Water-based drilling fluid compositions and methods for drilling subterranean wells

Abstract

Water-based drilling fluids may include an aqueous base fluid and a mixture of polyethylene polyamines in an amount of from 1 lb.sub.m/bbl to 20 lb.sub.m/bbl relative to the total volume of the water-based drilling fluid. The polyethylene polyamines of the mixture may have a first chemical structure H.sub.2NCH.sub.2CH.sub.2(NHCH.sub.2CH.sub.2).sub.xNH.sub.2, where x may be an integer greater than or equal to 3. The average molecular weight of the polyethylene polyamines in the water-based drilling fluid having the first chemical structure may be from 200 g/mol to 400 g/mol. Methods for drilling a subterranean well with the water-based drilling fluids are also disclosed.

Claims

1. A water-based drilling fluid comprising: an aqueous base fluid that does not comprise salt water or seawater; and a mixture of polyethylene polyamines in an amount of from 1 lb.sub.m/bbl to 20 lb.sub.m/bbl relative to the total volume of the water-based drilling fluid, the polyethylene polyamines of the mixture comprising a first chemical structure H.sub.2NCH.sub.2CH.sub.2(NHCH.sub.2CH.sub.2).sub.xNH.sub.2, where x is an integer greater than or equal to 3, and where the polyethylene polyamines of the mixture comprise hexaethyleneheptamine; where the average molecular weight of the polyethylene polyamines of the mixture in the water-based drilling fluid comprising the first chemical structure is from 200 g/mol to 400 g/mol; and where one or more of: the water-based drilling fluid has a plastic viscosity of from 1 cP to 25 cP; the water-based drilling fluid has a yield point of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2; the water-based drilling fluid has a gel strength after 10 seconds of from 1 lb.sub.f/100 ft.sup.2 to 15 lb.sub.f/100 ft.sup.2; or the water-based drilling fluid has a gel strength after 10 minutes of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2.

2. The water-based drilling fluid of claim 1, where the water-based drilling fluid comprises the aqueous base fluid in an amount of from 50 lb.sub.m/bbl to 340 lb.sub.m/bbl relative to the total volume of the water-based drilling fluid.

3. The water-based drilling fluid of claim 1, where the polyethylene polyamines of the mixture comprise linear polyethylene polyamines, cyclic polyethylene polyamines, branched polyethylene polyamines, or combinations of these.

4. The water-based drilling fluid of claim 1, where the polyethylene polyamines of the mixture further comprise tetraethylenepentamine, pentaethylenehexamine, or both.

5. The water-based drilling fluid of claim 4, where the sum of the weight percent of the tetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptamine is at least 50 wt. % of the polyethylene polyamines of the mixture.

6. The water-based drilling fluid of claim 1, where the water-based drilling fluid has a plastic viscosity of from 1 cP to 25 cP.

7. The water-based drilling fluid of claim 1, where the water-based drilling fluid has a yield point of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2.

8. The water-based drilling fluid of claim 1, where the water-based drilling fluid has a gel strength after 10 seconds of from 1 lb.sub.f/100 ft.sup.2 to 15 lb.sub.f/100 ft.sup.2.

9. The water-based drilling fluid of claim 1, where the water-based drilling fluid has a gel strength after 10 minutes of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2.

10. The water-based drilling fluid of claim 1, further comprising one or more viscosifiers, one or more fluid loss control agents, one or more weighting agents, or combinations of these.

11. A method for drilling a subterranean well, the method comprising: operating a drill in a subterranean formation in the presence of a water-based drilling fluid, where the water-based drilling fluid comprises: an aqueous base fluid that does not comprise salt water or seawater; and a mixture of polyethylene polyamines in an amount of from 1 lb.sub.m/bbl to 20 lb.sub.m/bbl relative to the total volume of the water-based drilling fluid, the polyethylene polyamines comprising a first chemical structure H.sub.2NCH.sub.2CH.sub.2(NHCH.sub.2CH.sub.2).sub.xNH.sub.2, where x is an integer greater than or equal to 3, and where the mixture of polyethylene polyamines comprises hexaethyleneheptamine; where the average molecular weight of the polyethylene polyamines in the water-based drilling fluid comprising the first chemical structure is from 200 g/mol to 400 g/mol, and wherein one or more of: the water-based drilling fluid has a plastic viscosity of from 1 cP to 25 cP; the water-based drilling fluid has a yield point of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2; the water-based drilling fluid has a gel strength after 10 seconds of from 1 lb.sub.f/100 ft.sup.2 to 15 lb.sub.f/100 ft.sup.2; or the water-based drilling fluid has a gel strength after 10 minutes of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2.

