CN114687687A - Oil-containing drilling cutting treatment method - Google Patents

Oil-containing drilling cutting treatment method Download PDF

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CN114687687A
CN114687687A CN202210421200.9A CN202210421200A CN114687687A CN 114687687 A CN114687687 A CN 114687687A CN 202210421200 A CN202210421200 A CN 202210421200A CN 114687687 A CN114687687 A CN 114687687A
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oil
extraction
supercritical
standard
oil phase
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陈德良
曾宪成
何佳
马勇鹏
刘剑飞
焦文强
李银峰
董浩聪
王雪梅
廉云飞
孙堃
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Henan Ruishida Separation Equipment Technology Co ltd
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Henan Ruishida Separation Equipment Technology Co ltd
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
    • E21B21/06—Arrangements for treating drilling fluids outside the borehole
    • E21B21/068—Arrangements for treating drilling fluids outside the borehole using chemical treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D11/00—Solvent extraction
    • B01D11/04—Solvent extraction of solutions which are liquid
    • B01D11/0403—Solvent extraction of solutions which are liquid with a supercritical fluid
    • B01D11/0411—Solvent extraction of solutions which are liquid with a supercritical fluid the supercritical fluid acting as solvent for the solvent and as anti-solvent for the solute, e.g. formation of particles from solutions

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  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

The invention aims to provide a method for treating oily drilling cuttings, and belongs to the technical field of oily solid waste treatment in oil and gas field unconventional oil and gas development drilling. The invention makes supercritical CO2Carrying out extraction reaction on the fluid and oil-phase substances in the oil-containing drilling cuttings for 1.3-1.7 hours, then conveying the drilling cuttings waste residues after the extraction reaction to a combustion furnace cavity in a thermal desorption module, heating the temperature to 300-400 ℃ for desorption pyrolysis, wherein the pyrolysis time is 2-4 hours. TPH in the treated pyrolytic waste residue reaches the requirement of GB4284-2018 standard limit; COD in waste residue leachateCrThe indexes are stably improved to reach the grade 1 emission standard of GB8978-1996, the pyrolytic waste residues reach the I type solid waste standard requirements of the national standard GB18599-2020 general industrial solid waste storage and landfill pollution control standard, the total recovery rate of the oil phase reaches more than 99 percent, and the high-valued recovery of the oil phase of the drilling oil-containing drilling cuttings, the waste residue upgrading treatment and the safe disposal are realized.

Description

Oil-containing drilling cutting treatment method
Technical Field
The invention relates to the technical field of oil-containing solid waste treatment in oil and gas field unconventional oil and gas development drilling, in particular to a method for treating oil-containing drill cuttings generated by drilling by applying an oil-based drilling fluid technology to exploration and development of shale oil and gas and compact oil.
Background
The horizontal well oil-based drilling fluid technology is one of the key core technologies for horizontal well drilling in exploration and development of shale oil gas and compact oil. In recent years, with the increasing difficulty of oil exploitation in China and the large-scale commercial development of unconventional shale oil gas and compact oil, the use scale of the oil-based drilling fluid with strong lubricity, good stability and excellent fluid loss control property is increased year by year. In the using process of the oil-based drilling fluid, rocks in a stratum cut by a drill bit are carried out of the ground, a layer of oil-based drilling fluid (called as oil-containing drilling cutting solid waste) is adhered to the surface of rock debris, and investigation shows that the horizontal well section length of the shale gas oil gas drilling well is 1200 m-3200 m at present, and the oil-containing drilling cutting generation amount of a single well is about 500 t-800 t. The components of the oil-containing drilling cuttings are related to the properties of oil-based drilling fluid, the rock properties in the stratum and the performance of a drilling fluid circulation system, and mainly contain harmful pollutants such as oils (base oil such as diesel oil, white oil and the like), heavy metals, organic emulsifiers, filtrate reducers, tackifiers, shale inhibitors, viscosity reducers, lubricants, weighting agents, flocculants and the like, wherein most organic additives have poor degradability. In 2021, oily drill cuttings have been listed in the national records of hazardous waste (code HW 08), if improper disposal of these cuttings would adversely affect and harm the surrounding ecological environment.
