CA2435629C - Fracturing fluid base oil - Google Patents
Fracturing fluid base oil Download PDFInfo
- Publication number
- CA2435629C CA2435629C CA 2435629 CA2435629A CA2435629C CA 2435629 C CA2435629 C CA 2435629C CA 2435629 CA2435629 CA 2435629 CA 2435629 A CA2435629 A CA 2435629A CA 2435629 C CA2435629 C CA 2435629C
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- CA
- Canada
- Prior art keywords
- fluid
- less
- fracturing
- fracturing fluid
- diesel
- 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.)
- Expired - Fee Related
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Classifications
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/62—Compositions for forming crevices or fractures
- C09K8/64—Oil-based compositions
Abstract
A fracturing fluid base oil is formed as a blend of diesel and stabilized light condensates consisting essentially of hydrocarbons in the range of C6-C24, preferably consisting essentially of C7-C9 and C10-C16 hydrocarbons. The hydrocarbons may be non-, partially or fully hydrotreated and may comprise n-alkanes 10 to 80 % by wt, preferably <40% by wt, isoalkanes 10-80% by wt, preferably >40% by wt, and aromatics no greater than 30% by wt, preferably <20% by wt. The blended fluid has a preferred viscosity less than 1.25 cSt at 40°C and a pour paint less than -30°C, preferably less than -40°C. The density should be less than 840 kg/m3 and preferably less than 810 kg/m3. The Reid vapor Pressure should be lass than 7.5 kPa, preferably less than 3 kPa. The flash point should be greater than 10°C, preferably greater than 15°C.
Description
FRACTURING FLUID BASE OIL
BACKGROUND OF THE INVENTION
01 The oil and gas well fracturing industry is constantly challenged by the desire to produce cost effective fluids and production enhancing used in downhole operations.
02 Fracturing is the process by which fluids are injected into downhole oil and gas bearing formations and subject to pressures that cause cracks to form in the reservoir bearing rock. The process of fracturing a well is usually referred to as a "frac". Creation of fractures is intended to increase reservoir production by increasing permeability. The fracturing fluids used in a frac generally contain entrained proppants that hold the cracks open after fracturing, thus sustaining the advantage of the permeability of the formation. Fracturing can thus often make non-commercial wells profitable. Fracturing is very useful in areas with mature wells such as Alberta, Canada.
03 One difficulty posed by fracturing fluids is that they require removal from the formation after fracturing. If the fracturing fluids remain in the formation after fracturing, they can actually block the pores of the reservoir rock. The somewhat expensive frac then can actually reduce production from the fractured well.
For this reason, stabilized light condensates have long been used in well fracturing.
The C5-C9 concentration in stabilized light condensates allows for improved clean up of the well after fracturing. The drawback to frac fluids made from condensates is the low flash points, typically 0-15 C, which can cause safety concerns.
04 Diesel, while it has been used as a frac fluid, is considered less advantageous for clean up, and may cause certain formations to become plugged. However, diesel is beneficial for use with gelling agents. Frac fluids preferably have increased viscosity
BACKGROUND OF THE INVENTION
01 The oil and gas well fracturing industry is constantly challenged by the desire to produce cost effective fluids and production enhancing used in downhole operations.
02 Fracturing is the process by which fluids are injected into downhole oil and gas bearing formations and subject to pressures that cause cracks to form in the reservoir bearing rock. The process of fracturing a well is usually referred to as a "frac". Creation of fractures is intended to increase reservoir production by increasing permeability. The fracturing fluids used in a frac generally contain entrained proppants that hold the cracks open after fracturing, thus sustaining the advantage of the permeability of the formation. Fracturing can thus often make non-commercial wells profitable. Fracturing is very useful in areas with mature wells such as Alberta, Canada.
03 One difficulty posed by fracturing fluids is that they require removal from the formation after fracturing. If the fracturing fluids remain in the formation after fracturing, they can actually block the pores of the reservoir rock. The somewhat expensive frac then can actually reduce production from the fractured well.
For this reason, stabilized light condensates have long been used in well fracturing.
The C5-C9 concentration in stabilized light condensates allows for improved clean up of the well after fracturing. The drawback to frac fluids made from condensates is the low flash points, typically 0-15 C, which can cause safety concerns.
04 Diesel, while it has been used as a frac fluid, is considered less advantageous for clean up, and may cause certain formations to become plugged. However, diesel is beneficial for use with gelling agents. Frac fluids preferably have increased viscosity
2 for pumping into the well by use of gelling agents. The gelled, high viscosity, frac fluid is better able to entrain the proppants for delivery downhole in deeper wellbores.
