WO2019194705A1

WO2019194705A1 - Well-drilling waste neutralization method and neutralization device

Info

Publication number: WO2019194705A1
Application number: PCT/RU2019/000206
Authority: WO
Inventors: Mikhail Ivanovich SERDYUK
Original assignee: Serdyuk Mikhail Ivanovich
Priority date: 2018-04-03
Filing date: 2019-04-01
Publication date: 2019-10-10
Also published as: EP3774096A1; EP3774096A4; EA202092079A1; EA037837B1; RU2679056C1

Abstract

The well-drilling waste neutralization method includes separation of drilling sludge from the drilling fluid, drilling sludge discharge into a sludge pit, chemical and technological treatment of sludge until obtaining a composite mixture including, but not limited to, a humic mineral component; installation of drilling sludge dividers represented by a metal fixture in the form of bottomless cells placed and fixed, at least in their upper part; drilling sludge discharge into the formed cells, each being filled to 80% by volume. The chemical and technological treatment is performed in a batchwise manner - individually in each of the cells with constant stirring. The humic mineral component is injected in the amount of about 3-5% of the total drilling sludge quantity and stirred within 30-60 minutes. Significant parameters are checked until values below maximum allowable concentrations are reached. The fixture is removed from the pit, and soil from the rehabilitated areas is added. The well-drilling waste neutralization device consists of dividers in the form of a metal fixture for installation inside a sludge pit to create a structure with vertically oriented bottomless cells; a metal grid installed on top of the fixture. Guides in the form of rails are provided on the grid together with a working platform moving along them. The grid has an operator's workplace and provides for capability for placing chemicals and drilling sludge stirring equipment The use of the claimed group of inventions ensures the improvement of the neutralized drilling sludge quality.

Description

Well-Drilling Waste Neutralization Method and Neutralization Device

The group of inventions relates to neutralization of drilling wastes and can be used for disposal of drill cutting wastes when drilling deep wells of various purpose.

Various well-drilling waste neutralization methods are known from the following patent documents: RF Patents for Invention Nos. 2631681, 2595172, 2572763, 2528035, 2524708, 2508170, 2439098, 2428256, 2425815.

A method for neutralization of well drilling wastes is known from RF Patent for Invention No. 2213121, said method comprising sludge pit reclamation, including evacuating the liquid phase of waste drilling fluid from the pit, eliminating the fluidity of its coagulates, filling the remaining drilling wastes with mineral soil, and site levelling. Before the evacuation, contaminant concentrations are determined in waste drilling fluid, and the content of contaminants in the fluid is brought to levels below maximum allowable concentrations. The liquid phase is evacuated from the sludge pit through a sludge pit dike opening.

A waste drilling sludge neutralization method is known from RF Patent for Invention No. 2486166, said method comprising the preparation of a process area, collection, excavation and delivery of contaminated soils to the process area, preparation of oil-contaminated soil, application of a humic mineral complex and provision of oil-contaminated soil biostructuring processes. The method for waste drilling sludge neutralization includes liming, chemical coagulation, application of flocculants and a humic mineral complex, step-by-step removal of drilling sludge to a buffer layer with laying of drilling sludge to a maximum layer of 8-10 cm, drying of drilling sludge, and stockpiling for further disposal. The humic mineral complex is obtained in the course of low-temperature mechanochemical extraction of humic acids by disintegration of brown coal in a disperser with mixing of the crushed brown coal with alkali.

A disadvantage of the analogs described above consists in the lack of the guaranteed high-quality treatment of the entire drilling sludge volume contained in a sludge pit, in any part thereof - in the corners, on the bottom, etc., both to a sufficient degree of chemical treatment with reagents and a sufficient degree of mechanical mixing, with regard to both duration and intensity, as a result, eliminating undermixed areas in any segment of the sludge pit.

