CHEMICAL COMPOSITIONS AND METHODS OF USING SAME FOR REMEDIATING SULFUR-CONTAINING COMPOSITIONS AND OTHER CONTAMINANTS ENCOUNTERED IN DRILLING WELLS

Abstract

A modified drilling mud includes a drilling mud selected from a group consisting of water-based mud (WBM), oil-based mud (OBM) and synthetic-based mud (SBM), and a liquid treatment composition including water and collectively 35-55 weight percent of one or more hydroxide compounds, wherein a ratio of the liquid treatment composition to the drilling mud in the modified drilling mud is in a range of 10 gallons of the liquid treatment composition per 42,000 gallons of drilling mud to 100 gallons of the liquid treatment composition per 42,000 gallons of drilling mud.

Claims

1. A modified drilling mud comprising: a drilling mud selected from a group consisting of water-based mud (WBM), oil-based mud (OBM) and synthetic-based mud (SBM); and a liquid treatment composition including water and collectively 35-55 weight percent of one or more hydroxide compounds, wherein a ratio of the liquid treatment composition to the drilling mud in the modified drilling mud is in a range of 10 gallons of the liquid treatment composition per 42,000 gallons of drilling mud to 100 gallons of the liquid treatment composition per 42,000 gallons of drilling mud.

2. The modified drilling mud according to claim 1, wherein the liquid treatment composition further comprises 0.5-4 wt %, of a chelating agent.

3. The modified drilling mud according to claim 2, wherein the chelating agent is EDTA.

4. The modified drilling mud according to claim 1, wherein the liquid treatment composition further comprises 0.02-3 wt % of an organic acid, including at least one of fulvic acid and humic acid.

5. The modified drilling mud according to claim 1, wherein the liquid treatment composition further comprises 0.5-4 wt % of MEA.

6. The modified drilling mud according to claim 1, wherein the liquid treatment composition further comprises 10-30 volume % of an organic liquid having a vapor pressure greater than the vapor pressure of water.

7. The modified drilling mud according to claim 6, wherein the organic liquid is selected from the group consisting of alcohols, hexane, toluene, xylene.

8. The modified drilling mud according to claim 1, wherein a pH of the liquid treatment composition is 14.0

9. A method for using drilling mud for reducing or preventing the release of H.sub.2S into the ambient atmosphere surrounding a well drilling platform during a well drilling operation, comprising the steps of: preparing a modified drilling mud using the liquid treatment composition according to claim 1; and pumping appropriate amounts of the modified drilling mud down hole into a well bore being drilled in a throughout a well drilling operation such that when any gasses released from the well bore during the drilling operation the gasses must pass through the modified drilling mud with a contact time of at least 0.5 second.

10. The method according to claim 9, wherein the step of pumping appropriate amounts of the modified drilling mud down hole into the well bore involves pumping appropriate amounts of the modified drilling mud down hole into a space between a drill pipe and a platform drill stem of the well drilling operation such that the drilling mud substantially fills the space between the drill pipe and the platform drill stem.

11. The method according to claim 9, comprising further steps of: collecting used drilling mud during the well drilling operation; reconditioning the used drilling mud to have a composition corresponding to the modified drilling mud prepared in the preparing step; and pumping the reconditioned drilling mud down hole into the well bore such that when any gasses are released from the well bore during the drilling operation the gasses must pass through the reconditioned drilling mud with a contact time of at least 0.5 second.

Description

DETAILED DESCRIPTION OF PRESENT EXEMPLARY EMBODIMENTS

[0023] Exemplary embodiments of the present invention will be described below. Primary aspects of the present invention involve preparation of a modified drilling mud, which may be WBM, OBM and/or SBM, by addition of a liquid treatment composition including water and one or more hydroxide compounds dissolved in the water at a collective concentration of 35-55 wt %, and preferably 45-55 wt %, and use of the modified drilling mud for drilling a well into the earth for extracting fluids including crude oil, natural gas and so-called produced water, such that the treatment composition can remediate any toxic gasses, including H.sub.2S and NH.sub.3, that might other be released as the well is being drilled and might otherwise accumulate in the ambient atmosphere around a drilling platform of the well and create hazardous conditions for any workers on or around the drilling platform.

[0024] According to a first exemplary embodiment of the present invention, a modified drilling mud comprises: a drilling mud selected from a group consisting of water-based mud (WBM), oil-based mud (OBM) and synthetic-based mud (SBM); and a liquid treatment composition including water and collectively 35-55 weight percent of one or more hydroxide compounds, wherein a ratio of the liquid treatment composition to the drilling mud in the modified drilling mud is in a range of 10 gallons of the liquid treatment composition per 42,000 gallons of drilling mud to 100 gallons of the liquid treatment composition per 42,000 gallons of drilling mud.

