine.

The object of the present invention is therefore to propose a way of at least partially recycling the drilling sludge that arises during drilling work.

To solve this problem, the invention proposes a method according to claim 1, which is also explained in more detail in the description of the figures.

The approach according to the invention is not only limited to the method, as just stated, but also includes a processing system for processing drilling sludge that occurs during an earth drilling, the processing system having at least one input bunker, at least one processing or separation stage for separating the soil or . Comprises rock components from the drilling mud and a drilling fluid template.

Furthermore, the approach according to the invention comprises a system for the processing and at least partial recycling of drilling mud that occurs during an earth drilling, which is used in particular to carry out the method according to the invention, the system being a processing plant as just specified, a drilling device that collects the drilling mud that occurs in a collector and has a transport means which is used to transport drilling fluid held in the processing plant to the drilling device at the location of the earth drilling and to transport drilling mud collected in the collector of the drilling device to the processing plant.

The invention proposes a third way of using the drilling mud. It is a complete recycling process, which is described by the process, the processing plant and the system, for the processing and at least partially Recycling of the drilling sludge produced during earth drilling. Several positive effects are in the foreground:
First, the precious water is used several times in the described elimination process, which conserves this natural resource.

The recycling process also produces bentonite that is either excreted as bulk goods or, because it is dissolved in the water, is still in the drilling fluid after the recycling step. The proposal according to the invention therefore also reduces the consumption of bentonite, since this additive is also used several times.

The drilling fluid supply is advantageously located at the processing plant, which means that the transport vehicles used are always loaded, once with prepared drilling fluid to the construction site and on the way back with (contaminated) drilling mud. The central processing plant guarantees a high processing quality. The processing plant can be capacitively designed so that effective process control is possible, which is also the basis for an economically successful concept.

The separated soil or rock components are cleverly stored in the area of the processing plant and can be reused there, for example, as building materials, for example in road construction and the like. Since the constituents have different grain sizes, mechanical separation will be carried out with a large number of sieves and the like; the fractionation of the material that takes place in this way is advantageous for the further use of these materials.

The central use of a processing plant also allows a complete documentation of the utilization of the drilling sludge created at the construction site and thus also ensures that this material is not spread on agricultural land, for example, and then possibly ends up in the food chain.

The system according to the invention also ensures that the drilling mud that arises is actually disposed of by the construction site, since the data documentation means that it is known what amount of drilling fluid was delivered there.

The proposal according to the invention combines an economically viable concept with a high level of environmental protection in a simple and convincing manner.

Furthermore, the proposal advantageously provides that drilling mud delivered to the processing plant is analyzed, and depending on the analysis result either a separation of the soil or rock components from the drilling mud, a separation of the soil or rock components from the drilling mud and a subsequent one Conditioning of the soil or rock components or conditioning of the drilling mud and subsequent disposal takes place.

Depending on the analysis provided on the input side, which is carried out in an analysis stage, the further processing, preparation or separation of the drilling mud then takes place. In a first variant it is provided that, if the analysis reaches a harmless result, only one (for example mechanical) separation of the soil or rock components from the drilling mud takes place. If a substance is discovered during the analysis that excludes conventional processing, there are basically at least two further variants for the further procedure. Often times the harmful ingredient is non-volatile i.e. suitably separable from the water, which makes up the majority of the drilling mud, and in a first variant the soil or rock components are separated from the drilling mud, for example with the help of a thermal separation step, and then the remaining soil or rock components are carried out with it conditioned to the pollutant.

Conditioning is understood to mean the addition of a binding agent and the processing of the drilling mud into a solid that cannot be washed out, for example a concrete, that is, under certain circumstances, an otherwise usable product. Alternatively, this resulting solid can also be disposed of.

The analysis provided here takes place in an automated step, paying attention to common pollutants such as heavy metals, etc.

In terms of system engineering, this is preferably implemented in such a way that an analysis stage is provided in the conveying direction of the drilling mud before, in or after the input bunker, and the drilling mud is fed to different processing or separation stages for processing depending on the analysis result.

Usually the delivered drilling mud is stored in the input bunker, which represents a corresponding work supply for the processing plant. It can be advantageous for the analysis to be carried out before the loading into the entry bunker, for example in order to take the delivered cargo to another location after the analysis and to feed it there for processing. Alternatively, it is of course possible that the analysis or analysis stage in or after the input bunker is provided, and then depending on the analysis result, quasi in the river, the drilling mud is fed to one or the other processing.