12. The method of claim 11, further comprising introducing the water-based drilling fluid into the subterranean formation.

13. The method of claim 12, where introducing the water-based drilling fluid into the subterranean formation comprises injecting the water-based drilling fluid through a drill string of the drill.

14. The method of claim 11, further comprising circulating at least a portion of the water-based drilling fluid within the subterranean formation.

15. The method of claim 11, where the water-based drilling fluid comprises the aqueous base fluid in an amount of from 50 lb.sub.m/bbl to 340 lb.sub.m/bbl relative to the total volume of the water-based drilling fluid.

16. The method of claim 11, where the polyethylene polyamines of the mixture comprise linear polyethylene polyamines, cyclic polyethylene polyamines, branched polyethylene polyamines, or combinations of these.

17. The method of claim 11, where the water-based drilling fluid has a plastic viscosity of from 1 cP to 25 cP.

18. The method of claim 11, where the water-based drilling fluid has a yield point of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2.

19. The method of claim 11, where the water-based drilling fluid has a gel strength after 10 seconds of from 1 lb.sub.f/100 ft.sup.2 to 15 lb.sub.f/100 ft.sup.2.

20. The method of claim 11, where the water-based drilling fluid has a gel strength after 10 minutes of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2.

Description

EXAMPLES

(1) The various embodiments of water-based drilling fluid compositions will be further clarified by the following examples. The examples are illustrative in nature, and should not be understood to limit the subject matter of the present disclosure.

Example 1—Hydration Suppression Testing

(2) To observe the effects of the presently disclosed water-based drilling fluid in reducing or preventing the hydration of subterranean formations, a hydration suppression test was performed using bentonite clay. As bentonite clay is susceptible to swelling, similar to the clay particles present in a shale formation, the volume of bentonite clay will increase when exposed to a water-based drilling fluid and, as a result, the viscosity of the water-based drilling fluid will increase. Therefore, as stated previously, the ability of a water-based drilling fluid to reduce or prevent the hydration of a subterranean formation may be measured by the rheology of the water-based drilling fluid after exposure to bentonite clay.

(3) In this regard, four different water-based drilling fluid samples were prepared. The first sample (Comparative Sample A) included only 350 grams (g) of water. Samples 1-3 were each prepared by first mixing 350 g of water with 1 g of a mixture of polyethylene polyamines, 5 g of a mixture of polyethylene polyamines, and 10 g of a mixture of polyethylene polyamines, respectively, for 5 minutes. The mixture of polyethylene polyamines incorporated into Samples 1-3 was ETHYLENEAMINE E-100 obtained from Huntsman (Texas, United States of America). ETHYLENEAMINE E-100 is a mixture of polyethylene polyamines having an average molecular weight of 250 g/mol to 300 g/mol. The resulting samples included the mixture of polyethylene polyamines in concentrations of approximately 1 lb.sub.m/bbl (Sample 1), 5 lb.sub.m/bbl (Sample 2), and 10 lb.sub.m/bbl (Sample 3). Each sample was then mixed with 30 g of drilling grade bentonite for 20 minutes. After mixing, the samples were each hot rolled at 150 degrees Fahrenheit (° F.) for 16 hours. After hot rolling, the rheology of each sample was measured using a rheometer as described previously. The rheology of each sample was measured twice, once at room temperature (RT) and once at 120° F., using a viscometer (commercially available as Model 35 from Fann Instrument Company). The composition and rheology of each sample are listed in Table 1.