[0025] The composition of the drilling mud used in the modified drilling mud, whether it is a WBM, an OBM or a SBM, can be a conventional composition which is determined by a mud engineer based on the characteristics of the given well drilling operation according to conventional practices. Components of the conventional WBM, an OBM or a SBM drilling muds may typically include clay, weighting material, an emulsifier, a wetting agent, etc. The clay may include bentonite and/or other appropriate clays, the weighting material may include barite, etc. The particular amounts of the different components will vary depending on the fluid pressures and other characteristics of the given well drilling operation that the drilling mud is to be used with because the drilling mud must have appropriate density, viscosity, weighting, etc. suitable for the given well drilling operation as discussed herein, but the amount of the liquid treatment composition will be in the discussed range.

[0026] The liquid treatment composition used in preparing the drilling mud may be one of the treatment compositions previously proposed by the inventor as set forth in PCT/US2018/050913 and PCT/US2018/06401, U.S. Pat. No. 10,913,911 and US Patent Application Publication No. 2021-0230487-A1, as well as variations thereof. However, due to the nature of drilling mud and its particular functions, the primary required aspect of the treatment composition is its ability to quickly remediate H.sub.2S, NH.sub.3 and other toxic gaseous contaminants that might otherwise escape from the well and rise up through or around the drill pipe, and this can be reliably achieved provided that the liquid treatment composition contains an appropriate amount of the hydroxide compound(s) suitable for quickly remediating the toxic gasses down to safe levels upon relative short contact of 0.5-30 seconds. The inventor has determined that if the liquid treatment composition is water based and contains 35-55 weight percent collectively of one or more hydroxide compounds, an appropriate amount of such treatment composition combined to be combined with the conventional drilling mud is a ratio of 10 to 100 US gallons of the liquid treatment composition per 1000 barrels, or 42,000 US gallons, of the drilling mud. The effectiveness of such the aqueous based treatment composition for quickly and efficiently remediating H.sub.2S and other contaminants in fluids is discussed in PCT/US2018/050913 and PCT/US2018/06401, U.S. Pat. No. 10,913,911 and US Patent Application Publication No. 2021-0230487-A1.

[0027] Other components that may be included in the inventor's previously proposed treatment compositions as discussed in PCT/US2018/050913 and PCT/US2018/06401, U.S. Pat. No. 10,913,911 and US Patent Application Publication No. 2021/0230487-A1, such as an anti-bacterial agent, MEA as an anti-scaling agent, organic acids such as fulvic acid and humic acid which help to prevent formation and release of precipitates, etc. may also be included in the liquid treatment composition used in forming the modified drilling mud according to the present invention. For example, the liquid treatment compositions may include: a chelating agent such as EDTA may be included in an amount of 0.5-4 wt % of the liquid treatment composition; an organic acid such as fulvic acid and humic acid may be included in an amount of 0.02-3 wt % of the liquid treatment composition, MEA may be included in an amount of 0.5-4 wt % of the liquid treatment composition; etc. Also, a relatively low molecular weight organic liquid such as an alcohol, hexane, toluene, xylene, etc. may be included in an amount of 5-30 volume % of the liquid treatment composition for increasing vapor pressure of the modified drilling mud, especially WBM which conventionally includes little or no organic liquids therein. However, the particular functions of some of these other components, e.g., preventing formation and release of precipitates and scale, anti-bacterial effect, etc., may not be that important for the drilling mud. Hence, these other components, may be omitted in the aqueous based treatment composition used in forming a drilling mud according to the present invention.

[0028] On the other hand, the liquid treatment composition used in forming a modified drilling mud according to the present invention may further include EDTA, which among other things increases the efficiency of hydroxide compound(s) in remediating H.sub.2S. Thus, the treatment composition according to the present invention may include a small amount, e.g., 0.5-4 wt %, of a chelating agent such as EDTA in addition to the hydroxide compound(s).

[0029] The modified drilling mud according to the present invention may be used in essentially the same manner as conventional drilling mud, e.g., after the modified engineered mud is prepared it may be pumped down hole, e.g., between a drill pipe and a platform drill stem of the well drilling operation, at high pressure to equalize the formation pressure at the well being drilled. The conventional aspects of a well drilling operation remain essentially the same, e.g., as the well is being drilled the drilling mud mixes together with the earth fragments generated by the drilling operation and the mixture is brought to the earth's surface so that the earth fragments may be separated from the drilling mud, after which the drilling mud is reconditioned and reused in the drilling operation, and the process is repeated.

