Method for extracting solid-free mineral oil from oil-based drilling cuttings at low temperature

Abstract

The invention discloses a method for extracting mineral oil from oil-based drilling cuttings at low temperature, which comprises the following steps of: mixing the oil-based drilling cuttings with a dust inhibitor by adopting a segmented and graded oil-solid separation method, and desorbing in a first-section rotary thermal desorption furnace to obtain light mineral oil and a residual solid phase; the residual solid phase is sorted, and the solid phase with the particle size smaller than or equal to 38 micrometers is sorted out to serve as a sorted solid phase material; and mixing the separated solid-phase material with a cracking catalyst, and carrying out cracking in a two-stage rotary pyrolyzing furnace to obtain the heavy mineral oil. According to the method for extracting the mineral oil from the oil-based drilling cuttings at the low temperature, the mineral oil can be efficiently extracted from the oil-based drilling cuttings at the low temperature of 300 DEG C or below, the oil recovery rate can be increased to 85% or above, the impurity content of the recovered mineral oil is 0.5 wt% or below, the oil quality is good, and low-temperature efficient oil recovery is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil-based drilling cuttings resource recovery, in particular to a method for low-temperature extraction of solid-free mineral oil from oil-based drilling cuttings. BACKGROUND

[0002] In the process of oil and gas exploration, due to the special structure of the stratum, oil-based drilling fluid needs to be used to protect the drilling bit. In this process, a large amount of mixed drilling cuttings of oil-based drilling fluid is discharged to the ground. These oil-based drilling cuttings containing cuttings are treated by a solid control system and then recycled, but at the same time, a large amount of waste oil-based drilling cuttings is also produced. Oil-based drilling cuttings, as a major, emerging and complex hazardous solid waste in the oil industry, have shown a rapid growth trend in production in recent years with the advancement of shale gas exploration and development. According to the latest version of the National Hazardous Waste List, such oil-based drilling cuttings belong to HW08 hazardous waste, which contains a large amount of waste mineral oil pollutants. If not effectively treated, it will not only cause serious harm to the ecological environment such as land and water resources, but also waste a large amount of available resources.

[0003] At present, the most widely used industrialized treatment for oil-based drilling cuttings is pyrolysis. According to the different treatment temperatures, it can be divided into low-temperature pyrolysis (LTTD, 100-350℃) and high-temperature pyrolysis (HTTD, 350-600℃). Comprehensive analysis of existing patent reports, such as CN 116947083 A, CN 118065785 A, CN 118699043 A, CN 118491145 A, CN 112852466 B, CN 111732967 B, etc. The current pyrolysis method mainly exists problems such as high pyrolysis temperature (≥400℃, directly leading to high disposal cost, easy coking of equipment, etc.), high content of solid impurities in recovered mineral oil (≥8%), strong suspension (need to be statically settled for more than 10d before reuse, which cannot meet the requirements of drilling), etc.

[0004] In summary, the existing pyrolysis treatment technology for oil-based drilling cuttings has the problems of low overall recovery efficiency, high energy consumption and low purity of recovered mineral oil, which restricts the industrial application of oil-based drilling cuttings pyrolysis treatment technology. SUMMARY

[0005] In view of the problems of high energy consumption, high impurity content of recovered oil and low recovery rate in the existing oil-based drilling cuttings pyrolysis oil extraction, the application discloses a method for low-temperature extraction of solid-free mineral oil from oil-based drilling cuttings. On the basis of sufficient analysis of the characteristics of mineral oil and drilling cuttings in oil-based drilling cuttings and the action mechanism of the two, a low-temperature two-stage mineral oil extraction process of low-temperature thermal desorption in the first stage and low-temperature thermal cracking in the second stage is innovatively proposed, and a dust inhibitor and a cracking catalyst are developed. The method has the advantages of low operating temperature (≤300 DEG C), low oil content of tailings (≤0.3wt%), low impurity content of recovered mineral oil (≤0.5wt%) and high oil recovery rate (≥85%), and better realizes the goals of efficient resource utilization and harmless disposal of tailings of mineral oil in oil-based drilling cuttings.

[0006] Based on the problems of the existing oil-based drilling cuttings pyrolysis oil extraction, the main purpose of the application is to provide an oil-based drilling cuttings oil extraction method with low temperature, low impurity content, low mineral oil residual rate and high oil recovery rate, so as to realize efficient reuse of mineral oil in oil-based drilling cuttings.

[0007] As an aspect of the application, a method for low-temperature extraction of mineral oil from oil-based drilling cuttings is provided, comprising the following steps:

[0008] S1, uniformly mixing the oil-based drilling cuttings and the dust inhibitor, and then placing them in a one-stage rotary thermal desorption furnace to perform desorption at 265-300 DEG C, to complete extraction of light mineral oil, and to obtain light mineral oil and residual solid phase;

[0009] S2, sorting the residual solid phase, with a sorting limit of 38 microns, to sort out solid phase with a particle size of ≤38 microns as sorted solid phase material;

[0010] S3, uniformly mixing the sorted solid phase material and the cracking catalyst, and then placing them in a two-stage rotary pyrolysis furnace to perform cracking at 280-300 DEG C, to complete oil-solid separation, and to obtain heavy mineral oil.

[0011] In the application, the light mineral oil refers to mineral oil with a carbon chain number < 16, and the heavy mineral oil refers to mineral oil with a carbon chain number ≥ 16.

[0012] In a specific implementable manner, the desorption time of step S1 is 30-60 min, and the cracking time of step S3 is 25-40 min.

[0013] In a specific implementable manner, in step S1, the mass fraction of the oil-based drilling cuttings is 95-97 parts, and the mass fraction of the dust inhibitor is 3-5 parts, based on 100 mass parts of the total mass of the oil-based drilling cuttings and the dust inhibitor.

[0014] In a specific implementable manner, in step S1, the dust inhibitor is kaolinite or illite or any combination thereof.

[0015] In a specific implementable manner, in step S1, the particle size of the dust inhibitor is ≤100 μm.

[0016] In a specific implementable manner, in step S1, the dust inhibitor is compounded by kaolinite and illite with a mass ratio of (0.5-3):1.

[0017] In a specific implementable manner, in step S3, the mass fraction of the sorted solid phase material is 92-95 parts and the mass fraction of the cracking catalyst is 5-8 parts, based on 100 parts of the total mass of the sorted solid phase material and the cracking catalyst.

[0018] In a specific implementable manner, in step S3, the cracking catalyst is nickel chlorite, bauxite or potassium feldspar or any combination thereof.

[0019] In a specific implementable manner, in step S3, the particle size of the cracking catalyst is ≤38 μm.

[0020] As another aspect of the present application, the above-mentioned method for low-temperature extraction of mineral oil from oil-based drill cuttings is applied to the resourceization of oil-based drill cuttings.

[0021] The above-mentioned technical solution provided by the embodiments of the present application has at least the following beneficial effects:

[0022] 1. The present application takes oil-based drill cuttings generated in the process of shale gas development as the disposal object, and realizes efficient separation of mineral oil and drill cuttings in the oil-based drill cuttings at a lower temperature (265-300℃). The oil content of the deoiled tailings is less than 0.3wt%, which meets the current highest standard of environmental protection, and the recovered mineral oil can be directly reused in the oil-based drilling fluid preparation system, effectively ensuring the low-cost green development of shale gas.

