CN113845289B

CN113845289B - Comprehensive utilization method of drill cuttings and sludge in oil and gas field

Info

Publication number: CN113845289B
Application number: CN202010593294.9A
Authority: CN
Inventors: 杨茂华; 陈雨艳; 杨利方; 龙炳清; 杨秀勇; 何建华
Original assignee: Sichuan Weisheng Environmental Protection Co ltd
Current assignee: Sichuan Weisheng Environmental Protection Co ltd
Priority date: 2020-06-26
Filing date: 2020-06-26
Publication date: 2023-05-09
Anticipated expiration: 2040-06-26
Also published as: CN113845289A

Abstract

The invention relates to a comprehensive utilization method of oil-containing drill cuttings and oil-containing sludge in an oil-gas field, which comprises demulsification, oil recovery and barite recovery; the residue is granulated and roasted to produce building material.

Description

Comprehensive utilization method of drill cuttings and sludge in oil and gas field

Technical Field

The invention relates to a comprehensive utilization method of oil-containing drill cuttings and oil-containing sludge in an oil-gas field.

Background

Oil-containing drill cuttings and oil-containing sludge of an oil-gas field are dangerous solid wastes, and if discharged into the environment, the oil-gas field can cause serious pollution to the ecological environment. The main methods for treating the oil-containing drill cuttings and the oil-containing sludge of the oil-gas field at present comprise safe landfill, solidification treatment, drying treatment, cooperative treatment of building materials and the like. The safe landfill occupies a large amount of land, and has environmental risk factors; the products of the curing treatment and the drying treatment are unstable, and the storage of the products also has environmental safety risks; the energy consumption of the cooperative treatment of the building materials is high. The oil-gas field oil-containing drill cuttings and oil-containing sludge contain a large amount of useful substances, are valuable resources, and have great value in developing a comprehensive utilization method of the oil-gas field oil-containing drill cuttings and the oil-containing sludge, and are the problems which are urgently needed to be solved in China and even worldwide at present.

Disclosure of Invention

Aiming at the problems existing in the existing oil-gas field oil-containing drilling cuttings and oil-containing sludge treatment or disposal method, the invention aims to find an efficient and economic comprehensive utilization method of the oil-gas field oil-containing drilling cuttings and the oil-containing sludge, which is characterized in that in the first step, oil-containing drilling cuttings or the oil-containing sludge which are more than 4% by dry basis weight and can be demulsified are added into demulsifier, 5-15% of aluminum sulfate solution is added, 0.6-1.5 kg of aluminum sulfate is added per cubic meter of slurry, the solid-liquid ratio in the slurry is 1:1.5-1:2.5 by weight, when the solid-liquid ratio of the oil-containing drilling cuttings or the oil-containing sludge is less than 1:2.5, the adjustment of the solid-liquid ratio is not carried out, and stirring is maintained for 5-15 min at the temperature of 85-100 ℃; after demulsification is completed, carrying out solid-liquid separation while the liquid phase is hot, sending the separated liquid phase into an oil-water separator for standing, when the oil-water interface of the liquid phase is completely formed, sending the oil phase into an oil temporary storage tank in excess, sending oil at the upper part of the oil temporary storage tank into petrochemical enterprises for processing and utilization, returning water phase at the lower part of the oil temporary storage tank to the oil-water separator, using part of the water phase separated by the oil-water separator for barite separation, sending the rest part of the water phase separated by the oil-water separator into a reverse osmosis device for treatment, discharging clear water separated by the device after reaching standards, and sending separated concentrated water for subsequent granulation and utilization; directly conveying residues with the water content of less than 50% obtained by the solid-liquid separation process of the oil-containing drilling cuttings and the oil-containing sludge, the barite content of which is less than or equal to 4%, which can be subjected to solid-liquid separation, to the following third step of treatment, treating separated liquid phases according to the method, and conveying residues with the barite content of which is more than 4% obtained by the demulsification and solid-liquid separation processes to the second step of treatment; secondly, diluting residues obtained in the demulsification and solid-liquid separation processes by using a water phase produced by the oil-water separator in the first step, controlling the water content of slurry to be 85% -95%, feeding the slurry into a cyclone separator in a tangential direction, enabling the rotation speed of a wall to be 0.7 m/s-2.0 m/s, enabling the retention time to be 20 s-60 s, discharging barite slurry from the lower part of the cyclone separator, carrying out solid-liquid separation on the slurry, feeding the solid phase into an oil-gas field drilling site to serve as a raw material, returning the separated water phase to the dilution process, feeding the slurry discharged from the upper part of the cyclone separator into a sedimentation tank, enabling the sedimentation time to be 1 h-3 h, and enabling the supernatant liquid part of the sedimentation tank to be used in the dilution process, and enabling the rest part to be treated by the reverse osmosis device; carrying out solid-liquid separation on slurry at the lower part of the sedimentation tank, returning separated water to the dilution process, and carrying out the third step treatment on the separated residue, wherein the water content of the separated residue is less than 50%; thirdly, mixing residues generated in the steps, oil-containing drilling cuttings and oil-containing sludge which can not be demulsified in any proportion, and granulating with clay, wherein the proportions of the residues, the clay and the clay are 75-85% and 15-25% of each other on a dry basis, the particle size of the manufactured particles is 0.5-3.0 mm, the water content is 35-50%, and when the water content is more than 50%, the dried materials generated in the subsequent drying process are used for adjusting; the fourth step, the granular materials produced in the third step are put into a waste heat furnace for drying and light oil distillation, the temperature is 400-650 ℃, the secondary waste heat obtained after the flue gas waste heat of the roasting furnace is utilized for drying is used as a heat source, the light oil components are recovered from gas phase through condensation, the condensed water is sent to the reverse osmosis device for treatment, the waste gas is treated by the prior art and then reaches the standard, the dust recovered by waste gas treatment is returned to the granulating process, the material part after drying and light oil extraction is returned to the granulating process according to the requirement, the rest part is sent to the roasting furnace for roasting, the temperature is 800-1200 ℃, the time is 6-8 min, the roasting product enters a passivating device, the building material is obtained after the passivating device stays for 40-80 min at 600-800 ℃, and the passivating device utilizes all roasting flue gas to compensate the heat loss of the device; the flue gas exiting the passivation device is used in the aforementioned particulate drying and light oil extraction processes.

