WO2021028864A1 - Process for the bioremediation of an area polluted by oil and/or gas wells - Google Patents

Process for the bioremediation of an area polluted by oil and/or gas wells Download PDF

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Publication number
WO2021028864A1
WO2021028864A1 PCT/IB2020/057622 IB2020057622W WO2021028864A1 WO 2021028864 A1 WO2021028864 A1 WO 2021028864A1 IB 2020057622 W IB2020057622 W IB 2020057622W WO 2021028864 A1 WO2021028864 A1 WO 2021028864A1
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Prior art keywords
phase
bioremediation
ground
oil
area
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PCT/IB2020/057622
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French (fr)
Inventor
Antonio Bertolotto
Original Assignee
Paneco Iberica - Energias Renovaveis Lda
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Publication of WO2021028864A1 publication Critical patent/WO2021028864A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09C—RECLAMATION OF CONTAMINATED SOIL
    • B09C1/00—Reclamation of contaminated soil
    • B09C1/10—Reclamation of contaminated soil microbiologically, biologically or by using enzymes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09C—RECLAMATION OF CONTAMINATED SOIL
    • B09C1/00—Reclamation of contaminated soil
    • B09C1/002—Reclamation of contaminated soil involving in-situ ground water treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09C—RECLAMATION OF CONTAMINATED SOIL
    • B09C1/00—Reclamation of contaminated soil
    • B09C1/005—Extraction of vapours or gases using vacuum or venting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09C—RECLAMATION OF CONTAMINATED SOIL
    • B09C1/00—Reclamation of contaminated soil
    • B09C1/06—Reclamation of contaminated soil thermally
    • B09C1/065—Reclamation of contaminated soil thermally by pyrolysis
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09C—RECLAMATION OF CONTAMINATED SOIL
    • B09C1/00—Reclamation of contaminated soil
    • B09C1/10—Reclamation of contaminated soil microbiologically, biologically or by using enzymes
    • B09C1/105—Reclamation of contaminated soil microbiologically, biologically or by using enzymes using fungi or plants
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/004—Sludge detoxification
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09C—RECLAMATION OF CONTAMINATED SOIL
    • B09C2101/00—In situ

Definitions

  • the present invention relates to the technical field of remediation, in particular to the technical field of the remediation of areas wherein oil extraction activities have been carried out.
  • the increasingly serious problems related to oil extraction activities notably include the severe environmental pollution caused by these activities, whose effects persist even after the operation of an oil well is terminated .
  • the purpose of the present invention is to provide a complex method capable of acting simultaneously with the exploitation activities of oil and gas wells, thus preventing that, once terminated the exploitation of the oilfield, the soil, subsoil, groundwater and air are permanently or irreparably damaged by polluting agents.
  • the present invention provides a method for the bioremediation of an area polluted by oil and/or gas extraction activity carried out in said area and causing the emission of polluting gases into the air and the pollution of soil, impregnated with oil, said method comprising one or more of the following phases: I) purification of the gases produced by said activity;
  • the method according to the present invention advantageously provides for the improvement, remediation, recovery and treatment of sites polluted by oil and/or gas wells.
  • Figures 1 to 3 are attached to facilitate the understanding of the present invention. Figures 1 to 3 illustrate preferred implementations of the invention, but do not intend to limit its purpose.
  • Figure 1 shows the wells located inside the perimeter of the area intended for bioremediation.
  • Figure 1 the reference numbers 5.1, 5.2, 4.1, 3.1, 7.1, 8.2, 8.1,
  • FIG. 1 shows, in graphic form, the operating phases I and II of the method according to the present invention, where:
  • Area 1A is the area wherein peripheral wells shown in Fig. 1 are located;
  • Area IB is the area wherein transfert wells shown in Fig. 1 are located;
  • Area 1C is the area wherein the base well shown in Fig. 1 is located;
  • Figure 3 shows, in graphic form, the first preliminary phase, the second preliminary phase and the operating phases III (which is integrated with the operating phase IV) of the method according to the present invention, wherein: A - First preliminary phase;
  • the present invention provides a method for the improvement, remediation, recovery and treatment of sites polluted by oil and/or gas wells.
  • bioremediation is used as a synonym of "remediation” and is intended to denote a group of activities intended to restore or even improve the conditions of a site after its exploitation, particularly after oil and/or gas extraction activities performed on the site itself.
  • the aforementioned site can be advantageously used once again for agricultural and/or residential activities.
  • the term "site” is intended to denote an area of territory that has suffered the effects of oil and/or gas extraction activities. This area includes the topsoil, the soil, the subsoil and the groundwater.
  • the topsoil is defined as the outermost layer on the surface of the ground.
  • the subsoil is intended to expand to a depth that is adequate, optimal and sufficient to remove the pollutants, as will be described herein below.
  • the term “soil” is used in the description below in its broadest meaning and is, therefore, intended to include each of the topsoil, the soil and the subsoil.
  • ground is intended to denote both the area of land used for a particular purpose or activity and, notably, the substance of which the soil is made (i.e. the topsoil, the soil and the subsoil). According to the latter definition, the term “ground” is used as a synonym of "earth”.