The prior treatment technology of the oil-containing drilling cuttings mainly comprises incineration, consolidation stabilization, chemical heat washing separation, organic solvent extraction and supercritical CO2Extraction and other treatment technologies. The incineration technology can thoroughly inorganically oxidize organic matters such as oil, additives and the like in the oil-containing drill cuttings to realize reduction and harmless treatment, but the incineration method has relatively high cost, so that the valuable oil, oil-soluble mud additive substances and other available resources in the drill cuttings are seriously wasted, and the risk of secondary environmental pollution such as dioxin and the like generated by burning tail gas exists; the consolidation stabilization technology adds a curing agent to inhibit the migration of organic matters such as oil and oil-soluble mud additives, heavy metals, chloride ions and other pollutants by a chemical or physical method, has simple operation and low cost, but has the risk of secondary pollution caused by the leakage of the pollutants for the oily drilling cuttings with higher oil content; the chemical hot washing separation method has mild conditions and moderate cost, but can generate a large amount of wastewater, and simultaneously, the total petroleum hydrocarbon content (TPH for short) in the waste residue does not reach the standard (generally 20000 mg/kg-50000 mg/kg), the subsequent treatment difficulty is increased, and the comprehensive treatment cost is higher; the organic extraction technology is used for extracting and separating oil phase substances (base oil and oil-soluble mud additives) in the oil-containing drilling cuttings by using an organic solvent, and the method has the advantages that the quality of the extracted oil phase is good, but the method has the defects of relatively complex process, large equipment investment and high cost caused by solvent recovery through secondary distillation, solvent residues exist in the recovered oil phase and waste residues, the odor is large, and the large-scale application is limited; supercritical CO2Extraction techniques vary the CO in the system by varying the pressure and temperature2The phase state, the density and the performance of dissolving oil-soluble substances of the oil-soluble substances improve the yield and the quality of products, the extraction rate is up to 99 percent, but in the extraction process, about half of the extraction time in the early stage enables the oil phase recovery rate to be up to more than 90 percent, the oil phase recovery rate in the residual extraction time in the later stage is less than 10 percent, the extraction efficiency is lower, the total energy consumption cost is higher, and the supercritical CO is adopted to ensure that the oil-soluble substances are extracted by the oil-phase extraction method2Drill cuttings treated by extraction technologyThe waste residue can not meet the I-type solid waste standard requirement of the national standard GB18599-2020 Standard for general Industrial solid waste storage and landfill pollution control.
Disclosure of Invention
The invention aims to provide a method for treating oil-containing drilling cuttings, which has simple process and low treatment cost and is realized by supercritical CO2The organic synergistic combination of efficient extraction and recovery of oil phase and thermal desorption and degradation of organic matters solves the technical problems that the existing oily drilling cutting treatment system has high energy consumption and treatment cost, and the treated drilling cutting waste residue can not meet the type I solid waste standard requirement of the national standard GB18599-2020 general industry solid waste storage and landfill pollution control standard.
In order to achieve the purpose, the invention adopts the following technical scheme: the oil-containing drilling cutting treatment method specifically comprises the following steps:
supercritical extraction treatment: firstly, conveying the oil-containing drilling cuttings into an extraction kettle, closing a cover to seal the extraction kettle, and then adding CO2Supercritical CO prepared by supercritical fluid preparation and recovery module2Conveying to an extraction kettle to make supercritical CO2Carrying out extraction reaction with oil phase substances in the oil-containing drilling cuttings for 1.3-1.7 hours; finally, the extracted supercritical CO is treated2Conveying the mixture of fluid and oil phase substance to a separation kettle to make supercritical CO2Conversion of fluids to gaseous CO2Separating from oil phase substances; the separated oil phase substance enters an oil storage tank, and the separated gaseous CO2Recovery to CO2The supercritical fluid preparation and recovery module is used circularly;
thermal desorption treatment: drilling cutting waste residues after extraction reaction of the extraction kettle enter a combustion furnace cavity in the thermal desorption module, the temperature is heated to 300-400 ℃ for desorption pyrolysis, the pyrolysis time is 2-4 h, and the pyrolyzed waste residues reach the standard and are discharged outside.
