CA2913344A1 - Downhole removal of h2s and co2 - Google Patents
Downhole removal of h2s and co2 Download PDFInfo
- Publication number
- CA2913344A1 CA2913344A1 CA2913344A CA2913344A CA2913344A1 CA 2913344 A1 CA2913344 A1 CA 2913344A1 CA 2913344 A CA2913344 A CA 2913344A CA 2913344 A CA2913344 A CA 2913344A CA 2913344 A1 CA2913344 A1 CA 2913344A1
- Authority
- CA
- Canada
- Prior art keywords
- acid gas
- fluid
- formation
- active ingredient
- well
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000012530 fluid Substances 0.000 claims abstract description 44
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 40
- 239000002253 acid Substances 0.000 claims abstract description 34
- 238000004519 manufacturing process Methods 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 21
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 18
- 239000004480 active ingredient Substances 0.000 claims abstract description 18
- 239000007864 aqueous solution Substances 0.000 claims abstract description 18
- 230000008569 process Effects 0.000 claims abstract description 15
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims abstract description 10
- 229910000029 sodium carbonate Inorganic materials 0.000 claims abstract description 5
- 235000017550 sodium carbonate Nutrition 0.000 claims abstract description 5
- 239000007789 gas Substances 0.000 claims description 33
- 239000000243 solution Substances 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 239000004215 Carbon black (E152) Substances 0.000 claims description 6
- 229930195733 hydrocarbon Natural products 0.000 claims description 6
- 150000002430 hydrocarbons Chemical class 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 4
- 159000000000 sodium salts Chemical class 0.000 claims description 4
- 238000010924 continuous production Methods 0.000 claims 1
- 239000000654 additive Substances 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 7
- 238000005201 scrubbing Methods 0.000 description 7
- 230000000996 additive effect Effects 0.000 description 6
- 239000011734 sodium Substances 0.000 description 6
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 4
- 229910052708 sodium Inorganic materials 0.000 description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000002706 hydrostatic effect Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910052979 sodium sulfide Inorganic materials 0.000 description 1
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/34—Arrangements for separating materials produced by the well
- E21B43/38—Arrangements for separating materials produced by the well in the well
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Gas Separation By Absorption (AREA)
Abstract
A process for the removal of acid gas from fluid produced from a subterranean formation into a subterranean well includes the steps of producing fluid from the subterranean formation into an area selected from the group consisting of the subterranean well, a production tube in the well, an annular space defined therebetween, and combinations thereof so as to produce a production fluid containing acid gas; and introducing an aqueous solution of an active ingredient selected from the group consisting of Na2CO3, NaOH, and combinations thereof into the area so as to contact the aqueous solution with the fluid as the fluid travels from a down-hole production tube to a surface well facility so as to contact the active ingredient with the acid gas and thereby remove the acid gas from the production fluid.
Description
Mk 02913344 2015-11-24 BACKGROUND OF THE INVENTION
[0001] Environmental concerns have driven the need to reduce acid gas containing compounds from subterranean fluids because they are known to produce acid rain and airborne particulate material. State and local governments have enacted regulations including timetables for the development of one or more treatment methods which are capable of abating the problem. Further, the presence of acid gases such as CO2 and H2S is detrimental in the use of various commercial fluids.
During processing, fluids containing acid gas are also responsible for accelerated corrosion times in tooling and instrumentation. The need for a really effective method of removing acid gases from geothermal fluids is clear.
[0001] Environmental concerns have driven the need to reduce acid gas containing compounds from subterranean fluids because they are known to produce acid rain and airborne particulate material. State and local governments have enacted regulations including timetables for the development of one or more treatment methods which are capable of abating the problem. Further, the presence of acid gases such as CO2 and H2S is detrimental in the use of various commercial fluids.
During processing, fluids containing acid gas are also responsible for accelerated corrosion times in tooling and instrumentation. The need for a really effective method of removing acid gases from geothermal fluids is clear.