  • the wells are organised according to the following classification:
  • a pyrogasifier and a structure for the production of electrical energy are located in its immediate vicinity (as shown in Figure 2);
  • - peripheral well located furthest away; - transfert well: located in an intermediate position between the base well and the peripheral wells; one or more peripheral wells may converge on a single transfert well (as shown in Figure 1).
  • the base, transfert and peripheral well “functions” are preferably assigned based on the distance between each of the wells and, therefore, on the possibility of managing them in the most efficient and appropriate manner, depending on the pollution of the area in the immediate vicinity of the well and on the estimated "life" of the well itself, defined as how long its exploitation is expected to last.
  • the method according to the invention comprises a plurality of phases.
  • Two main phases may be distinguished, namely a preliminary phase and an operating phase, each of them comprising in turn one or more phases (or sub-phases), as described below in greater detail.
  • the preliminary phase comprises a first preliminary phase and a second preliminary phase.
  • the first preliminary phase includes the so-called “diagnosis”, i.e. the verification of the site and documents, to define the project and the schedule thereof (cf. reference number 3.4 in Figure 3).
  • the first preliminary phase advantageously comprises the actions required for the characterization of the state of pollution of the air, soil, subsoil and groundwater.
  • said actions include appropriate chemical and microbiological analyses.
  • the Nm3 of gas to be treated can be quantitatively evaluated, as well as the composition of the gases and the m3/day of oil spilled and/or sludge produced to be treated.
  • a financial plan and a positive and negative Environmental Impact Assessment (EIA) can also be elaborated.
  • the second preliminary phase comprises the construction of all the necessary structures and, therefore, the completion of the executive project (cf. reference number 3.5 in Figure 3).
  • the operating phase comprises the activities of remediation, which characterize the method according to the invention and differentiate it from the known processes.
  • the operating phase comprises one or more operational interventions.
  • the operating phase comprises several operational interventions. Said operational interventions are referred to herein below as “operating phases” followed by a number (i.e. I, II, etc.).
  • the method according to the present invention comprises at least one of the operating phases I to III described below.
  • the method according to the present invention comprises all the operating phases I to III described below.
  • the method according to the present invention comprises the operating phase IV described below.
  • the method according to the present invention comprises all the operating phases I to IV.
  • the operating phase comprises a phase of purification of the gases produced by the oil and/or gas extraction activity, particularly the gases generated by the well(s). This phase is referred to below as the operating phase I.
  • the operating phase I is carried out by means of an intake and purification plant positioned directly above the well, upstream of a flare (cf. reference 1.1 in Figure 2).
  • a flare cf. reference 1.1 in Figure 2.
  • purification includes the following phases: a) a countercurrent washing phase with micro- nebulized water; b) a condensation phase, from which dirty washing water is obtained; c) a cryogenic phase which eliminates pollutants; d) an osmosis phase which purifies the dirty washing water.
  • the water used in the purification plant is in turn obtained from a modular biological purifier (MES-WP U&I - Marcopolo Ecotone System Water Purification Urban and Industry).
  • MES-WP U&I Marcopolo Ecotone System Water Purification Urban and Industry
  • the gas obtained by combustion of a flare (which is illustrated in Figure 2) and/or the gas obtained from a power plant, also referred to as CHP (cf. reference number 1.3 in Figure 2), may also be subjected to the operating phase I of gas purification.
  • the operating phase comprises a phase of treatment of the oil- impregnated grounds, during which sludge is separated from oil. This phase is referred to below as operating phase II.
  • the operating phase II is carried out either simultaneously or after other operating phases (e.g. the operating phase I).
  • the so-called “ponds” or “small lakes” are treated, which comprise or consist of liquid oil purges, chemical substances used in drilling processes and drilling debris that accumulates in special underground tanks.
  • the operating phase II is carried out with the aim of separating the oil and the sludge one from each other, wherein the oil is formed by liquid oil residues and the sludge is formed by dirty and/or oil-impregnated ground.
  • a mobile rail-mounted plant is used for this purpose, which performs the separation based on the different molecular weights.
  • the oil separated during this phase advantageously represents a commercial product and is, therefore, intended for the market.
  • the sludge is preferably stored for possible disposal and/or valorization.
  • the operating phase comprises a phase of soil remediation. This phase is referred to below as the operating phase III.
  • the operating phase III is advantageously carried out after the above described operating phase II.
  • the operating phase III is implemented through a microbiological and/or agronomic bioremediation programme.
  • the operating phase III comprises a microbiological bioremediation phase and/or an agronomic bioremediation phase.
  • the operating phase III comprises both a microbiological bioremediation phase and an agronomic bioremediation phase.
  • the microbiological bioremediation phase comprises at least one phase of scraping of the soil, during which the ground which was in contact with the oil (e.g. in the so- called “small lakes”) is scraped.
  • this phase of scraping portions of ground are removed (scraped) and are referred to below as “removed ground”, for the sake of brevity.
  • Said at least one phase of scraping is advantageously carried out to a depth determined by the surveys performed in the first preliminary phase.