As an improvement of the invention, during the thermal desorption treatment, a working mode of one-time feeding and one-time discharging is adopted, so that oxygen is prevented from being brought in due to continuous feeding.
As an improvement of the invention, the system also comprises a pyrolysis oil gas recovery module and a tail gas purification treatment module;
the pyrolysis oil gas recovery module is used for recovering high-temperature oil gas generated in the thermal desorption process, the separated oil phase is conveyed to the oil storage tank, the separated wastewater is treated and then discharged after reaching the standard, and the non-condensable gas returns to the combustion furnace for combustion;
the tail gas purification treatment module is used for purifying the combustion tail gas of the combustion furnace so as to enable the combustion tail gas to reach the standard and be discharged outside.
The invention has the beneficial effects that: a process for treating the oily drilling cuttings includes extracting supercritical CO in extracting reactor2The fluid and oil phase substances in the oil-containing drilling cuttings are subjected to extraction reaction for 1.3-1.7 hours, the recovery rate of an oil phase reaches over 84%, then the drilling cuttings waste residues after the extraction reaction are conveyed into a combustion furnace cavity in a thermal desorption module, the temperature is heated to 300-400 ℃ for desorption pyrolysis, the pyrolysis time is 2-4 hours, low-content petroleum hydrocarbons in the drilling cuttings waste residues are recovered through thermal desorption, and water-soluble organic pollutants in the drilling cuttings waste residues are degraded in a stable and deep mode. TPH in the pyrolysis waste residue reaches the requirement of GB4284-2018 standard limit value; COD in waste residue leachateCrThe indexes are stably upgraded to reach the grade 1 emission standard of GB8978-1996, the pyrolytic waste residues reach the I type solid waste standard requirements of the national standard GB18599-2020 general industrial solid waste storage and landfill pollution control standard, the total oil phase recovery rate is up to more than 99%, and high-valued recovery, waste residue upgrading treatment and safe disposal of the oil phase of the drilling oil-containing drilling cuttings are realized. Compared with pure supercritical CO in the prior art, the invention2The extraction technology shortens the extraction reaction time by more than 40 percent on the premise of keeping the total recovery rate of high-quality oil phase substances, greatly improves the treatment efficiency of supercritical extraction equipment, and reduces the extraction energy consumption cost by more than 40 percent.
The temperature of a combustion furnace cavity in the thermal desorption module is set to be 300-400 ℃ for desorption pyrolysis, so that the resource utilization rate of the pyrolysis waste residue is high and the environment is protected on the premise of ensuring the quality of the recovered oil phase. If the temperature is too low (lower than 300 ℃), the thermal desorption of the drilling cutting waste residue is insufficient, so that the oil phase recovery rate is reduced, and the pyrolytic waste residue cannot meet the standard requirement of class I solid waste of the national standard GB 18599-2020; if the temperature is too high (higher than 400 ℃), as the high-temperature pyrolysis waste residue is mostly ash and carbon components, the particle size is small, structural force is lacked, dust is easy to raise, secondary pollution is caused, and the resource utilization rate is low.
Furthermore, in the thermal desorption treatment process, a working mode of one-time feeding and one-time discharging, namely an intermittent working mode, is adopted, so that oxygen is prevented from being brought in due to continuous feeding, part of petroleum hydrocarbon in the extracted drilling cutting waste residue is oxidized and degraded due to the invasion of the oxygen, and cannot be effectively recovered, so that the quality and recovery rate of an oil phase recovered by thermal desorption are influenced, and even the waste of petroleum hydrocarbon resources is caused.
Drawings
Fig. 1 is a process flow diagram of a method of treating oil-laden cuttings in accordance with the present invention.
In the figure: 1. an extraction kettle; 2. CO 22A supercritical fluid preparation and recovery module; 3. a separation kettle; 4. an oil storage tank; 5. a pyrolysis oil gas recovery module; 6. a tail gas purification treatment module; 7. a thermal desorption module.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention and are not to be construed as limiting the present invention.
