Leaching agent for oil-containing drill cuttings and oil-containing drilling waste and using method thereof
Technical Field
The invention relates to the technical field of drilling, in particular to a leaching agent for oil-containing drill cuttings and oil-containing drilling wastes and a using method thereof, and specifically relates to a leaching agent for deoiling oil-containing drill cuttings and oil-containing drilling wastes generated by using oil-based drilling fluid and a using method thereof.
Background
In the process of oil and gas drilling, with the increasing drilling quantity of complex wells such as deep wells, ultra-deep wells, shale gas horizontal wells, multilateral wells and the like, the underground conditions are more and more complex, and the adoption of the oil-based drilling fluid is an important way for avoiding the occurrence of underground complex accidents. For oil-based drilling fluids with considerable advantages, the drilling fluid comprises a plurality of toxic and harmful chemical substances, and besides the components of the drilling fluid system, a large amount of drilling waste is generated in the drilling and completion process, and the main pollutants of the drilling waste are oil-containing drill cuttings. The oily waste contains harmful substances such as heavy metals, petroleum hydrocarbons, surfactants, wetting agents, salt ions and the like. These substances are highly bio-toxic and are difficult to degrade in the natural environment. Various chemical treatment agents added into the drilling fluid enable a bridging structure between the oil-based drilling fluid and drilling waste to be more stable, and the process treatment difficulty and the treatment cost are objectively increased.
With the increasing problems of borehole wall instability caused by water swelling of shale and the use of brine drilling fluids, the importance of oil-based mud to safe drilling of complex formations has been gradually recognized. Especially the development of high temperature, high pressure and high salinity formations on shale gas and Tarim, requires the use of oil-based drilling fluids, which generates large amounts of oily waste to be disposed of.
The oily operation waste generated by the drilling and completion operation by using the oil-based drilling fluid has serious environmental pollution and great treatment difficulty, and the problems of high treatment energy consumption, incomplete oil phase separation, secondary pollution and the like are not completely solved by the existing physical, chemical, biological treatment and other technologies. Because the existing treatment technology is not matched, immature and high in cost, a large amount of drilling waste is treated by a simple treatment method, the requirement of environmental protection cannot be completely met, and great potential protection hazards exist.
Therefore, how to solve the environmental problem caused by using the oil-based drilling fluid and develop an efficient, economical and applicable drilling waste treatment technology becomes an important subject of drilling fluid workers.
Disclosure of Invention
The invention aims to provide a leaching agent for oil-containing drill cuttings and oil-containing drilling wastes and a using method thereof. The invention adopts a method of compounding organic solvents, selects proper main leaching agent and auxiliary leaching agent, and prepares a high-efficiency leaching agent. The leaching agent can be used for deoiling the oily drill cuttings and oily drilling wastes generated by using the oil-based drilling fluid.
In order to achieve the above object, the present invention provides a leaching agent for oil-containing drill cuttings and oil-containing drilling wastes, which comprises the following raw materials by volume: 80-100 parts of polymethoxy dimethyl ether, 0-20 parts of methyl tert-butyl ether and 0-20 parts of petroleum ether; wherein the polymerization degree of the polymethoxy dimethyl ether is 2-4, and the boiling range of the petroleum ether is 60-90 ℃.
According to an embodiment of the present invention, preferably, the raw material of the leaching agent for the oil-containing drill cuttings and the oil-containing drilling waste comprises, by volume: 90 parts by volume of polymethoxy dimethyl ether, 6.5-7 parts by volume of methyl tert-butyl ether and 3-3.5 parts by volume of petroleum ether; more preferably, the raw material of the leaching agent for the oil-containing drill cuttings and oil-containing drilling wastes comprises the following components in parts by volume: 90 parts by volume of polymethoxy dimethyl ether, 6.67 parts by volume of methyl tert-butyl ether and 3.33 parts by volume of petroleum ether.
In the leaching agent for the oil-containing drill cuttings and oil-containing drilling wastes, the boiling points of the raw materials are preferably distributed at 100 ℃ and 150 ℃, and the flash points are preferably distributed at 50-65 ℃.