  • the scraping may be "superficial” or “deep”.
  • the “superficial” scraping is carried out at a depth between about 1 cm and about 20 cm. This means that the ground present at a depth between about 1 cm and about 20 cm is subjected to this phase of scraping.
  • the "deep” scraping is carried out at a depth greater than about 20 cm and up to about 10 meters, preferably at a depth up to about 5 meters, more preferably up to about 4 meters, about 3 meters, about 2 meters, about 1 meter or about 50 cm.
  • the depth at which the scraping of the ground is carried out depends essentially on the concentration and the type of pollutants that are present in the ground.
  • different piles of ground are formed depending on the degree of pollution of the removed ground, in correspondence with a zone wherein the phase of scraping was performed.
  • zone is intended to denote a portion of land.
  • the removed ground accumulated after this phase of scraping is subsequently treated with a bioremediation substrate.
  • a mixture consisting essentially of about 90% of ground and about 10% of the bioremediation substrate is prepared.
  • the removed ground is treated with a bioactivator system, preferably an aqueous solution of a bioactivator system.
  • a bioactivator system preferably an aqueous solution of a bioactivator system.
  • said bioactivator system is represented by a microbial consortium.
  • the removed ground is treated with an aqueous solution of a bioactivator system represented by a microbial consortium, for example with Enzyveba NK1 (Marcopolo).
  • the removed ground is treated with a bioremediation substrate and a bioactivator system.
  • the removed ground is treated first with a bioremediation substrate and subsequently with a bioactivator system.
  • the layers or zones from which the ground was scraped are treated with a bioremediation substrate.
  • said layers or zones are treated by placing a layer of the bioremediation substrate of about 10 cm thick, which is preferably subsequently buried by a special machine at a depth of around 100 mm.
  • the bioremediation substrate is very rich in microbial agents, bacterial agents and fungal agents that are specialized:
  • said bioremediation substrate comprises a mixed composted soil restructuring and conditioning compound, derived from the controlled fermentation of bovine manure using the Pfeiffer method.
  • the removed ground is continuously aerated in order to keep constant the temperature and the moisture.
  • the removed (scraped) ground and/or the layers or zones from which the ground was removed (scraped) are periodically sprayed with Enzyveba NK12 (Marcopolo)
  • the agronomic bioremediation phase comprises the cultivation of a large herbage on cyclical batches, based on water availability.
  • the herbage is a type of rapidly developing forage crop.
  • the agronomic bioremediation phase may also comprise the sowing of crop varieties provided with high absorption capacity, such as sunflowers, hemp or Ficus benjamina.
  • the herbage is optionally grinded and optionally buried, preferably in the top 20 cm of thickness of the ground.
  • the intervention area is demarcated with native bushes and plants in order to protect the area to be remedied from the invasion of sand.
  • Ligneous materials typical of desert areas may also be used, if necessary.
  • the piles of ground with low levels of pollution can be used to reconstitute the layers or zones from which the ground was removed (scraped).
  • the primary remediation is completed over a period of time of approximately 10-20 years.
  • the primary remediation may be followed by a planting phase of native plants mixed with native bushes throughout the entire area and, therefore, not only along the perimeter.
  • the extent of the areas to be remedied depends essentially on the intensity of the pollution. Therefore, the areas to be remedied which are close to the well and the spill areas will be more extended, while the surrounding areas which are polluted only by most atmospheric deposits from the well will be less extended.
  • the operating phase comprises a phase of valorization of waste products generated by one or more of the above identified operating phases I to III.
  • This phase of valorization is referred to below as the operating phase IV.
  • the operating phase IV may comprise one or more of the following activities: the gas recovered and purified during the operating phase I is used for the production of electrical energy in suitable thermal engines, and - the purified oil obtained from the operating phase II is sent to the market, since it represents a commercial product in itself.
  • the crop varieties provided with high absorption capacity and obtained during the agronomic bioremediation of the operating phase III are cutted after their cycle is complete (i.e. the life cycle or the cycle useful for the present purposes) and then sent to a process of pyrogasification in a pyrogasifier.
  • portions of heavily polluted piles of ground formed during the operating phase III (cf. reference number 3.7 in Figure 3), kept covered by a polyethylene film, are periodically collected and then sent to a process of pyrogasification in a pyrogasifier.
  • the sludge separated during the operating phase II is subjected to a precess of pyrogasification in a pyrogasifier.
  • the pyrogasifier is represented by the reference number 3.1 in Figure 3.
  • the process of pyrogasification generates a gas, which is preferably subjected to a process of purification, for example to the operating phase I.
  • a process of purification for example to the operating phase I.
  • said gas is subjected to a phase of production of electrical energy or hot water.
  • the process of pyrogasification generates a biogas, also referred to as biocare.
