U.S. patent application number 14/550935 was filed with the patent office on 2016-05-26 for method to enhance microbial gas production from unconventional reservoirs and kerogen deposits.
The applicant listed for this patent is Marcus G. Theodore. Invention is credited to Marcus G. Theodore.
Application Number | 20160145978 14/550935 |
Document ID | / |
Family ID | 56009696 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160145978 |
Kind Code |
A1 |
Theodore; Marcus G. |
May 26, 2016 |
METHOD TO ENHANCE MICROBIAL GAS PRODUCTION FROM UNCONVENTIONAL
RESERVOIRS AND KEROGEN DEPOSITS
Abstract
A biostimulation method comprising injecting sulfur dioxide into
water producing H.sup.+, SO.sub.2, SO.sub.3.sup.=, HSO.sub.3.sup.-,
dithionous acid (H.sub.2S.sub.2O.sub.4), and other sulfur
intermediate reduction products in sulfurous acid, and then
applying the sulfurous acid at the oxidation reduction potential
required to biostimulate either aerobic or anaerobic organisms at
the active margins of the black shale and coal bed deposits at a pH
sufficient to reduce bicarbonate and carbonate buildup to a)
increase CO.sub.2 production to drive the production of methane by
chemoautotrophic assimilation of CO.sub.2 by hydrogen consuming
methanogens, b) increase porosity and flows through the black shale
and coal bed deposits, and c) provide SO.sub.2, SO.sub.3.sup.-,
HSO.sub.3.sup.-, and dithionous acid (H.sub.2S.sub.2O.sub.4) and
other sulfur intermediate reduction products to provide soluble
nutrients with bicarbonates and carbonate conducive to the growth
of microbial consortia under either aerobic or anaerobic conditions
to stimulate syntrophic bacteria and methanogenic archaea to
produce methane.
Inventors: |
Theodore; Marcus G.; (Salt
Lake City, UT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Theodore; Marcus G. |
Salt Lake City |
UT |
US |
|
|
Family ID: |
56009696 |
Appl. No.: |
14/550935 |
Filed: |
November 22, 2014 |
Current U.S.
Class: |
166/246 |
Current CPC
Class: |
C09K 8/582 20130101 |
International
Class: |
E21B 43/00 20060101
E21B043/00; E21B 47/00 20060101 E21B047/00 |
Claims
1. A biostimulation method of natural microbial populations active
at margins of black shale and coal bed deposits where the organic
matter has hydrologic flows there through consisting of: a.
injecting sulfur dioxide into water producing H.sup.+, dissolved
SO.sub.2, SO.sub.3.sup.-, HSO.sub.3.sup.-, dithionous acid
(H.sub.2S.sub.2O.sub.4), and sulfur intermediate reduction products
all referred to as sulfurous acid, and b. applying the sulfurous
acid to the black shale and coal bed deposits and adjusting the
oxidation potential of the sulfurous acid either: i. with the
addition of oxygen and additional acid to effectuate a downhole
acidic pH and an oxidation reduction potential of between -50 and
-150 mV to create an oxidizing solution to provide aerobic
conditions to stimulate aerobic microbial consortia to produce
methane; or ii. without the addition of additional oxygen and
additional acid to effectuate a downhole acidic pH and an oxidation
reduction potential of between +50 and -100 mV to create a reducing
solution to provide anaerobic conditions to stimulate anaerobic
syntrophic bacteria and methanogenic archaea microbial consortia to
produce methane; the sulfurous acid applied sufficiently to: ci.
reduce bicarbonate and carbonate buildup to produce CO.sub.2, which
drives the production of methane by chemoautotrophic assimilation
of CO.sub.2 by hydrogen consuming methanogens, cii. increase
porosity and flows through the black shale and coal bed deposits,
and ciii. provide dissolved SO.sub.2, SO.sub.3.sup.=,
HSO.sub.3.sup.-, and dithionous acid (H.sub.2S.sub.2O.sub.4) and
sulfur intermediate reduction products to produce soluble
bicarbonates and carbonate nutrients at the oxidation reduction
potential conducive to the growth of microbial consortia to produce
methane.
2. (canceled)
3. The biostimulation method according to claim 1, further
comprising adding supplemental nutrients to the sulfurous acid.