[0002] Na2CO3 and other sodium salts are known to be used in aqueous solutions to scrub H25 and CO2. Methods exist today where additives are injected in multiple stages in facilities that are above ground in order to purge the fluids of the acidic gases. Although these methods have been improving over time, to ensure the removal of the gases, the fluids still have to be transported to other facilities. This subjects the machinery and transportation facility and equipment to corrosive gases while endangering the people who operate them.
SUMMARY OF THE INVENTION
SUMMARY OF THE INVENTION
[0003] In a hydrocarbon production environment, one possible solution would be to find a way to perform the scrubbing operation downhole, inside the well. However the issue that prevents such use is the possibility of damage to the formation. The contact of the Na2CO3 with the formation can lead to changes of the properties of the porous media, resulting in damage to the formation and reduction in well production. The primary object of the invention is to further address the need for effective acid gas scrubbing.
ak 02913344 2015-11-24
ak 02913344 2015-11-24
[0004] According to the invention, the foregoing objects and advantages have been attained.
[0005] According to the invention, a process for the removal of acid gas from fluid produced from a subterranean formation into a subterranean well is provided which comprises the steps of: producing fluid from the subterranean formation into an area selected from the group consisting of the subterranean well, a production tube in the well, an annular space defined therebetween, and combinations thereof so as to produce a production fluid containing acid gas; and introducing an aqueous solution of an active ingredient selected from the group consisting of Na2003, NaOH, and combinations thereof into said area, so as to contact the aqueous solution with the fluid as the fluid travels from a down-hole production tube to a surface well facility so as to contact the material with the acid gas and thereby remove the acid gas from the production fluid.
[0006] By controlling the amount of solution and material injected, and maintaining a proper pressure balance in the well, contact between the solution and the formation can be prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] A detailed description of preferred embodiments of the invention follows with reference to the attached drawing, wherein:
[0008] Figure 1 illustrates an application of a method according to the invention inside the well.
DETAILED DESCRIPTION
DETAILED DESCRIPTION
[0009] The invention relates to improvements in methods of scrubbing hydrocarbon fluids for H25, CO2 and other acid gases.
[0010] As set forth above, surface scrubbing of fluids to remove acid gases can be effective at removing the acid gases, Mk 02913344 2015-11-24 but exposes facilities for transportation of the fluids to the location where acid gas is removed to damage and corrosion from the acid gases. In accordance with the present invention, in the environment of downhole production of hydrocarbon fluids, many such fluids contain acid gases as discussed. In accordance with the present invention, the fluid with acid gas can be treated downhole with a scrubbing additive, and careful monitoring of the amount of additive to be used and of the pressure in the well as compared to that of the formation can result in effective downhole treatment without exposing the formation to damage from the scrubbing solution.
[0011] According to the invention, aqueous solutions of Na2CO3 and NaOH are injected continuously into contact with the continuous subterranean fluid stream that is rising up after being produced from the formation.
[0012] Referring generally to Figure 1, a subterranean well 1 is shown having a production tube 2 with an annular space 3 defined between the walls of the subterranean well 1 and the production tube 2. The production fluid 4 while being continuously pumped up through the production tube 2 is scrubbed with an aqueous solution 6 that is continuously sprayed at a specified depth 7 from coil tubing 5 which is inside the production tube 2. The aqueous solution 6 mixes with the production fluid 4 creating a reaction product 8.
[0013] One advantage of the invention is the use of stoichiometry and pressure differences to ensure that after injection, the aqueous solution 6 does not reach the formation 9 of the well. If the solution 6 comes in contact with the formation 9, it could lead to damage, a change in the porous media properties, and reduction of hydrocarbon production rates from the well.
Mk 02913344 2015-11-24
Mk 02913344 2015-11-24
[0014] Permeation of either the NaOH or Na2003 into the formation is a key source of concern, and is carefully prevented as disclosed herein.