The leaching agent for the oily drill cuttings and the oily drilling wastes can be prepared by a conventional method of mixing polymethoxy dimethyl ether with methyl tertiary butyl ether and petroleum ether.
According to the specific property and similarity intermiscibility principle of the oil-containing drilling cuttings/oil-containing drilling wastes, the invention adopts an organic solvent compounding method and selects a proper main leaching agent and an auxiliary leaching agent to develop a high-efficiency leaching agent, wherein the boiling point of the leaching agent is distributed at 100-150 ℃, and the flash point is distributed at 50-65 ℃.
Under the action of a wetting agent and the bottom pressure, the oil-based drilling fluid can be attached to the surface of drill cuttings and the inner pores, so that the subsequent oil phase desorption is not thorough, and the oil content of the treated drill cuttings is still high. The wetting agent comprises various surface element compositions and various functional groups, and the existence of the surface functional groups can lead the charge distribution on the surface of the drill cuttings to be uneven and become adsorption sites of specific adsorbates, so that the oil-based drilling mud can be firmly adsorbed on the surface of the drill cuttings and is difficult to desorb. The main leaching agent adopted by the invention, namely the polymethoxy dimethyl ether, can effectively reduce the surface adsorption energy between the drilling fluid and the drilling cuttings and realize high-efficiency desorption under the condition of low energy; the auxiliary leaching agents adopted by the invention, namely methyl tert-butyl ether and petroleum ether, are used for forming an azeotropic structure with the main leaching agent, so that the energy consumed in the fractionation process can be greatly reduced, and the purposes of energy conservation and environmental protection are achieved.
The leaching agent provided by the invention realizes a high flash point through the compounding of an organic solvent under the condition of a lower boiling point, can adapt to worse field conditions, and is safer to use on site; the oxygen content is higher, the toxicity is reduced, the environment is friendly, the degradation is easy under the natural environment, and the requirements of environmental protection and HSE are met; and the desorbed drilling fluid is not demulsified, so that the oil-based drilling fluid can be recycled. The leaching agent not only achieves the oil removal efficiency of the traditional pyrolysis method, but also avoids secondary pollution, and greatly improves the treatment efficiency of the oily drilling cuttings/oily drilling wastes.
In addition, the invention also provides a use method of the leaching agent for the oily drill cuttings and oily drilling wastes, which comprises the following steps:
mixing the oil-bearing drill cuttings and/or oil-bearing drilling waste with a leaching agent in a blender; stirring for a certain time at a certain shearing rate for leaching, standing until the solid phase naturally settles, performing solid-liquid separation on the solid phase at the bottom of the stirrer, and drying to obtain the deoiled oil-containing drilling cuttings and/or oil-containing drilling waste.
In the above-described method of use, preferably, the mixing ratio of the oily drill cuttings and/or oily drilling waste with the leaching agent is 1 part by mass of the oily drill cuttings and/or oily drilling waste: 3-8 parts by volume (more preferably 6 parts by volume) of leaching agent.
In the use method, preferably, the shear rate is 200-600r/min, and the stirring leaching time is 4-10 min; more preferably, the shear rate is 300r/min and the time for agitation to effect leaching is 7 min.
In the above using method, preferably, the drying is drying at 80-120 ℃ for 12-36 h; more preferably, the drying is drying at 95 ℃ for 24 h.
According to an embodiment of the present invention, preferably, the above-mentioned using method further comprises the steps of: and fractionating the liquid phase obtained by solid-liquid separation at a certain vacuum degree and temperature to recover the leaching agent and obtain the leached emulsified diesel oil.
In the above-mentioned use method, it is preferable that the temperature of the fractionation is 110-.
According to a specific embodiment of the present invention, preferably, the above-mentioned using method specifically comprises the following steps:
the required amount of leaching agent is determined in the following ratio: 1 part by mass of oil-containing drill cuttings and/or oil-containing drilling waste: 3-8 parts by volume (more preferably 6 parts by volume) of leaching agent;
adding a certain mass of oil-containing drilling cuttings and/or oil-containing drilling wastes into a stirrer, and then adding a leaching agent according to a certain mass/volume ratio; stirring at the shear rate of 200-600r/min (more preferably 300r/min) at room temperature for 4-10min (more preferably 7min) to leach, standing until the solid phase naturally settles, performing solid-liquid separation on the solid phase at the bottom of the stirrer, drying the solid phase obtained after separation at the temperature of 80-120 ℃ (more preferably 95 ℃) for 12-36h (more preferably 24h) to obtain the oil-containing drill cuttings and/or oil-containing drilling waste after oil removal treatment; the liquid phase obtained after the separation is fractionated under the conditions of a pressure difference of-0.01 MPa, 110-130 ℃ (more preferably 120 ℃) to recover the leaching agent and obtain the leached emulsified diesel.