It is provided that conditioning takes place by adding a binding agent, such as in particular cement, lime or a cement-lime mixture. Surprisingly, it has been found that this binding agent does not impair the setting of the drilling mud to form a product with the usual concrete strength. This is all the more astonishing as the drilling mud contains bentonite, which binds a lot of moisture and also contains other additives such as polymers, etc. A concrete produced in this way can no longer be washed out chemically, which in particular improves its landfill and storability, but also its further use, for example as a building material or aggregate in road construction, or as liquid soil in sewer construction, etc.

By varying the proportions of drilling mud, cement and / or lime, water and other additives, you can influence the strength and density of the end product. With a larger proportion of cement, a stronger concrete is obtained, a landfill concrete is obtained with a mass of 120-200 kg cement per ton of drilling mud. With such conditioning of the drilling mud, no wastewater is produced.

According to the invention, the use of cement, lime or a lime-cement mixture for conditioning of drilling mud that is produced during earth drilling, in particular containing bentonite and mixed with soil or rock components, is proposed. This proposal also solves the problem set at the beginning, because it provides a means for reusing the drilling mud at least partially, for example as aggregate or building material.

It is preferably proposed that approx. 5-25% [wt.] Cement, lime or a lime-cement mixture, based on the mass of the drilling mud, is used for conditioning the drilling mud.

In particular, an interval is specified for the proportion of cement, lime or a lime-cement mixture in the use according to the invention, which is described by an upper and lower limit.

For example, the following values are provided as the lower limit: 5, 8, 10, 12,% [weight] based on the mass of the drilling mud.

The following values, for example, apply as the upper limit: 15, 18, 20, 22, 25% [weight] based on the mass of the drilling mud.

The disclosure of this application encompasses the set of all of the intervals formed by all possible combinations of the aforementioned upper and lower limits.

The lime-cement mixture has the following mixing ratios.

The proportion of lime in the mixture is also described by an interval:
The following values, for example, are provided as the lower limit: 5, 10, 15, 25, 35, 40% [weight] based on the mass of the mixture.

For example, the following values are provided as the upper limit: 30, 40, 50, 60, 65, 75, 85, 90% [weight] based on the mass of the mixture.

The proportion of cement in the mixture is also described by an interval:
For example, the following values are provided as the lower limit: 5, 10, 15, 25, 35, 40% [weight] based on the mass of the mixture.

For example, the following values are provided as the upper limit: 30, 40, 50, 60, 65, 75, 85, 90% [weight] based on the mass of the mixture.

The disclosure of this application encompasses the set of all intervals defined by all possible combinations of the aforementioned upper and lower limits. According to the invention, the mixture can also have further constituents, which is why the two proportions do not necessarily have to total 100%. It is clear that the disclosure excludes such variants which in the sum of the individual components exceed 100%.

It is also provided that the drilling mud is separated by a thermal separation stage. Although this separation stage is relatively energy-intensive, it leads to a considerable reduction in material, ie mass, which is particularly advantageous for a subsequent landfill. The thermal separation stage is also used if a pollutant was found during the analysis provided on the input side, which, for example, can only be isolated in a suitable manner by the thermal separation stage.

It is provided that the water evaporated in the thermal separation stage is condensed and the condensation heat released in the process is used to preheat the drilling mud. With such a configuration, at least part of the energy used is recovered and the water is not lost, in particular because the condensed water from the thermal separation stage is advantageously fed to the drilling fluid reservoir.

In a further preferred embodiment it is provided that the composition of the drilling fluid is monitored in the drilling fluid reservoir and, if necessary, drilling fluid suspension agent is added in a controlled manner. Such a procedure ensures that the drilling fluid that is kept available has a sufficient and guaranteed quality. It cannot be ruled out that the preparation of the drilling mud also removes drilling fluid suspension medium from the drilling mud or the liquid, which is then disadvantageous in further use.

It is also provided that the drilling mud is separated mechanically, in particular by sieving or centrifuging. Such processing is more cost-effective and is particularly useful if no harmful pollutants were found during the analysis.

According to the invention it is provided that when the soil or rock components are separated from the drilling mud, the precipitated or rock components are stored. Storage within the meaning of the invention is, for example, that mechanically or thermally separated constituents of the drilling mud are conditioned and deposited.