[0015] In a preferred embodiment of the invention, as a result of contact of Na2003 and H25, sodium sulfide is produced along with water according to the following reactions:
H2S Na2 CO3 Na2 S H20 CO2 Na2003 + 200 + H20 - 2HCOONa + 002
H2S Na2 CO3 Na2 S H20 CO2 Na2003 + 200 + H20 - 2HCOONa + 002
[0016] After the H2S is consumed by Na.2003 and produces sodium salts, the equilibrium is moved to the right in the reaction formula, resulting in the following reactions:
CO2 + H20 ---> CO3- + 2H+
Na2003 + 2H20 Na + + H2003 + OH
OH- + 214+ 4 H20
CO2 + H20 ---> CO3- + 2H+
Na2003 + 2H20 Na + + H2003 + OH
OH- + 214+ 4 H20
[0017] Thus, contact of H2S and 002 with Na2003 ultimately results in water soluble sodium salts containing the sulfur and carbon from the acid gas, and these water soluble salts can be removed from the well in the water stream produced therefrom.
[0018] As mentioned above, it is a key concern to avoid contact between the solution and the formation, as the sodium-containing additives are known to cause formation damage. The problem of contacting the solution with the formation is therefore addressed, as mentioned above, through manipulation of process stoichiometry and through manipulation of differential pressure between the well and the formation.
[0019] With an understanding of the amount of acid gas present in the produced fluid, an amount of additive can be utilized such that the additive is entirely or at least substantially consumed chemically during the reaction, and therefore there is no additive remaining to contact the formation. This type of manipulation is referred to as controlling the additive through stoichiometry.
Mk 02913344 2015-11-24
Mk 02913344 2015-11-24
[0020] Alternatively, or in addition, the pressure within the well can be kept slightly lower than the pressure in the formation such that fluids are not forced into the formation, and thereby the solution does not actually contact the formation.
[0021] The aqueous solution (Na2003) is preferably injected at a concentration of active ingredient of less than about 11%
weight for a typical formation fluid. The solution, which could be for example a 10% wt. solution, can be injected at rates, based on the incoming fluid flow, as follows.
Approximately 12-30 cm3 (cc) of solution can be used per 1 ft3 of subterranean fluid containing between 1,000 and 4,000 ppm (0.1-0.4%) H2S and/or between 10,000 and 30,000 ppm (1 and 3%) 002.
weight for a typical formation fluid. The solution, which could be for example a 10% wt. solution, can be injected at rates, based on the incoming fluid flow, as follows.
Approximately 12-30 cm3 (cc) of solution can be used per 1 ft3 of subterranean fluid containing between 1,000 and 4,000 ppm (0.1-0.4%) H2S and/or between 10,000 and 30,000 ppm (1 and 3%) 002.
[0022] Further, approximately 25-30 cm3 (cc) of solution can be used per 1 ft3 of subterranean fluid containing between 10,000 and 20,000 ppm H2S and/or between 40,000 and 50,000 ppm (4 and 5%) 002.
[0023] The above two paragraphs provide ranges for particular cases of how much aqueous solution (Na2003) is to be used in order to stoichiometrically avoid contact of the active ingredient (Na2003) of the solution with the formation.
[0024] Similar reactions occur when the active ingredient is NaOH. The important parameter, which can be determined by a person skilled in the art using known chemical relationships, is to introduce only as much sodium as will be consumed by reaction with the H2S, such that the active ingredient is stoichiometrically presented from contacting the formation. This determination can preferably also involve a prior determination of the amount of H2S in the produced reservoir fluids.
[0025] Thus, according to a preferred embodiment of the invention, a sample of formation fluid is obtained and analyzed to determine its H2S content, preferably both H2S and Mk 02913344 2015-11-24 Co2. This content can then be used, for example on a per volume basis, to determine a proper amount of active ingredient, or sodium, to introduce in the aqueous solution such that the active ingredient or sulfur will be consumed in reaction with the H2S and Co2 and thereby be stoichiometrically prevented from reaching the formation. In this way, the harmful components of H2S and Co2 are converted to water soluble products that are easily separated from water soluble products that are easily separated from water produced from the well, without exposing the well head, pipelines, etc., to corrosive H2S and also while protecting the formation from being damaged by the active ingredient.
[0026] In accordance with a further embodiment of the invention, contact of the active ingredient in solution with the formation can be prevented by maintaining hydrostatic or dynamic pressure in the well at a lower level than formation pressure. This pressure imbalance, which should be small, keep fluid flow in the direction away from the formation and thereby keeps the solution and active ingredient from damaging the formation.