[0023] 2. The present application makes full use of the characteristics and action mechanism of mineral oil and drill cuttings in oil-based drill cuttings, and proposes a segmented and graded oil-solid separation method according to the combination difference between mineral oil of different carbon numbers and drill cuttings of different particle sizes, i.e. light mineral oil is subjected to oil-solid separation and recovery in a first thermal desorption furnace, while a dust inhibitor is developed and used, so as to reduce the impurity content of the recovered mineral oil to less than 0.5wt%, and improve the utilization value of the mineral oil; heavy mineral oil is subjected to oil-solid separation and recovery in a second catalytic cracking furnace, while a cracking catalyst is developed and used, so as to successfully reduce the oil recovery temperature to below 300℃, and increase the recovery rate of the mineral oil to more than 85%, realizing low-temperature and efficient oil recovery. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to make the skilled in the art better understand the technical solutions of the present application, the drawings needed in the embodiment description will be briefly introduced below, obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by the skilled in the art without any creative effort, wherein:

[0025] Figure 1 The particle size distribution diagram of the three kinds of oil-based drilling cuttings solid phases involved in the embodiments of the present application.

[0026] Figure 2 The mineral composition diagram of the three kinds of oil-based drilling cuttings solid phases involved in the embodiments of the present application. DETAILED DESCRIPTION

[0027] In order to make the skilled in the art better understand the technical solutions of the present application, the drawings needed in the embodiment description will be briefly introduced below, obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by the skilled in the art without any creative effort, wherein:

[0028] The inventors have studied the method for extracting mineral oil from oil-based drilling cuttings, and found that the existing technology for processing oil-based drilling cuttings can be divided into low-temperature pyrolysis (LTTD, 100-350℃) and high-temperature pyrolysis (HTTD, 350-600℃); among them, the high-temperature pyrolysis method has higher oil recovery rate and better oil quality, but has high energy consumption for heating and problems such as high disposal cost and easy coking of equipment; the low-temperature pyrolysis method has lower energy consumption for heating, but has lower oil recovery rate, high impurity content of the recovered mineral oil solid phase, poor oil quality, high oil content in the oil-removed tailings, high tailings treatment cost and easy soil pollution; none of them can meet the inventors' expectations. The inventors have made further research and unexpectedly found that: by using a staged and graded oil-solid separation method, i.e. light mineral oil is subjected to oil-solid separation and recovery in a first-stage thermal desorption furnace, heavy mineral oil is subjected to oil-solid separation and recovery in a second-stage catalytic cracking furnace, and a dust suppressant is added in the thermal desorption process and a cracking catalyst is added in the catalytic cracking process, the mineral oil can be efficiently extracted from the oil-based drilling cuttings at a low temperature below 300℃, the oil recovery rate can be increased to more than 85%, the impurity content of the recovered mineral oil is less than 0.5wt%, the oil quality is good, and low-temperature efficient oil recovery is realized.

[0029] Unless otherwise specified, the parts referred to in the present application are weight parts, and the percentages referred to in the present application are mass percentages.

[0030] In the embodiments and comparative examples of the present application:

[0031] In the embodiments and comparative examples, the oil-based drilling cuttings sample 1, the oil-based drilling cuttings sample 2 and the oil-based drilling cuttings sample 3 used are three representative oil-based drilling cuttings produced in the horizontal section of the drilling link in the shale gas development process, and the oil content, water content and residue content thereof are shown in Table 1:

[0032] Table 1 oil, water, residue three-phase composition of oil-based drilling cuttings

[0033] Oil-based drill cuttings Oil content / % Water content / % Sludge content / % Sample 1 8.79 8.30 82.91 Sample 2 13.26 8.50 78.24 Sample 3 18.74 8.90 72.36

[0034] The particle size distribution diagram of the oil-based drilling cuttings solid phase of the oil-based drilling cuttings samples 1-3 is shown in Figure 1 , Figure 1 Sample 1 in the figure refers to the oil-based drilling cuttings sample 1, Figure 1 Sample 2 in the figure refers to the oil-based drilling cuttings sample 2, Figure 1 Sample 3 in the figure refers to the oil-based drilling cuttings sample 3. It can be known from the figure that in the three oil-based drilling cuttings samples, the components distributed in the particle size below 38 μm all account for more than 70%, which belongs to the fine particle category, and on the one hand, the combination with mineral oil is close, and the separation is difficult, on the other hand, in the oil-solid pyrolysis separation process, oil gas is easy to enter the mineral oil collection system, which seriously affects the quality of the recovered mineral oil. Figure 1 The mineral composition diagram of the oil-based drilling cuttings solid phase of the oil-based drilling cuttings samples 1-3 is shown in

[0035] , Figure 2 The first batch of samples in the figure refers to the oil-based drilling cuttings sample 1, Figure 2 The second batch of samples in the figure refers to the oil-based drilling cuttings sample 2, Figure 2 The first batch of samples in the figure refers to the oil-based drilling cuttings sample 3. It can be known from the figure that in the first batch of samples and the second batch of samples, barite is relatively close in composition, and five types of minerals such as quartz, calcite, dolomite, mica and barite are mainly used; the third batch of samples is slightly different, and the minerals such as quartz, chlorite and feldspar are mainly used. Calcite, barite and dolomite; but overall, there are carbonate and barite components in the three oil-based drilling cuttings samples which are relatively firm in combination with mineral oil, further increasing the difficulty of oil-solid separation. Figure 2 Figure 2 In the examples and comparative examples of the present application,

[0036] Light mineral oil refers to mineral oil with carbon chain number < 16, and heavy mineral oil refers to mineral oil with carbon chain number ≥ 16;

[0037] The oil-removed tailings refer to the total of the first-stage tailings and the second-stage tailings;

[0038] The recovered mineral oil refers to the total of the light mineral oil and the heavy mineral oil obtained by separation;

[0039] The oil recovery rate refers to the sum of the mass of the light mineral oil and the heavy mineral oil obtained by separation, and the percentage of the total mass of the mineral oil in the oil-based drilling cuttings sample.

[0040] Example 1:

[0041] Example 1:

[0042] ​The embodiment provides a method for extracting mineral oil at low temperature from oil-based drilling cuttings, and comprises the following steps:

[0043] (1) uniformly mixing oil-based drilling cuttings sample 1 and kaolinite at a mass ratio of 96:4, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C, and the desorption time is 25 min; light mineral oil and residual solid phase are obtained;

[0044] (2) sorting the residual solid phase obtained in step (1), and the sorting limit value is 38 mu m; the solid phase with a particle size of less than 38 mu m is sorted as a sorted solid phase material; and the solid phase with a particle size greater than 38 mu m is sorted as a first-stage tail residue;

[0045] (3) uniformly mixing the sorted solid phase material and nickel chlorite at a mass ratio of 94:6, and then placing the mixture in a second rotary pyrolysis furnace to perform pyrolysis, the pyrolysis temperature is 300 DEG C, and the pyrolysis time is 25 min; heavy mineral oil and a second-stage tail residue are obtained.

[0046] The oil content of the oil-removed tail residue in the embodiment is 0.28wt%, the impurity content of the recovered mineral oil is 0.42wt%, and the oil recovery rate is 86.15%.

