CA2681450C - Method of supplying fuel to a heavy crude production unit, corresponding heavy crude production process and corresponding heavy crude production unit - Google Patents

Abstract

The invention relates to a method for supplying fuel to a production unit (10) for heavy crude oil, said unit comprising: a feed pipe (12) with diluent (s) intended to transport at least one diluent for a processing unit (11) to said production unit (10), an evacuation pipe (13) for conveying the heavy crude produced on the production unit, mixed with the diluent (s) from the unit production line (10) to the treatment unit (11), characterized in that the supply line (12) is used by diluting (s) to transport a fuel mixture and diluent (s) to the unit of production. A heavy crude production process according to the invention uses this feeding process to convey a fuel into the production unit and use it for the production of the heavy crude. The invention also relates to a heavy crude production unit implementing the production method according to the invention.

Description

METHOD FOR SUPPLYING FUEL TO A UNIT OF
HEAVY RAW PRODUCTION, PROCESS FOR PRODUCTION OF
HEAVY RAW AND PRODUCTION UNIT OF HEAVY RAW
CORRESPONDENTS.
The present invention relates to a method for supplying fuel from a heavy crude production unit and a producing a heavy crude using said feed method. She also concerns a unit for the production of a heavy crude for the implementation of the production process.

Compared to conventional light crude oil, heavy crudes and extra-heavy crudes, also known as heavy or extra-heavy oils heavy and natural bitumens, usually have a proportion much larger amount of heavy carbon compounds, one more high content of sulfur, nitrogen and heavy metals. However, refineries are designed to deal mainly with the classic light crude oil. That's why it's economically it is preferable to build an upgrader, English), which values heavy crude oil as a synthetic crude oil lighter, which will then be transported to any refinery classic to be transformed into commercial products (essences, diesel .. ).
In addition, the exploitation of heavy and extra-heavy crudes, generally defined by a density less than 20 API, is particularly difficult because of their high viscosity. One of The main problems faced by oil tankers are that of the transport of heavy oils such as those from the deposits Athabasca in Canada or the Orinoco Oil Belt in Canada.
Venezuela, from the point of production (heavy or extra heavy oil wells) heavy oil sands mining sites ...), up to processing sites (heavy crude upgrading units, refineries able to process heavy crudes ...).
Several solutions have been proposed to make crudes transportable heavy goods. One of these solutions is to dilute the crude heavy oil or light petroleum fractions, which allows to reduce the density and the viscosity of the effluent, to values

2 compatible with the specifications of the transport pipes (183.5 mPa.s at 37.7 C and 15 APIs in Venezuela and 350 mPa.s at 7.5 C in winter and 18.5 C in summer and 19 APIs in Canada for example).
Two schemes are then possible. In the first schema, the diluent is not recycled, and it is the diluted heavy crude that is routed to the customer refineries.
In a second scheme, the diluent is recycled, when there is a plant for upgrading heavy crude. The gross heavy diluted can then be sent by pipeline to this site treatment, where the diluent is separated by distillation of the heavy crude so to be sent back to the production site by a second pipeline and reused, on the spot.
This loop is shown schematically in the figure 1, on which a pipe 1 transports the heavy crude produced by a production unit 3 and diluted to a treatment unit 4, a line 2 carrying a diluent from the treatment unit 4 to the production unit 3. The diluent is mixed with the heavy crude at production unit 3 in order to allow its transport to the unit of treatment 4.
When the viscosity of the heavy crudes is not too great, these retain some mobility (ie some degree of fluidity) under the pressure and temperature conditions of the tank.
It is therefore possible to produce them by recovery methods such as the simple natural depletion of the deposit, called also cold production since it does not use a external energy input, outside of the activation of the well.
Viscous heavy crudes can not be produced from of a well unless previously heated or diluted. We speaks in this case of hot production. One of the technologies used consists of a continuous injection of water vapor, and is called SAGD (Steam Assisted Gravity Drainage). This technology relies on drilling a pair of horizontal wells, a well of production located at the base of the deposit and an injection well drilled at a few meters above the first. The water vapor injected into the injection well heats the bituminous layer. The heavy fluid fluidified

3 and the water of condensation flows by gravity to the well of production, from where they are pumped to the surface.
Due to the physical mechanisms involved, cold production like hot production can only recover a part heavy crude oil in place: in cold production, the recovery rate of extra heavy crude is usually less than 10%, while the hot production, much more efficient, can achieve recovery of about 20% or more depending on the characteristics of the field. Hot production can therefore also be applied to deposits of heavy crude having some mobility to improve the recovery rate.