[0027] Excellent results have been obtained in accordance with the present invention, without exposing the formation to the expected significant damage due to contact with sodium-based scrubbing materials. Thus, in accordance with the present invention, a solution is provided whereby hydrocarbon fluids containing acid gases can be treated downhole to remove the acid gas before leaving the well, such that the well, surface facilities and pipelines are not exposed to acid gas.
[0028] It is to be understood that the invention is not limited to the illustrations described and shown herein, which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are susceptible of modification of form, size, arrangement of parts and details of operation. The invention rather is intended to encompass all such modifications which are within its spirit and scope as defined by the claims.
Claims (12)
1. A process for the removal of acid gas from fluid produced from a subterranean formation into a subterranean well comprising the steps of:
producing fluid from the subterranean formation into an area selected from the group consisting of the subterranean well, a production tube in the well, an annular space defined therebetween, and combinations thereof so as to produce a production fluid containing acid gas; and introducing an aqueous solution of an active ingredient selected from the group consisting of Na2CO3, NaOH, and combinations thereof into said area, so as to contact the aqueous solution with the fluid as the fluid travels from a down-hole production tube to a surface well facility so as to contact said material with said acid gas and thereby remove said acid gas from the production fluid.
producing fluid from the subterranean formation into an area selected from the group consisting of the subterranean well, a production tube in the well, an annular space defined therebetween, and combinations thereof so as to produce a production fluid containing acid gas; and introducing an aqueous solution of an active ingredient selected from the group consisting of Na2CO3, NaOH, and combinations thereof into said area, so as to contact the aqueous solution with the fluid as the fluid travels from a down-hole production tube to a surface well facility so as to contact said material with said acid gas and thereby remove said acid gas from the production fluid.
2. The process as claimed in claim 1, wherein the aqueous solution is introduced via coil tubing to a specified depth in said area.
3. The process as claimed in claim 1, wherein the aqueous solution is sprayed from a location along the production tube in order to cover a width of said area.
4. The process as claimed in claim 3, wherein the solution is sprayed from multiple locations along the production tube in order to cover the width of said area.
5. The process as claimed in claim 1, wherein the introducing step reacts the solution with said acid gas to produce sodium salts in a water solution and a hydrocarbon product which is substantially free of acid gases.
6. The process as claimed in claim 1, wherein said aqueous solution does not reach said subterranean formation of said well.
7. The process as claimed in claim 6, wherein said aqueous solution is kept from said subterranean formation by maintaining pressure in said area lower than formation pressure.
8. The process as claimed in claim 1, wherein the solution is introduced in an amount such that the active ingredient is stoichiometrically prevented from reaching the formation.
9. The process as claimed in claim 8, further comprising the steps of determining an amount of acid gas in the fluid, and selecting an amount of the active ingredient such that the active ingredient is less than what would be required to fully react with the amount of acid gas, whereby the active ingredient is stoichiometrically prevented from reaching the formation.
10. The process as claimed in claim 1, wherein the solution is introduced at a ratio of 1 mole of active ingredient per mole of acid gas.
11. The process as claimed in claim 1, wherein products of the introducing step are water soluble in a water production stream.
12. The process as claimed in claim 1, wherein the producing step and the introducing step are continuous processes.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US14/879,326 | 2015-10-09 | ||
| US14/879,326 US20170101859A1 (en) | 2015-10-09 | 2015-10-09 | Downhole removal of h2s and co2 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2913344A1 true CA2913344A1 (en) | 2017-04-09 |
Family
ID=58498987
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2913344A Abandoned CA2913344A1 (en) | 2015-10-09 | 2015-11-24 | Downhole removal of h2s and co2 |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US20170101859A1 (en) |
| CA (1) | CA2913344A1 (en) |
-
2015
- 2015-10-09 US US14/879,326 patent/US20170101859A1/en not_active Abandoned
- 2015-11-24 CA CA2913344A patent/CA2913344A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| US20170101859A1 (en) | 2017-04-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |
Effective date: 20181126 |