[0047] Example 2:

[0048] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drilling cuttings, and comprises the following steps:

[0049] (1) uniformly mixing oil-based drilling cuttings sample 1 and illite at a mass ratio of 95:5, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C, and the desorption time is 30 min; light mineral oil and residual solid phase are obtained;

[0050] (2) sorting the residual solid phase obtained in step (1), and the sorting limit value is 38 mu m; the solid phase with a particle size of less than 38 mu m is sorted as a sorted solid phase material; and the solid phase with a particle size greater than 38 mu m is sorted as a first-stage tail residue;

[0051] (3) uniformly mixing the sorted solid phase material and nickel chlorite at a mass ratio of 94:6, and then placing the mixture in a second rotary pyrolysis furnace to perform pyrolysis, the pyrolysis temperature is 300 DEG C, and the pyrolysis time is 25 min; heavy mineral oil and a second-stage tail residue are obtained.

[0052] The oil content of the oil-removed tail residue in the embodiment is 0.30wt%, the impurity content of the recovered mineral oil is 0.50wt%, and the oil recovery rate is 85.72%.

[0053] Example 3:

[0054] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drilling cuttings, and comprises the following steps:

[0055] (1) oil-based drilling cuttings sample 1 is mixed with dust suppressant at a mass ratio of 97:3, and then placed in a first-stage rotary thermal desorption furnace for desorption at 300°C for 30 min; light mineral oil and a remaining solid phase are obtained;

[0056] In step (1), the dust suppressant is compounded from kaolinite and illite at a mass ratio of 3:1.

[0057] (2) The remaining solid phase obtained in step (1) is sorted, with a sorting limit of 38 μm; a solid phase with a particle size of ≤38 μm is sorted out as a sorted solid phase material; and a solid phase with a particle size greater than 38 μm is sorted out as a first-stage tailing.

[0058] (3) The sorted solid phase material is mixed with nickel chlorite at a mass ratio of 94:6, and then placed in a second-stage rotary pyrolysis furnace for pyrolysis at a pyrolysis temperature of 300°C for 25 min; heavy mineral oil and a second-stage tailing are obtained.

[0059] The oil content of the oil-removed tailing in this embodiment is 0.15wt%, the impurity content of the recovered mineral oil is 0.24wt%, and the oil recovery rate is 90.34%.

[0060] Example 4:

[0061] The embodiment provides a method for extracting mineral oil from oil-based drilling cuttings at low temperature, comprising the following steps:

[0062] (1) oil-based drilling cuttings sample 1 is mixed with dust suppressant at a mass ratio of 97:3, and then placed in a first-stage rotary thermal desorption furnace for desorption at 300°C for 30 min; light mineral oil and a remaining solid phase are obtained;

[0063] In step (1), the dust suppressant is compounded from kaolinite and illite at a mass ratio of 3:1.

[0064] (2) The remaining solid phase obtained in step (1) is sorted, with a sorting limit of 38 μm; a solid phase with a particle size of ≤38 μm is sorted out as a sorted solid phase material; and a solid phase with a particle size greater than 38 μm is sorted out as a first-stage tailing.

[0065] (3) The sorted solid phase material is mixed with nickel chlorite at a mass ratio of 94:6, and then placed in a second-stage rotary pyrolysis furnace for pyrolysis at a pyrolysis temperature of 300°C for 25 min; heavy mineral oil and a second-stage tailing are obtained.

[0066] The oil content of the oil-removed tailing in this embodiment is 0.15wt%, the impurity content of the recovered mineral oil is 0.24wt%, and the oil recovery rate is 90.34%.

[0067] Example 5:

[0068] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, and comprises the following steps:

[0069] (1) uniformly mixing oil-based drill cutting sample 1 with a dust inhibitor at a mass ratio of 95:5, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C, and the desorption time is 30 min; light mineral oil and residual solid phase are obtained;

[0070] In step (1), the dust inhibitor is compounded by kaolinite and illite at a mass ratio of 1:1;

[0071] (2) performing sorting on the residual solid phase obtained in step (1), and the sorting limit value is 38 mu m, the solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material; and the solid phase with a particle size greater than 38 mu m is taken as a first-stage tailing;

[0072] (3) uniformly mixing the sorted solid phase material with nickel chlorite at a mass ratio of 94:6, and then placing the mixture in a second rotary pyrolysis furnace to perform pyrolysis, the pyrolysis temperature is 300 DEG C, and the pyrolysis time is 25 min; heavy mineral oil and second-stage tailing are obtained.

[0073] The oil content of the oil-removed tailing in the embodiment is 0.26wt%, the impurity content of the recovered mineral oil is 0.43wt%, and the oil recovery rate is 86.44%.

[0074] Embodiment 6:

[0075] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, and comprises the following steps:

[0076] (1) uniformly mixing oil-based drill cutting sample 1 with a dust inhibitor at a mass ratio of 95:5, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C, and the desorption time is 30 min; light mineral oil and residual solid phase are obtained;

[0077] In step (1), the dust inhibitor is compounded by kaolinite and illite at a mass ratio of 1:2;

[0078] (2) performing sorting on the residual solid phase obtained in step (1), and the sorting limit value is 38 mu m, the solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material; and the solid phase with a particle size greater than 38 mu m is taken as a first-stage tailing;

[0079] (3) uniformly mixing the sorted solid phase material with nickel chlorite at a mass ratio of 94:6, and then placing the mixture in a second rotary pyrolysis furnace to perform pyrolysis, the pyrolysis temperature is 300 DEG C, and the pyrolysis time is 25 min; heavy mineral oil and second-stage tailing are obtained.

[0080] The oil content of the oil-removed tailing in the embodiment is 0.29wt%, the impurity content of the recovered mineral oil is 0.48wt%, and the oil recovery rate is 85.84%.

[0081] Embodiment 7:

[0082] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drilling cuttings, and comprises the following steps:

[0083] (1) uniformly mixing oil-based drilling cuttings sample 1 and a dust inhibitor at a mass ratio of 97:3, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C, and the desorption time is 30 min; light mineral oil and residual solid phase are obtained;

[0084] In step (1), the dust inhibitor is compounded by kaolinite and illite at a mass ratio of 3:1;

[0085] (2) performing sorting on the residual solid phase obtained in step (1), and the sorting limit value is 38 mu m, and the solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material; and the solid phase with a particle size greater than 38 mu m is taken as a first-stage tailing;

[0086] (3) uniformly mixing the sorted solid phase material and a cracking catalyst at a mass ratio of 94:6, and then placing the mixture in a second rotary pyrolysis furnace to perform cracking, the cracking temperature is 300 DEG C, and the cracking time is 25 min; heavy mineral oil and second-stage tailing are obtained;

[0087] In step (3), the cracking catalyst is compounded by nickel chlorite and bauxite at a mass ratio of 1:1.

[0088] The oil content of the oil-removed tailings in the embodiment is 0.10wt%, the impurity content of the recovered mineral oil is 0.25wt%, and the oil recovery rate is 91.80wt%.

[0089] Embodiment 8:

[0090] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drilling cuttings, and comprises the following steps:

[0091] (1) uniformly mixing oil-based drilling cuttings sample 1 and a dust inhibitor at a mass ratio of 97:3, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C, and the desorption time is 30 min; light mineral oil and residual solid phase are obtained;

[0092] In step (1), the dust inhibitor is compounded by kaolinite and illite at a mass ratio of 3:1;

[0093] (2) performing sorting on the residual solid phase obtained in step (1), and the sorting limit value is 38 mu m, and the solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material; and the solid phase with a particle size greater than 38 mu m is taken as a first-stage tailing;

[0094] (3) the sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 94:6, and then is placed in a two-stage rotary pyrolysis furnace to crack at a cracking temperature of 300 DEG C for 25 min; heavy mineral oil and a two-stage tail residue are obtained;

[0095] In step (3), the cracking catalyst is compounded by nickel chlorite and bauxite at a mass ratio of 1:4.