In the context of the invention, it can alternatively be seen that mechanically or thermally separated components of the drilling mud are reused as building materials. This also describes the storage of the separate components.

In addition, the invention also encompasses the fact that the separate components, sorted according to grain size and / or intended use, are stored as bulk goods or packaged sacked goods or the like.

In this context, it is pointed out in particular that all the features and properties described in relation to the processing plant, but also procedures, can also be transferred and used in the context of the invention and are also disclosed as being co-disclosed. The same also applies in the opposite direction, that is, structural features that are device-related features mentioned only in relation to the method or use can also be used within the framework of the claims for the processing plant or the system are taken into account and claimed and are also part of the disclosure.

Furthermore, it is pointed out in particular that all the features and properties described in relation to the processing plant, but also procedures, can be applied in the same way with regard to the formulation of the system according to the invention and can be used within the meaning of the invention and are also disclosed. The same also applies in the opposite direction, which means that features mentioned only in relation to the system can also be taken into account and claimed within the scope of the claims for the processing plant and are also part of the disclosure.

Furthermore, it is pointed out in particular that all the features and properties described in relation to the system, but also procedures, can also be transferred and used in the sense of the invention and are also disclosed as being co-disclosed.

Furthermore, it is pointed out in particular that all the features and properties described with regard to the use, but also procedures, can be applied in the same way with regard to the formulation of the method according to the invention and can be used within the meaning of the invention and are also disclosed. The same also applies in the opposite direction, that is, features that are only mentioned in relation to the method and that describe the use can also be taken into account and claimed for the use within the scope of the claims and are also part of the disclosure.

Fig. 1

in einer schematischen Ansicht das erfindungsgemäße Verfahren

In the drawing, the invention is shown schematically in particular in one embodiment. Show it:

Fig. 1

the method according to the invention in a schematic view

In the figure, elements that are the same or that correspond to one another are each designated by the same reference symbols and are therefore not described again unless expedient. The disclosures contained in the entire description can be applied analogously to the same parts with the same reference symbols or the same component names. The position details chosen in the description, such as for example above, below, to the side, etc., refer to the figure immediately described and shown and are to be transferred accordingly to the new position in the event of a change in position. Furthermore, individual features or combinations of features from the different ones shown and described can also be used Represent exemplary embodiments for themselves independent, inventive or inventive solutions.

In the Figure 1 the entire circuit of the drilling fluid is shown schematically. The illustration begins with the filling of the storage container 23 on the drilling device 2 with fresh drilling fluid, which was delivered here by the means of transport 3, 3a. The fresh drilling fluid is then fed from the storage tank 23 to the drilling device 2 via the line 21 for cooling and lubrication, as described, when the drilling device 2 (an exemplary horizontal drilling device) is in operation. Used drilling fluid is collected as drilling mud via the line 22 in the collector 20 and collected there until the means of transport 3, 3b picks it up there, which is consequently the same means of transport 3, 3a that previously filled the fresh drilling fluid into the reservoir 23.

In the next step, the transport means 3, 3c drives the drilling mud removed from the collector 2 to the input bunker 10 of the processing plant 1. Before, in or after the input bunker 10 is the analysis stage 11, in which an analysis of the delivered drilling mud is carried out and based on this analysis result a decision is made as to how the delivered drilling mud is processed with the aid of the various separation stages 12, 12a, 12b, 12c. On the output side of the input bunker 10, there is therefore a discharge line 13, to which the various separation stages 12, 12a, 12b, 12c can be connected by shut-off valves 14a, 14b and 14c. It is also provided that an automatically operating analysis stage 11 acts on the respective shut-off valves 14a, 14b, and 14c by means of corresponding actuating elements, and thus allows an automated flow of the drilling mud.

Along the discharge line 13 there are various separation stages 12, 12a, 12b, 12c, which are used according to the degree of contamination of the drilling mud supplied. For example, the first separation stage 12a is used for heavily soiled or contaminated drilling mud, in the direction of flow of the drilling mud in the drainage line 13, the second separation stage 12, 12 b for less soiled or contaminated drilling mud, and the last separation stage 12, 12 c only serves to separate the soil with a mechanical dominance - and rock components of drilling mud that is not contaminated per se. Therefore, the different concepts for the preparation or separation of the drilling mud fed into the separation stages differ from one another.