In addition, the invention also provides application of the polymethoxy dimethyl ether in preparing a leaching agent for oil-containing drill cuttings and oil-containing drilling wastes.
In the above application, preferably, the leaching agent for the oily drill cuttings and oily drilling waste consists of 80-100 parts by volume of polymethoxy dimethyl ether, 0-20 parts by volume of methyl tertiary butyl ether and 0-20 parts by volume of petroleum ether. More preferably, the leaching agent for the oily drill cuttings and oily drilling waste consists of 90 volume parts of polymethoxy dimethyl ether, 6.5 to 7 volume parts of methyl tertiary butyl ether and 3 to 3.5 volume parts of petroleum ether. Particularly preferably, the leaching agent for the oily drill cuttings and oily drilling waste consists of 90 volume parts of polymethoxy dimethyl ether, 6.67 volume parts of methyl tertiary butyl ether and 3.33 volume parts of petroleum ether.
In the above application, preferably, the polymerization degree of the polymethoxy dimethyl ether is 2 to 4.
In the above application, preferably, the petroleum ether has a boiling range of 60 to 90 ℃.
In the above application, preferably, the leaching agent for the oil-containing drill cuttings and oil-containing drilling waste has a boiling point distribution of 100-150 ℃ and a flash point distribution of 50-65 ℃.
The polymethoxy dimethyl ether can be mutually soluble with diesel oil in any proportion, is a novel diesel oil additive, and after the polymethoxy dimethyl ether is used for deoiling treatment, the desorbed oil-based mud has no demulsification effect, and the demulsification voltage is better than that of the oil-based mud before treatment.
Aiming at the characteristic analysis of oily drilling cuttings/oily drilling wastes generated by drilling with the oil-based drilling fluid, the invention mainly solves two problems of how to overcome intermolecular acting force among oily waste components to reduce energy consumption and how to reduce adsorption free energy of oil phase, water phase and solid phase three-phase interfaces to realize deep desorption of the oil phase, deeply researches molecular mass transfer diffusion efficiency, multiphase interface behavior change rule and nano emulsion ultralow interfacial tension desorption action mechanism to form a novel separation system, provides the leaching agent for deep desorption of the oil phase under the low-energy condition and the use method thereof, ensures that the solid phase oil content after treatment is less than or equal to 2.0 percent, the recovery rate of the oil phase and the separation system is more than or equal to 80 percent, and provides technical guarantee for large-scale use, environmental improvement and resource utilization of the oil-based drilling fluid.
The leaching agent provided by the invention can greatly simplify the treatment steps and treatment cost of the oily drilling cuttings/oily drilling wastes, the treatment process is simple, and the oily drilling cuttings/oily drilling wastes can effectively reduce the content of oily substances and improve the environmental protection efficiency to reach the discharge standard after being treated. And the leaching agent and the emulsified diesel oil recovered by fractionation can be recycled, so that the utilization rate of the oil-based drilling fluid and the leaching agent is greatly improved, and the use cost is reduced.
The leaching agent provided by the invention is suitable for the treatment work of oil-containing drilling cuttings and other drilling oil-containing wastes on a drilling site, and realizes the efficient, economic and environment-friendly standard treatment of various oil-containing drilling cuttings and other drilling oil-containing wastes; in addition, the leaching agent provided by the invention is also significant for treating petroleum-polluted soil and cleaning sludge at the bottom of gasoline and diesel tanks. The leaching agent for the oily drilling cuttings and the oily drilling wastes and the using method thereof provided by the invention realize the environment protection of solid-phase material discharge and complete standard reaching, solve the environmental hidden trouble from the source, are imperative for pollution treatment and resource recycling, can fully realize resource recycling, solve the problem of ecological environment influence caused by oil-based mud drilling, realize the sustainable development of oil fields, and create huge environmental benefit and economic benefit at the same time. And the combination of high flash point and low boiling point of the leaching agent is realized by compounding the leaching agent, so that less energy is needed in the distillation process, a green and environment-friendly treatment mode is realized, and the environment-friendly standard of emission reduction is reached.
