AU2010334769B2

AU2010334769B2 - In-situ microbial oxygen generation and hydrocarbon conversion in a hydrocarbon containing formation

Info

Publication number: AU2010334769B2
Application number: AU2010334769A
Authority: AU
Inventors: Bartholomeus Petrus Lomans
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 2009-12-24
Filing date: 2010-12-23
Publication date: 2014-02-13
Anticipated expiration: 2030-12-23
Also published as: GB2488937A8; GB201210573D0; GB2488937B; GB2488937A; CA2783297C; WO2011076925A1; AU2010334769A1; CA2783297A1; US20120255726A1

Abstract

A method for in-situ microbial oxygen generation in an underground hydrocarbon containing formation comprises : - injecting into the formation an oxygen generating composition comprising thermophilic chlorate reducing micro-organisms, such as bacteria of the genus Archaeoglobus, Geobacillus and/or Thermus, which multiply at a temperature of at least 60° C; and - inducing the multiplied micro-organisms to convert the hydrocarbons and/or other pore fluid components in-situ into transportable or disposable products

Description

WO 2011/076925 PCT/EP2010/070666 IN-SITU MICROBIAL OXYGEN GENERATION AND HYDROCARBON CONVERSION IN A HYDROCARBON CONTAINING FORMATION BACKGROUND OF THE INVENTION The invention relates to a method for in-situ oxygen generation in a hydrocarbon containing formation. Such a method is known from US patent 5,163,510. 5 The method known from this prior art reference comprises: - injecting into the formation a fluid comprising a source of oxygen that chemically releases oxygen into the formation; - inducing micro-organisms present in the formation to 10 multiply using the oil as their carbon source and the chemically produced oxygen in the injection water as their oxygen source; and - allowing the multiplied micro-organisms to convert oil from the environment. 15 In this known method the source of oxygen is provided by injecting water comprising an oxidizing compound selected from the group consisting of H 2 0 2 , NaClO 3 , KClO 4 , NaNO 3 and combinations thereof, which are assumed to be chemically converted to result in oxygen. This assumption 20 is based on the fact that oxygen generation from Microbial Chlorate Reduction was for the first time reported in 1996 by van Ginkel at al in 1996, Archives of Microbiology 166:321-326. In accordance with the teachings of US patent 25 5,163,510 the chemically generated oxygen is then used by microbes to convert hydrocarbons. Limitations of the use of the known oxidizing compounds known from US patent 5,163,510 for chemical oxygen generation are that H 2 0 2 may dissociate during or 30 shortly after the injection process, and that chemical WO 2011/076925 PCT/EP2010/070666 -2 conversion of NaNO 3 , NaClO 3 and KClO 4 do not generate oxygen at temperatures lower than 1200 Celsius. Moreover, the microbes Pseudomonas putida, Pseudomonas aeruginosa, Corynebacterium lepus, Mycobacterium rhodochrous 5 and Mycobacterium vaccae disclosed in US patent 5,163,510 are non-thermophilic micro-organisms, which are unable to reduce chlorate and/or multiply at temperature of at least 60 0 C. This will prevent the method known from US patent 5,163,510 to be beneficial for application throughout an 10 entire hydrocarbon containing formation as the ambient temperature in a hydrocarbon containing formation often exceeds 60 0 C. The use of microbial chlorate reduction as mechanism for in-situ oxygen generation and thereby stimulating microbial 15 activity using hydrocarbons as carbon and energy source has been reported for the bioremediation of hydrocarbon spills at ambient atmospheric temperatures in the following prior art references: - Coates et al., 1998, Nature 396(6713): 730 20 - Coates et al., 1999, Applied Environmental Microbiology 65(12): 5234-5341 - Coates et al., 2004, US patent 2004/0014196A1 , which prior art references are collectively referred to as Coates et al (1998, 1999, 2004) 25 - Tan et al., 2006, Biodegradation 17(1): 113-119 - Mehboob et al., 2009: Applied Microbiology and Biotechnology 83(4): 739-747 - Langenhoff et al., 2009, Bioremediation Journal, 13(4): 180-187 30 There is a need to provide an method for in-situ thermophilic microbial oxygen generation wherein a controlled amount of oxygen is microbiologically produced in-situ deeper in the hydrocarbon containing formation where the temperature is at least 60 0

C.