The first embodiment is as follows:
the embodiment of the method only carries out supercritical CO on the oily drill cuttings2The extraction separation treatment specifically comprises the following steps:
supercritical extraction treatment: the method comprises the steps of collecting 5065m deep well shale gas drilling oil-containing drill cuttings in a certain shale gas productivity demonstration area of Chongqing. Firstly, conveying the oil-containing drilling cuttings to a material basket of an extraction kettle 1 through a feeding pump, closing a cover to seal the extraction kettle 1, wherein the pressure and the temperature of the extraction kettle are respectively 10MPa and 45 ℃, and then, introducing CO into the extraction kettle 12Supercritical CO produced by supercritical fluid production and recovery module 22Conveying to the extraction kettle 1 by a conveying pump to ensure that the supercritical CO is generated2With oil phase material in oil-containing drill cuttingsCarrying out extraction reaction for 3 h; finally, the extracted supercritical CO is treated2Conveying the mixture of the fluid and the oil phase substance to a separation kettle, wherein the pressure and the temperature of the separation kettle are 7MPa and 60 ℃, so that the supercritical CO is generated2Conversion of fluids to gaseous CO2Separating from oil phase substances; the separated oil phase substance enters an oil storage tank 4, and the separated gaseous CO2Recovery to CO2The supercritical fluid preparation and recovery module 2 is recycled. And measuring the oil phase substances recovered by the separation kettle at intervals of 30min within the range of 0-3 h of the extraction reaction, and pumping the oil phase substances into an oil storage tank 4 for storage.
And after the extraction reaction reaches 3 hours, depressurizing and cooling the extraction kettle until normal pressure and normal temperature are reached, starting the quick opening device of the extraction kettle, hoisting the material taking basket, and discharging the low-oil-content drilling cutting waste residues after extraction. Collecting the extracted drilling cutting waste residue after extraction treatment for 3h, and sequentially analyzing the content of residual oil phase in the waste residue, TPH (thermoplastic vulcanizate) and pH and COD (chemical oxygen demand) in the waste residue leachateCrThe results of the indexes of pollutants such as color, SS and the like are shown in a table 1, a comparison table of the treatment effects of the first to the fourth pairs of the oily drilling cuttings and a table 2, a comparison table of the total recovery rate of the oil phase treated by the first to the fourth pairs of the oily drilling cuttings.
The second embodiment:
the embodiment of the method for treating the oily drill cuttings by supercritical CO2The extraction separation and thermal desorption comprehensive treatment method specifically comprises the following steps:
supercritical extraction treatment: collecting 4980m deep well shale gas drilling oil-containing drill cuttings in a certain shale gas productivity demonstration area in Chongqing region. Firstly, conveying the oil-containing drilling cuttings to a material basket of an extraction kettle 1 through a feeding pump, closing a cover to seal the extraction kettle 1, wherein the pressure and the temperature of the extraction kettle are respectively 8MPa and 45 ℃, and then, introducing CO into the extraction kettle 12Supercritical CO produced by supercritical fluid production and recovery module 22Conveying to the extraction kettle 1 by a conveying pump to ensure that the supercritical CO is generated2Carrying out extraction reaction with oil phase substances in the oil-containing drilling cuttings for 1.3 h; finally, the extracted supercritical CO is treated2Conveying the mixture of the fluid and the oil phase substance to a separation kettle, wherein the pressure and the temperature of the separation kettle are 7MPa and 60 ℃, so that the supercritical CO is generated2Conversion of fluids to gaseous CO2Separating from oil phase substances; the separated oil phase substance enters the oil storage tank 4,separated gaseous CO2Recovery to CO2The supercritical fluid preparation and recovery module 2 is recycled. And measuring the oil phase substances recovered by the separation kettle at intervals of 30min within the range of 0-1.3 h of the extraction reaction, and pumping the oil phase substances into an oil storage tank 4 for storage.