The first separation stage 12, 12 a conditions the drilling mud in such a way that it can be stored in the landfill 4. The conditioning takes place by adding binding agent via the filling area 15 at the separation stage 12a. The binding agent, for example lime, cement or a lime-cement mixture, leads to a concrete-like bond between the drilling mud and the For example, it can be landfilled, as pollutants can no longer be washed out of them.

The second separation stage 12b is designed as a thermal separation stage and reduces the mass and volume of the drilling mud by evaporating the water in the drilling mud. A water vapor cloud 16 is therefore also indicated here and the separation stage 12b comprises a heater 17. Instead of losing the evaporated water in a water vapor cloud 16, provision is also made for the evaporated water to be condensed back in a heat exchanger and then fed to the drilling fluid reservoir 19 via line 18 .

The third separation stage 12c is also connected to the drilling fluid reservoir 19 via a line 100. This third separation stage 12c is designed as a mechanically acting separation stage. In the case of a mechanically acting separation stage 12c, mechanical concepts are used which, for example, use gravity, different masses or different grain sizes of the constituents for a division / separation. The separation stage 12c therefore comprises, for example, one or more components of the following group: vibrating sieve, cyclone, sieves, shakers, centrifuges (although this list is not exhaustive). Cleverly, this separation stage also comprises several components of the above-described group arranged one behind the other. The reference number 5 denotes a heap of rubble of the soil and rock components that occur as bulk material and are produced in this separation stage 12c. This material can be reused, for example, as building material in road construction or as an aggregate in other applications.

The drilling fluid reservoir 19 holds new, ready-mixed drilling fluid intended for use, which is then filled into the transport vehicle 3, 3d as required in order to transport it to the construction site where the drilling device 2 is located.

A mixer 101 is provided in the drilling fluid reservoir 19, which ensures that the prepared drilling fluid is homogenized. A sensor 102 is provided which monitors the quality of the drilling fluid held in reserve and in particular monitors the proportion of drilling fluid suspension medium. If the proportion of drilling fluid suspension medium is too low, then the drilling fluid suspension medium is refilled from the supply 103. This can also be done automatically. The mixer 101 ensures a uniform distribution of the newly introduced drilling fluid suspension agent.

As a means of transport 3, a tanker vehicle is seen in this overview, but without restricting the invention, in particular the system according to the invention, to this. It is clear that a container transporter is also provided instead of a tanker as the means of transport 3, who unloads or loads the corresponding containers at the construction site or the processing plant 1.

Claims (9)

1. Method comprising the following steps:

   - filling a storage container (23) on a drilling device (2) with fresh drilling fluid, which is delivered by a means of transport (3, 3a);

   - supplying the fresh drilling fluid from the storage container (23) during operation of the drilling device (2) via a line (21) for cooling and lubrication;

   - catching and collecting used drilling fluid as drilling mud in a collector (20) via a line (22) until the means of transport (3, 3b) picks this up there, which is the same means of transport (3, 3a) that introduced the fresh drilling fluid into the storage container (23);

   - then driving the drilling mud removed from the collector (2) to an input bunker (10) of a treatment plant (1) with the means of transport (3, 3c);

   - performing an analysis of the delivered drilling mud in an analysis stage (11) located before, in or after the input bunker (10);

   - deciding how the delivered drilling mud is treated using different separation stages (12, 12a, 12b, 12c) based on the analysis result,

   ∘ wherein a discharge line (13) is connected to the input bunker (10) at the output-side, to which line the various separation stages (12, 12a, 12b, 12c) can be connected by shut-off valves (14a, 14b, and 14c),

   ∘ wherein the analysis stage (11) operates automatically and acts on the respective shut-off valves (14a, 14b, and 14c) by means of corresponding adjusting elements, and thus allows an automated flow of the drilling mud;

   ∘ wherein the various separation stages (12, 12a, 12b, 12c) are located along the discharge line (13), which are used according to the degree of pollution of the drilling mud supplied,

   ▪ wherein the first separation stage (12a) is used for heavily polluted or contaminated drilling mud,

   ▪ the second separation stage (12, 12 b) in the direction of flow of the drilling mud in the discharge line (13) is used for less polluted or contaminated drilling mud, and

   ▪ the last separation stage (12.12 c) only provides a mechanically dominated separation of the soil and rock components from drilling mud that is not contaminated per se,

   ▪ wherein the different concepts for the treatment or separation of the drilling mud supplied to the separation stages (12, 12a, 12b, 12c) differ from one another;