[0030] According to another embodiment of the present invention, there is provided a method for using a modified drilling mud according to the first embodiment of the invention to greatly reduce or prevent the release of H.sub.2S, NH.sub.3 and other toxic contaminants from subterranean fluids from a well bore during a well drilling operation, comprising the steps of:

[0031] preparing the modified drilling mud using the liquid treatment composition according to the first embodiment of the invention; and

[0032] pumping appropriate amounts of the modified drilling mud down hole into a well bore being drilled in a throughout a well drilling operation such that when any gasses are released from the well bore during the drilling operation the gasses must pass through the modified drilling mud with a contact time of at least 0.5 second.

[0033] The step of pumping appropriate amounts of the modified drilling mud down hole into the well bore may involve pumping appropriate amounts of the drilling mud down hole into a space between a drill pipe and a platform drill stem of the well drilling operation as necessary throughout the well drilling operation such that the drilling mud substantially fills the space between the drill pipe and the platform drill stem.

[0034] The method for using a modified drilling mud according to the second embodiment of present invention may further involve steps of: collecting used drilling mud during the well drilling operation; reconditioning the used drilling mud to have a composition corresponding to the modified drilling mud prepared according to the first embodiment of the present invention; and pumping appropriate amounts of the reconditioned drilling mud down hole into a well bore being drilled in a throughout a well drilling operation such that when any gasses are released from the well bore during the drilling operation the gasses must pass through the reconditioned drilling mud with a contact time of at least 0.5 second.

[0035] As the novel drilling mud including a treatment composition according to the present invention is repeatedly reconditioned for reuse throughout a drilling operation it is important that the content of the liquid treatment composition in the drilling mud be maintained at an appropriate level to assure that it will be effective for remediating the H.sub.2S, NH.sub.3 and other toxic components of the sour gas that might otherwise be released from the well during the drilling operation. The inventor's previously proposed treatment composition used in the novel drilling mud according to the present invention will generally have a pH of 14 due to the high content of hydroxide compounds contained therein, and the drilling mud containing the treatment composition may also have a pH of about 13 to 14, so that pH is a characteristic of the novel drilling mud that may be monitored to assure that the content of the treatment composition in the drilling mud be maintained at an appropriate level.

[0036] Such method of using the modified drilling mud according to the second embodiment of the invention is very advantageous over conventional methods of using conventionally known types of drilling mud known at the time of the present invention because the liquid treatment composition included in the modified drilling mud according to the present invention is very effective at quickly remediating H.sub.2S, NH.sub.3 and other toxic, materials that may otherwise be released in gaseous phase from the well bore as it is being drilled. Again, 0.5 second of contact time between the toxic gasses and the modified drilling mud is sufficient to remediate the toxic gasses, but preferably contact time will be in a range of 0.5 to 30 seconds, and preferably at least 1.5 seconds.

[0037] Conversely, with the known methods involving use of conventional drilling mud, various amounts of such toxic materials may be released as vapor phase gases from a well bore as it is being drilled, and are ultimately released into the ambient atmosphere around the drilling platform above the well bore creating potential safety hazards to any workers on or around the platform, and forcing the well drilling operation to be shut down. Such toxic gases are contained in or dissolved into the fluids to be extracted from the well bore while these fluids are in liquid phase still down in the earth under great pressures, but as the fluids rise up toward the surface of the earth through the well as it is being drilled, pressures are greatly reduced and these toxic materials are released from the fluids in gaseous or vapor phase according to Henry's Law. The gaseous phase toxic materials will then migrate from the formation into the drilling cavity or well bore forming pockets of toxic gases including H.sub.2S and NH.sub.3 that rise up through the conventional drilling mud and are then released into the atmosphere around the drilling platform.

[0038] According to an example of the present invention, a conventional OBM was modified by addition of 25 US gallons of a liquid treatment, composition as disclosed in PCT/US2018/064015, which included water, about 50 wt % collectively of KOH and NaOH, and 0.5 wt % collectively of fulvic acid and humic acid per 42,000 US gallons of the OBM. This modified drilling mud was used in an operation of drilling a well into the earth for extracting crude oil, natural gas and so-call produced water from a subterranean deposit, wherein the drilling operation had previously been stopped due to unsafe levels of more than 5 ppm of each of H.sub.2S and NH.sub.3 which accumulated in the ambient atmosphere around the drilling platform. The crude oil, natural gas and produced water in the subterranean deposit, which would eventually be extracted through the well collectively contained about 60,000 ppm of H.sub.2S and about 75,000 ppm of NH.sub.3. In this example, the modified OBM according to the present invention was completely successful at remediating the H.sub.2S and NH.sub.3 such that the atmosphere around the drilling platform of the drilling operation contained far less than 5 ppm, essentially zero ppm, of each of H.sub.2S and NH.sub.3 and the drilling operation was deemed appropriately safe to be restarted. In the two weeks immediately after the drilling operation was restarted levels of gaseous materials in the atmosphere around the drilling operation remained very low, essentially zero ppm, such that the drilling operation was been able to safely, continuously operate and to be completed over the two weeks.