The closest analog of the claimed method is the well-drilling waste

neutralization method described in RF Patent for Invention No. 2392256. The method includes separation of drilling sludge from the drilling fluid circulating in the drilling process, and storage of drilling sludge in sludge pits. The drilling sludge is processed into a sludge semi-product which is supplemented with humic mineral concentrate as a composite mixture modifier, and the territories of all soil excavations for placement of neutralized drilling products are returned into land circulation. Sludge pits are constructed as several temporary operative parallel pits, each of them receiving sludge from drilling of different rock strata alternately penetrated by a drilling tool. A process station in the form of several parallel basins is provided to obtain an end product, and ameliorant maturation is arranged in each of them on a rotating basis.

A disadvantage of the closest analog consists in an increase of exposed disturbed lands needed for arrangement of several earth drilling pits, i.e. efforts toward rehabilitation of contaminated territories lead to even greater disturbed areas where earth pits, basins, sumps, etc. are provided for storage and further maturation of drilling sludges, more precisely, their substances. And, despite the fact that it is planned to temporarily occupy these work areas for cleaning and treatment of sludges, the time of such actions may, however, significantly extend for various reasons - climatic, financial, organizational ones (for example, for the reason of insufficient quantity of additional chemicals because it is necessary to treat the constructed pits themselves as well, rehabilitate them and return them into land circulation).

There are also various known devices for implementation of well-drilling waste neutralization methods. The technical solution described above according to RF Patent for Invention No. 2392256 with several sludge pits can be also considered as an attempt to solve (in terms of design) the problems of treatment quality improvement for various drilling mass groups during well penetration by means of various tanks represented by a row of sludge pits in this solution.

The presence of a row of sludge pits has obvious disadvantages (see above). This leads to even larger territories of concern with dubious advantages regarding drilling sludge treatment quality.

A neutralization device is known from RF Useful Model Patent No. 71115. The device consists of a body and a sludge loading tank. The body is divided by a partition into two chambers: a collection chamber and a water separation chamber, and is equipped on the bottom with a removable tray and nozzles for water draining. The sludge loading tank is located in the collection chamber, installed on a frame, provided with a cover, and made of metal mesh in such a way to create a channel for steam passage inside the tank. The body is equipped with a bell connected with the tank bottom to provide capability for steam injection into the tank.

A drilling sludge neutralization device is known from RF Useful Model

Patent No. 142084. The device consists of a tank provided with a vibrating bottom. Inside the tank, there is a sieve equipped with floats to provide capability for sieve movement in vertical direction within the tank; there is a pump inside the sieve. To create vibration waves, the tank is provided with an ultrasonic vibrator and an ultraviolet radiator.

The closest analog of the claimed device is the technical solution described in RF Useful Model Patent No. 170033. The device represents a mobile range formed by a set of the equally shaped and sized leak-proof tanks which are interconnected by sealing and, at the same time, coupling members of straight, angular and other shapes. Each of the tanks in the version shown in the patent has the shape of an inverted truncated pyramid. Each tank includes a bottom and side walls. These specially prepared tanks are delivered to the site intended for accumulation, placement and further disposal. As a matter of fact, the claimed mobile range is a set of the inserts that represent leak-proof tanks, and it just acts as a container with drilling sludge, where, at best, drilling mass matures with the use of chemicals.

A disadvantage of the closest analog consists in its crude design which is not sufficient for implementing the efficient process of drilling sludge treatment, for example, using a stirring device, such as an agitator. In addition, the presence of a bottom drastically complicates the process of removing the tanks with drilling sludge from the sludge pit after the sludge is ready.

These disadvantages have been eliminated in the device invention claimed in this patent.

The object of the claimed group of inventions is to ensure improvement in the quality of treated drilling sludge neutralization to levels below maximum allowable concentrations by means of the claimed method with reduced treatment time.