The gel is broken by agents contained in the frac fluid for removal of the frac fluid from the reservoir rock.
SUMMARY OF THE INVENTION
05 This invention provides an improved base oil for use in wellbore fluids during fracturing operations by combining the desirable properties of diesel and stabilized light condensates and removing the undesirable properties of gas condensate fluids.
Surprisingly, the blend produced maintains the advantages of both fluids.
06 The fracturing fluid base oil according to the invention is one constituent of a fracturing fluid and the fracturing fluid may also contain gellants, activators, bactericides, friction reducers, corrosion control, clay control, and breaker control agents when used for fracturing. The improved base oil is a blend of diesel and stabilized light condensates consisting essentially of hydrocarbons in the range of C6-C24, preferably consisting essentially of C7-C16 hydrocarbons. The hydrocarbons may be non-, partially or fully hydrotreated and may comprise n-alkanes 10 to 80 %
by wt, preferably <40% by wt, isoalkanes 10-80% by wt, preferably >40% by wt, and aromatics no greater than 30% by wt, preferably <20% by wt. The blended fluid has a preferred viscosity less than 1.25 cSt at 40 C and a pour point less than -30 C, preferably less than -40 C. The density should be less than 840 kg/m3 and preferably less than 810 kg/m3. The Reid Vapor Pressure should be less than 7.5 kPa, preferably less than 3 kPa. The flash point should be greater than 10 C, preferably greater than 15 C.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
07 Predominantly in this patent document means greater than 50% by wt.
Consists essentially of X means at least 90% by wt X. The word "comprising" in the
The gel is broken by agents contained in the frac fluid for removal of the frac fluid from the reservoir rock.
SUMMARY OF THE INVENTION
05 This invention provides an improved base oil for use in wellbore fluids during fracturing operations by combining the desirable properties of diesel and stabilized light condensates and removing the undesirable properties of gas condensate fluids.
Surprisingly, the blend produced maintains the advantages of both fluids.
06 The fracturing fluid base oil according to the invention is one constituent of a fracturing fluid and the fracturing fluid may also contain gellants, activators, bactericides, friction reducers, corrosion control, clay control, and breaker control agents when used for fracturing. The improved base oil is a blend of diesel and stabilized light condensates consisting essentially of hydrocarbons in the range of C6-C24, preferably consisting essentially of C7-C16 hydrocarbons. The hydrocarbons may be non-, partially or fully hydrotreated and may comprise n-alkanes 10 to 80 %
by wt, preferably <40% by wt, isoalkanes 10-80% by wt, preferably >40% by wt, and aromatics no greater than 30% by wt, preferably <20% by wt. The blended fluid has a preferred viscosity less than 1.25 cSt at 40 C and a pour point less than -30 C, preferably less than -40 C. The density should be less than 840 kg/m3 and preferably less than 810 kg/m3. The Reid Vapor Pressure should be less than 7.5 kPa, preferably less than 3 kPa. The flash point should be greater than 10 C, preferably greater than 15 C.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
07 Predominantly in this patent document means greater than 50% by wt.
Consists essentially of X means at least 90% by wt X. The word "comprising" in the
3 claims is used in its inclusive sense and does not exclude other elements being present.
08 The fracturing fluid according to the invention is preferably produced by blending a fluid made from the stabilization of light condensates with diesel or an equivalent high carbon number fluid. Stabilized light condensates are commercially available fracturing fluids made throughout the province of Alberta. These light condensate products are made by atmospheric distillation of a feedstock that is a NGL
(natural gas liquid). These stabilized light condensate fracturing fluids are desirable for fracturing due to the light ends they contain, C5-C9. These carbons are preferred for improved clean-up of the post fracture liquid. The heavier carbon number fluid such as diesel has hydrocarbons Cl0-C16 that are desirable for improved chemical reaction with the additives used to carry out a fracture.
09 The improved base oil is a blend of diesel and stabilized light condensates consisting essentially of hydrocarbons in the range of C6-C24, preferably consisting essentially of C7-C16 hydrocarbons. The hydrocarbons may be non-, partially or fully hydrotreated and may comprise n-alkanes 10 to 80 % by wt, preferably <40% by wt, isoalkanes 10-80% by wt, preferably >40% by wt, and aromatics no greater than 30% by wt, preferably <20% by wt. The blended fluid has a preferred viscosity less than 1.25 cSt at 40 C and a pour point less than -30 C, preferably less than -40 C.
The density should be less than 840 kg/m3 and preferably less than 810 kg/m3.
The Reid Vapor Pressure should be less than 7.5 kPa, preferably less than 3 kPa.