  • the biocare is used as an aggregator in a bioremediation product comprising (cf. reference 3.2 in Figure 3): a mixed composted soil restructuring and conditioning compound (organic fertilizer), derived from the fermentation of selected bovine manure from farms and of agricultural plant by-products (fermentation controlled using the Pfeiffer method); an example thereof is represented by the product Humus AnEnzy® (Marcopolo Engineering S.p.A), and a bioactivator comprising a microbial consortium; an example thereof is represented by the product
  • a bioremediation product comprising (cf. reference 3.2 in Figure 3): a mixed composted soil restructuring and conditioning compound (organic fertilizer), derived from the fermentation of selected bovine manure from farms and of agricultural plant by-products (fermentation controlled using the Pfeiffer method); an example thereof is represented by the product Humus AnEnzy® (Marcopolo Engineering S
  • Enzyveba® (Marcopolo Engineering S.p.A.).
  • Said mixture represents a complex product having a high bioremediation capacity thanks to its rich content of organic compounds and minerals, as well as of specialised native microbes.
  • a first advantage is that it is possible not to interrupt the activities of gas and oil extraction while performing the bioremediation of the soil.
  • the method for the bioremediation according to the present invention works not only after, but also during, the exploitation activities of wells and oilfields. Therefore, the method for the bioremediation according to the present invention can be performed simultaneously with the exploitation activities of oil and gas wells.
  • the remediation activities are already substantially complete when the extraction activities are terminated, so that the area of interest is already almost completely redeveloped and returned to society.
  • the present invention allows the recovery of the land and territory, the valorization of the gas and biogas, as well as of the wastes represented by sludge and oil.
  • the present invention provides for the elimination of air pollution, which allows to reduce the greenhouse gases and, therefore, to limit the activities to the detriment of the ozone layer.

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  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
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Abstract

The present invention relates to a method for the bioremediation of an area polluted by oil and/or gas extraction activity carried out in said area and causing the emission of polluting gases into the air and the pollution of soil, impregnated with oil, comprising one or more of the following phases: I) purification of the gases produced by said activity; II) treatment of oil-impregnated grounds to separate sludge from oil; III) soil remediation.

Description

DESCRIPTION
"Process for the bioremediation of an area polluted by oil and/or gas wells"
Technical field of the invention
The present invention relates to the technical field of remediation, in particular to the technical field of the remediation of areas wherein oil extraction activities have been carried out.
State of the art
The increasingly serious problems related to oil extraction activities notably include the severe environmental pollution caused by these activities, whose effects persist even after the operation of an oil well is terminated .
Today, some companies undertake to recover the oil that is separated from impurities by filtering or centrifuging; any sludge that is produced is subsequently made inert using chemical aggregators and cement, thus forming useful materials that can be reused for the construction of roads, paving or fences.
However, methodologies are not available yet that offer "closed-loop" solutions to this problem. Summary of the invention
The purpose of the present invention is to provide a complex method capable of acting simultaneously with the exploitation activities of oil and gas wells, thus preventing that, once terminated the exploitation of the oilfield, the soil, subsoil, groundwater and air are permanently or irreparably damaged by polluting agents.
In this respect, the present invention provides a method for the bioremediation of an area polluted by oil and/or gas extraction activity carried out in said area and causing the emission of polluting gases into the air and the pollution of soil, impregnated with oil, said method comprising one or more of the following phases: I) purification of the gases produced by said activity;
II) treatment of oil-impregnated grounds to separate sludge from oil;
III) soil remediation.
The method according to the present invention advantageously provides for the improvement, remediation, recovery and treatment of sites polluted by oil and/or gas wells.
Brief description of the drawings
Figures 1 to 3 are attached to facilitate the understanding of the present invention. Figures 1 to 3 illustrate preferred implementations of the invention, but do not intend to limit its purpose.
Figure 1 shows the wells located inside the perimeter of the area intended for bioremediation. In Figure 1: the reference numbers 5.1, 5.2, 4.1, 3.1, 7.1, 8.2, 8.1,
7.1, 6.1, 6.2 refer to peripheral wells; the reference numbers 2, 3, 4, 5, 6, 7, 8 refer to transfert wells; and the reference number 1 refers to the base well.
Figure 2 shows, in graphic form, the operating phases I and II of the method according to the present invention, where:
Area 1A is the area wherein peripheral wells shown in Fig. 1 are located;
Area IB is the area wherein transfert wells shown in Fig. 1 are located;
Area 1C is the area wherein the base well shown in Fig. 1 is located;
1.7 - Storage of oil separated from sludge;
1.6 - Mobile oil-sludge separation zone;
1.8 - Storage of sludge separated from oil;
1.5 - Dirty oil accumulation tank;
1.1 - Gas purifier;
1.2 - Black camp water purifier;
1.3 - Combined heat and power (CHP);
1.4 - Afterburner;
1.9 - Pyrogasifier.