WO 2011/076925 PCT/EP2010/070666 -3 There is furthermore a need to provide an enabling process for the stimulation of in-situ thermophilic microbial conversion of hydrocarbons wherein oxygen is microbiologically produced from the injected oxygen source 5 only at high temperature locations in a hydrocarbon containing formation where injected or indigenous micro organisms encounter the injected electron acceptor in addition to an electron donor, such as hydrocarbons, volatile fatty acids, etc. 10 There is also a need for a method for thermophilic microbial oxygen generation through chlorate reduction at the oil water interface, in contrast to chemical generation of oxygen known from US patent 5,163,510 that can also occur in oil-poor parts of the reservoir. 15 Utilization of microbes to enhance hydrocarbon recovery is hampered by the limited bioavailability and biodegradability of the hydrocarbons under hot reservoir conditions. Thus there is also a need to provide a way to improve 20 bioavailability and biodegradability in hot hydrocarbon containing formations where the ambient temperature is at least 60 0 C. SUMMARY OF THE INVENTION In accordance with the invention there is provided a 25 method for in-situ oxygen generation in an underground hydrocarbon containing formation, the method comprising injecting into the formation an oxygen generating composition which releases oxygen (02) by reduction of chlorate (C10 3 -), wherein: 30 - the formation has a temperature of at least 60 C; - the composition comprises thermophilic chlorate reducing micro-organisms, which multiply at an ambient temperature of at least 600 C,; and - the multiplied thermophilic chlorate reducing micro- WO 2011/076925 PCT/EP2010/070666 -4 organisms convert the hydrocarbons and/or other pore fluids in-situ into transportable or disposable products. In an embodiment the thermophilic chlorate reducing micro-organisms comprise bacteria of the genus 5 Archaeoglobus, Geobacillus and/or Thermus and use hydrogen (H) and electrons(e) provided by hydrocarbons, volatile fatty acids and/or other pore fluids in the formation followed by dismutation of chlorite(ClO2) by the micro organisms on the basis of the reactions: 10 C103 + 2H +2e -> ClO2 +H 2 0 C102 -> Cl +02 In a suitable embodiment the thermophilic chlorate reducing micro-organisms multiply at an ambient temperature of at least 800 C and comprise bacteria of the genus 15 Archaeoglobus fulgidis. Optionally, the method according to the invention furthermore comprises: - injecting into the formation an oxygen generating composition, which comprise or generates chlorate in the 20 formation and which releases oxygen (02) by thermophilic microbial reduction of chlorate(ClO3) by the micro organisms, using hydrogen (H) and electrons (e) provided by the hydrocarbons, volatile fatty acids and/or other pore fluid components, such as oil & gas contaminants such as H 2 S, 25 thiophenes and mercaptanes, followed by dismutation of chlorite (Cl02) by micro-organisms on the basis of the reactions: C103 + 2H +2e -> C102 +H 2 0 C102- -> Cl- +02; 30 - inducing multiplication of the thermophilic chlorate reducing micro-organisms (Archaeoglobus, Geobacillus, Thermus), other chlorate-reducing thermophilic micro organisms and other micro-organisms that can use the hydrocarbons, volatile fatty acids and/or other pore fluid WO 2011/076925 PCT/EP2010/070666 -5 components (e.g. oil & gas contaminants as H 2 S, thiophenes and mercaptanes) as their carbon source and/or electron donor and the injected composition or the oxygen generated by thermophilic chlorate reduction thereby as their electron 5 acceptor and/or oxygen source; and - inducing the multiplied micro-organisms to convert the hydrocarbons and/or other pore fluid components in-situ into transportable products, such as in Microbial Enhanced Oil Recovery(MEOR) and/or ECBM Enhanced Coal Bed Methane(ECBM) 10 processes. The multiplied thermophilic micro-organisms generated in accordance with the method according to present invention may be used for in-situ conversion of coal, shale oil, oilshale, bitumen and/or a viscous crude oil 15 into a synthetic crude oil with a reduced viscosity and/or to convert associated contaminants, such as H 2 S, thiophenes and mercaptanes, into oxidized sulfur fractions that remain within the reservoir brine. The method according to the invention may be used to 20 improve bioavailability and biodegradability of hydrocarbons at thermophilic (60 - 120'C) & anaerobic conditions in underground formations containing hydrocarbons, volatile fatty acids and other pore fluid components and micro-organisms, by the process of 25 Thermophilic Microbial Chlorate Reduction. The process will generate oxygen in-situ that will enhance bioavailability and biodegradability, which subsequently will enables enhanced recovery of hydrocarbons (of improved quality) via other process like Microbial 30 Enhanced Oil Recovery (MEOR), Microbial Enhanced Coalbed Methane (MECBM) or pretreatment of heavy hydrocarbon crudes (heavy oil, bitumen) prior to processes as Steam Assisted Gravity Drainage (SAGD). The oxygen generating composition may comprise WO 2011/076925 PCT/EP2010/070666 -6 perchlorate (C10 4 -) from which chlorate(Cl0 3 -) is generated using electrons released by hydrocarbons, volatile fatty acids and/or other pore fluid components (e.g. oil & gas contaminants as H 2 S, thiophenes and 5 mercaptanes) as electron donor on the basis of the following reaction: C104 + 2H+ + 2e -> C103 + H 2 0. The hydrocarbons may comprise viscous crude oil, coal and/or other long chain hydrocarbons and the micro 10 organisms may comprise thermophilic (per)chlorate reducing bacteria or archaea, such as archaea and bacteria of the genus Archaeoglobus, Geobacillus, Thermus and/or other thermophilic genera able to reduce chlorate and convert fatty acids or long chain hydrocarbons into 15 short chain hydrocarbons being indigenous to the formation or introduced by injection. The other pore fluid components may comprise fatty acids, natural gas contaminants; H 2 S, thiophenes, and mercaptanes, in which case the micro-organisms may 20 comprise archaea and bacteria of the genus Archaeoglobus, Sulfolobus, Ferroglobus, Thiobacillus, Thiomicrospira or other genera able to convert natural gas contaminants. These and other features, embodiments and advantages of the method according to the invention are described in 25 the accompanying claims, abstract and the following detailed description of a non-limiting hypothetical example. The present invention novelty compared to the inventions previously reported resides in: 30 Providing a microbial chlorate-reducing and oxygen generating process (i.e. different from the invention of US patent 5,163,510, in which oxygen is assumed to be chemically produced (not by chlorate-reducing WO 2011/076925 PCT/EP2010/070666 -7 microorganisms) and only assumes microbial utilization of oxygen); Providing such microbial chlorate-reducing and oxygen-releasing process that can operate at high 5 temperatures in the range from 60'C up to 120'C relevant to hydrocarbon containing reservoirs. The microbial method according to the invention can operate at an elevated temperature of at least 600 C and is therefore different from the bioremediation method 10 disclosed in US patent application 2004/0014196 Al (Coates), which releases oxygen at temperatures < 40'C and the method known from US patent 5,163,510 that enables the use of micro-organisms at a temperature below 600 C (but not higher) and therefore seriously limits the 15 application of the known method in hot hydrocarbon containing formations. The thermophilic microbial chlorate-reducing and oxygen-releasing method according to the invention enhances bioavailability and biodegradability of 20 hydrocarbons, which subsequently enables enhanced recovery of upgraded hydrocarbons from hydrocarbon containing formations optionally by: a) enhanced oil recovery from oil bearing formations (MEOR), 25 b) enhanced methane production of coal reservoirs (ECBM), c) pretreatment of heavy oil deposits before SAGD operation; and d) in-situ conversion of oil and natural gas contaminants; H 2 S, thiophenes and mercaptanes, which 30 conversion involves decontamination of hydrocarbons and is therefore different from US patent 2004/0014196A1, which aims to bioremediate hydrocarbons in a shallow low temperature environment or US patent 5,163,510, which aims to stimulate MEOR only.