(4) TABLE-US-00001 TABLE 1 Hydration Suppression Testing of Water-Based Drilling Fluids Comparative Sample A Sample 1 Sample 2 Sample 3 Composition Water (g) 350 350 350 350 Mixture of Polyethylene — 1 5 10 Polyamines (g) Bentonite (g)  30 30 30 30 Rheology RT 120° F. RT 120° F. RT 120° F. RT 120° F. 600 rpm 112  95 31 24  22  17  20  15  300 rpm 73 67 20 16  12  9 12  10  200 rpm 62 54 15 13  8 7 9 8 100 rpm 44 34 11 9 4 4 7 6 6 rpm 14 12  6 4 3 2 5 4 3 rpm 11 10  4 3 2 1 4 4 PV (cP) 39 28 11 8 10  8 8 5 YP (lb.sub.f/100ft.sup.2) 34 39  9 8 2 1 4 5 10-Second Gel Strength (lb.sub.f/100ft.sup.2) 13 13  8 4 4 3 5 4 10-Minute Gel Strength (lb.sub.f/100ft.sup.2) 41 44 12 5 7 7 10  9

(5) As shown by Table 1, water-based drilling fluids that include a mixture of polyethylene polyamines are capable of maintaining a lesser plastic viscosity, yield point, 10-second gel strength, and 10-minute gel strength when compared to a water-based drilling fluid that does not include the polyethylene polyamines of the present disclosure. This indicates that water-based drilling fluids of the present disclosure may be capable of reducing or preventing the hydration of subterranean formations. In particular, the mixture of polyethylene polyamines prevented the bentonite clay from swelling when in contact with the water-based drilling fluid and, as a result, prevented an increase in rheological properties, such as plastic viscosity, of the water-based drilling fluid.

Example 2—Comparison of Polyethylene Polyamine Mixtures

(6) To compare the effects of different mixtures of polyethylene polyamines, a hydration suppression test was performed using bentonite clay, as detailed in Example 1. Comparative Sample B and Comparative Sample C were each prepared by first mixing 350 g of water with 1 g of tetraethylenepentamine (commercially available from Huntsman Corporation) and 5 g of tetraethylenepentamine, respectively, for 5 minutes. After mixing, Comparative Sample B and Comparative Sample C were each hot rolled at 150° F. for 16 hours. After hot rolling, the rheology of both Comparative Sample B and Comparative Sample C was measured using a rheometer as described previously. The rheology of both Comparative Sample B and Comparative Sample C was measured twice, once at room temperature (RT) and once at 120° F., using a viscometer (commercially available as Model 35 from Fann Instrument Company). The composition and rheology of both Comparative Sample B and Comparative Sample C as well as Sample 1-3 of Example 1 are listed in Table 2.

(7) TABLE-US-00002 TABLE 2 Hydration Suppression Testing of Polyethylene Polyamine Mixtures Comparative Comparative Sample 1 Sample 2 Sample 3 Sample B Sample C Composition Water (g) 350 350 350  350 350 Mixture of Polyethylene 1 5 10 — — Polyamines (g) Tetraethylenepentamine (g) — — — 1 5 Bentonite (g) 30 30 30 30 30 Rheology RT 120° F. RT 120° F. RT 120° F. RT 120° F. RT 120° F. 600 rpm 31 24  22  17  20  15  34 30 33 29 300 rpm 20 16  12  9 12  10  23 20 18 18 200 rpm 15 13  8 7 9 8 19 15 14 15 100 rpm 11 9 4 4 7 6 14 10  9 11 6 rpm  6 4 3 2 5 4  8  4  3  5 3 rpm  4 3 2 1 4 4  6  2  3  4 PV 11 8 10  8 8 5 11 10 15 11 YP  9 8 2 1 4 5 12 10  3  7 Gel Strength, 10 sec  8 4 4 3 5 4  6  5  6  7 Gel Strength, 10 min 12 5 7 7 10  9  6  5 20 40

(8) As shown by Table 2, water-based drilling fluids that include a mixture of polyethylene polyamines having an average molecular weight of 250 g/mol to 300 g/mol are capable of maintaining a similar or lesser plastic viscosity, yield point, 10-second gel strength, and 10-minute gel strength when compared to a water-based drilling fluid that included only tetraethylenepentamine. This indicates that water-based drilling fluids that include mixtures of polyethylene polyamines having a greater average molecular weight when compared to other mixtures of polyethylene polyamines are capable of a greater reduction of the hydration of subterranean formations.