But the major disadvantage of hot production, is that it requires a very important input of energy. It is indeed necessary to fuel for furnaces and / or boilers to produce water vapor, among others.

Generally, natural gas is used as fuel. But it is not necessarily available nearby, and moreover, its price is a risk for the future.
Other alternative fuels, such as heavy crude himself. Part of it would be used to provide energy on the production site. Nevertheless, this solution involves a decrease in the net production capacity of the oil site, up to 15-20%.
Another solution is to use a solid fuel such as coal or coke, transported by land for burning.
The cost of these materials and their transportation, especially when oil production are located in hard-to-reach areas geographically, constitute a significant disadvantage.

It is therefore a major need to find an alternative solution to meet the growing energy needs of production of heavy crudes.

4 For this purpose, the invention proposes a method for feeding fuel of a heavy crude production unit, said unit comprising:
- a diluent supply line intended for carry at least one diluent from a treatment unit to said production unit - an evacuation pipe intended to transport the crude produced on the production unit, mixed with the extender (s) since the production unit to the processing unit, characterized in that the supply line is used in diluent (s) to transport a combustible mixture and diluent (s) to the production unit.

Said diluent is capable of being mixed with the heavy crude produced on the production unit to allow its transport by pipeline.

The method according to the invention has the advantage of using a existing system, namely the existing pipelines, to bring a diluent, or a mixture of thinners, at the crude production site heavy, so it can be implemented without major modification existing facilities.

The method according to the invention can also be implemented at demand, that is to say according to the energy needs of the site of production, by sending more or less fuel or not just as it is the case for the classic diluent loop. In addition, method according to the invention can be used in batch mode (batch in English).
Advantageously, the fuel is a hydrocarbon fraction.
Preferably, a heavy hydrocarbon fraction will be used, generally difficult to valorize, having a carbon residue Conradson CCR greater than or equal to 10% by weight, and preferentially greater than or equal to 15% by weight, and even more preferentially greater than or equal to 20% weight.

The hydrocarbon fraction will for example be obtained from the treatment a heavy crude by said processing unit. However, we will use preferably a hydrocarbon fraction resulting from the treatment of heavy crude produced by said production unit.

5 The processing unit makes it possible to perform a valuation (upgrading in English), which involves converting heavy oil into a product whose density and viscosity resemble those of a classic light oil. Such a processing unit (factory valuation) usually consists of several units - units of atmospheric and vacuum distillation, - deasphalting units.
- coking units.
- hydrocracking units (in fixed bed / ebullating bed / bed slurry).
- hydrotreating units.

It is possible to use a hydrocarbon fraction chosen from atmospheric distillation residue, the vacuum distillation residue, the deasphalting pitch and the hydrocracking residue from the treatment of a heavy crude that will preferably be heavy crude product by said production unit.

Advantageously, the diluent is chosen from light cuts or petroleum derivatives such as condensate, naphtha (in particular, coker naphtha), kerosene, diesel, LCO, blends of distillates ...
In a variant, the diluent is chosen from organic solvents such as alcohols such as methanol, ethanol, propanol, isopropanol and hexanol, esters and ethers such as MTBE, TAME, as well as synthetic paraffins from gas treatment or biomass.
Preferably, and especially when the distance between the processing unit of the production unit is large, the fuel and the diluent (s) are chosen so that the mixture fuel - diluent (s) has stability limit S-value> _ 1 (ASTM D7157), preferably S-value> 1.35. this allows

6 avoid deposits in the pipeline due to instability in the fuel-diluent mixture.