After the extraction reaction reaches 1.3h, the extraction kettle 1 is depressurized and cooled until the normal pressure and the normal temperature are reached, the quick opening device of the extraction kettle 1 is started, the material basket is taken out, and the low oil-containing drilling cutting waste residues after extraction are discharged.
Thermal desorption treatment: the above-mentioned low oily drill chip waste residue after unloading the extraction from extraction cauldron 1 basket is carried to the combustion furnace cavity in thermal desorption module 7 through the conveyer, heats the temperature to 300 ℃ and carries out desorption pyrolysis, and the pyrolysis time is 4h, and the pyrolysis waste residue after the pyrolysis is up to standard and is discharged outward. In the thermal desorption treatment process, a one-time feeding and one-time discharging working mode is adopted, namely, after the low-oil drilling cutting waste residue is added into a combustion furnace at one time, the combustion furnace is sealed for pyrolysis, after pyrolysis is finished, the pyrolysis drilling cutting waste residue is discharged, oxygen is prevented from being brought in due to continuous feeding, partial petroleum hydrocarbon in the extraction drilling cutting waste residue is prevented from being effectively recycled due to oxidative degradation due to invasion of oxygen, and therefore the quality and the recovery rate of an oil phase recovered by thermal desorption are influenced, and even the waste of petroleum hydrocarbon resources is caused. Preferably, the combustion furnace is a jacketed rotary furnace. High-temperature oil gas generated in the thermal desorption process is recycled and separated through a thermal decomposition oil gas recycling module 5, the separated oil phase is conveyed to the oil storage tank 4, other soluble organic matters are cracked into micromolecule gaseous state and are absorbed into wastewater through water condensation, the wastewater is treated by adopting an electro-Fenton-electrochemical catalysis combined process and then is discharged after reaching the standard, and non-condensable gas is returned to the combustion furnace for combustion; the combustion tail gas generated in the thermal desorption process is purified by the tail gas purification treatment module 6 and then discharged after reaching the standard.
Collecting supercritical CO2Extracting drilling cutting waste residue after extraction treatment for 1.3h and pyrolyzing drilling cutting waste residue after thermal desorption treatment, and respectively analyzing the content of residual oil phase in the waste residue, TPH and pH and COD in the waste residue leachateCrThe results of the indexes of pollutants such as color and SS are shown in the table 1, the first to the fourth pairs of the treatment effects of the oil-containing drilling cuttings are comparedTable 2 examples one to four comparative tables of total oil phase recovery for oil-containing drill cuttings treatment.
Example three:
the embodiment of the method for treating the oily drill cuttings by supercritical CO2The extraction separation and thermal desorption comprehensive treatment method specifically comprises the following steps:
supercritical extraction treatment: the oil-containing drilling cuttings of deep well shale gas drilling in the 5300m demonstration area for the shale gas productivity in the Chongqing region are collected. Firstly, conveying the oil-containing drilling cuttings to a material basket of an extraction kettle 1 through a feeding pump, closing a cover to seal the extraction kettle 1, wherein the pressure and the temperature of the extraction kettle are respectively 10MPa and 45 ℃, and then, introducing CO into the extraction kettle 12Supercritical CO prepared by supercritical fluid preparation and recovery module 22Conveying to the extraction kettle 1 by a conveying pump to ensure that the supercritical CO is generated2Carrying out extraction reaction with oil phase substances in the oil-containing drilling cuttings for 1.5 h; finally, the extracted supercritical CO is treated2Conveying the mixture of the fluid and the oil phase substance to a separation kettle, wherein the pressure and the temperature of the separation kettle are 7MPa and 60 ℃, so that the supercritical CO is generated2Conversion of fluids to gaseous CO2Separating from oil phase substances; the separated oil phase substance enters an oil storage tank 4, and the separated gaseous CO2Recovery to CO2The supercritical fluid preparation and recovery module 2 is recycled. And measuring the oil phase substances recovered by the separation kettle at intervals of 30min within the range of 0-1.5 h of the extraction reaction, and pumping the oil phase substances into an oil storage tank 4 for storage.