Figure 3 shows, in graphic form, the first preliminary phase, the second preliminary phase and the operating phases III (which is integrated with the operating phase IV) of the method according to the present invention, wherein: A - First preliminary phase;
B - Second preliminary phase;
C - Operating phase III (integrated with operating phase IV);
D - Core drilling for soil sampling;
E - Analysis;
3.4 Diagnostic Project;
3.5 Executive Project;
3.6 - Scraping of polluted oil-impregnated ground;
3.7 - Piles of polluted ground;
3.1 - Pyrogasifier;
H - Hot cold;
J - Electrical energy;
3.8 - Second scraping to remove less polluted ground;
3.9 - Piles of ground in aerobic bioremediation with Enzyveba®;
F - Enzyveba®;
G - Anenzy®;
3.10 - Herbaceous and absorbent crop with Humus Anenzy® and Enzyveba®;
3.14 - Perimeter plants around grass and sunflowers;
3.2 - Biogas (biocare) + Humus Anenzy® + Enzyveba®;
3.3 - Organic-mineral bioremediation substrate;
3.15 - Bioremediated earth overflow enriched with organic- mineral substrate; 3.16 - Absorbent crops of plants for finishing bioremediation .
Detailed description of the invention
The present invention provides a method for the improvement, remediation, recovery and treatment of sites polluted by oil and/or gas wells.
For the purposes of this invention, the term "bioremediation" is used as a synonym of "remediation" and is intended to denote a group of activities intended to restore or even improve the conditions of a site after its exploitation, particularly after oil and/or gas extraction activities performed on the site itself.
According to the present invention, the aforementioned site can be advantageously used once again for agricultural and/or residential activities.
The terms "bioremediation" and "remediation", "recovery" are, hence, used interchangeably herein below.
The term "site" is intended to denote an area of territory that has suffered the effects of oil and/or gas extraction activities. This area includes the topsoil, the soil, the subsoil and the groundwater. The topsoil is defined as the outermost layer on the surface of the ground. The subsoil is intended to expand to a depth that is adequate, optimal and sufficient to remove the pollutants, as will be described herein below. The term "soil" is used in the description below in its broadest meaning and is, therefore, intended to include each of the topsoil, the soil and the subsoil.
The terms "site" and "area" are used interchangeably herein below.
The term "ground" is intended to denote both the area of land used for a particular purpose or activity and, notably, the substance of which the soil is made (i.e. the topsoil, the soil and the subsoil). According to the latter definition, the term "ground" is used as a synonym of "earth".
According to the present invention, the wells are organised according to the following classification:
- base (or central) well; in an optimal position relative to the other wells, and therefore preferably central; a pyrogasifier and a structure for the production of electrical energy are located in its immediate vicinity (as shown in Figure 2);
- peripheral well: located furthest away; - transfert well: located in an intermediate position between the base well and the peripheral wells; one or more peripheral wells may converge on a single transfert well (as shown in Figure 1).
The base, transfert and peripheral well "functions" are preferably assigned based on the distance between each of the wells and, therefore, on the possibility of managing them in the most efficient and appropriate manner, depending on the pollution of the area in the immediate vicinity of the well and on the estimated "life" of the well itself, defined as how long its exploitation is expected to last.
In a preferred embodiment, the method according to the invention comprises a plurality of phases. Two main phases may be distinguished, namely a preliminary phase and an operating phase, each of them comprising in turn one or more phases (or sub-phases), as described below in greater detail.
Preliminary Phase
In a preferred embodiment, the preliminary phase comprises a first preliminary phase and a second preliminary phase.
The first preliminary phase includes the so-called "diagnosis", i.e. the verification of the site and documents, to define the project and the schedule thereof (cf. reference number 3.4 in Figure 3). The first preliminary phase advantageously comprises the actions required for the characterization of the state of pollution of the air, soil, subsoil and groundwater.
Preferably, said actions include appropriate chemical and microbiological analyses. Advantageously, at the end of the first preliminary phase, the Nm3 of gas to be treated can be quantitatively evaluated, as well as the composition of the gases and the m3/day of oil spilled and/or sludge produced to be treated.
According to an embodiment of the invention, considering the number of years that the well in question has been producing gas and oil/sludge, data for the sizing of the necessary facilities and machinery can be elaborated .
According to another embodiment of the invention, plant simulations for each operating phase according to the principle of Q-T-S (Quantity, Time, Space: Q = Quantity of mass to be recovered; T = Operating time to assign to the technology/process; S = Space to assign, in terms of available/required surface areas) can be created and elaborated . According to another embodiment of the invention, a financial plan and a positive and negative Environmental Impact Assessment (EIA) can also be elaborated.
The second preliminary phase comprises the construction of all the necessary structures and, therefore, the completion of the executive project (cf. reference number 3.5 in Figure 3).
Operating Phase
Advantageously, the operating phase comprises the activities of remediation, which characterize the method according to the invention and differentiate it from the known processes. According to different embodiments of the invention, the operating phase comprises one or more operational interventions. Preferably, the operating phase comprises several operational interventions. Said operational interventions are referred to herein below as "operating phases" followed by a number (i.e. I, II, etc.).
The method according to the present invention comprises at least one of the operating phases I to III described below. Preferably, the method according to the present invention comprises all the operating phases I to III described below. Preferably, the method according to the present invention comprises the operating phase IV described below. Preferably, the method according to the present invention comprises all the operating phases I to IV.
Operating phase I
According to an embodiment of the invention, the operating phase comprises a phase of purification of the gases produced by the oil and/or gas extraction activity, particularly the gases generated by the well(s). This phase is referred to below as the operating phase I.