The flash point should be greater than 10 C, preferably greater than 15 C.
The stabilized light condensate may be obtained from a variety of sources.
Most gas production plants produce stabilized light condensate as a by-product.
11 The stabilized light condensate is blended simply by mixing, without any additional processing, with diesel or an equivalent high aromatic fluid.
Diesel is a
08 The fracturing fluid according to the invention is preferably produced by blending a fluid made from the stabilization of light condensates with diesel or an equivalent high carbon number fluid. Stabilized light condensates are commercially available fracturing fluids made throughout the province of Alberta. These light condensate products are made by atmospheric distillation of a feedstock that is a NGL
(natural gas liquid). These stabilized light condensate fracturing fluids are desirable for fracturing due to the light ends they contain, C5-C9. These carbons are preferred for improved clean-up of the post fracture liquid. The heavier carbon number fluid such as diesel has hydrocarbons Cl0-C16 that are desirable for improved chemical reaction with the additives used to carry out a fracture.
09 The improved base oil is a blend of diesel and stabilized light condensates consisting essentially of hydrocarbons in the range of C6-C24, preferably consisting essentially of C7-C16 hydrocarbons. The hydrocarbons may be non-, partially or fully hydrotreated and may comprise n-alkanes 10 to 80 % by wt, preferably <40% by wt, isoalkanes 10-80% by wt, preferably >40% by wt, and aromatics no greater than 30% by wt, preferably <20% by wt. The blended fluid has a preferred viscosity less than 1.25 cSt at 40 C and a pour point less than -30 C, preferably less than -40 C.
The density should be less than 840 kg/m3 and preferably less than 810 kg/m3.
The Reid Vapor Pressure should be less than 7.5 kPa, preferably less than 3 kPa.
The flash point should be greater than 10 C, preferably greater than 15 C.
The stabilized light condensate may be obtained from a variety of sources.
Most gas production plants produce stabilized light condensate as a by-product.
11 The stabilized light condensate is blended simply by mixing, without any additional processing, with diesel or an equivalent high aromatic fluid.
Diesel is a
4 fuel obtained from petroleum distillation that is used in diesel engines.
Diesel has a relatively low ignition temperature (540 C) and is ignited by the heat of compression.
Diesel varies in quality depending on the manner in which it is produced, and is typically a mixture of a number of refinery blendstocks with similar boiling ranges.
Blendstock quality depends on the source of the feedstock and the process used for its production. Low sulphur content and high cetane value is desirable in a diesel.
Straight-run materials produced by distillation from crude oil generally have excellent cetane value, and therefore, they require little more than hydrotreating to control sulfur levels. Gasoline production often occurs in large fluid catalytic cracking (FCC) units, which produce light-cycle oil (LCO). LCO is a high aromatic fluid and tends to be high in sulphur, with considerable polyaromatic hydrocarbon content. LCO is used as a component part of diesel, but it is preferred not to have high LCO
content in the diesel. Blendstocks, such as LCO and coker gasoil, produced by carbon rejection processes are generally high in aromatics and low in cetane value and make poor diesel. On the other hand, blendstocks produced by hydrocracking have excellent cetane value, are low in sulfur, and make excellent diesel. Poor diesel fuel requires additives such as cetane, lubricity, conductivity, deicers and ignition enhancers.
12 Depending on what type of refinery process is used dictates the level of aromatics present in the diesel. An exemplary diesel is SuncorTM diesel available from Suncor, Calgary, Alberta, Canada. SuncorTM diesel is low in sulfur, and has a low level of aromatics in the fuel. Low sulphur, low aromatic diesel is preferred.
13 Exemplary fluid blends are given in the following table.
Gas condensate TESTS Diesel frac fluid Blend RVP <1 kPa 7.5 kPa 2.5 kPa Flash Point (PMCC) 58 C 5 C 19 C
Density 837 kg/m3 760 kg/m3 804 kg/m3 Pour point -37 C <-45 C <-45 C
Initial gel strengths - standard chemical loading (6 and 3) Fluid Viscosity @80 C (cP 100s"') Gas Condensate 275 Blend 400 Diesel 480 14 The fracturing fluid thus produced should only be used for on shore fracturing operations. Immaterial modifications may be made to the blended fluid described here without departing from the invention.
Diesel may comprise 25-75% by wt of the blended fluid.
Diesel has a relatively low ignition temperature (540 C) and is ignited by the heat of compression.
Diesel varies in quality depending on the manner in which it is produced, and is typically a mixture of a number of refinery blendstocks with similar boiling ranges.
Blendstock quality depends on the source of the feedstock and the process used for its production. Low sulphur content and high cetane value is desirable in a diesel.