After the extraction reaction reaches 1.5h, the extraction kettle 1 is depressurized and cooled until the normal pressure and the normal temperature are reached, the quick opening device of the extraction kettle 1 is started, the material basket is taken out, and the low oil-containing drilling cutting waste residues after extraction are discharged.
Thermal desorption treatment: the above-mentioned low oiliness drill chip waste residue after unloading the extraction from extraction cauldron 1 basket is carried to the combustion furnace cavity in the thermal desorption module 7 through the conveyer, heats the temperature to 350 ℃ and carries out desorption pyrolysis, and the pyrolysis time is 3h, and the pyrolysis waste residue after the pyrolysis is up to standard is arranged outward. In the thermal desorption treatment process, a working mode of one-time feeding and one-time discharging is adopted, so that oxygen is prevented from being brought in due to continuous feeding, part of petroleum hydrocarbon in the extracted drilling cutting waste residue is oxidized and degraded due to the invasion of the oxygen, and cannot be effectively recovered, so that the quality and recovery rate of an oil phase recovered by thermal desorption are influenced, and even the waste of petroleum hydrocarbon resources is avoided. High-temperature oil gas generated in the thermal desorption process is recycled and separated through a thermal decomposition oil gas recycling module 5, the separated oil phase is conveyed to the oil storage tank 4, other soluble organic matters are cracked into micromolecule gaseous state and are absorbed into wastewater through water condensation, the wastewater is treated by adopting an electro-Fenton-electrochemical catalysis combined process and then is discharged after reaching the standard, and non-condensable gas is returned to the combustion furnace for combustion; the combustion tail gas generated in the thermal desorption process is purified by the tail gas purification treatment module 6 and then discharged after reaching the standard.
Collecting supercritical CO2Respectively analyzing the content of residual oil phase in the waste residue, TPH (thermoplastic vulcanizate) and pH (chemical oxygen demand) and COD (chemical oxygen demand) in the waste residue leachate after the extraction treatment of the extracted waste cuttings waste residue and the thermal desorption treatment of the thermal cuttings waste residue after the extraction treatment for 1.5hCrThe results of the indexes of pollutants such as chromaticity, SS and the like are shown in the table 1, the comparison table of the treatment effects of the first to the fourth pairs of oil-containing drilling cuttings in the example and the table 2, the comparison table of the total recovery rate of the oil phase treated by the first to the fourth pairs of oil-containing drilling cuttings in the example and the table 2.
Example four:
the embodiment of the method for treating the oily drill cuttings by supercritical CO2The extraction separation and thermal desorption comprehensive treatment method specifically comprises the following steps:
supercritical extraction treatment: collecting oil-containing drill cuttings of deep well shale gas drilling in 5150m of a certain shale gas capacity demonstration area in Chongqing areas. Firstly, conveying the oil-containing drilling cuttings to a material basket of an extraction kettle 1 through a feeding pump, closing a cover to seal the extraction kettle 1, wherein the pressure and the temperature of the extraction kettle are respectively 12MPa and 45 ℃, and then, introducing CO into the extraction kettle 12Supercritical CO prepared by supercritical fluid preparation and recovery module 22Conveying to the extraction kettle 1 by a conveying pump to ensure that the supercritical CO is generated2Carrying out extraction reaction with oil phase substances in the oil-containing drilling cuttings for 1.7 h; finally, the extracted supercritical CO is treated2Conveying the mixture of the fluid and the oil phase substance to a separation kettle, wherein the pressure and the temperature of the separation kettle are 7MPa and 60 ℃, so that the supercritical CO is generated2Conversion of fluids to gaseous CO2Separating from oil phase substances; the separated oil phase substance enters an oil storage tank 4, and the separated gaseous CO2Recovery to CO2Supercritical fluid preparation and recovery moduleAnd 2, recycling. And measuring the oil phase substances recovered by the separation kettle at intervals of 30min within the range of 0-1.7 h of the extraction reaction, and pumping the oil phase substances into an oil storage tank 4 for storage.
After the extraction reaction reaches 1.7h, the extraction kettle 1 is depressurized and cooled until the normal pressure and the normal temperature are reached, the quick opening device of the extraction kettle 1 is started, the material basket is taken out, and the low oil-containing drilling cutting waste residues after extraction are discharged.