Preferably, the operating phase I is carried out by means of an intake and purification plant positioned directly above the well, upstream of a flare (cf. reference 1.1 in Figure 2). Once captured, the gas generated by the well is subjected to purification, which includes the following phases: a) a countercurrent washing phase with micro- nebulized water; b) a condensation phase, from which dirty washing water is obtained; c) a cryogenic phase which eliminates pollutants; d) an osmosis phase which purifies the dirty washing water.
From this process, a purified gas and some waste products are obtained.
According to an embodiment, the water used in the purification plant, particularly during the countercurrent washing phase a), is in turn obtained from a modular biological purifier (MES-WP U&I - Marcopolo Ecotone System Water Purification Urban and Industry).
According to another embodiment, if available, well water or properly desalinated seawater can be used instead. According to an embodiment of the invention, the gas obtained by combustion of a flare (which is illustrated in Figure 2) and/or the gas obtained from a power plant, also referred to as CHP (cf. reference number 1.3 in Figure 2), may also be subjected to the operating phase I of gas purification.
Operating phase II According to an embodiment of the invention, the operating phase comprises a phase of treatment of the oil- impregnated grounds, during which sludge is separated from oil. This phase is referred to below as operating phase II. According to different embodiments, the operating phase II is carried out either simultaneously or after other operating phases (e.g. the operating phase I).
According to an embodiment of the invention, the so- called "ponds" or "small lakes" are treated, which comprise or consist of liquid oil purges, chemical substances used in drilling processes and drilling debris that accumulates in special underground tanks.
The operating phase II is carried out with the aim of separating the oil and the sludge one from each other, wherein the oil is formed by liquid oil residues and the sludge is formed by dirty and/or oil-impregnated ground.
According to an embodiment of the invention, a mobile rail-mounted plant is used for this purpose, which performs the separation based on the different molecular weights. The oil separated during this phase advantageously represents a commercial product and is, therefore, intended for the market. On the other hand, the sludge is preferably stored for possible disposal and/or valorization.
Operating phase III According to an embodiment of the invention, the operating phase comprises a phase of soil remediation. This phase is referred to below as the operating phase III.
The operating phase III is advantageously carried out after the above described operating phase II.
Preferably, the operating phase III is implemented through a microbiological and/or agronomic bioremediation programme. In other words, according to different embodiments of the invention, the operating phase III comprises a microbiological bioremediation phase and/or an agronomic bioremediation phase. Preferably, the operating phase III comprises both a microbiological bioremediation phase and an agronomic bioremediation phase.
The microbiological bioremediation phase comprises at least one phase of scraping of the soil, during which the ground which was in contact with the oil (e.g. in the so- called "small lakes") is scraped. By means of this phase of scraping, portions of ground are removed (scraped) and are referred to below as "removed ground", for the sake of brevity.
Said at least one phase of scraping is advantageously carried out to a depth determined by the surveys performed in the first preliminary phase.
According to different embodiments, the scraping may be "superficial" or "deep". The "superficial" scraping is carried out at a depth between about 1 cm and about 20 cm. This means that the ground present at a depth between about 1 cm and about 20 cm is subjected to this phase of scraping. The "deep" scraping is carried out at a depth greater than about 20 cm and up to about 10 meters, preferably at a depth up to about 5 meters, more preferably up to about 4 meters, about 3 meters, about 2 meters, about 1 meter or about 50 cm. This means that the ground present at a depth greater than about 20 cm and up to about 10 meters, preferably at a depth up to 5 meters, more preferably up to about 4 meters, about 3 meters, about 2 meters, about 1 meter or about 50 cm, is subjected to this phase of scraping. The depth at which the scraping of the ground is carried out depends essentially on the concentration and the type of pollutants that are present in the ground.
According to a preferred embodiment, different piles of ground are formed depending on the degree of pollution of the removed ground, in correspondence with a zone wherein the phase of scraping was performed. The term "zone" is intended to denote a portion of land.
Preferably, even the least polluted grounds undergo a phase of scraping. According to an embodiment of the invention, the removed ground accumulated after this phase of scraping (in the aforementioned piles) is subsequently treated with a bioremediation substrate.
Preferably, a mixture consisting essentially of about 90% of ground and about 10% of the bioremediation substrate is prepared.
According to an embodiment of the invention, the removed ground is treated with a bioactivator system, preferably an aqueous solution of a bioactivator system. Preferably, said bioactivator system is represented by a microbial consortium.
Preferably, the removed ground is treated with an aqueous solution of a bioactivator system represented by a microbial consortium, for example with Enzyveba NK1 (Marcopolo). According to a preferred embodiment, the removed ground is treated with a bioremediation substrate and a bioactivator system. For example, the removed ground is treated first with a bioremediation substrate and subsequently with a bioactivator system. According to an embodiment, the layers or zones from which the ground was scraped are treated with a bioremediation substrate. Preferably, said layers or zones are treated by placing a layer of the bioremediation substrate of about 10 cm thick, which is preferably subsequently buried by a special machine at a depth of around 100 mm. Advantageously, the bioremediation substrate is very rich in microbial agents, bacterial agents and fungal agents that are specialized:
- in degrading hydrocarbon substances, and - in acting as a soil improver for remediation agricultural crops.