The essence of the claimed invention with regard to the method is

characterized by the fact that in the well-drilling waste neutralization method comprising: separation of drilling sludge from the drilling fluid, drilling sludge discharge into a sludge pit, chemical and technological treatment of sludge until obtaining a composite mixture including, but not limited to, a humic mineral component, and return of a product obtained as a result of drilling waste

neutralization into land circulation in the affected areas, the process is commenced with installing drilling sludge dividers inside the sludge pit, which are represented by a metal fixture in the form of bottomless cells placed and fixed, at least in their upper part; drilling sludge is individually discharged into the formed cells, each being filled to about 80% by volume; chemical and technological treatment, including treatment with a humic mineral component, is performed in a batchwise manner - individually in each of the cells with constant stirring; the humic mineral component is injected in the amount of about 3-5% of the total drilling sludge quantity and stirred within 30-60 minutes; significant parameters are checked until values below maximum allowable concentrations are reached; then the metal fixture is removed from the sludge pit, and soil from the rehabilitated areas is added.

A method with the above mentioned operations is also claimed in which stirring is provided at a rate of about 30-60 revolutions per minute.

A method is also claimed in which treatment in each of the cells is performed in a sequential order.

A method is also claimed in which, along with the features described above, batchwise treatment in multiple cells is performed at the same time.

The essence of the claimed invention with regard to the device is that the well-drilling waste neutralization device is represented by dividers in the form of a metal fixture which can be installed inside a sludge pit to create a structure with vertically oriented bottomless cells covered on top with a metal grid where guides are provided in the form of rails with a working platform moving along them with an operator's workplace and with capability for placing chemicals and drilling sludge stirring equipment on it.

A device is also claimed in which, along with the features described above, the guides have working platform end stops along the perimeter of the grid to avoid working platform sliding off.

In addition, a device is claimed in which retainers are provided along the guides along the working platform travel in order to stop the platform during operation.

A device is also claimed in which a protective cover is provided on the metal grid over the top surface of the sludge pit to avoid climatic effects on the interior space of the pit.

A device is also claimed in which, along with the features described above, the cells in their upper plane have a size of 2 c 2 m.

A device is also claimed in which a controller with a control panel is

additionally provided to control the sufficient injection of chemicals, stirring and neutralization. The technical result of the claimed group of inventions is achieved by introducing a new operation (in the method) that has an influence on the rest of the process of drilling sludge treatment, from the beginning to the very end.

Introducing the operation of dividing the whole drilling sludge mass to be treated into equal, convenient portions is implemented in the equipment specially prepared for this purpose and represented by dividers in the form of bottomless cells. These techniques have been tried out taking into account the overall dimensions of the operated equipment - mixers, agitators, etc., their work zone sweep diameter and with elimination of "dead areas" during stirring. Earlier, before these claimed method and device, agitators were unable to cover all processed material of the sludge pit to a sufficient degree - with care and without

interruptions, and operators had no opportunity to proportionally inject minimally required, but sufficient quantity of chemicals into individual batches of drilling sludge. The dynamic check of the changing drilling mass was possible on a very selective basis only, whereas the claimed solution offers a simple way for doing so, if desired or necessary, in each of the cells.

The differences of the claimed method and device as described below eliminate unreacted areas in the whole treated sludge mass, while making the treatment process high-quality, cost-efficient and maximally profitable.

The operation of dividing the sludge pit throughout the volume into equal parts using the claimed new structural devices with the help of a prepared strong working metal fixture in the form of dividers through the length and breadth of the sludge pit, which are installed to provide a capability of dismantling after the treatment of the whole processed sludge mass is finished, as well as other additional structural assemblies for their functioning, should be considered as new in the claimed method.

The method can be implemented by both sequential treatment of sludge in each of the cells and simultaneous parallel treatment using any properly sized mechanical, vibrating and ultrasonic agitators, etc. in multiple cells at the same time. This mode is reasonable, for example, if contractors have the sufficient quantity of connected stirring means and cells and there is a lack of climatic conditions suitable for performing operations (before an expected snowfall or incessant rains). In such a case, preference is given to a somewhat more costly mode that not only guarantees the quality of cleaning and neutralization, but also ensures that the operations will be completed before the extreme conditions occur, which is important in the conditions of the North or areas with the increased amount of precipitation.