4. The biostimulation method according to claim 1, further
comprising adding syntrophic bacteria and/or cyanobacteria and
methanogenic archaea to the sulfurous acid to inoculate the black
shale and coal bed deposits microbial consortia.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Related Applications
[0002] This application is a continuation-in-part of the "Method to
Enhance Microbial Gas Production from Unconventional Reservoirs and
Kerogen Deposits" patent application, Ser. No. 13/385,443 filed
Feb. 21, 2012.
[0003] 2. Field
[0004] This invention relates to methane and petroleum production.
More particularly, it relates to the production of methane and
petroleum via biostimulation of microbial metabolism from the
margins of a basin where the organic matter is less mature and
hydrologic flow systems are active.
[0005] 3. State of the Art
[0006] Unconventional gas deposits, such as those produced from
coal beds and shales containing kerogen are new sources of methane
gas. Black shales and coal beds contain carbon deposits where
microbial methanogenis and modification of thermogenic gas is
present at the shallower margins of a basin where the organic
matter is less mature and hydrologic flows are present. These
deposits contain kerogen, which is a mixture of organic chemical
compounds that make up a portion of the organic matter in
sedimentary rocks. It is insoluble in normal organic solvents
because of the huge molecular weight (upwards of 1,000 Daltons) of
its component compounds. The soluble portion is known as bitumen.
Production of oil and gas from kerogen is usually accomplished
under geophysical pressure and temperature conditions at deeper
depths (thermogenic gas play), over long periods of time where
organic material experiences more thermal cracking. When heated to
the right temperatures in the Earth's crust, some types of kerogen
release crude oil or natural gas. For example, oils are formed
around 60-160.degree. C. and gas is formed around 150-200.degree.
C., depending on how quickly the source rock is heated.
[0007] Kerogen is formed from the decomposition and degradation of
living matter, such as diatoms, planktons, spores and pollens. In
the break-down process, large biopolymers from proteins and
carbohydrates begin to partially or completely dismantle. Under
pressure, these dismantled components can form new geopolymers,
which are the precursors of kerogen.
[0008] The formation of geopolymers account for the large molecular
weights and diverse chemical compositions associated with kerogen.
The smallest geopolymers are the fulvic acids, the medium
geopolymers are the humic, and the largest geopolymers are the
humins. When organic matter is contemporaneously deposited with
geologic material, subsequent sedimentation and progressive burial
or overburden provides sufficient geothermal pressures over
geologic time to become kerogen. Changes such as the loss of
hydrogen, oxygen, nitrogen, and sulfur and other functional group
result in isomerization and aromatization at increasing depths or
burial eventually producing petroleum or methane gases.
[0009] This geophysical production of petroleum and methane, gas
from black shale and coal bed deposits containing kerogen is
extremely slow. Consequently, new sources of natural gas require
enhancing microbial gas from unconventional reservoirs. The present
method described below expedites the production of petroleum and
methane from unconventional gas play. It biostimulates certain
bacteria and micro-organisms with sulfurous acid delivered
nutrients to break down kerogen and other organic matter into
petroleum and methane.
[0010] Clement et al (WO 2011/153467 A2, claiming priority to Jun.
4, 2010; cited on PTO-982 mailed Jan. 7, 2013) teaches introducing
compositions in situ to enhance the biogenic production of methane
in coal and shale deposits containing kerogen in coal seams and
coal be methane wells. Clement et al.'s approach is to add various
combination of amendments as stimulants for microbial respiration
screened for methane production using gas chromatography (paragraph
034 last three lines). These stimulants are listed in paragraphs
52-54, and include a wide range of components ranging from vanadium
to yeast extract to sulfuric acid with different oxidation states
to stimulate the microbial organisms to produce methane via
hydrolysis, coal depolymerization, anaerobic or aerobic degradation
of polyaromatic hydrocarbons, homoacetogenesis, and methanogenisis
and any combinations thereof (paragraph 54). This complex addition
of multiple different stimulants is difficult to administer in the
field, and requires the storage of a wide variety of different
chemicals as well as gas chromatograph testing capability.