Thermal desorption treatment: the above-mentioned low oiliness drill chip waste residue after unloading the extraction from extraction cauldron 1 basket is carried to the combustion furnace cavity in the thermal desorption module 7 through the conveyer, heats the temperature to 300 ℃ and carries out desorption pyrolysis, and the pyrolysis time is 2h, and the pyrolysis waste residue after the pyrolysis is up to standard is arranged outward. In the thermal desorption treatment process, an intermittent treatment mode, namely a one-time feeding and one-time discharging working mode, is adopted, so that the phenomenon that oxygen is brought in due to continuous feeding, part of petroleum hydrocarbon in the extracted drilling cutting waste residue is oxidized and degraded due to the invasion of the oxygen, and cannot be effectively recovered, so that the quality and the recovery rate of an oil phase recovered by thermal desorption are influenced, and even the waste of petroleum hydrocarbon resources is caused is avoided. High-temperature oil gas generated in the thermal desorption process is recycled and separated through a thermal decomposition oil gas recycling module 5, the separated oil phase is conveyed to the oil storage tank 4, other soluble organic matters are cracked into micromolecule gaseous state and are absorbed into wastewater through water condensation, the wastewater is treated by adopting an electro-Fenton-electrochemical catalysis combined process and then is discharged after reaching the standard, and non-condensable gas is returned to the combustion furnace for combustion; the combustion tail gas generated in the thermal desorption process is purified by the tail gas purification treatment module 6 and then discharged after reaching the standard.
Collecting supercritical CO2Respectively analyzing the content of residual oil phase in the waste residue, TPH (thermal pressure hydrogen) and the pH value and COD (chemical oxygen demand) in the leachate of the waste residue by extracting the extracted drilling cutting waste residue after 1.7h of extraction treatment and thermally desorbing the extracted drilling cutting waste residueCrThe results of the pollutant indexes such as the color and the SS are shown in the table 1, the comparison table of the treatment effect of the first to the fourth pairs of the oily drilling cuttings and the table 2, the comparison table of the total recovery rate of the oil phase of the first to the fourth pairs of the oily drilling cuttings:
Figure 32116DEST_PATH_IMAGE001
table 1 comparison of the effect of the treatment of the oily drill cuttings in the first to fourth pairs of examples
Figure 401786DEST_PATH_IMAGE002
Table 2 comparison of total recovery of oil phase for one to four pairs of oil-containing drill cuttings treatments
In summary, from tables 1 and 2, it can be seen that: after the supercritical extraction treatment is carried out on the oil-containing drilling cuttings by adopting the embodiment, the extraction reaction time is 3 hours, and the total recovery rate of oil phase substances is not lower than 99.6%. Extraction of COD from drilling cuttings waste residueCr359mg/L, far exceeds COD in national standard GB8978-1996 Integrated wastewater discharge StandardCr<60 mg/L. The extracted drilling cutting waste residue can not meet the I-type solid waste standard requirement of the national standard GB18599-2020 Standard for general Industrial solid waste storage and landfill pollution control.
After the oil-containing drilling cuttings are treated by the method in the second to fourth embodiments, the total recovery rate of oil-phase substances is more than 99.3%, and the TPH in the pyrolytic drilling cuttings waste residue is 96-215 mg/kg, which is far lower than the standard limit value (TPH) of the agricultural sludge pollutant control standard (GB 4284-2018)<3000 mg/kg); COD in pyrolytic drilling cutting waste residue leachateCrThe basic control items such as pH and the like are all lower than the limit value of the 1-level standard in the national standard GB8978-1996 integrated wastewater discharge standard, the waste residue reaches the standard requirement of the I-type solid waste in the national standard GB18599-2020 general industrial solid waste storage and landfill pollution control standard, the extraction reaction time is 1.3 h-1.7 h, compared with the embodiment I, the extraction time is saved by more than 40%, the treatment efficiency of supercritical extraction equipment is greatly improved, and the extraction energy consumption cost is reduced by more than 40%. The oil phase substances in the oil-containing drilling cuttings are recycled at high value, the waste residues are subjected to standard improvement treatment, the waste residues can be subjected to safe treatment such as brick burning, road building and soil backfilling, and the method is simple in process, low in cost, good in economical efficiency, safe and environment-friendly.