WO 2011/076925 PCT/EP2010/070666 -8 The method according to the invention generates oxygen in-situ that will enhance bioavailability and biodegradability, which subsequently will enable enhanced recovery of hydrocarbons (of improved quality) via other 5 process like Microbial Enhanced Oil Recovery (MEOR), Microbial Enhanced Coalbed Methane (MECBM) or pretreatment of heavy hydrocarbon crudes (heavy oil, bitumen) prior to processes as Steam Assisted Gravity Drainage (SAGD). The process can also enable in-situ 10 natural gas contaminant removal resulting in upgraded hydrocarbons. The invention should therefore be considered as a strong enabling process for other subsurface thermophilic microbial processes. When used in this specification and claims the term 15 thermophilic chlorate reducing micro-organisms means that these micro-organisms multiply at an ambient temperature of at least 600 C. These and other features, embodiments and advantages of the method according to the invention are described in 20 the accompanying claims, abstract and the following detailed description of non-limiting embodiments depicted in the accompanying drawing. BRIEF DESCRIPTION OF THE DRAWING FIG.1 shows the consumption of lactate as an electron 25 donor and conversion of chlorate to chloride at 85 0 C by the thermophilic Archaeoglobus fulgidus DSM4139 microorganism in laboratory experiment that demonstrates the viability of the method according to the invention at an elevated temperature. 30 DETAILED DESCRIPTION OF THE DEPICTED EMBODIMENT FIG.1 shows the results of a laboratory experiments which demonstrated that Archaea from the genus Archaeoglobus can perform chlorate reduction at temperatures up to 85-95 0

C.