Conversely, applicant's method only requires a source of sulfurous
acid and air, and a conductivity meter, gas flow meter, and
microbial sampling and testing equipment. The sulfurous acid
oxidation reduction potential is adjusted as required to provide
the required anaerobic or aerobic conditions to biostimulate the
production of methane.
[0011] No anaerobic or aerobic reaction controls or concentrations
are specified in Clement et al as to how to optimize methane
stimulation from the different stimulants. Nor does Clement et al
expressly teach: [0012] a. biostimulating microbial populations
active at margins of coal black shale and coal bed deposits where
the organic matter is less mature. [0013] b. maintaining the
sulfurous acid at a pH concentration sufficient to reduce
bicarbonate and carbonate buildup increasing the porosity and flows
through the black shale and coal bed deposits. [0014] c. injecting
sulfur dioxide into water producing H.sup.+, SO.sub.2,
SO.sub.3.sup.=, HSO.sub.3.sup.-, dithionous acid
(H.sub.2S.sub.2O.sub.4), and other sulfur reduction product.
[0015] Clement also fails to disclose monitoring microbial
populations and changing the oxidation/reduction potential of
sulfurous acid for enhancing methane production either between -50
and -150 mV creating an oxidizing solution by adding oxygen and
additional acid to provide aerobic conditions for aerobic
biostimulation; or between +50 and -100 mV without the addition of
oxygen and additional acid to produce a reducing solution to
provide anaerobic conditions for anaerobic biostimulation. Clement
et al, thus fails to suggest or provide any guidance as to the
conditions required fur sulfurous acid to act as a
biostimulant.
[0016] Jackson et al, (US Patent Application Publication
20105/0247705 A1, cited on PTO-892 mailed Jan. 7, 2013)) is a
sulfurous acid generator. It does not explicitly teach that
injecting sulfur dioxide into water produces H.sup.+, SO.sub.2,
SO.sub.3.sup.-, HSO.sub.3.sup.-, dithionous acid
(H.sub.2S.sub.2O.sub.4) to provide microbial CO.sub.2 gas
conditions for methogens to act under anaerobic conditions.
[0017] The present method described below delivers sulfurous acid
at a pH and oxidation reduction potential to stimulate natural
microbial populations active at margins of black shale and coal bed
deposits where the organic matter is less mature and has hydrologic
flows there through under either aerobic or anaerobic conditions to
increase methane gas production.
SUMMARY OF THE INVENTION
[0018] Natural alteration of organic matter into methane by
microorganisms in oxygen-depleted subsurface environments is a
widespread and common process called methanogenesis. The biogenic
generation of methane from the molecules of kerogen is achieved by
a symbiotic consortium of microorganisms. Syntrophic bacteria of
the consortium break down the organic molecules through anaerobic
respiration and fermentation into simple, water-soluble compounds
(e.g. acetate, CO.sub.2, H.sub.2), which are ultimately transformed
into CH.sub.4 by methanogenic archaea. Other microorganisms produce
methane under aerobic conditions.
[0019] The method comprises monitoring and measuring the methane
gas production from the margins of black shale and coal bed
deposits. Next, the microbial populations at the margins of black
shale and coal bed deposits where the organic matter is less mature
and hydrologic flows there through are active to stimulate the
production of methane by delivering supplemental nutrients (a
treatment referred to as "biostimulation") with sulfurous acid.
Methane production is stimulated by delivering water, acid,
sulfites, sulfates, and other nutrients to the microbial consortia
under either anaerobic or aerobic conditions to stimulate the
syntrophic bacteria and methanogenic archae.
[0020] Under anaerobic reducing conditions, [0021] a)
denitrification occurs:
C.sub.aH.sub.bO.sub.c+(4a'b/4-c/2)O.sub.2.fwdarw.aCO.sub.2+(2b-2a-
+c)H2O+(4a+b-2c)OH.sup.-+(2a+1/2-c)N.sub.2 [0022] b) sulfate
reduction occurs:
C.sub.aH.sub.bO.sub.c+(2/5a+1/10B-1/5c)SO.sub.4.fwdarw.aCO.sub.2+-
(2/5-2/5a+1/5c)H2O+(2/5a+1/10b-1/5c)H2S [0023] c) methanogenisis
occurs:
C.sub.aH.sub.bO.sub.c+(a-b/4-c/2)H.sub.2O.fwdarw.(a/2-b/8+c/4)CO.sub.2+(a-
/2+b/8-c/4)CH.sub.4 (Buswell reaction)
[0024] The Buswell reaction results from three separate biological
reactions by three different types of syntrophic microorganisms:
[0025] a) acetogenic bacteria generate acetate and hydrogen that is
toxic to themselves:
[0025]
C.sub.aH.sub.bO.sub.c+(a-c)H.sub.2O=1/2aCH.sub.3CO.sup.-.sub.2+1/-
2aH.sup.++1/2(b-2c)H.sub.2 [0026] b) hydrogenotrophic methanogens
remove the hydrogen to protect the acetogenic bacteria:
[0026] CO.sub.2+4H.sub.2.fwdarw.CH.sub.4+2H.sub.2O [0027] c)
acetoclastic bacteria use the acetate to form methane and carbon
dioxide:
[0027] C.sub.aH.sub.bO.sub.c+H.sup.+.fwdarw.CH.sub.4+CO.sub.2
[0028] As anaerobic conditions are generally required for the
microbial consortia in deep black shale and coal bed deposits,
sulfur dioxide (SO.sub.2) is injected into water to be injected
into the kerogen beds forming as weak acid to provide H.sup.+,
SO.sub.2, SO.sub.3.sup.=, HSO.sub.3.sup.-, dithionons acid
(H.sub.2S.sub.2O.sub.4), and other sulfur intermediate reduction
products. Sulfur dioxide acts as a strong reducing agent in water
and in the presence of minimal oxygen no additional acid is
required to be added to insure the electrical conductivity level of
the sulfur dioxide treated water is sufficient for release of
electrons from the sulfur dioxide, sniffles, bisulfites, and
dithionous acid to form a reducing solution. The sulfur dioxide
treated water provides the oxidation/reduction potential within the
black shale and coal bed for the syntrophic bacteria of the
consortium break down the organic molecules through anaerobic
respiration and fermentation into simple, water-soluble compounds
(e.g. acetate, CO.sub.2, H.sub.2), which are ultimately transformed
into CH.sub.4 by methanogenic archaea.
[0029] The acetoclastic bacteria chemical reaction is also driven
to the right to form more methane by the addition of the weak
sulfurous acid:
CH.sub.3CO.sup.-.sub.2+H.sup.+.fwdarw.CH.sub.4+CO.sub.2.
[0030] The oxidation/reduction potential of the sulfurous acid in
milivolts for anoxic conditions with no dissolved oxygen is usually
between +50 and -100 mV, although the exact potential is dependent
upon the consortium bacteria present.
[0031] The sulfurous acid also acts to dissolve and free up
carbonates/bicarbonates to open up pores and channels in the black
shale and coal beds to better deliver nutrients and carbon dioxide
to the microbial consortia. Sulfurous acid is a powerful reducing
agent, which removes oxygen; thereby insuring anaerobic conditions
for the syntrophic bacteria and methanogenic archae. The freed up
added CO.sub.2 also drives to the right the chemoautotrophic
assimilation of CO.sub.2 by the hydrogen consuming methanogens to
produce more methane:
CH.sub.2+4H.sub.2.fwdarw.CH.sub.4+2H.sub.2O
[0032] If sufficient microbial consortia are not present in the
kerogen beds, cultures of syntrophic bacteria, and methanogenic
archae may be delivered along with the sulfurous acid into the
black shale and coal beds to start the methanogenesis process.
[0033] Generally, the source-rocks of interest are the Lower
Jurassic black shales of the eastern Paris Basin (i.e. type II
kerogens), Corings into various points within the shales are
drilled to deliver the sulfurous acid at various points within the
hydrologic flows of the bed. Other drill holes penetrate the bed at
various points to collect the generated gases.
[0034] The presence of methane in sample culture extracts of the
sulfurous acid correlates with the detection of archaea and
methanogens by qPCR. Thus it may be necessary to monitor the
presence of methanogens in the sulfurous acid microcosms by
periodic sampling.
[0035] If other bacterial, archaeal and methanogen populations
nearer the surface of black shale and coal bed deposits are
involved in the production of methane or petroleum under aerobic
conditions, the oxidation/reduction potential of the sulfurous acid
solutions may be modified to stimulate these other bacterial,
archaeal and methanogen populations. For example, in the event that
aerobic conditions are required for activation of methanogenesis
where cyanobacteria and microalgae, fungi, lichens and mosses are
present as well as an array of prokaryotic species from biological
soil crusts, oxygen and additional acid may be injected into the
sulfur dioxide (SO.sub.2) water to provide H.sup.+, SO.sub.2,
SO.sub.3.sup.=, HSO.sub.3.sup.-, dithionous acid
(H.sub.2S.sub.2O.sub.4), and other sulfur intermediate reduction
products forming a sulfur dioxide treated water to insure that the
electrical conductivity level of the sulfur dioxide treated water
is sufficient to accept electrons to create an oxidizing solution.
The oxidation/reduction potential in millivolts for oxidizing is
between -50 to -150 mV under aerated conditions with sufficient
free oxygen, alkalinity, pH, temperature and time.
[0036] The production of methane is thus adjusted via
biostimulation at the oxidation/reduction potentials required by
bacterial, archaeal and methogen populations for optimal gas
production. This is accomplished by pH adjustment using additional
acid and oxygen if required for oxidation to increase gas
production volumes. Conversely, additional acid and oxygen is
omitted if required for reduction to increase as production
volumes. Therefore, a single sulfurous acid solution is used with
sub bituminous coal beds and selectively adjusted to generate and
increase the its production from immature source-rocks as well as
shale deposits.
[0037] Standard as measuring equipment is used to measure the
methane production under various oxidation and reduction
conditions. Periodic sampling of the sub bituminous coal and shale
bed sulfurous waters to determine the type of bacterial populations
is often included. Core samples or the withdrawal of a portion of
the coal bed waters from the sulfurous acid injection system is
used to extract samples for microbiological analysis. pH meters
monitor the sulfurous acid pH, and dissolved oxygen meters and ORP
meters are used to measure the dissolved, oxygen and oxidation
reduction potentials of the sulfurous acid solutions. As the
methane gas production is tracked, the sulfurous acid
oxidation/reduction conditions are then adjusted and held at the
levels required to optimize methane gas production from the
different bacterial, archae and methanogen populations.
[0038] To generate microbial gas play, the hydrologic framework may
require the natural inoculation with additional microorganisms.
Basin margins, where the organic matter is less mature and
fractures therein more open are targeted to allow nutrients to
penetrate the deposit.
[0039] The foregoing method employing sulfurous acid to deliver
bacterial, archae and methanogen populations with nutrients under
anaerobic or aerobic conditions for biostimulation produces methane
and petroleum from kerogen and sub bituminous coal beds are a
faster rate than that produced by geophysical production.
DESCRIPTION OF THE DRAWINGS
[0040] FIG. 1 is a drawing of the synthetic carbon cycle.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0041] FIG. 1 is a drawing of the synthetic carbon cycle produced
by Haeseler & Behar, in their article "Methanogenisis: A Part
of the Carbon Cycle with Implication for Unconventional Biogenic
Gas Resources" presented at the Natural Gas Geochemistry: Recent
Developments, Applications and Technologies seminar May 9-12, 2011
at the AAPG HEDBERG Conference in Beijing. China, which illustrates
methanogenisis of the present method acting on organic compounds in
fossil fuels to produce methane and hydrocarbon compounds. The
present method delivers water, sulfur nutrients, and carbonates to
fossil beds under anaerobic or aerobic conditions for
biostimulation of the symbiotic consortium of microorganisms to
break down organic molecules through anaerobic respiration and
fermentation into simple, water-soluble compounds to produce
methane and petroleum from the margins of kerogen and sub
bituminous coal beds at a faster rate than that produced by
geophysical production.
[0042] The present invention may be embodied in other specific
forms without departing from its structures, methods, or other
essential characteristics as broadly described herein and claimed
hereinafter. The described embodiments are to be considered in all
respects only as illustrative, and not restrictive. The scope of
the invention is, therefore, indicated by the appended claims,
rather than by the foregoing description. All changes that come
within the meaning and range of equivalency of the claims are to be
embraced within their scope.
* * * * *