Detailed Description
The technical solutions of the present invention will be described in detail below in order to clearly understand the technical features, objects, and advantages of the present invention, but the present invention is not limited to the practical scope of the present invention.
Example 1
Weighing the following raw materials: 10g of oil-containing drilling cuttings and 60ml of poly (methoxy dimethyl ether) with the polymerization degree of 3.
The using method comprises the following steps:
step 1: placing the weighed oily drilling cuttings and leaching agent (60 ml of polymethoxy dimethyl ether with the polymerization degree of 3) in a stirrer, and stirring for 7min under the condition that the shear rate is 300 r/min;
step 2: stirring, standing for a period of time, standing for solid phase precipitation, naturally layering solid and liquid, centrifuging the lower layer solid phase, and drying at 95 deg.C for 24 hr;
and step 3: after solid-liquid separation is carried out on the leached oil-containing drilling cuttings and the leaching agent, putting a liquid phase into a three-neck flask, and then distilling at the temperature of 120 ℃ and under the negative pressure difference of 0.01MPa to respectively obtain emulsified diesel oil and the leaching agent.
The leaching agent in the embodiment does not need special treatment and can be directly added into the oil-containing drill cuttings for use.
Example 2
Weighing the following raw materials: 10g of oil-containing drilling cuttings, 58ml of polymethoxy dimethyl ether with the polymerization degree of 3 and 2ml of petroleum ether (the boiling range is 60-90 ℃).
The using method comprises the following steps: essentially the same as in example 1, except that the leaching agents were 58ml of polymethoxy dimethyl ether having a degree of polymerization of 3 and 2ml of petroleum ether (boiling range 60-90 ℃ C.).
Example 3
Weighing the following raw materials: 10g of oil-containing drilling cuttings, 56ml of polyoxymethylene dimethyl ether with the polymerization degree of 3 and 4ml of petroleum ether (the boiling range is 60-90 ℃).
The using method comprises the following steps: essentially the same as in example 1, except that the leaching agents were 56ml of polyoxymethylene dimethyl ether having a degree of polymerization of 3 and 4ml of petroleum ether (boiling range 60-90 ℃ C.).
Example 4
Weighing the following raw materials: 10g of oil-containing drilling cuttings, 54ml of polymethoxy dimethyl ether with the polymerization degree of 3 and 6ml of petroleum ether (the boiling range is 60-90 ℃).
The using method comprises the following steps: the same as example 1 except that 54ml of polyoxymethylene dimethyl ethers having a degree of polymerization of 3 and 6ml of petroleum ether (boiling range 60-90 ℃ C.) were used as leaching agents.
Example 5
Weighing the following raw materials: 10g of oil-containing drilling cuttings, 58ml of polyoxymethylene dimethyl ether with the polymerization degree of 3 and 2ml of methyl tert-butyl ether.
The using method comprises the following steps: the same as example 1 except that 58ml of polyoxymethylene dimethyl ethers having a degree of polymerization of 3 and 2ml of methyl t-butyl ether were used as leaching agents.
Example 6
Weighing the following raw materials: 10g of oil-containing drilling cuttings, 56ml of polyoxymethylene dimethyl ether with the polymerization degree of 3 and 4ml of methyl tert-butyl ether.
The using method comprises the following steps: the same as example 1 except that 56ml of polyoxymethylene dimethyl ethers having a degree of polymerization of 3 and 4ml of methyl t-butyl ether were used as leaching agents.
Example 7
Weighing the following raw materials: 10g of oil-containing drilling cuttings, 54ml of polyoxymethylene dimethyl ether with the polymerization degree of 3 and 6ml of methyl tert-butyl ether.
The using method comprises the following steps: the same as example 1 except that 54ml of polyoxymethylene dimethyl ethers having a degree of polymerization of 3 and 6ml of methyl t-butyl ether were used as leaching agents.
Example 8
Weighing the following raw materials: 10g of oil-containing drilling cuttings, 56ml of polyoxymethylene dimethyl ether with the polymerization degree of 3, 2ml of methyl tert-butyl ether and 2ml of petroleum ether (the boiling range is 60-90 ℃).
The using method comprises the following steps: the same as example 1 except that the leaching agents were polyoxymethylene dimethyl ethers having a degree of polymerization of 3 (56 ml), methyl t-butyl ether (2 ml) and petroleum ether (boiling range 60-90 ℃ C.) (2 ml).
Example 9
Weighing the following raw materials: 10g of oil-containing drilling cuttings, 54ml of polyoxymethylene dimethyl ether with the polymerization degree of 3, 4ml of methyl tert-butyl ether and 2ml of petroleum ether (the boiling range is 60-90 ℃).
The using method comprises the following steps: the same as example 1 except that the leaching agents were 54ml of polyoxymethylene dimethyl ethers having a degree of polymerization of 3, 4ml of methyl t-butyl ether and 2ml of petroleum ether (boiling range 60-90 ℃ C.).
Example 10
Weighing the following raw materials: 10g of oil-containing drilling cuttings, 54ml of polymethoxy dimethyl ether, 2ml of methyl tertiary butyl ether and 4ml of petroleum ether (the boiling range is 60-90 ℃).
The using method comprises the following steps: the same as example 1 except that the leaching agents were 54ml of polyoxymethylene dimethyl ethers having a degree of polymerization of 3, 2ml of methyl t-butyl ether and 4ml of petroleum ether (boiling range 60-90 ℃ C.).
The leaching agents for oily drill cuttings provided in examples 1 to 10 of the present invention were subjected to performance testing as follows:
1. test objects:
oil-containing drill cuttings: the oil sludge settled in the waste oil-based drilling fluid pool is centrifuged to be used as an oil-containing drilling cutting blank sample, and the oil content is 36 percent through tests.
Test samples 1 to 10: the test samples 1-10 were treated with the leachants of examples 1-10, respectively, and the oil content of the dried solid phase of step 2 was tested after the experimental procedure was completed.
2. The test method comprises the following steps:
measurement of oil content of drill cuttings:
after a certain amount of test object is wrapped with absorbent filter paper, the mass of the test object is weighed by an analytical balance, and then the test object is placed in a Soxhlet extractor for extraction. After extraction for 16h, the filter paper coated with the test object was taken out, dried and its mass was measured with an analytical balance. The poor quality before and after this is the oil content of the test object.
wherein M is1The total weight of the sample and the filter paper before the Soxhlet extraction is carried out;
M2the total weight of the sample and the filter paper after the soxhlet extraction was performed.
TABLE 1 oil content parameter data table for each test object
Table 2 liquid phase fractionation data table for each test object
Examples
|
Solvent recovery (%)
|
Fractionation time (95%) (h)
|
Example 1
|
80.2
|
3.2
|
Example 2
|
82.6
|
1.8
|
Example 3
|
84.5
|
1.6
|
Example 4
|
86.7
|
1.3
|
Example 5
|
83.4
|
1.5
|
Example 6
|
85.7
|
1.0
|
Example 7
|
89.2
|
0.9
|
Example 8
|
90.5
|
1.0
|
Example 9
|
92.8
|
0.8
|
Example 10
|
91.2
|
0.9 |
As can be seen from the data in tables 1 and 2, the oil content, the solvent recovery rate and the safety and environmental protection performance of drill cuttings treated by the leaching agent provided by the embodiment of the invention are obviously better than those of other leaching agent samples, especially by using the leaching agent provided by the embodiment 9, the oil content after sample treatment and the solvent recovery rate during the fractionation process are optimal. Therefore, the leaching agent provided by the embodiment of the invention can effectively reduce the oil content of the oily drilling cuttings generated by using the oil-based drilling fluid and has good solvent recovery rate, so that the oily drilling cuttings can be treated in a safe and environment-friendly way, and the pollution and damage of the oily drilling cuttings to the environment are reduced. The leaching agent provided by the embodiment of the invention has low cost and wide application range.