   ∘ wherein the first separation stage (12, 12 a) conditions the drilling mud in such a way that it can be stored in a landfill (4), wherein the conditioning is carried out by adding binder over a filling region (15) at the separation stage (12a), and the binder leads to a concrete-like compound of the drilling mud from which pollutants can no longer be washed out;

   ∘ wherein the second separation stage (12b) is designed as a thermal separation stage and reduces the mass and volume of the drilling mud by evaporating the water in the drilling mud, wherein the separation stage (12b) comprises a heater (17), wherein it is provided that the evaporated water is condensed back in a heat exchanger and then fed via a line (18) to a drilling fluid receptacle (19);

   ∘ wherein the third separation stage (12c) is connected to the drilling fluid receptacle (19) via a line (100) and is designed as a mechanically acting separation stage, wherein the soil and rock components produced in this third separation stage (12c) form a pile of rubble (5) as bulk material;

   - provision of new, ready-mixed drilling fluid intended for use with the drilling fluid receptacle (19), which is then filled into the transport vehicle (3, 3d) if necessary, in order to transport the fluid to the construction site where the drilling device (2) is located, wherein a mixer (101) is provided in the drilling fluid receptacle (19), which ensures homogenisation of the prepared drilling fluid, wherein a sensor (102) is provided, which monitors the quality of the drilling fluid stored.
2. Method according to claim 1, characterised in that the binder in the first separation stage (12 a) is lime, cement, or a lime and cement mixture.
3. Method according to any one of claims 1 or 2, characterised in that at least one mechanical concept from the following group is used in the mechanically acting third separation stage (12c): use of gravity, different masses or different particle sizes of the components for division/separation.
4. Method according to claim 3, characterised in that the third separation stage (12 c) comprises one or more components from the following group: vibrating screen, cyclone, screens, shakers, centrifuges.
5. Method according to claim 4, characterised in that the third separation stage (12 c) comprises a plurality of components of the group described above arranged one behind the other.
6. Method according to any one of the preceding claims, characterised in that the material of the pile of rubble (5) of the third separation stage (12c) accumulating as bulk material is reused as building material in road construction or as an additive in other applications.
7. Method according to any one of the preceding claims, characterised in that the sensor (102) monitors the proportion of drilling fluid suspending agent, wherein, if the proportion of drilling fluid suspending agent is too low, the drilling fluid suspending agent is replenished from a supply (103), and the mixer (101) ensures an even distribution of the newly introduced drilling fluid suspending agent.
8. Treatment plant (1) for the treatment of drilling mud arising from an earth drilling, wherein the treatment plant (1) has at least one input bunker (10), at least one processing or separation stage (12, 12a, 12b, 12c) for separating the soil or rock components from the drilling mud and a drilling fluid receptacle (19), wherein an analysis stage (11) is provided in the conveying direction of the drilling mud before, in, or after the input bunker (10), and the drilling mud is fed to different processing or separation stages (12, 12a, 12b, 12c) for treatment depending on the analysis result, characterised in that

   - a first separation stage (12, 12a) is provided for conditioning heavily polluted drilling muds and the first separation stage (12, 12a) has a filling region (15) for adding a binder, wherein the binder is in particular lime, cement, or a lime and cement mixture and the binder is intended to convert the drilling mud into a concrete-like composite and

   - a second separation stage (12b) is provided, which is designed as a thermal separation stage and comprises a heater (17), wherein the second separation stage (12b) is provided to evaporate the water in the drilling mud and

   - a third separation stage (12c) is provided, which is designed as a mechanically acting separation stage and which has one or more components from the following group: vibrating screen, cyclone, screens, shakers, centrifuges, wherein the third separation stage (12c) is intended to separate soil and rock components from drilling mud that is not contaminated per se, and the third separation stage (12c) is connected to the drilling fluid receptacle (19) via a line (100).
9. System for the treatment and at least partial recycling of drilling mud arising in an earth drilling, which is used in particular to carry out the method according to any one of claims 1 to 7, wherein the system comprises: a treatment plant (1) according to claim 8, a drilling device (2) which catches the accumulating drilling mud in a collector (20), and a means of transport (3) which serves to transport drilling fluid stored in the treatment plant (1) to the drilling device (2) at the location of the earth drilling, and, with the drilling device (2), to transport to the treatment plant (1) drilling mud collected in the collector (20).

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