The invention aims to realize that after oil-containing drill cuttings and oil-containing sludge of an oil-gas field enter a demulsifier, demulsification, breaking and gelation are carried out under the actions of demulsifier, stirring and higher temperature, and solid-liquid separation can be carried out while hot, so that emulsification and regeneration of gelled substances can be avoided. The process separates a large amount of water from the oil-containing drill cuttings and the oil-containing sludge, thereby not only creating favorable conditions for reducing energy consumption in the subsequent process, but also providing guarantee for the roasting process to reach the temperature required for producing high-quality building materials. The problems that the thermal analysis temperature of the existing oil-containing drill cuttings and oil-containing sludge is low and products cannot be directly utilized are thoroughly solved. Sludge with different barite contents is treated separately at the front end, so that the recycling of barite with thinner resources and higher value is facilitated.

The granulation process strictly controls the water content, and has the following advantages: the quality of the particles can be ensured, the heat load in the drying process can be reduced, and a large amount of water vapor can be avoided to damage the particles; is favorable for extracting light oil components; the dust generation amount in the subsequent roasting process is greatly reduced; the fine particles are fully contacted, and favorable conditions are created for sintering the fine particles, so that the high-quality building material is obtained. The subsequent passivation process enables powder in the particles to be sintered and heavy metal to be passivated thoroughly.

Compared with the existing method, the method has the outstanding advantages of realizing the full resource utilization of the oil-containing drill cuttings and the oil-containing sludge of the oil-gas field, recovering the barite and the light oil, producing high-quality building materials, eliminating the harm of the oil-containing drill cuttings and the oil-containing sludge to the ecological environment, and having obvious economic benefit and environmental benefit.

Detailed Description

Example 1: 2000kg of oily drill cuttings (the water content is 66.4 percent and the weight of the heavy rock is 3.2 percent) are treated, and 1153.3kg of building material is obtained through the processes of proportioning (the residue is 85 percent and the clay is 15 percent based on dry basis), adding materials which are dried and extracted by 55 percent of the total weight of the two materials, granulating (0.5 mm-3 mm), drying and extracting light oil (400-650 ℃, recovering 10.2kg of light oil), roasting (800-1200 ℃, 6 min) and passivating (600-800 ℃ and 40 min).

Example 2:5000kg of oily sludge (the water content is 93.4 percent, the weight of the barite is 22.3 percent based on dry basis), and the oily sludge is demulsified (1.1 kg of aluminum sulfate is added into each cubic meter of oily sludge at the temperature of between 85 and 100 ℃ for 5 minutes), separated from hot solids (the water content of residues is 48.5 percent), separated from oil and water (22.4 kg of recovered oil), separated from residues by rotational flow (the retention time is 20 seconds, the wall rotation speed is 0.7 m/s) and separated from solid and liquid (116.2 kg of barite slag with the water content of 37.6 percent is obtained); the slurry after the barite recovery is subjected to precipitation (1 h) and solid-liquid separation to obtain residue with the water content of 48.9%, and 243kg of building material is obtained through the processes of proportioning (residue 75% based on dry basis, clay 25%), granulating (0.5-3 mm), drying and light oil extraction (400-650 ℃, 20.2kg of light oil is recovered), roasting (800-1200 ℃, 6 min) and passivation (600-800 ℃ and 60 min).