The higher fuel / diluent ratio is limited by the amount of thinner that is needed to form a product transportable by pipeline. Thus, preferably, the upper limit of the fuel / diluent ratio is between 70% and 80%, and sufficient for the mixture to be transportable.

Generally the lower limit of the fuel / diluent ratio is between 10% and 20%. As the relationship between viscosity of the mixture and the volume of diluent added, is exponential, the maximum decrease in viscosity corresponds to a certain rate of solvent that need not be exceeded.
The invention also relates to a method for producing a heavy crude by means of a heavy crude production unit, unit comprising:
- a diluent supply line intended for carry at least one diluent from a treatment unit to said production unit, - an evacuation pipe intended to transport the crude produced on the production unit, mixed with the extender (s) since the production unit to the processing unit, Said method comprising:
(a) the transportation of fuel mixed with at least a diluent according to the fuel supply method according to the invention, (b) separation on the fuel production unit and the diluent.

Said diluent is capable of being mixed with the heavy crude produced on the production unit to allow its transport by pipeline, Step (b) of separating the fuel and the diluent can be performed either by distillation or in a simpler way by a liquid-vapor separation carried out continuously (Flash in English). In

7 Indeed, the fuel and diluent used according to the present invention generally having very different characteristics, they can be easily separated completely by simple flash.

This separation step can be completed, depending on the type of hydrocarbon fraction recycled with the diluent, by other physicochemical separation treatments (eg deasphalting).

Advantageously, this process comprises a combustion step or gasification of the separated fuel in the production unit.
The invention also relates to a production unit of a heavy crude for the implementation of the production process according to the invention, said unit comprising:
- a diluent supply line intended for carry at least one diluent from a treatment unit to said production unit, - an evacuation pipe intended to transport the crude produced on the production unit, mixed with the extender (s) since the production unit to the processing unit, characterized in that it comprises a separation device connected to the supply line with diluent (s), said device being capable of separating the fuel-diluent mixture circulating in said supply line.
Advantageously, the unit comprises a gasification device or combustion of the separated fuel by means of the separation, said combustion device being able to produce the energy necessary to extract the heavy crude using said fuel.
As a combustion device, it will be used for example a fluidized bed boiler (CFBB).

The feeding method according to the invention has several advantages:
- use of an existing device (pipelines already in place) requiring only the addition of a separation device on the site of WO 2008/14222

8 PCT / FR2008 / 000393 production and possibly debottlenecking of the diluent pipeline existing (pumping station);
- implementation on demand, as needed energy from the production site.
- advantageous implementation when the treatment site comprises a coking unit fed with vacuum residue:
the opportunity of general debottlenecking of the site without touching the coker, the vacuum residue supplement generated by the treatment supplement extra heavy crude being sent to the place of production to be used as fuel.
The invention is now described with reference to the drawings annexed, non-restrictive, in which:
Figure 1 is a schematic representation of the pipelines (pipelines) connecting a heavy crude production unit to a unit of treatment ;
Figure 2 is a schematic representation of a unit of processing and a production unit according to the invention.
FIG. 2 represents a production unit 10 of a heavy crude connected to a processing unit 11 of the heavy crude produced by means of supply and evacuation lines 13. Pipe feed 12 brings a diluent to the production unit, the evacuation pipeline carrying the heavy crude product mixed with the diluent to the treatment unit. According to the process according to the invention, power supply 12 will be used to carry the fuel from the treatment unit in mixture with the diluent, to the production unit.
The production unit 10 according to the invention is provided with a separation device 14 for separating the fuel and diluent supplied by the supply line 12. Fuel C
separated is transported to a combustion device 15 for the production of energy for the production of heavy crude BL. The Separate diluent D is mixed with the heavy crude produced for transport to the treatment unit via the pipeline evacuation 13.
The processing unit comprises a separation device 16 of the diluent and heavy crude that separates the diluent D to return it to