Preferably, said bioremediation substrate comprises a mixed composted soil restructuring and conditioning compound, derived from the controlled fermentation of bovine manure using the Pfeiffer method.
According to a preferred embodiment, the removed ground, optionally treated as described above, is continuously aerated in order to keep constant the temperature and the moisture. According to a preferred embodiment of the invention, the removed (scraped) ground and/or the layers or zones from which the ground was removed (scraped) are periodically sprayed with Enzyveba NK12 (Marcopolo
Engineering S.p.A.) as well as with an aqueous solution of Humus AnEnzy® (Marcopolo Engineering S.p.A.). This further prompts the remediation.
According to an embodiment, the agronomic bioremediation phase comprises the cultivation of a large herbage on cyclical batches, based on water availability. For example, the herbage is a type of rapidly developing forage crop. The agronomic bioremediation phase may also comprise the sowing of crop varieties provided with high absorption capacity, such as sunflowers, hemp or Ficus benjamina.
Once the herbage cycle is complete, the herbage is optionally grinded and optionally buried, preferably in the top 20 cm of thickness of the ground.
In a preferred embodiment, 3 to 4 cycles of agronomic bioremediation are required to obtain the purification or remediation of the soil. According to an embodiment of the invention, where necessary, the intervention area is demarcated with native bushes and plants in order to protect the area to be remedied from the invasion of sand.
Ligneous materials typical of desert areas may also be used, if necessary.
According to an embodiment, the piles of ground with low levels of pollution, once regenerated, can be used to reconstitute the layers or zones from which the ground was removed (scraped). Preferably, the primary remediation is completed over a period of time of approximately 10-20 years. The primary remediation may be followed by a planting phase of native plants mixed with native bushes throughout the entire area and, therefore, not only along the perimeter. The extent of the areas to be remedied depends essentially on the intensity of the pollution. Therefore, the areas to be remedied which are close to the well and the spill areas will be more extended, while the surrounding areas which are polluted only by most atmospheric deposits from the well will be less extended. In this regard, according to a particular embodiment, an area of about 10 km around each well is wetted or sprayed cyclically with an aqueous solution of Enzyveba NK12 for a period of about 3 months, preferably at night. Operating phase IV According to an embodiment of the invention, the operating phase comprises a phase of valorization of waste products generated by one or more of the above identified operating phases I to III. This phase of valorization is referred to below as the operating phase IV. The operating phase IV may comprise one or more of the following activities: the gas recovered and purified during the operating phase I is used for the production of electrical energy in suitable thermal engines, and - the purified oil obtained from the operating phase II is sent to the market, since it represents a commercial product in itself.
According to an embodiment, the crop varieties provided with high absorption capacity and obtained during the agronomic bioremediation of the operating phase III are cutted after their cycle is complete (i.e. the life cycle or the cycle useful for the present purposes) and then sent to a process of pyrogasification in a pyrogasifier.
According to an embodiment, portions of heavily polluted piles of ground formed during the operating phase III (cf. reference number 3.7 in Figure 3), kept covered by a polyethylene film, are periodically collected and then sent to a process of pyrogasification in a pyrogasifier.
According to an embodiment, the sludge separated during the operating phase II is subjected to a precess of pyrogasification in a pyrogasifier.
The pyrogasifier is represented by the reference number 3.1 in Figure 3.
The process of pyrogasification generates a gas, which is preferably subjected to a process of purification, for example to the operating phase I. Preferably, once purified, said gas is subjected to a phase of production of electrical energy or hot water.
Besides said gas, the process of pyrogasification generates a biogas, also referred to as biocare. According to an embodiment, the biocare is used as an aggregator in a bioremediation product comprising (cf. reference 3.2 in Figure 3): a mixed composted soil restructuring and conditioning compound (organic fertilizer), derived from the fermentation of selected bovine manure from farms and of agricultural plant by-products (fermentation controlled using the Pfeiffer method); an example thereof is represented by the product Humus AnEnzy® (Marcopolo Engineering S.p.A), and a bioactivator comprising a microbial consortium; an example thereof is represented by the product
Enzyveba® (Marcopolo Engineering S.p.A.).
Said mixture represents a complex product having a high bioremediation capacity thanks to its rich content of organic compounds and minerals, as well as of specialised native microbes.
Based on the above description, the advantages offered by this invention are evident.
Particularly, a first advantage is that it is possible not to interrupt the activities of gas and oil extraction while performing the bioremediation of the soil.
In fact, the method for the bioremediation according to the present invention works not only after, but also during, the exploitation activities of wells and oilfields. Therefore, the method for the bioremediation according to the present invention can be performed simultaneously with the exploitation activities of oil and gas wells.