Claims

1. The comprehensive utilization method of oil-containing drill cuttings and oil-containing sludge in oil and gas fields is characterized in that firstly, oil-containing drill cuttings or oil-containing sludge which accounts for more than 4% of dry weight and can be demulsified are added into demulsifier, 5-15% of aluminum sulfate solution is added, 0.6-1.5 kg of aluminum sulfate is added into each cubic meter of slurry, the solid-liquid ratio in the slurry is 1:1.5-1:2.5 by weight, when the solid-liquid ratio of the oil-containing drill cuttings or the oil-containing sludge is less than 1:2.5, the solid-liquid ratio is not adjusted, and stirring is maintained for 5-15 min at the temperature of 85-100 ℃; after demulsification is completed, carrying out solid-liquid separation while the liquid phase is hot, sending the separated liquid phase into an oil-water separator for standing, when the oil-water interface of the liquid phase is completely formed, sending the oil phase into an oil temporary storage tank in excess, sending oil at the upper part of the oil temporary storage tank into petrochemical enterprises for processing and utilization, returning water phase at the lower part of the oil temporary storage tank to the oil-water separator, using part of the water phase separated by the oil-water separator for barite separation, sending the rest part of the water phase separated by the oil-water separator into a reverse osmosis device for treatment, discharging clear water separated by the device after reaching standards, and sending separated concentrated water for subsequent granulation and utilization; directly conveying residues with the water content of less than 50% obtained by the solid-liquid separation process of the oil-containing drilling cuttings and the oil-containing sludge, which are less than or equal to 4% by weight and can be subjected to solid-liquid separation, to the following third step of treatment, conveying the separated liquid phase into an oil-water separator for treatment according to the method, and conveying residues with the weight of more than 4% by weight of the sludge obtained by the demulsification and solid-liquid separation processes to the second step of treatment; diluting residues obtained in the demulsification and solid-liquid separation processes by using a water phase produced by the oil-water separator in the first step, controlling the water content of slurry to be 85% -95%, feeding the slurry into a cyclone separator in a tangential direction, enabling the rotation speed of a wall to be 0.7 m/s-2.0 m/s, enabling the retention time to be 20 s-60 s, discharging barite slurry from the lower part of the cyclone separator, carrying out solid-liquid separation on the slurry, feeding the solid phase into a drilling site of an oil-gas field as a raw material, returning the separated water phase to the dilution process in the second step, feeding the slurry discharged from the upper part of the cyclone separator into a sedimentation tank, enabling the sedimentation time to be 1 h-3 h, enabling the supernatant liquid part of the sedimentation tank to be used in the dilution process in the second step, and enabling the rest part to be treated by the reverse osmosis device; carrying out solid-liquid separation on slurry at the lower part of the sedimentation tank, returning separated water to the second-step dilution process, and carrying out the third-step treatment on the separated residue, wherein the water content of the separated residue is less than 50%; thirdly, mixing residues generated in the steps, oil-containing drilling cuttings and oil-containing sludge which can not be demulsified in any proportion, and granulating with clay, wherein the proportions of the residues, the clay and the clay are 75-85% and 15-25% of the dry basis respectively, the particle size of the produced particles is 0.5-3.0 mm, the water content is 35-50%, and when the water content is more than 50%, the dried materials generated in the subsequent drying process are used for adjusting; the fourth step, the granular materials produced in the third step are put into a waste heat furnace for drying and light oil distillation, the temperature is 400-650 ℃, the secondary waste heat obtained after the flue gas waste heat of the roasting furnace is utilized for drying is used as a heat source, the light oil components are recovered from gas phase through condensation, the condensed water is sent to the reverse osmosis device for treatment, the waste gas is treated by the prior art and then reaches the standard, the dust recovered by waste gas treatment is returned to the granulating process, the material part after drying and light oil extraction is returned to the granulating process according to the requirement, the rest part is sent to the roasting furnace for roasting, the temperature is 800-1200 ℃, the time is 6-8 min, the roasting product enters a passivating device, the building material is obtained after the passivating device stays for 40-80 min at 600-800 ℃, and the passivating device utilizes all roasting flue gas to compensate the heat loss of the device; the flue gas discharged from the passivation device is used for the particle drying and light oil extraction processes; after the oil-containing drill cuttings and the oil-containing sludge of the oil-gas field enter a demulsifier, demulsification, breaking and gelation are carried out under the actions of demulsifier, stirring and higher temperature, and solid-liquid separation can be carried out while the oil-gas field is hot, so that emulsification and regeneration of gelled substances can be avoided; sludge with different barite contents is treated separately at the front end, so that the recycling of barite with thinner resources and higher value is facilitated.