The introduced first (before the beginning of any chemical and even

mechanical actions - before drilling sludge discharge into a sludge pit) operation of the formation of the cells dividing the whole treated mass into the parts which thus, due to this design and process step, become more easily treatable (in both mechanical and chemical ways) until the full completion of each of the operations at all work stages, as well as with visual check of each area of the treated mass, allows, if necessary, some correction of the whole stage or method by time or quantity of interacting materials due to the additional time needed if work problems are encountered, for example, in case of rock stratum complication in the course of well drilling. The optimally selected mode of action - stirring within 30-60 minutes, and a humic mineral component in the amount of about 3-5% of the total drilling sludge quantity provide guaranteed quality up to the achievement of values below maximum allowable concentrations. However, for uncomplicated rock strata in the course of penetration, we may sometimes limit ourselves to lesser amount of interaction time with obligatory stirring of the appropriate treated sludge portion in each of the pit cells. The visual check of the sludge material color change from stage to stage suggests the treatment readiness time at each specific stage and allows considering the changing color of sludge as a criterion of readiness to the next action stage. The instrumental check with the use of indicating sensors is more accurate along with comparing samples with computer library reference standards.

This is a tentative criterion of the treated material sufficiency for and readiness to preparation to application into the soil of land areas. For more detailed studies, when seeding of the rehabilitated areas is planned, apparatus-based check is used to verify density, acidity and other significant parameters. On this basis, recommendations are made on the optimum use of the rehabilitated soils or their further improvement, provided that it is reasonable to bring them up to the required level of usage for forest plantations, arable lands, pastures, etc.

Thus, the technical result of the claimed drilling sludge neutralization method providing a capability for the visual check of readiness of each batch to the next stage of processing the drilling sludge, which undergoes changes in the course of treatment, makes it possible to eliminate the unnecessary action time and save the resources spent. On the other hand, eliminating the excess of chemicals and changing the action time prevent from drilling sludge treatment quality

deterioration due to more thorough, batchwise treatment of each fragment of the whole material mass (through division into cells). Due to the modern technological infrastructure, such as the equipment of wells, conventional computer equipment and a conventional controller, along with the claimed features, the claimed method corresponds to the high level of the claimed technical solution in this area and is suitable for industrial use with significant saving of costs without product quality deterioration.

The claimed device is explained using the Fig. schematically showing a sludge pit with already installed cells, guides and a working platform.

Items 1-4 in the figure indicate the following:

1 - cell,

2 - metal grid,

3 - guides in the form of rails,

4 - working platform.

The method is implemented as follows, including the use of the claimed device in it

Based on the sludge pit design, the quantity of cells is calculated. The dividers in the form of a metal fixture, which have been previously delivered to the sludge pit, are installed using a crane into the sludge pit which is empty or filled with drilling sludge. Bottomless cells 1 formed as a result of metal fixture installation are interconnected by fasteners to provide additional structural stability and strength. The sludge level in each of cells 1 is checked; each cell shall be filled to about 80% by volume.

Metal grid 2 is installed onto bottomless cell 1 at the upper base; guides in the form of rails 3 with working platform 4, where an operator's workplace is provided, are mounted on grid 2. To ensure control over the sufficient injection of chemicals, stirring and neutralization, the device is provided with a control panel and a controller. The guides along the perimeter of grid 2 are provided with working platform end stops, and there are retainers along the guides, allowing for stopping the working platform. There is an additional element, a metal cover, designed to avoid climatic effects on the interior space of the sludge pit. The cover is installed after working platform removal and work completion for some time or after the completion of sludge treatment in the pit. The recommended size of cells in their upper plane is 2 ^c 2 m. A cell height in the invention embodiment example is 2.5 m.

There may be more than one stirring device, depending on the required drilling sludge processing rate in general.

The neutralization of drilling sludge is based on chemical and technological treatment by adding various chemicals into it with their thorough stirring. The overall technological process of drilling sludge neutralization is the same in each cell.

A humic mineral component is added into the drilling sludge placed into cells and treated using any existing technique. The drilling sludge is mixed with the humic mineral component using an agitator with the required power rating to provide stirring at 30-60 revolutions per minute. The calculated amount of the chemicals used, including the humic mineral component, is dosed and delivered to a cell with an activated agitator; then it is filled into the cell. The amount of the filled humic mineral component is equal to 3-5% of the weight of drilling sludge in the cell. The stirring time is 30-60 minutes. An agitator with two propeller-type blades located perpendicular to each other and providing the counter-stirring of the reaction mass has proved itself in the example of practical approval.