[0096] The oil content of the oil-removed tail residue of the embodiment is 0.15 wt%, the impurity content of the recovered mineral oil is 0.28 wt%, and the oil recovery rate is 90.76 wt%.

[0097] Example 9:

[0098] The embodiment provides a method for extracting mineral oil at a low temperature from oil-based drill cuttings, comprising the following steps:

[0099] (1) oil-based drill cuttings sample 1 is mixed with a dust suppressant at a mass ratio of 97:3, and then is placed in a one-stage rotary thermal desorption furnace to desorb at 300 DEG C for 30 min; light mineral oil and a remaining solid phase are obtained;

[0100] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1.

[0101] (2) the remaining solid phase obtained in step (1) is sorted, and a solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material; a solid phase with a particle size greater than 38 mu m is a one-stage tail residue;

[0102] (3) the sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 94:6, and then is placed in a two-stage rotary pyrolysis furnace to crack at a cracking temperature of 300 DEG C for 25 min; heavy mineral oil and a two-stage tail residue are obtained;

[0103] In step (3), the cracking catalyst is compounded by nickel chlorite and bauxite at a mass ratio of 1:5.

[0104] The oil content of the oil-removed tail residue of the embodiment is 0.24 wt%, the impurity content of the recovered mineral oil is 0.42 wt%, and the oil recovery rate is 88.78 wt%.

[0105] Example 10:

[0106] The embodiment provides a method for extracting mineral oil at a low temperature from oil-based drill cuttings, comprising the following steps:

[0107] (1) oil-based drill cuttings sample 1 is mixed with a dust suppressant at a mass ratio of 97:3, and then is placed in a one-stage rotary thermal desorption furnace to desorb at 300 DEG C for 30 min; light mineral oil and a remaining solid phase are obtained;

[0108] In step (1), the dust inhibitor is compounded by kaolinite and illite with a mass ratio of 3:1;

[0109] (2) The remaining solid phase obtained in step (1) is sorted, and the sorting limit value is 38 μm. The solid phase with a particle size of ≤38 μm is sorted as a sorted solid phase material. The solid phase with a particle size greater than 38 μm is a first-stage tailings;

[0110] (3) The sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 94:6, and then is placed in a second-stage rotary pyrolysis furnace for cracking at a cracking temperature of 300°C and a cracking time of 25 min. Heavy mineral oil and second-stage tailings are obtained;

[0111] In step (3), the cracking catalyst is compounded by nickel chlorite and bauxite with a mass ratio of 4:1.

[0112] The oil content of the oil-removed tailings in this embodiment is 0.13wt%, the impurity content of the recovered mineral oil is 0.26wt%, and the oil recovery rate is 90.42wt%.

[0113] Example 11:

[0114] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, comprising the following steps:

[0115] (1) Oil-based drill cuttings sample 1 is mixed with a dust inhibitor at a mass ratio of 97:3, and then is placed in a first-stage rotary thermal desorption furnace for desorption at 300°C for 30 min. Light mineral oil and a remaining solid phase are obtained;

[0116] In step (1), the dust inhibitor is compounded by kaolinite and illite with a mass ratio of 3:1;

[0117] (2) The remaining solid phase obtained in step (1) is sorted, and the sorting limit value is 38 μm. The solid phase with a particle size of ≤38 μm is sorted as a sorted solid phase material. The solid phase with a particle size greater than 38 μm is a first-stage tailings;

[0118] (3) The sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 94:6, and then is placed in a second-stage rotary pyrolysis furnace for cracking at a cracking temperature of 300°C and a cracking time of 25 min. Heavy mineral oil and second-stage tailings are obtained;

[0119] In step (3), the cracking catalyst is compounded by nickel chlorite and bauxite with a mass ratio of 4:1.

[0120] The oil content of the oil-removed tailings in this embodiment is 0.13wt%, the impurity content of the recovered mineral oil is 0.26wt%, and the oil recovery rate is 90.42wt%.

[0121] Embodiment 12:

[0122] The embodiment provides a method for extracting mineral oil from oil-based drilling cuttings at low temperature, comprising the following steps:

[0123] (1) uniformly mixing oil-based drilling cuttings sample 1 with a dust suppressant at a mass ratio of 97:3, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C, and the desorption time is 30 min; light mineral oil and residual solid phase are obtained;

[0124] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1;

[0125] (2) performing sorting on the residual solid phase obtained in step (1), and the sorting limit value is 38 mu m, and the solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material; and the solid phase with a particle size greater than 38 mu m is taken as a first-stage tailing;

[0126] (3) uniformly mixing the sorted solid phase material with a cracking catalyst at a mass ratio of 94:6, and then placing the mixture in a second rotary pyrolysis furnace to perform cracking, the cracking temperature is 300 DEG C, and the cracking time is 25 min; heavy mineral oil and second-stage tailing are obtained;

[0127] In step (3), the cracking catalyst is compounded by nickel chlorite and potassium feldspar at a mass ratio of 2:1.

[0128] The oil content of the oil-removed tailings in the embodiment is 0.17wt%, the impurity content of the recovered mineral oil is 0.26wt%, and the oil recovery rate is 91.28wt%.

[0129] Embodiment 13:

[0130] The embodiment provides a method for extracting mineral oil from oil-based drilling cuttings at low temperature, comprising the following steps:

[0131] (1) uniformly mixing oil-based drilling cuttings sample 1 with a dust suppressant at a mass ratio of 97:3, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C, and the desorption time is 30 min; light mineral oil and residual solid phase are obtained;

[0132] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1;

[0133] (2) performing sorting on the residual solid phase obtained in step (1), and the sorting limit value is 38 mu m, and the solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material; and the solid phase with a particle size greater than 38 mu m is taken as a first-stage tailing;

[0134] (3) the sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 94:6, and then is placed in a two-stage rotary pyrolysis furnace to crack at a cracking temperature of 300 DEG C for 25 min; heavy mineral oil and a two-stage tail residue are obtained;

[0135] In step (3), the cracking catalyst is compounded by nickel chlorite and potassium feldspar at a mass ratio of 1:1.

[0136] The oil content of the oil-removed tail residue of the embodiment is 0.15 wt%, the impurity content of the recovered mineral oil is 0.28 wt%, and the oil recovery rate is 87.65 wt%.

[0137] Embodiment 14:

[0138] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, comprising the following steps:

[0139] (1) oil-based drill cuttings sample 1 is mixed with a dust suppressant at a mass ratio of 97:3, and then is placed in a one-stage rotary thermal desorption furnace to desorb at 300 DEG C for 30 min; light mineral oil and a remaining solid phase are obtained;

[0140] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1.

[0141] (2) the remaining solid phase obtained in step (1) is sorted, and a solid phase with a particle size of less than or equal to 38 microns is sorted out as a sorted solid phase material; a solid phase with a particle size greater than 38 microns is a one-stage tail residue;

[0142] (3) the sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 94:6, and then is placed in a two-stage rotary pyrolysis furnace to crack at a cracking temperature of 300 DEG C for 25 min; heavy mineral oil and a two-stage tail residue are obtained;

[0143] In step (3), the cracking catalyst is compounded by nickel chlorite and potassium feldspar at a mass ratio of 1:2.

[0144] The oil content of the oil-removed tail residue of the embodiment is 0.15 wt%, the impurity content of the recovered mineral oil is 0.28 wt%, and the oil recovery rate is 87.65 wt%.

[0145] Embodiment 15:

[0146] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, comprising the following steps:

[0147] (1) oil-based drill cuttings sample 1 is mixed with a dust suppressant at a mass ratio of 95:5, and then is placed in a one-stage rotary thermal desorption furnace to desorb at 265 DEG C for 60 min; light mineral oil and a remaining solid phase are obtained;

[0148] In step (1), the dust inhibitor is compounded by kaolinite and illite with a mass ratio of 3:1;

[0149] (2) The remaining solid phase obtained in step (1) is sorted, and the sorting limit value is 38 μm. The solid phase with a particle size of ≤38 μm is sorted out as a sorted solid phase material; and the solid phase with a particle size greater than 38 μm is taken as a first-stage tailings;

[0150] (3) The sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 92:8, and then is placed in a second-stage rotary pyrolysis furnace for cracking at a cracking temperature of 280°C and a cracking time of 40 min. Heavy mineral oil and second-stage tailings are obtained.

[0151] In step (3), the cracking catalyst is compounded by nickel chlorite and potassium feldspar with a mass ratio of 1:2.

[0152] The oil content of the deoiled tailings in this embodiment is 0.11wt%, the impurity content of the recovered mineral oil is 0.20wt%, and the oil recovery rate is 88.13wt%.

[0153] Example 16:

[0154] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, which comprises the following steps:

[0155] (1) Oil-based drill cuttings sample 2 is mixed with kaolinite at a mass ratio of 97:3, and then is placed in a first-stage rotary thermal desorption furnace for desorption at 300°C for 45 min. Light mineral oil and a remaining solid phase are obtained.

[0156] (2) The remaining solid phase obtained in step (1) is sorted, and the sorting limit value is 38 μm. The solid phase with a particle size of ≤38 μm is sorted out as a sorted solid phase material; and the solid phase with a particle size greater than 38 μm is taken as a first-stage tailings;

[0157] (3) The sorted solid phase material is mixed with bauxite at a mass ratio of 93:7, and then is placed in a second-stage rotary pyrolysis furnace for cracking at a cracking temperature of 300°C and a cracking time of 35 min. Heavy mineral oil and second-stage tailings are obtained.

[0158] The oil content of the deoiled tailings in this embodiment is 0.22wt%, the impurity content of the recovered mineral oil is 0.40wt%, and the oil recovery rate is 88.43wt%.

[0159] Example 17:

[0160] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, which comprises the following steps:

[0161] (1) oil-based drilling cuttings sample 2 and kaolinite are mixed uniformly at a mass ratio of 97:3, and then placed in a first-stage rotary thermal desorption furnace for desorption at 300 DEG C for 45 min; light mineral oil and a remaining solid phase are obtained;

[0162] (2) the remaining solid phase obtained in step (1) is sorted, and a sorting limit value is 38 μm; a solid phase with a particle size of ≤38 μm is sorted out as a sorted solid phase material; and a solid phase with a particle size greater than 38 μm is taken as a first-stage tail residue;

[0163] (3) the sorted solid phase material and potassium feldspar are mixed uniformly at a mass ratio of 92:8, and then placed in a second-stage rotary pyrolysis furnace for pyrolysis at a pyrolysis temperature of 300 DEG C for 35 min; heavy mineral oil and a second-stage tail residue are obtained.

[0164] The oil content of the oil-removed tail residue in this embodiment is 0.25wt%, the impurity content of the recovered mineral oil is 0.37wt%, and the oil recovery rate is 85.64wt%.

[0165] Example 18:

[0166] The embodiment provides a method for extracting mineral oil from oil-based drilling cuttings at low temperature, which comprises the following steps:

[0167] (1) oil-based drilling cuttings sample 2 and kaolinite are mixed uniformly at a mass ratio of 97:3, and then placed in a first-stage rotary thermal desorption furnace for desorption at 300 DEG C for 45 min; light mineral oil and a remaining solid phase are obtained;

[0168] (2) the remaining solid phase obtained in step (1) is sorted, and a sorting limit value is 38 μm; a solid phase with a particle size of ≤38 μm is sorted out as a sorted solid phase material; and a solid phase with a particle size greater than 38 μm is taken as a first-stage tail residue;

[0169] (3) the sorted solid phase material and a pyrolysis catalyst are mixed uniformly at a mass ratio of 95:5, and then placed in a second-stage rotary pyrolysis furnace for pyrolysis at a pyrolysis temperature of 300 DEG C for 35 min; heavy mineral oil and a second-stage tail residue are obtained.

[0170] In step (3), the pyrolysis catalyst is compounded by bauxite and potassium feldspar at a mass ratio of 1:1.

[0171] The oil content of the oil-removed tail residue in this embodiment is 0.11wt%, the impurity content of the recovered mineral oil is 0.21wt%, and the oil recovery rate is 90.21wt%.

[0172] Example 19:

[0173] The embodiment provides a method for extracting mineral oil from oil-based drilling cuttings at low temperature, which comprises the following steps:

[0174] (1) oil-based drilling cuttings sample 2 and kaolinite are mixed uniformly at a mass ratio of 97:3, and then placed in a first-stage rotary thermal desorption furnace, and desorption is carried out at 300 DEG C, and the desorption time is 45 min; light mineral oil and a remaining solid phase are obtained;

[0175] (2) the remaining solid phase obtained in step (1) is sorted, and the sorting limit value is 38 μm; a solid phase with a particle size of ≤38 μm is sorted out as a sorted solid phase material; and a solid phase with a particle size greater than 38 μm is sorted out as a first-stage tail residue;

[0176] (3) the sorted solid phase material and a cracking catalyst are mixed uniformly at a mass ratio of 95:5, and then placed in a second-stage rotary pyrolysis furnace for cracking; the cracking temperature is 300 DEG C, and the cracking time is 35 min; heavy mineral oil and a second-stage tail residue are obtained;

[0177] In step (3), the cracking catalyst is compounded by bauxite and potassium feldspar at a mass ratio of 1:2.

[0178] The oil content of the oil-removed tail residue in this embodiment is 0.18wt%, the impurity content of the recovered mineral oil is 0.26wt%, and the oil recovery rate is 88.53wt%.

[0179] Example 20:

[0180] The embodiment provides a method for extracting mineral oil from oil-based drilling cuttings at low temperature, comprising the following steps:

[0181] (1) oil-based drilling cuttings sample 2 and kaolinite are mixed uniformly at a mass ratio of 97:3, and then placed in a first-stage rotary thermal desorption furnace, and desorption is carried out at 300 DEG C, and the desorption time is 45 min; light mineral oil and a remaining solid phase are obtained;

[0182] (2) the remaining solid phase obtained in step (1) is sorted, and the sorting limit value is 38 μm; a solid phase with a particle size of ≤38 μm is sorted out as a sorted solid phase material; and a solid phase with a particle size greater than 38 μm is sorted out as a first-stage tail residue;

[0183] (3) the sorted solid phase material and a cracking catalyst are mixed uniformly at a mass ratio of 95:5, and then placed in a second-stage rotary pyrolysis furnace for cracking; the cracking temperature is 300 DEG C, and the cracking time is 35 min; heavy mineral oil and a second-stage tail residue are obtained;

[0184] In step (3), the cracking catalyst is compounded by bauxite and potassium feldspar at a mass ratio of 1:3.

[0185] The oil content of the oil-removed tail residue in this embodiment is 0.20wt%, the impurity content of the recovered mineral oil is 0.28wt%, and the oil recovery rate is 86.37wt%.

[0186] Example 21:

[0187] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, and comprises the following steps:

[0188] (1) uniformly mixing oil-based drill cuttings sample 2 and kaolinite at a mass ratio of 97:3, and then placing the mixture in a first-stage rotary thermal desorption furnace to perform desorption at 300 DEG C for 45 min; light mineral oil and residual solid phase are obtained;

[0189] (2) performing sorting on the residual solid phase obtained in step (1), and taking the solid phase with a particle size of less than or equal to 38 mu m as a sorted solid phase material, and taking the solid phase with a particle size greater than 38 mu m as a first-stage tail residue;

[0190] (3) uniformly mixing the sorted solid phase material and a cracking catalyst at a mass ratio of 95:5, and then placing the mixture in a second-stage rotary pyrolysis furnace to perform cracking at a cracking temperature of 300 DEG C for 35 min; heavy mineral oil and a second-stage tail residue are obtained;

[0191] In step (3), the cracking catalyst is composed of bauxite and potassium feldspar at a mass ratio of 2:1.

[0192] The oil content of the oil-removed tail residue in the embodiment is 0.13 wt%, the impurity content of the recovered mineral oil is 0.22 wt%, and the oil recovery rate is 90.88 wt%.

[0193] Embodiment 22:

[0194] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, and comprises the following steps:

[0195] (1) uniformly mixing oil-based drill cuttings sample 2 and kaolinite at a mass ratio of 95:5, and then placing the mixture in a first-stage rotary thermal desorption furnace to perform desorption at 265 DEG C for 60 min; light mineral oil and residual solid phase are obtained;

[0196] (2) performing sorting on the residual solid phase obtained in step (1), and taking the solid phase with a particle size of less than or equal to 38 mu m as a sorted solid phase material, and taking the solid phase with a particle size greater than 38 mu m as a first-stage tail residue;

[0197] (3) uniformly mixing the sorted solid phase material and a cracking catalyst at a mass ratio of 92:8, and then placing the mixture in a second-stage rotary pyrolysis furnace to perform cracking at a cracking temperature of 280 DEG C for 40 min; heavy mineral oil and a second-stage tail residue are obtained;

[0198] In step (3), the cracking catalyst is composed of bauxite and potassium feldspar at a mass ratio of 2:1.

[0199] The oil content of the oil-removed tail residue in the embodiment is 0.06 wt%, the impurity content of the recovered mineral oil is 0.15 wt%, and the oil recovery rate is 92.36 wt%.

[0200] Example 23:

[0201] The embodiment provides a method for extracting mineral oil from oil-based drilling cuttings at low temperature, comprising the following steps:

[0202] (1) uniformly mixing oil-based drilling cuttings sample 3 with a dust suppressant at a mass ratio of 95:5, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C for 60 min; light mineral oil and residual solid phase are obtained;

[0203] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1;

[0204] (2) performing sorting on the residual solid phase obtained in step (1), and sorting out solid phase with a particle size of less than or equal to 38 mu m as a sorted solid phase material; solid phase with a particle size greater than 38 mu m is taken as a first-stage tailing;

[0205] (3) uniformly mixing the sorted solid phase material with a cracking catalyst at a mass ratio of 95:5, and then placing the mixture in a second rotary pyrolysis furnace to perform cracking at a cracking temperature of 300 DEG C for 40 min; heavy mineral oil and second-stage tailing are obtained;

[0206] In step (3), the cracking catalyst is compounded by nickel chlorite, bauxite and potassium feldspar at a mass ratio of 4:1:1.

[0207] The oil content of the oil-removed tailings in the embodiment is 0.07 wt%, the impurity content of the recovered mineral oil is 0.42 wt%, and the oil recovery rate is 93.75 wt%.

[0208] Example 24:

[0209] The embodiment provides a method for extracting mineral oil from oil-based drilling cuttings at low temperature, comprising the following steps:

[0210] (1) uniformly mixing oil-based drilling cuttings sample 3 with a dust suppressant at a mass ratio of 95:5, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C for 60 min; light mineral oil and residual solid phase are obtained;

[0211] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1

[0212] (2) performing sorting on the residual solid phase obtained in step (1), and sorting out solid phase with a particle size of less than or equal to 38 mu m as a sorted solid phase material; solid phase with a particle size greater than 38 mu m is taken as a first-stage tailing;

[0213] (3) the sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 95:5, and then is placed in a two-stage rotary pyrolysis furnace, a pyrolysis temperature is 300 DEG C, and a pyrolysis time is 40 min; heavy mineral oil and a two-stage tail residue are obtained;

[0214] In step (3), the cracking catalyst is compounded by nickel chlorite, bauxite and potassium feldspar at a mass ratio of 4:2:1.

[0215] The oil content of the oil-removed tail residue in this embodiment is 0.08wt%, the impurity content of the recovered mineral oil is 0.32wt%, and the oil recovery rate is 93.25wt%.

[0216] Example 25:

[0217] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, which comprises the following steps:

[0218] (1) an oil-based drill cutting sample 3 is mixed with a dust suppressant at a mass ratio of 95:5, and then is placed in a one-stage rotary thermal desorption furnace, desorption is carried out at 300 DEG C, and a desorption time is 60 min; light mineral oil and a remaining solid phase are obtained;

[0219] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1;

[0220] (2) the remaining solid phase obtained in step (1) is sorted, a sorting limit value is 38 mu m, a solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material, and a solid phase with a particle size greater than 38 mu m is sorted out as a one-stage tail residue;

[0221] (3) the sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 95:5, and then is placed in a two-stage rotary pyrolysis furnace, a pyrolysis temperature is 300 DEG C, and a pyrolysis time is 40 min; heavy mineral oil and a two-stage tail residue are obtained;

[0222] In step (3), the cracking catalyst is compounded by nickel chlorite, bauxite and potassium feldspar at a mass ratio of 2:1:1.

[0223] The oil content of the oil-removed tail residue in this embodiment is 0.10wt%, the impurity content of the recovered mineral oil is 0.33wt%, and the oil recovery rate is 92.88wt%.

[0224] Example 26:

[0225] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, which comprises the following steps:

[0226] (1) oil-based drilling cuttings sample 3 is mixed with dust suppressant at a mass ratio of 95:5, and then placed in a first-stage rotary thermal desorption furnace, and desorption is carried out at 300 DEG C for 60 min; light mineral oil and a remaining solid phase are obtained;

[0227] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1;

[0228] (2) the remaining solid phase obtained in step (1) is sorted, and a sorting limit value is 38 mu m; a solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material; and a solid phase with a particle size greater than 38 mu m is sorted out as a first-stage tailing;

[0229] (3) the sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 95:5, and then placed in a second-stage rotary pyrolysis furnace; cracking is carried out at a cracking temperature of 300 DEG C for 40 min; heavy mineral oil and a second-stage tailing are obtained;

[0230] In step (3), the cracking catalyst is compounded by nickel chlorite, bauxite and potassium feldspar at a mass ratio of 1:1:1.

[0231] The oil content of the oil-removed tailings in this embodiment is 0.12wt%, the impurity content of the recovered mineral oil is 0.34wt%, and the oil recovery rate is 90.95wt%.

[0232] Example 27:

[0233] The embodiment provides a method for extracting mineral oil from oil-based drilling cuttings at low temperature, comprising the following steps:

[0234] (1) oil-based drilling cuttings sample 3 is mixed with dust suppressant at a mass ratio of 95:5, and then placed in a first-stage rotary thermal desorption furnace, and desorption is carried out at 300 DEG C for 60 min; light mineral oil and a remaining solid phase are obtained;

[0235] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1;

[0236] (2) the remaining solid phase obtained in step (1) is sorted, and a sorting limit value is 38 mu m; a solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material; and a solid phase with a particle size greater than 38 mu m is sorted out as a first-stage tailing;

[0237] (3) the sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 95:5, and then placed in a second-stage rotary pyrolysis furnace; cracking is carried out at a cracking temperature of 300 DEG C for 40 min; heavy mineral oil and a second-stage tailing are obtained;

[0238] In step (3), the cracking catalyst is compounded by nickel chlorite, bauxite and potassium feldspar at a mass ratio of 1:5:3.

[0239] The oil content of the oil-removed tailings of this embodiment is 0.15wt%, the impurity content of the recovered mineral oil is 0.36wt%, and the oil recovery rate is 89.28wt%.

[0240] Example 28:

[0241] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, comprising the following steps:

[0242] (1) uniformly mixing oil-based drill cuttings sample 3 and a dust suppressant at a mass ratio of 95:5, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C, and the desorption time is 60 min; obtaining light mineral oil and residual solid phase;

[0243] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1;

[0244] (2) sorting the residual solid phase obtained in step (1), and the sorting limit value is 38 mu m, and the solid phase with a particle size of less than or equal to 38 mu m is sorted out as a sorted solid phase material; and the solid phase with a particle size greater than 38 mu m is taken as a first tailings;

[0245] (3) uniformly mixing the sorted solid phase material and a cracking catalyst at a mass ratio of 95:5, and then placing the mixture in a second rotary pyrolysis furnace, the cracking temperature is 300 DEG C, and the cracking time is 40 min; obtaining heavy mineral oil and second tailings;

[0246] In step (3), the cracking catalyst is compounded by nickel chlorite, bauxite and potassium feldspar at a mass ratio of 1:4:2.

[0247] The oil content of the oil-removed tailings of this embodiment is 0.15wt%, the impurity content of the recovered mineral oil is 0.36wt%, and the oil recovery rate is 89.28wt%.

[0248] Example 29:

[0249] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, comprising the following steps:

[0250] (1) uniformly mixing oil-based drill cuttings sample 3 and a dust suppressant at a mass ratio of 95:5, and then placing the mixture in a first rotary thermal desorption furnace to perform desorption at 300 DEG C, and the desorption time is 60 min; obtaining light mineral oil and residual solid phase;

[0251] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1;

[0252] (2) The remaining solid phase obtained in step (1) is sorted, the sorting limit value is 38 pm, and the solid phase with a particle size of ≤38 pm is sorted out as a sorted solid phase material; the solid phase with a particle size greater than 38 pm is a first-stage tailings;

[0253] (3) The sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 95:5 and then placed in a second-stage rotary pyrolysis furnace, the pyrolysis temperature is 300°C, and the pyrolysis time is 40 min; heavy mineral oil and second-stage tailings are obtained;

[0254] In step (3), the cracking catalyst is compounded by nickel chlorite, bauxite and potassium feldspar at a mass ratio of 1:4:1.

[0255] The oil content of the deoiled tailings in this embodiment is 0.26wt%, the impurity content of the recovered mineral oil is 0.42wt%, and the oil recovery rate is 87.59wt%.

[0256] Example 30:

[0257] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, comprising the following steps:

[0258] (1) The oil-based drill cuttings sample 3 is mixed with a dust suppressant at a mass ratio of 95:5, and then placed in a first-stage rotary thermal desorption furnace, and desorption is carried out at 300°C, the desorption time is 60 min; light mineral oil and a remaining solid phase are obtained;

[0259] In step (1), the dust suppressant is compounded by kaolinite and illite at a mass ratio of 3:1;

[0260] (2) The remaining solid phase obtained in step (1) is sorted, the sorting limit value is 38 pm, and the solid phase with a particle size of ≤38 pm is sorted out as a sorted solid phase material; the solid phase with a particle size greater than 38 pm is a first-stage tailings;

[0261] (3) The sorted solid phase material is mixed with a cracking catalyst at a mass ratio of 95:5 and then placed in a second-stage rotary pyrolysis furnace, the pyrolysis temperature is 300°C, and the pyrolysis time is 40 min; heavy mineral oil and second-stage tailings are obtained;

[0262] In step (3), the cracking catalyst is compounded by nickel chlorite, bauxite and potassium feldspar at a mass ratio of 1:1:3.

[0263] The oil content of the deoiled tailings in this embodiment is 0.29wt%, the impurity content of the recovered mineral oil is 0.45wt%, and the oil recovery rate is 85.68wt%.

[0264] Example 31:

[0265] The embodiment provides a method for extracting mineral oil at low temperature from oil-based drill cuttings, comprising the following steps:

[0266] (1) oil-based drilling cuttings sample 3 was mixed with a dust suppressant at a mass ratio of 95:5, and then placed in a first-stage rotary thermal desorption furnace for desorption at 265 DEG C for 60 min; light mineral oil and a remaining solid phase were obtained;

[0267] In step (1), the dust suppressant is compounded from kaolinite and illite at a mass ratio of 3:1;

[0268] (2) the remaining solid phase obtained in step (1) was sorted, with a sorting limit of 38 μm; a solid phase with a particle size of ≤38 μm was sorted out as a sorted solid phase material; a solid phase with a particle size greater than 38 μm was taken as a first-stage tail residue;

[0269] (3) the sorted solid phase material was mixed with a cracking catalyst at a mass ratio of 92:8, and then placed in a second-stage rotary pyrolysis furnace for cracking at a cracking temperature of 280 DEG C for 40 min; heavy mineral oil and a second-stage tail residue were obtained;

[0270] In step (3), the cracking catalyst is compounded from nickel chlorite, bauxite and potassium feldspar at a mass ratio of 1:1:3.

[0271] The oil content of the oil-removed tail residue of the embodiment is 0.21wt%, the impurity content of the recovered mineral oil is 0.19wt%, and the oil recovery rate is 89.74wt%.

[0272] Comparative Example 1

[0273] The present comparative example provides a method for extracting mineral oil from oil-based drilling cuttings at low temperature, comprising the following steps:

[0274] (1) oil-based drilling cuttings sample 3 was placed in a first-stage rotary thermal desorption furnace for desorption at 300 DEG C for 60 min; light mineral oil and a remaining solid phase were obtained;

[0275] (2) the remaining solid phase obtained in step (1) was sorted, with a sorting limit of 38 μm; a solid phase with a particle size of ≤38 μm was sorted out as a sorted solid phase material; a solid phase with a particle size greater than 38 μm was taken as a first-stage tail residue;

[0276] (3) the sorted solid phase material was mixed with a cracking catalyst at a mass ratio of 95:5, and then placed in a second-stage rotary pyrolysis furnace for cracking at a cracking temperature of 300 DEG C for 40 min; heavy mineral oil and a second-stage tail residue were obtained;

[0277] In step (3), the cracking catalyst is compounded from nickel chlorite, bauxite and potassium feldspar at a mass ratio of 4:1:1.