9 the production unit via line 12, and the heavy crude BL. This separation is usually carried out by atmospheric distillation.
The heavy crude then undergoes vacuum distillation in a column 17. The RSV vacuum residue produced, which can represent up to about 50% of the heavy crude, can be processed in a unit of The processing unit may also be provided with a deasphalting unit 19 for treating the residue under vacuum RSV.
When the processing unit comprises a coking unit 18, the vacuum residue is converted into coke and more light. Part of this residue can be sent via line 20 to the inlet of the supply pipe 12 into which it is introduced in diluent, to be transported to the production unit and serve as fuel after separation from the diluent.
When the treatment unit includes a unit of deasphalting 19, the vacuum residue is converted into oil deasphalted DAO and deasphalting pitch. Pitch of deasphalting can be returned via a pipe 21 at the entrance of the supply line 12 in which it is introduced in a mixture at diluent, to be transported to the production unit and to serve as a fuel after separation from the diluent.

EXAMPLES
The following examples illustrate the invention and its advantages without however, limit its scope.
Several fuel mixtures and diluents were tested.
The fuels tested are as follows:
- Vacuum residue (RSV) of the Venezuelan crude extra-heavy Zuata - Braid resulting from pentane deasphalting of bitumen Athabasca produced thermally (SAGD); most liquid product heavy.
The properties of the fuels are as follows Table 1: properties of the fuels tested Brai RSV
Mass density at 15 C k m3 1099.1 1051.6 Kinematic viscosity at 190 C mm2 s 403.9 Kinematic viscosity at 200 C mm 2 s 580.8 Kinematic viscosity at 210 C mm2 s 189.2 Kinematic viscosity at 230 C mm 2 s 266.1 The solvents tested are as follows - Light Naphtha 5 - Heavy Naphtha - Naphtha total (32% light Naphtha + 68% heavy Naphtha) - Kerosene cut - Naphtha of coker

Table 2: Properties of the diluents tested Naphtha Naphtha Naphtha Naphtha Cup light heavy total coker kerosene Volumic mass at 15 C k m3 649.3 734.0 705.7 797.4 802.9 In this non-limiting example, we have imposed ourselves surplus, the following constraints:
(1) The mixture must have a stability reserve, (S-Value> 1.35 ASTM D7157) sufficient to avoid any problem decantation.

(2) the mixture must meet the specifications of the pipelines (pipelines in English):
- In Venezuela:
- 183.5 mPa.s at 37.7 ° C max, 15 API min.
- In Canada:
- 0,935 of max. and 350 mPa.s max, at 7,5 C in winter - 0,935 of max. and 350 mPa.s max. at 18.5 C in summer.
The diluent and fuel mixtures were studied for two compositions:

11 85% by diluent mass + 15% by mass of fuel, - 70% by weight diluent + 30% by combustible mass, The test results are summarized in Tables 3 and 4.
The main conclusions are:
(a) Unstable mixtures can be classified in two categories:
- Highly unstable: two phases appear (no Miscibility).
- Slightly unstable: immiscibility is not visible at the eye but a measure of stability or a simple test to the task show that the product is unstable (S-value <1).

(b) The following mixtures do not have a reserve of sufficient stability:
70/30 heavy naphtha / pitch, 70/30 total naphtha / pitch, 85/15 cut kerosene / pitch.
85/15 light naphtha / RSV
70/30 light naphtha / RSV

(c) Stable mixtures (S-Value> 1.35) respect the constraint density of pipelines.

(d) In terms of viscosity, all tested mixtures comply the target specifications except the mixture 30% pitch + 70% kerosene cut that does not respect the winter constraint of Canadian pipelines.