Example 3—Formulation of Water-Based Drilling Fluid

(9) A water-based drilling fluid having a density of 90 pcf was formulated based on the measurements of Example 1. The water-based drilling fluid was prepared by mixing the components, as listed in Table 3. After mixing, the water-based drilling fluid was hot rolled at 150° F. for 16 hours. After hot rolling, the rheology of the water-based drilling was measured at 120° F. using a rheometer as described previously. The composition and rheology of the water-based drilling fluid are listed in Table 3.

(10) TABLE-US-00003 TABLE 3 Composition and Rheology of Water-Based Drilling Fluid Composition Water (lb.sub.m/bbl) 273.2 XC Polymer (lb.sub.m/bbl) 0.75 Starch (lb.sub.m/bbl) 4 NaCl (lb.sub.m/bbl) 58 NaOH (lbm/bbl) 0.5 Barite (lb.sub.m/bbl) 142.6 CaCO.sub.3 - 50 Microns (lb.sub.m/bbl) 10 CaCO.sub.3 - 25 Microns (lb.sub.m/bbl) 10 Polyethylene Polyamines (lb.sub.m/bbl) 5 Rheology 600 rpm 42 300 rpm 28 200 rpm 21 100 rpm 14  6 rpm 5  3 rpm 4 PV (cP) 14 YP (lb.sub.f/100ft.sup.2) 14 10-Second Gel Strength (lb.sub.f/100ft.sup.2) 4 10-Minute Gel strength (lb.sub.f/100ft.sup.2) 7

(11) As shown by Table 3, the presence of additional additives in the water-based drilling fluid, such as a viscosifier (XC polymer), a fluid loss control agent (starch), and a weighting agent (barite), did not adversely affect the rheology of the water-based drilling fluid when compared to the rheology of water-based drilling fluids that included only water and the mixture of polyethylene polyamines. This indicates that the mixture of polyethylene polyamines is both suitable to reduce the hydration of subterranean formations and suitable for use in water-based drilling fluids that includes additives. In particular, the mixture of polyethylene polyamines will not adversely affect the rheology of the water-based drilling fluid when additional additives are included to adjust properties of the water-based drilling fluid, such as density.

(12) It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosure. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the disclosure may occur to persons skilled in the art, the scope of the disclosure should be construed to include everything within the scope of the appended claims and their equivalents.

(13) In a first aspect of the present disclosure, a water-based drilling fluid may include an aqueous base fluid and a mixture of polyethylene polyamines in an amount of from 1 lb.sub.m/bbl to 20 lb.sub.m/bbl relative to the total volume of the water-based drilling fluid. The polyethylene polyamines of the mixture may have a first chemical structure H.sub.2NCH.sub.2CH.sub.2(NHCH.sub.2CH.sub.2).sub.xNH.sub.2, where x may be an integer greater than or equal to 3. The average molecular weight of the polyethylene polyamines in the water-based drilling fluid having the first chemical structure may be from 200 g/mol to 400 g/mol.

(14) A second aspect of the present disclosure may include the first aspect where the water-based drilling fluid includes the aqueous base fluid in an amount of from 50 lb.sub.m/bbl to 340 lb.sub.m/bbl relative to the total volume of the water-based drilling fluid.

(15) A third aspect of the present disclosure may include either of the first or second aspects where the polyethylene polyamines of the mixture include linear polyethylene polyamines, cyclic polyethylene polyamines, branched polyethylene polyamines, or combinations of these.

(16) A fourth aspect of the present disclosure may include any of the first through third aspects where the polyethylene polyamines of the mixture include tetraethlyenepentamine, pentaethylenehexamine, hexaethyleneheptamine, or combinations of these.

(17) A fifth aspect of the present disclosure may include any of the first through fourth aspects where the sum of the weight percent of the tetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptamine is at least 50 wt. % of the polyethylene polyamines of the mixture.

(18) A sixth aspect of the present disclosure may include any of the first through fifth aspects where the water-based drilling fluid has a plastic viscosity of from 1 cP to 25 cP.

(19) A seventh aspect of the present disclosure may include any of the first through sixth aspects where the water-based drilling fluid has a yield point of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2.