Advantageously, most of the remediation activities are already substantially complete when the extraction activities are terminated, so that the area of interest is already almost completely redeveloped and returned to society. The present invention allows the recovery of the land and territory, the valorization of the gas and biogas, as well as of the wastes represented by sludge and oil.
Furthermore, the present invention provides for the elimination of air pollution, which allows to reduce the greenhouse gases and, therefore, to limit the activities to the detriment of the ozone layer.
In addition, the groundwater results to be much more preserved thanks to the method according to the invention. Further advantages of the invention are the safeguard of the human health and the environment.
The implementations described above can be combined with each other.
Of course, in no way is this invention restricted to the implementations herein described, and any person with an average knowledge of the field may envisage many ways of modifying it and replacing some technical characteristics with other equivalent ones, depending on the requirements of each situation, as defined in the attached claims.

Claims

1)Method for the bioremediation of an area polluted by oil and/or gas extraction activity carried out in said area and causing the emission of polluting gases into the air and the pollution of soil, impregnated with oil, said method comprising one or more of the following phases:
I) purification of the gases produced by said activity;
II) treatment of oil-impregnated grounds to separate sludge from oil;
III) soil remediation.
2)Method according to claim 1, wherein one or more of said phases I) to III) generate one or more waste products and said method comprises an additional phase IV) of valorization of said one or more waste products.
3)Method according to any one of the preceding claims, wherein said phase I) comprises the following phases: a) a countercurrent washing phase with micro- nebulized water; b) a condensation phase, from which dirty washing water is obtained; c) a cryogenic phase which eliminates pollutants; d) an osmosis phase which purifies the dirty washing water .
4)Method according to any one of the preceding claims, wherein said phase III) comprises a microbiological bioremediation phase.
5)Method according to claim 4, wherein the microbiological bioremediation phase comprises: a) a phase of scraping of the soil by means of which portions of ground are removed, thus obtaining removed ground and layers from which the ground was removed, and b)one or more of the following phases:
- treatment of the removed ground by means of a bioremediation product;
- aeration of the removed ground;
- treatment of the removed ground by means of a bioactivator product;
- treatment of the layers from which the ground was removed with a bioremediation product.
6)Method according to claim 5, wherein said phase of scraping is carried out at a depth from about 1 cm to about 20 cm.
7)Method according to claim 5, where said phase of scraping is carried out at a depth greater than 20 cm and up to about 10 meters.
8)Method according to claim 7, wherein said phase of scraping is carried out at a depth up to about 5 meters, preferably up to about 4 meters, about 3 meters, about 2 meters, about 1 meter, about 50 cm.
9)Method according to any one of claims 5 to 8, wherein said bioremediation product comprises a mixed composted soil restructuring and conditioning compound, derived from the controlled fermentation of bovine manure using the Pfeiffer method.
10)Method according to any one of claims 5 to 9, wherein said bioactivator product is represented by a microbial consortium.
11)Method according to any one of the preceding claims, wherein said phase III) comprises an agronomic bioremediation phase.
12)Method according to claim 11, wherein the agronomic bioremediation phase comprises at least one of the following: cultivation of herbage on the ground of said area, optional grinding of the herbage and optional burial of the grinded herbage, and sowing of crop varieties provided with high absorption capacity.
13)Method according to claim 12, wherein said crop varieties comprise one or more of: sunflowers, hemp or Ficus benjamina.
14)Method according to any one of claims 11 to 13, further comprising a phase of planting bushes and/or native plants along the perimeter of the area to be remedied .
15)Method according to any one of claims 2 to 14, wherein the valorization of said waste product(s) is obtained by one or more of the following activities:
- production of electrical energy from the purified gas obtained according to phase I), production of electrical energy from the gas generated by pyrogasification of any one of the following: crop varieties provided with high absorption capacity, sludge, portions of polluted removed ground.
PCT/IB2020/057622 2019-08-14 2020-08-13 Process for the bioremediation of an area polluted by oil and/or gas wells WO2021028864A1 (en)

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Citations (4)

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US9333382B2 (en) * 2013-10-12 2016-05-10 Zhejiang Zehan Environmental Technology Co., Ltd Enhanced combination method for phytoremediation of petroleum contaminated soil by Impatiens balsamina L. associated with the indigenous microorganisms
CN107457256A (en) * 2017-10-09 2017-12-12 常州蓝旗亚纺织品有限公司 A kind of restorative procedure of oil-polluted soils
US20180056346A1 (en) * 2016-08-23 2018-03-01 Bulldog Green Remediation, Inc. Methods for bioremediation of hydrocarbon-contaminated media

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101830614A (en) * 2010-04-15 2010-09-15 中国石油集团川庆钻探工程有限公司 Biological treatment method for waste mud in petroleum and natural gas exploration drilling work
US9333382B2 (en) * 2013-10-12 2016-05-10 Zhejiang Zehan Environmental Technology Co., Ltd Enhanced combination method for phytoremediation of petroleum contaminated soil by Impatiens balsamina L. associated with the indigenous microorganisms
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CN107457256A (en) * 2017-10-09 2017-12-12 常州蓝旗亚纺织品有限公司 A kind of restorative procedure of oil-polluted soils

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