WO 2011/076925 PCT/EP2010/070666 -9 Archaeoglobus have often been encountered in hydrocarbon containing high temperature reservoirs as evident from molecular and cultivation experiments. Moreover, members of this genus have been shown to be 5 able to convert fatty acids and alkanes. Members of this genus therefore are one of the most relevant candidates for the thermophilic microbial chlorate-reduction process. FIG.1 illustrates the results of a laboratory 10 experiment in which lactate was consumed as electron donor and chlorate was converted into chloride at 85 0 C by the micro-organism comprising bacteria of the genus Archaeoglobus fulgidus DSM4139. It is observed that thermophilic microbial 15 (Per)Chlorate Reduction at a temperature of at least 60 0 C has never been described in the prior art for hot hydrocarbon containing environments with fatty acids or hydrocarbons as electron donor and that the experiment revealed that bacteria of the genus Archaeoglobus 20 fulgidus DSM4139 will have an unexpectedly good performance for thermophilic microbial (Per)Chlorate Reduction in a hot hydrocarbon containing formation at an ambient temperature of at least 60 0 C. EXAMPLE 25 A suitable embodiment of the method according to the invention, comprises the following steps: a)Screening whether a target underground crude oil and/or natural gas containing reservoir formation has features, such as temperature, salinity, heterogeneity, oil 30 characteristics, micro-organisms, volatile fatty acids, hydrogen ions, acetate, propionate or butyrate and/or other potential electron donors, etc., which allow use of the method according to the invention; WO 2011/076925 PCT/EP2010/070666 - 10 b)Analyzing the composition of the water, oil and/or natural gas in the formation, for example by screening a sample taken from the formation; c)Identification of potentially interesting micro 5 organisms with molecular DNA technologies using either general (16S rRNA-related) primer sets or enzyme/functional group specific primer sets (nitrate/nitrite-reductase, (per)chlorate reductases, chlorite dismutase, or hyrdrocarbon (alkane) degrading 10 enzymes or using metagenomics; d)Isolation of potentially interesting indigenous microbes from available core, formation water, and oil samples using VFA's (acetate, proprionate, butyrate,etc.), hydrocarbon components (e.g. long chain 15 alkanes) or typical gas contaminants (e.g. H 2 S) as electron donor and nitrate, oxygen or perchlorate, chlorate or chlorite as electron acceptor. e)Determination of the optimal nutrient mix (electron donor, N/P nutrient, trace elements, SRB-inhibiting 20 chemicals, etc.) using the identified and/or cultivated micro-organisms; f)Microbial incubations using the potential successful nutrient compositions and gas contaminants, VFA's or oil components (e.g. long chain alkanes) to prove microbial 25 activity on lab scale; g)Optional middle phase could be to verify chance of success by core flood experiments; and e)The following actual chemical injection and in-situ conversion procedure: 30 el) Shut-in and clean-up of a near wellbore area of the crude oil, tar sand, shale oil, natural gas and/or other hydrocarbon containing reservoir formation (either chemically or by flushing); WO 2011/076925 PCT/EP2010/070666 - 11 e2)Injection of microbial cultures (single species or consortia derived from enrichments inoculated with production fluids from the treated reservoir) into the formation to boost the required indigenous microbial 5 species; e3) Injection of optimized nutrient mixture (main components being: oxygen, perchlorate and or chlorate and/or nitrate possibly continuously but more likely push-wise to avoid the development of a chlorate 10 utilizing biofilm limited to the wellbore to ensure deep placement into the reservoir formation and thereby stimulating the required indigenous microbial community; and e4) Monitoring of the in-situ conversion method according 15 to the invention based on increase in oil production, change in water-cut, change in produced oil and/or natural characteristics and/or composition, detection of target micro-organism(s) using molecular DNA technologies and/or cultivation dependent screening.