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Claims (23)

CLAIMS: 1. A method of supplying fuel to a production unit (10) of heavy crude, said unit comprising:
- a supply line (12) diluent (s) for transporting to less of a diluent from a processing unit (11) to said unit of production (10) an evacuation pipe (13) intended to transport the heavy crude product on the production unit, mixed with the diluent (s) from the unit of production (10) to the processing unit (11), characterized in that the piping (12) by diluting (s) to transport a combustible mixture and diluent (s) to the production unit. Fuel supply method according to claim 1, characterized in that the fuel is a hydrocarbon fraction. Fuel supply method according to claim 2, characterized in that the CCR Conradson Carbon residue of the hydrocarbon fraction is greater than or equal to 10% weight. Fuel supply method according to claim 3, characterized in that said Carbon Conradson CCR residue is greater than or equal to 15%
weight. 5. Fuel supply method according to any one of Claims 3 and 4, characterized in that said carbon Conradson residue CCR
is greater than or equal to 20% weight. 6. Fuel supply method according to any one of Claims 2 to 5, characterized in that the hydrocarbon fraction is from the treatment of a heavy crude by said processing unit. Fuel supply method according to claim 6, characterized in that said heavy crude is produced by said production unit. 8. Fuel supply method according to any one of Claims 2 to 7, characterized in that the hydrocarbon fraction is chosen from a residue of atmospheric distillation, a distillation residue under empty, a deasphalting pitch and a hydrocracking residue, resulting from the treatment of a gross heavy Fuel supply method according to claim 8, characterized in that said heavy crude is produced by said production unit. 10. Fuel supply method according to any one of Claims 1 to 9, characterized in that the diluent is selected from cuts light or oil derivatives. 11. Fuel supply method according to claim 10, characterized in that the diluent is selected from condensate, naphtha, naphtha coker, kerosene, diesel, LCO and distillate mixtures. 12. Fuel supply method according to any one of Claims 1 to 9, characterized in that the diluent is selected from solvents organic. Fuel supply method according to claim 12, characterized in that the diluent is selected from alcohols, esters, ethers and synthetic paraffins resulting from the treatment of gas or biomass. 14. Fuel supply method according to claim 13, characterized in that the alcohols are methanol, ethanol, propanol, of isopropanol or hexanol. Fuel supply method according to claim 13 or 14, characterized in that the ethers are MTBE or TAME. 16. Fuel supply method according to any one of Claims 1 to 15, characterized in that the fuel and the Thinner (s) are chosen in such a way that the fuel-diluent mixture (s) has a limit Stability S-value> = 1. Fuel supply method according to claim 16, characterized in that said stability limit S-value> = 1.35. 18. Fuel supply method according to any one of Claims 1 to 17, characterized in that the lower limit of the ratio fuel / diluent is between 10% and 20%. 19. Fuel supply method according to any one of Claims 1 to 18, characterized in that the upper limit of the ratio fuel / diluent is between 70% and 80%. 20. Process for producing a heavy crude using a production unit (10) heavy crude, said unit comprising:
- a supply line (12) diluent (s) for transporting to less of a diluent from a processing unit (11) to said unit of production (10) an evacuation pipe (13) intended to transport the heavy crude product on the production unit (10), mixed with the diluent (s) from the unit of production (10) to the treatment unit (11), said method comprising:
(a) conveying a fuel in admixture with at least one diluent according to the fuel supply method according to one of claims 1 to 19, (b) separating the fuel and diluent production unit. 21. Process for producing a heavy crude according to claim 20, characterized in that it comprises a step of combustion or gasification of separated fuel in the production unit. 22. Production unit (10) of a heavy crude for the implementation of the process production system according to any one of claims 20 and 21, said unit comprising:
- a supply line (12) diluent (s) for transporting to less of a diluent from a processing unit (11) to said unit of production (10) an evacuation pipe (13) intended to transport the heavy crude product on the production unit, mixed with the diluent (s) from the unit of production (10) to the processing unit (11), characterized in that it comprises a separation device (14) connected to the supply line (12) by diluting (s), said device being suitable for separate the fuel-diluent mixture circulating in said supply line. Production unit (10) according to claim 22, characterized in that it comprises a gasification or combustion device (15) of the combustible separated by means of the separating device (14), said combustion (15) being able to produce the energy necessary for the extraction of heavy crude oil using said combustible.