The end of stirring is checked visually by complete distribution of the humic mineral component in the reaction mass. A product is formed at the end of this stage. After it is obtained from cells, a composited sample is taken and prepared in compliance with regulatory documents. This sample is analyzed for compliance with the existing requirements. If the sample complies with them, the product in the sludge pit is mixed with the soil produced as a result of sludge pit excavation at the product/soil ratio of 1:1. The result is a soil/sludge mixture. If the sample does not comply with the existing standards, the process of treatment with the humic mineral component is continued until the product with concentrations not higher than maximum allowable values is obtained.

Upon completion of product formation, the special fixture (bottomless cells) is dismantled and removed along with the stirring device from the sludge pit. The side waterproofing layer of the sludge pit is also dismantled and removed from the sludge pit.

The product is mixed with soil using construction machinery, such as

bulldozers, excavating machines, etc. A moist soil/sludge mixture is formed as a result of mixing. The end of the technological process is visually checked by the formation of the uniform and evenly colored mixture.

The dry soil/sludge mixture is produced from the moist soil/sludge mixture as a result of natural processes of water evaporation within 10-20 days at ambient temperature within 20-25 °C and normal air humidity.

The obtained dry soil/sludge mixture is used as man-made soil for sludge pit backfilling on site in the field with levelling of the terrain.

The dry soil/sludge mixture is flattened using special machinery, and the top soil removed when the sludge pit was excavated is replaced; it is subsequently sown with herbs, planted with trees and shrubs and returned to the agricultural use.

Claims

Claims of Invention

1. The well-drilling waste neutralization method comprising: separation of drilling sludge from the drilling fluid, drilling sludge discharge into a sludge pit, chemical and technological treatment of sludge until obtaining a composite mixture including, but not limited to, a humic mineral component, and return of a product obtained as a result of drilling waste neutralization into land circulation in the affected areas and characterized in that the process is commenced with installing drilling sludge dividers inside the sludge pit, which are represented by a metal fixture in the form of bottomless cells placed and fixed, at least in their upper part; drilling sludge is individually discharged into the formed cells, each being filled to about 80 % by volume; chemical and technological treatment, including treatment with a humic mineral component, is performed in a batchwise manner— individually in each of the cells with constant stirring; the humic mineral component is injected in the amount of about 3-5 % of the total drilling sludge quantity and stirred within 30-60 minutes; significant parameters are checked until values below maximum allowable concentrations are reached; then the metal fixture is removed from the sludge pit, and soil from the rehabilitated areas is added.

2. The method as per cl. 1 characterized in that stirring is provided at a rate of about 30-60 revolutions per minute.

3. The method as per cl. 1 characterized in that treatment in each of the cells is performed in a sequential order.

4. The method as per cl. 1 characterized in that batchwise treatment in multiple cells is performed at the same time.

5. The well-drilling waste neutralization device characterized in that it is represented by dividers in the form of a metal fixture which can be installed inside a sludge pit to create a structure with vertically oriented bottomless cells covered on top with a metal grid where guides are provided in the form of rails with a working platform moving along them with an operator's workplace and with capability for placing chemicals and drilling sludge stirring equipment on it.

6. The device as per cl. 5 characterized in that the guides have working platform end stops along the perimeter of the grid to avoid working platform sliding off.

7. The device as per cl. 5 characterized in that retainers are provided along the guides along the working platform travel in order to stop the platform during operation.

8. The device as per cl. 5 characterized in that it has a protective cover on the metal grid over the top surface of the sludge pit to avoid climatic effects on the interior space of the pit.

9. The device as per cl. 5 characterized in that the cells in their upper plane have a size of 2x2 m.

10. The device as per cl. 5 characterized in that it is provided with a controller with a control panel to control the sufficient injection of chemicals, stirring and neutralization.