[0278] The oil content of the deoiled tailings after treatment of the present comparative example was 0.10wt%, the impurity content of the recovered mineral oil was 4.60wt%, and the oil recovery rate was 90.82wt%.

[0279] Comparing Comparative Example 1 with Comparative Example 23, it can be seen that the impurity content of the recovered mineral oil is significantly increased without the addition of a dust inhibitor.

[0280] Comparative Example 2:

[0281] The present example provides a method for low-temperature extraction of mineral oil from oil-based drill cuttings, comprising the following steps:

[0282] (1) uniformly mixing oil-based drill cuttings sample 1 with a dust inhibitor at a mass ratio of 97:3, and then placing it in a first-stage rotary thermal desorption furnace for desorption at 300℃ for 30min; obtaining light mineral oil and residual solid phase;

[0283] In step (1), the dust inhibitor is compounded from kaolinite and illite at a mass ratio of 3:1;

[0284] (2) sorting the residual solid phase obtained in step (1), with a sorting limit of 38μm, and sorting out solid phase with a particle size of ≤38μm as sorted solid phase material; solid phase with a particle size greater than 38μm as first-stage tailings;

[0285] (3) placing the sorted solid phase material in a second-stage rotary pyrolysis furnace for pyrolysis at a pyrolysis temperature of 300℃ for 25min; obtaining heavy mineral oil and second-stage tailings.

[0286] The oil content of the deoiled tailings of the present comparative example was 2.47wt%, the impurity content of the recovered mineral oil was 0.38wt%, and the oil recovery rate was 65.34wt%.

[0287] Comparing Comparative Example 2 with Examples 3, 7-12, it can be seen that the yield of the recovered mineral oil is significantly reduced without the addition of a pyrolysis catalyst, and the oil content of the tailings cannot meet the environmental protection standards.

[0288] Comparative Example 3:

[0289] The present comparative example provides a method for low-temperature extraction of mineral oil from oil-based drill cuttings, comprising the following steps:

[0290] (1) placing oil-based drill cuttings sample 2 in a first-stage rotary thermal desorption furnace for desorption at 300℃ for 45min; obtaining light mineral oil and residual solid phase;

[0291] (2) sorting the remaining solid phase obtained in step (1), with a sorting limit of 38 μm, and sorting out solid phase with a particle size of ≤38 μm as a sorted solid phase material; solid phase with a particle size greater than 38 μm as a first-stage tailings;

[0292] (3) pyrolyzing the sorted solid phase material in a second-stage rotary pyrolysis furnace, with a pyrolysis temperature of 300°C and a pyrolysis time of 35 min; obtaining heavy mineral oil and second-stage tailings.

[0293] The oil content of the deoiled tailings of the comparative example 3 was 5.42 wt%, the impurity content of the recovered mineral oil was 3.48 wt%, and the oil recovery rate was 60.39 wt%.

[0294] Compared with examples 16-20, comparative example 3 did not add a dust inhibitor and a pyrolysis catalyst, and the yield of the recovered mineral oil was significantly reduced, the impurity content was significantly increased, and the oil content of the tailings could not meet the environmental protection standard.

[0295] In summary, the oil content of the deoiled tailings of examples 1-31 was below 0.3 wt%, the impurity content of the recovered mineral oil was below 0.5 wt%, and the oil recovery rate was above 85%; indicating that the method of examples 1-31 for low-temperature extraction of mineral oil from oil-based drill cuttings achieved the goal of efficient resource utilization and harmless disposal of tailings of oil-based drill cuttings mineral oil, and realized low-temperature efficient oil recovery.

[0296] Examples 1-31 can be summarized as:

[0297] The method for low-temperature extraction of mineral oil from oil-based drill cuttings comprises the following steps:

[0298] S1, uniformly mixing oil-based drill cuttings with a dust inhibitor, and then placing the mixture in a first-stage rotary thermal desorption furnace for desorption at a temperature of 265-300°C to complete extraction of light mineral oil, and obtaining light mineral oil and a remaining solid phase;

[0299] S2, sorting the remaining solid phase, with a sorting limit of 38 μm, and sorting out solid phase with a particle size of ≤38 μm as a sorted solid phase material;

[0300] S3, uniformly mixing the sorted solid phase material with a pyrolysis catalyst, and then placing the mixture in a second-stage rotary pyrolysis furnace for pyrolysis at a temperature of 280-300°C to complete oil-solid separation, and obtaining heavy mineral oil.

[0301] In step S1, the desorption time is 30-60 min, and the pyrolysis time in step S3 is 25-40 min;

[0302] In step S1, based on 100 parts by mass of the total mass of the oil-based drill cuttings and the dust inhibitor, the mass of the oil-based drill cuttings is 95-97 parts, and the mass of the dust inhibitor is 3-5 parts.

[0303] In step S1, the dust inhibitor is kaolinite or illite or any combination thereof; the particle size of the dust inhibitor is ≤100 μm;

[0304] The dust inhibitor is preferably compounded by kaolinite and illite with a mass ratio of (0.5-3):1.

[0305] In step S3, the mass fraction of the sorted solid phase material is 92-95 parts and the mass fraction of the cracking catalyst is 5-8 parts, based on 100 parts of the total mass of the sorted solid phase material and the cracking catalyst;

[0306] The cracking catalyst is nickel chlorite, bauxite or potassium feldspar or any combination thereof; the particle size of the cracking catalyst is ≤38 μm.

Claims

1. A method of low temperature extraction of mineral oil from oil-based drillings, characterized in that, The method comprises the following steps: S1, after mixing the oil-based drill cuttings with a dust inhibitor, placing them in a first rotary thermal desorption furnace, and performing desorption at 265-300 DEG C to obtain light mineral oil and a remaining solid phase; S2, sorting the remaining solid phase to separate a solid phase with a particle size of less than or equal to 38 microns as a sorted solid phase material; S3, mixing the sorted solid phase material with a cracking catalyst, placing them in a second rotary pyrolysis furnace, and performing cracking at 280-300 DEG C to obtain heavy mineral oil.

2. The method of claim 1, wherein, The desorption time in step S1 is 30-60 min, and the cracking time in step S3 is 25-40 min.

3. The method of claim 1, wherein, In step S1, the mass fraction of the oil-based drill cuttings is 95-97 parts, and the mass fraction of the dust inhibitor is 3-5 parts, based on 100 parts of the total mass of the oil-based drill cuttings and the dust inhibitor.

4. The method of claim 3, wherein, The inhibitor is kaolinite or illite or any combination thereof.

5. The method of claim 4, wherein, The particle size of the inhibitor is less than or equal to 100 microns.

6. The method of claim 4, wherein, The inhibitor is compounded from kaolinite and illite in a mass ratio of (0.5-3):

1.

7. The method of claim 1 wherein, In step S3, the mass fraction of the sorted solid phase material is 92-95 parts, and the mass fraction of the cracking catalyst is 5-8 parts, based on 100 parts of the total mass of the sorted solid phase material and the cracking catalyst.

8. The method of claim 7, wherein, The cracking catalyst is nickel chlorite, bauxite or potassium feldspar or any combination thereof.

9. The method of claim 8, wherein, The particle size of the cracking catalyst is less than or equal to 38 microns.

10. The use of the method for extracting mineral oil from oil-based drill cuttings at low temperature according to any one of claims 1-9 in the resource utilization of oil-based drill cuttings.

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