Straight-run materials produced by distillation from crude oil generally have excellent cetane value, and therefore, they require little more than hydrotreating to control sulfur levels. Gasoline production often occurs in large fluid catalytic cracking (FCC) units, which produce light-cycle oil (LCO). LCO is a high aromatic fluid and tends to be high in sulphur, with considerable polyaromatic hydrocarbon content. LCO is used as a component part of diesel, but it is preferred not to have high LCO
content in the diesel. Blendstocks, such as LCO and coker gasoil, produced by carbon rejection processes are generally high in aromatics and low in cetane value and make poor diesel. On the other hand, blendstocks produced by hydrocracking have excellent cetane value, are low in sulfur, and make excellent diesel. Poor diesel fuel requires additives such as cetane, lubricity, conductivity, deicers and ignition enhancers.
12 Depending on what type of refinery process is used dictates the level of aromatics present in the diesel. An exemplary diesel is SuncorTM diesel available from Suncor, Calgary, Alberta, Canada. SuncorTM diesel is low in sulfur, and has a low level of aromatics in the fuel. Low sulphur, low aromatic diesel is preferred.
13 Exemplary fluid blends are given in the following table.
Gas condensate TESTS Diesel frac fluid Blend RVP <1 kPa 7.5 kPa 2.5 kPa Flash Point (PMCC) 58 C 5 C 19 C
Density 837 kg/m3 760 kg/m3 804 kg/m3 Pour point -37 C <-45 C <-45 C
Initial gel strengths - standard chemical loading (6 and 3) Fluid Viscosity @80 C (cP 100s"') Gas Condensate 275 Blend 400 Diesel 480 14 The fracturing fluid thus produced should only be used for on shore fracturing operations. Immaterial modifications may be made to the blended fluid described here without departing from the invention.
Diesel may comprise 25-75% by wt of the blended fluid.
Claims (10)
1. A fracturing fluid, comprising:
a blended fluid of diesel and a stabilized light condensate produced by atmospheric distillation of a natural gas liquid feedstock; and the blended fluid consisting essentially of C6-C24 hydrocarbons, and having 10-80% by wt n-alkanes, 10-80% by wt isoalkanes, less than 30% by wt aromatics, viscosity less than 1.25 cSt at 20°C, a pour point less than -30°C, density less than 840 kg/m3, and flash point greater than 10°C.
a blended fluid of diesel and a stabilized light condensate produced by atmospheric distillation of a natural gas liquid feedstock; and the blended fluid consisting essentially of C6-C24 hydrocarbons, and having 10-80% by wt n-alkanes, 10-80% by wt isoalkanes, less than 30% by wt aromatics, viscosity less than 1.25 cSt at 20°C, a pour point less than -30°C, density less than 840 kg/m3, and flash point greater than 10°C.
2. The fracturing fluid of claim 1 in which the blended fluid consists essentially of C7-C16 hydrocarbons.
3. The fracturing fluid of claim 1 or 2 in which the hydrocarbons comprise -40% by wt n-alkanes.
4. The fracturing fluid of any one of claim 1-3 in which the hydrocarbons comprise >40%
by wt isoalkanes.
by wt isoalkanes.
5. The fracturing fluid of any one of claim 1-4 in which the blended fluid comprises 40%
by wt aromatics.
by wt aromatics.
6. The fracturing fluid of any one of claim 1-5 having a pour point less than -40°C.
7. The fracturing fluid of any one of claim 1-6 having a density less than 810 kg/m3.
8. The fracturing fluid of any one of claim 1-7 having a flash point greater than 15°C.
9. The fracturing fluid of any one of claim 1-8 in which diesel comprises 25-75% by wt of the blended fluid.
10. The fracturing fluid of any one of claim 1-9 used for on shore fracturing operations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2435629 CA2435629C (en) | 2003-07-21 | 2003-07-21 | Fracturing fluid base oil |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2435629 CA2435629C (en) | 2003-07-21 | 2003-07-21 | Fracturing fluid base oil |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2435629A1 CA2435629A1 (en) | 2005-01-21 |
| CA2435629C true CA2435629C (en) | 2011-05-31 |
Family
ID=34069915
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2435629 Expired - Fee Related CA2435629C (en) | 2003-07-21 | 2003-07-21 | Fracturing fluid base oil |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2435629C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2636560C (en) | 2007-12-31 | 2015-04-07 | Shaun T. Mesher | Treatment of stimulating fluid |
-
2003
- 2003-07-21 CA CA 2435629 patent/CA2435629C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2435629A1 (en) | 2005-01-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20190722 |