(20) An eighth aspect of the present disclosure may include any of the first through seventh aspects where the water-based drilling fluid has a gel strength after 10 seconds of from 1 lb.sub.f/100 ft.sup.2 to 15 lb.sub.f/100 ft.sup.2.

(21) A ninth aspect of the present disclosure may include any of the first through eighth aspects where the water-based drilling fluid may have a gel strength after 10 minutes of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2.

(22) A tenth aspect of the present disclosure may include any of the first through ninth aspects that further include one or more viscosifiers, one or more fluid loss control agents, one or more weighting agents, or combinations of these.

(23) In an eleventh aspect of the present disclosure, a method for drilling a subterranean well may include operating a drill in a subterranean formation in the presence of a water-based drilling fluid. The water-based drilling fluid may include an aqueous base fluid and a mixture of polyethylene polyamines in an amount of from 1 lb.sub.m/bbl to 20 lb.sub.m/bbl relative to the total volume of the water-based drilling fluid. The polyethylene polyamines of the mixture may have a first chemical structure H.sub.2NCH.sub.2CH.sub.2(NHCH.sub.2CH.sub.2).sub.xNH.sub.2, where x may be an integer greater than or equal to 3. The average molecular weight of the polyethylene polyamines in the water-based drilling fluid having the first chemical structure may be from 200 g/mol to 400 g/mol.

(24) A twelfth aspect of the present disclosure may include the eleventh aspect that further includes introducing the water-based drilling fluid into the subterranean formation.

(25) A thirteenth aspect of the present disclosure may include the twelfth aspect where introducing the water-based drilling fluid into the subterranean formation comprises injecting the water-based drilling fluid through a drill string of the drill.

(26) A fourteenth aspect of the present disclosure may include any of the eleventh though thirteenth aspects that further include circulating at least a portion of the water-based drilling fluid within the subterranean formation.

(27) A fifteenth aspect of the present disclosure may include any of the eleventh though fourteenth aspects where the water-based drilling fluid includes the aqueous base fluid in an amount of from 50 lb.sub.m/bbl to 340 lb.sub.m/bbl relative to the total volume of the water-based drilling fluid.

(28) A sixteenth aspect of the present disclosure may include any of the eleventh though fifteenth aspects where the polyethylene polyamines of the mixture include linear polyethylene polyamines, cyclic polyethylene polyamines, branched polyethylene polyamines, or combinations of these.

(29) A seventeenth aspect of the present disclosure may include any of the eleventh though sixteenth aspects where the water-based drilling fluid has a plastic viscosity of from 1 cP to 25 cP.

(30) An eighteenth aspect of the present disclosure may include any of the eleventh though seventeenth aspects where the water-based drilling fluid has a yield point of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2.

(31) A nineteenth aspect of the present disclosure may include any of the eleventh though eighteenth aspects where the water-based drilling fluid has a gel strength after 10 seconds of from 1 lb.sub.f/100 ft.sup.2 to 15 lb.sub.f/100 ft.sup.2.

(32) A twentieth aspect of the present disclosure may include any of the eleventh though nineteenth aspects where the water-based drilling fluid may have a gel strength after 10 minutes of from 1 lb.sub.f/100 ft.sup.2 to 25 lb.sub.f/100 ft.sup.2.

(33) It should now be understood that various aspects of the water-based drilling fluid compositions and methods for drilling subterranean wells are described and such aspects may be utilized in conjunction with various other aspects.

(34) It is noted that one or more of the following claims utilize the term “where” as a transitional phrase. For the purposes of defining the present disclosure, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”

(35) It should be understood that any two quantitative values assigned to a property may constitute a range of that property, and all combinations of ranges formed from all stated quantitative values of a given property are contemplated in this disclosure.

(36) Having described the subject matter of the present disclosure in detail and by reference to specific embodiments, it is noted that the various details described in this disclosure should not be taken to imply that these details relate to elements that are essential components of the various embodiments described in this disclosure. Rather, the appended claims should be taken as the sole representation of the breadth of the present disclosure and the corresponding scope of the various embodiments described in this disclosure. Further, it will be apparent that modifications and variations are possible without departing from the scope of the appended claims. More specifically, although some aspects of the present disclosure are identified as particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.