The above is a detailed description of the method for treating oil-containing drill cuttings provided by the present invention, and specific examples are applied herein to explain the structural principle and the implementation of the present invention, and the above examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims (3)

1. The method for treating the oil-containing drill cuttings is characterized by comprising the following steps of:
supercritical extraction treatment: firstly, oil-containing drilling cuttings are conveyed into an extraction kettle, a cover is closed to seal the extraction kettle, and then CO is added2Supercritical CO prepared by supercritical fluid preparation and recovery module2Conveying to an extraction kettle to make supercritical CO2Carrying out extraction reaction with oil phase substances in the oil-containing drilling cuttings for 1.3-1.7 hours; finally, the extracted supercritical CO is treated2Conveying the mixture of fluid and oil phase substance to a separation kettle to make supercritical CO2Conversion of fluids to gaseous CO2Separating from oil phase substances; the separated oil phase substance enters an oil storage tank, and the separated gaseous CO2Recovery to CO2The supercritical fluid preparation and recovery module is used circularly;
thermal desorption treatment: drilling cutting waste residues after extraction reaction of the extraction kettle enter a combustion furnace cavity in the thermal desorption module, the temperature is heated to 300-400 ℃ for desorption pyrolysis, the pyrolysis time is 2-4 h, and the pyrolyzed waste residues reach the standard and are discharged outside.
2. The method for treating the oily drill cuttings according to claim 1, wherein in the thermal desorption treatment process, a one-time feeding mode and a one-time discharging mode are adopted, so that oxygen is prevented from being brought in due to continuous feeding.
3. The method for processing oil-containing drill cuttings according to claim 1 or 2, further comprising a pyrolysis oil gas recovery module and a tail gas purification treatment module;
the pyrolysis oil gas recovery module is used for recovering high-temperature oil gas generated in the thermal desorption process, the separated oil phase is conveyed to the oil storage tank, the separated wastewater is treated and then discharged after reaching the standard, and the non-condensable gas returns to the combustion furnace for combustion;
the tail gas purification treatment module is used for purifying the combustion tail gas of the combustion furnace so as to enable the combustion tail gas to reach the standard and be discharged outside.
CN202210421200.9A 2022-04-21 2022-04-21 Oil-containing drilling cutting treatment method Pending CN114687687A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104946291A (en) * 2015-06-05 2015-09-30 中国石油集团川庆钻探工程有限公司工程技术研究院 Method for treating drill cuttings through supercritical CO2 extraction
CN110922015A (en) * 2019-12-17 2020-03-27 西安华盛坤泰能源环保科技有限公司 Harmless treatment method and system for fluid oily sludge
CN214735562U (en) * 2021-04-25 2021-11-16 河南锐实达分离设备科技股份有限公司 Complete equipment for continuously treating oil-containing solid waste of drilling well
US20220041486A1 (en) * 2018-09-12 2022-02-10 Shanghai Huachang Environmental Protection Co., Ltd. Rotational flow rotation deoiling method and device for oil-based mud rock debris

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104946291A (en) * 2015-06-05 2015-09-30 中国石油集团川庆钻探工程有限公司工程技术研究院 Method for treating drill cuttings through supercritical CO2 extraction
US20220041486A1 (en) * 2018-09-12 2022-02-10 Shanghai Huachang Environmental Protection Co., Ltd. Rotational flow rotation deoiling method and device for oil-based mud rock debris
CN110922015A (en) * 2019-12-17 2020-03-27 西安华盛坤泰能源环保科技有限公司 Harmless treatment method and system for fluid oily sludge
CN214735562U (en) * 2021-04-25 2021-11-16 河南锐实达分离设备科技股份有限公司 Complete equipment for continuously treating oil-containing solid waste of drilling well

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