Claims

1. A method for in-situ oxygen generation in an underground hydrocarbon containing formation, the method 5 comprising injecting into the formation an oxygen generating composition which releases oxygen (02) by reduction of chlorate (C10 3 -), wherein: - the formation has a temperature of at least 60 C; - the composition comprises thermophilic chlorate 10 reducing micro-organisms which multiply at an ambient temperature of at least 600 C; and - the multiplied thermophilic chlorate reducing micro organisms convert the hydrocarbons and/or other pore fluids in-situ into transportable or disposable products. 15

2. The method of claim 1, wherein the thermophilic chlorate reducing micro-organisms comprise bacteria of the genus Archaeoglobus, Geobacillus and/or Thermus, which use hydrogen (H) and electrons(e) provided by hydrocarbons, volatile fatty acids and/or other pore 20 fluids in the formation followed by dismutation of chlorite(ClO2-) by the micro-organisms on the basis of the reactions: C103 + 2H +2e -> C102 +H 2 0 C102 -> Cl +02 25

3. The method of claim 2, wherein the thermophilic chlorate reducing micro-organisms multiply at an ambient temperature of at least 800 C and comprise bacteria of the genus Archaeoglobus fulgidis.

4. The method of any one of claims 1-3, wherein the 30 oxygen generating composition comprises perchlorate (C10 4 ) from which chlorate is generated using electrons released by the volatile fatty acids, hydrocarbons or other pore fluid components as electron donor on the 13 basis of the following reaction: C104- + 2H+ + 2e -> C103- + H20.

5. The method of claim 4, wherein the hydrocarbons comprise viscous crude oil and/or other long chain hydrocarbons and the bacteria comprise crude oil degrading aerobic bacteria, such as bacteria of the genus Geobacillus, Thermus and/or other bacteria that convert long chain hydrocarbons into short chain hydrocarbons.

6. The method of claim 5, wherein the multiplied bacteria dissociate crude oil from the formation by microbial dismutation of chlorite for the partial biotic and abiotic aerobic conversion of oil.

7. The method of claim 5 or 6, wherein the multiplied bacteria dissociate viscous crude oil from the formation by microbial dismutation of chlorite for the partial biotic and abiotic aerobic conversion of oil and the method is used to enhance crude oil recovery from the formation.

8. The method of claim 1, wherein the other pore fluids comprise natural gas contaminants, such as C02 and/or H 2 S, and the micro-organisms comprise bacteria of the genus Sulfolobus, Ferroglobus, Thiobacillus, Thiomicrospira or other genera able to convert natural gas contaminants.

9. The method of claim 8, wherein the formation comprises a H 2 S containing pollutant from which the oxygen generates more oxidized sulfur compounds like elemental sulfur, poly sulfide, poly thionates and H 2 SO4.

10. The method of claim 1, wherein the other pore fluid copmonents comprise hydrogen ions, acetate, propionate or butyrate and/or other volatile fatty acids and the injected chemical comprises perchlorate, chlorate and/or chlorite and another chemical, which can serve as electron acceptor or oxygen source, such as oxygen, nitrate, nitrite and hydrogen peroxide in order to ensure deep placement of the perchlorate, chlorate and/or chlorite into the formation.

11. The method of claim 10, wherein composition is injected either continuously or pulse-wise into the formation to ensure deep placement of the nitrate, nitrite, oxygen, perchlorate, chlorate or alternative electron acceptors into the formation.

12. The method of claim 1, wherein the micro-organisms are bacteria that are indigenous to the formation and furthermore introduced by injection into the formation. 14

13. The method of claim 1, wherein the micro-organisms comprise a single species microorganism or a mixture and/or consortia of micro-organisms.

14. The method of claim 1, wherein the micro-organisms are after a period of time substituted by single or multiple enzyme samples that can be water soluble or added as immobilized structures, such as bio-nano particles and/or the micro-organisms are present in and furthermore introduced by injection into the formation as highly active microbes or as spores, cysts or encapsulated microorganisms.

15. The method of claim 1, wherein the micro-organisms furthermore perform microbial conversion of hydrocarbons or natural gas contaminants or microorganism that comprise both the perchlorate/chlorate/chlorite as well as the hydrocarbon conversion/natural gas contaminant conversion activity, and/or the micro-organisms furthermore contain key enzymes from a nitrate- reduction and/or chlorate-reduction pathway such as perchlorate reductase, chlorate reductase, chlorite dismutase, nitrate reductase or nitrate reductase or combinations thereof.

16, A method for in-situ oxygen generation in an underground hydrocarbon containing formation, said method substantially as hereinbefore described with reference to the Example and/or the accompanying drawing. Shell Internationale Research Maatschappij B.V. Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON