WO2011021095A1

WO2011021095A1 - Emerging technologies for optimising recovery from heavy crude deposits

Info

Publication number: WO2011021095A1
Application number: PCT/IB2010/002045
Authority: WO
Inventors: Ronald Pantin; Luis Andres Rojas; Mkac Fuenmayor
Original assignee: Pacific Rubiales Energy Corp
Priority date: 2009-08-21
Filing date: 2010-08-19
Publication date: 2011-02-24
Also published as: CO6210132A1; US20120145415A1; CA2771469A1

Abstract

The invention relates to a method for extracting hydrocarbons from an underground reservoir, consisting in: providing at least one injection well (1) which includes an assembly of pipes suitable for injecting the media required to initiate and/or maintain the combustion reaction inside the reservoir (100); providing at least one production well which includes a substantially horizontal portion (6) and which comprises a set of pipes suitable for extracting the hydrocarbons entering the production well (2) via the substantially horizontal portion (6), wherein the substantially horizontal portion (6) includes a first end (7) and a second end (8) and said horizontal portion (6) of the production well (2) is arranged such that the second end (8) is located in a relative position that is closer to the injection well (1) than the first end (7); initiating the combustion reaction inside the reservoir by injecting oxidising gas through the set of pipes arranged inside the injection well (1), thereby generating a combustion front, the path of which first meets the second end (8) of the horizontal portion (6) and, subsequently, the first end (7) of same; and using the assembly of pipes located inside the production well (2) to extract from inside the reservoir the hydrocarbons entering the horizontal portion (6).

Description

EMERGING TECHNOLOGIES TO OPTIMIZE RECOVERY IN HEAVY CRUDE FACILITIES

The classic configuration of the state of the art for a hydrocarbon recovery process based on an in situ combustion process has a vertical injector comprising an inlet and an outlet, said inlet being disposed in the upper and superficial part of the well, and said exit arranged in the inner zone of the well. Additionally, a horizontal production well consisting of a first vertical duct portion and a horizontal duct portion is available. The horizontal duct portion of the production well substantially perpendicular to the vertical injector, and which is oriented towards the injector well. The end of the production well closest to the injector well is referred to in the art as "toe", and the end furthest from the injector well is called "heel". The "heel" end of the horizontal zone is in direct connection with the vertical portion of the production well, which extends to the surface, outside the hydrocarbon reservoir. This technique has been called "toe to heel", which is an arrangement that geometrically defines an inverted "L" and is known in the art as THAI. Examples of prior art are US 5,626,191, CA 2,255,071, CA 2,643,739, CA 2,579,854, CA 2,569,676, CA 2,246,461, US 6,167,966, and US publication 5,211,230 which , although prior to the THAI system as such, it advances some of its essential elements.

The invention proposes first of all the variant in the basic configuration, which consists in inverting the orientation of the horizontal portion of the production well with respect to the vertical injector. Under this configuration the horizontal portion of the production well is oriented in the same direction of propagation of the combustion front, which defines a "L" in which the substantially horizontal portion is oriented, in the opposite direction to the injector well. The proposed configuration bases its effectiveness on the way in which

1 CONFIRMATION COPY develops the combustion front which, in its trajectory, is improving the characteristics of crude oil and the mobility of oil with respect to water and finally, a better displacement of crude oil towards producing wells. Hence, it is ensured that the intake area of recovered oil is located farthest from the ignition zone, precisely because of the propagation effect of the combustion front, this would guarantee a broad route of the displacement of crude oil under more homogeneous conditions and cooler relative temperatures. If the invention proposes to extend the path of the combustion front by means of a change in the arrangement of horizontal or vertical production wells, without this implying sacrificing large areas of the reservoir, as is usually the case with state-of-the-art technologies.

Another objective of the invention is to provide multiple shunts for the same horizontal production well, in order to improve the recovery of crude oil. These multiple admission referrals define a well multilaterality. Also the vertical injector could have multiple outlet leads. Another additional objective of the invention would be to have a multi-well arrangement where the horizontal portion of each horizontal production well would be located radially and projected out of the area with respect to the vertical injector well, and as the area where the Ia starts combustion which is consistent with the main objective of the invention set forth above.

Another objective of the present invention would be to install a series of control sensors both at the surface and at the bottom of the wells, in order to control the combustion front in real time and at a distance. The concept has been called Operations Synchronization. DESCRIPTION OF THE FIGURES.

Figure 1 shows a typical schematic cross-sectional view of a configuration of injector well and horizontal producing well according to the state of the art.

Figure 2 shows a schematic cross-sectional view of a configuration of injector well and horizontal producer well according to the invention.

Figure 3 reveals a representation of an injector well and horizontal producing well that has multiple intake leads.

Figure 4 represents an injector well that has multiple outlet leads and a simple horizontal well according to the invention.

Figure 5 shows an injector well which has multiple outlet leads and a horizontal producing well that has multiple intake leads.

Figure 6 reveals a scheme of the multi-well configuration proposed by the present invention.

GENERAL DESCRIPTION OF THE INVENTION

The method of the invention comprises as a first step providing at least one injector well (1) through which the necessary means are injected to initiate and / or maintain the combustion reaction within the reservoir (100). Said injector well (1) comprises a pipe assembly necessary and adapted to fulfill its task of serving as an injector well in the process of the invention. As a second, it comprises providing at least one production well that comprises a substantially horizontal portion (6), and which has a suitable set of pipes to fulfill its function of extracting the hydrocarbon that enters into said production well (2). ) through the substantially horizontal portion (6). Said substantially horizontal portion (6) comprises a first end (7), and a second end (8). The end (8) determines a change of direction in the orientation of the well towards the vertical portion (5) thereof, the horizontal portion (6) being the production well of the invention positioned so that the end (8) is in a relative position closer to the injector well (1) than the end (7).

The next step in the process is to start the combustion reaction inside the reservoir by injecting oxidizing gas through the set of pipes present inside the injection well (1).

The next step in the process is to extract from the inside of the reservoir, through the assembly of pipes inside the production well (2), the hydrocarbon that enters the horizontal portion (6).

PREFERRED CONFIGURATION OF THE INVENTION

Figure 1 shows a basic configuration present in the state of the art. In said figure a vertical injector well (1) can be seen, which comprises two ends. A first end (3) of oxidation gas inlet (9) and a second end (4) where the oxidation gas enters

(9) inside the reservoir (1) 00. A horizontal production well (2), comprises a substantially horizontal portion (6). The substantially horizontal portion (6) comprises one end (7) commonly called "toe", and another end (8) which is called "heel" and which determines a change of direction in the orientation of the well towards the portion vertical of! same (5). In the reservoir there are clearly three areas adjacent to each other. The first zone A which is where the combustion begins (ignition zone) and is located near the injector well; The next one in a zone B where coke is formed and, finally, zone C Ia which is an area where the hydrocarbon is being displaced by the combustion front. Under this principle the hydrocarbon that is to be extracted is driven to enter the horizontal portion (6), by gravity and by pressure differences. The recovered oil leaves the reservoir through the horizontal producing well (2) through the end of the vertical portion (5).

From Figure 2 a configuration is observed to carry out the process of the invention. Said process comprises as a first step providing at least one injector well (1) through which the necessary means are injected to initiate and / or maintain the combustion reaction within the reservoir (100). Said injector well (1) comprises a pipe assembly necessary and adapted to fulfill its task of serving as an injector well in the process of the invention. The injector well (1) comprises a body and two ends. The first end (3) where the injection is initiated into the reservoir of the means required to carry out the combustion reaction. Among the means that can be injected into the reservoir (100) from the end (3) is an oxidizing gas. Among the gases that serve as oxidizing agents are; air, air enriched with oxygen, oxygen, or other oxidizing agent suitable for combustion. Among other means that can be injected into the reservoir with the oxidation gas, through the injector well (1), either simultaneously or sequentially, are agents that assist in combustion such as; carbon dioxide, hydrogen donor agents, water vapor, water, aqueous solutions containing chemical compounds and / or mixtures thereof. The injection of hydrogen donating agents is carried out in the cases in which it is desired to make, in addition to the extraction process, an improvement of the hydrocarbon directly into the reservoir, in order to increase the API grade thereof. The injection of agents that assist in combustion is carried out in cases where it is required to increase the speed of the combustion reaction at the points where the oxygen flow is low. In the event that water, water vapor or aqueous solutions containing chemical compounds are injected, it can be injected through the same injector well (1), or through a different injector well provided for that purpose. In the case of water vapor, it can be injected into the hydrocarbon reservoir together with the oxidizing gas, before the injection thereof, or afterwards to sweep the oil not displaced by the combustion front, depending on the characteristics of the hydrocarbon, of the petrophysical properties of the rock, and of the extension of the combustion operation.

The injector well (1) has a second lower end (4) which is inside the hydrocarbon reservoir (100). At the lower end (4) is where, generally, gases and / or liquid fluids that are injected into the reservoir leave. However, the injector well (1) can present, along or in part of the section submerged in the reservoir (100), a plurality of openings through which gases and / or liquid fluids enter into the reservoir . The plurality of openings may be in a relatively high position with respect to the lower end (4), or relatively low, very close or around said lower end (4). Likewise, it is contemplated in the invention the possibility of having at least 2 pluralities of openings on the section submerged in the reservoir of the injector well (1), preferably, a relatively high one, close to the roof of the reservoir, and another, relatively low, very close to said lower end (4). The choice of the position of the openings is chosen according to the geological conditions of the reservoir, and the flow through them can be controlled, during the process, to optimize the conditions of the combustion reaction, and consequently, the yield of reservoir production (amount of hydrocarbon displaced). The openings extend along the section submerged in the reservoir of the injector well (1), being able to occupy 100% of the length thereof, preferably between 10% and 60% of the length, more preferably, between 10% and 35% of the length.

In Figure 2 the presence of a horizontal production Well (2) can be observed. The process of the invention contemplates as a second step to provide at least one production well that comprises a substantially horizontal portion (6), and which presents a suitable set of pipes to fulfill its function of extracting the hydrocarbon that enters into the interior of said production well (2) through the substantially horizontal portion (6). Said substantially horizontal portion (6) comprises a first end (7), and a second end (8). The end (8) determines a change of direction in the orientation of the well towards the vertical portion (5) thereof. In Figure (2) it can be seen that, unlike the prior art (Figure 1), the horizontal portion (6) the production well of the invention is positioned so that the end (8) is in a relative position closer to the injector well (1), than the end (7). Due to this configuration, the hydrocarbon front displaced in its trajectory will first meet the end (8). The horizontal portion (6) can have at least a plurality of openings that can extend along the horizontal portion (6), preferably, being in a position close to the end (7). The plurality of openings can be extended along the horizontal portion (6) occupying 100% of the length thereof, preferably between 10% and 60% of the length, more preferably, between 10% and 35% of The length. The relative position of the horizontal portion (6) of the production well with respect to the end (4) of the injector well (1) can be relatively high, coplanar, or relatively low, depending on the geological conditions of the reservoir and the characteristics of the reservoir. hydrocarbon to be extracted. The present invention contemplates that the horizontal portion (6) of the production well (2) is horizontal, preferably substantially horizontal, although optionally it could be arranged at an angle with respect to the horizontal plane. Similarly, the same producing well (2) can comprise more than one horizontal portion (6), as described above, they may or may not be at the same relative height inside the well. The present invention also contemplates that the injector well (1) has a horizontal or substantially horizontal portion. Similarly, the same injector well (1) may comprise more than one horizontal portion, as described above, and they may or may not be at the same relative height within the well. If the injector well (1) has horizontal portions, they would comply with the fact that the end thereof would be the mentioned end (4), and the plurality of openings could be extended, occupying 100% of the length of the same, preferably between 10% and 60% of the length, more preferably, between 10% and 35% of the length.

The next step in the process is to start the combustion reaction inside the reservoir by injecting oxidizing gas through the set of pipes present inside the injection well (1). The initiation means of the combustion reaction can be varied, preferably, the reaction is initiated by means of prior steam injection, or heating by a natural gas heater, or electricity. The ignition of the mixture of gas and oxidant is created by an appropriate chemistry. For reference !, Figure 2 shows a situation of advance of the combustion front. Due to the particular configuration of the horizontal portion (6) of the production well of the invention, the combustion front, regardless of the way in which it moves, will first meet the end (8) of the horizontal portion (6) and, subsequently, with the end (7) of said horizontal portion (6). Within the reservoir (100) there are clearly three zones adjacent to each other, zone A which is where combustion begins (ignition zone), zone B where coke is formed, and finally, zone C which is an area where the hydrocarbon that is being displaced is located and that, finally by gravity and / or by pressure difference, will enter the interior of the horizontal portion (6) through the plurality of openings present in said horizontal portion (6) . The next step in the process is to extract from the inside of the reservoir, through the assembly of pipes inside the production well (2), the hydrocarbon that enters the horizontal portion (6). The hydrocarbon extraction is carried out by standard extraction techniques that are not shown in the figures to facilitate the understanding of the essential aspects of the invention. Note, that the first relevant difference between the invention and the state of the art, derives from the orientation of the production well (2) since, the direction in which the horizontal portion (6) extends, is the same in which the combustion front propagates, and preferably oriented in the opposite direction to the injection well (1). This is contrary to what happens in the state of the art where the portion (6) (figure 1) where it extends in the opposite direction to the direction in which the combustion front is propagated and oriented towards the injection well. Looking at figures 3, 4, and 5, it can be seen that alternatively, combinations of injector-producer wells can be available, where one could have a vertical injector (1) without leads and a horizontal well (2) with leads or multiple lateral projections (11) and (12) (figure 3). Another possible alternative within the context of the invention contemplates an injector well (1) with lateral leads (13) and (14), combined with a horizontal well (2) without leads (Figure 4). Additionally, the use of an injector well (1) with multiple lateral leads (13) and (14) with a horizontal producing well (2) is provided, which in turn is also provided with multiple lateral leads (11) and (12) (figure 5). The derivations are not limited in any case to those suggested from the figures, being able to be greater in number and in different arrangement or relative height above the reservoir; The configuration of the leads can be horizontal, inclined. The number and arrangement of the derivations is variable and dependent on the geology of the reservoir and the conditions of exploitation. Multilateralism, or in other words, having multiple lateral shunts has the purpose of improving the supply of oxidizing agent or improving the uptake of displaced hydrocarbon, by having a greater relative area of admission in the derivations provided for this purpose of the horizontal well. Regardless of the type and number of leads that could be found on the injector well (1) and / or on the horizontal producing well (2), the process of the invention will always be carried out observing the relevant difference with respect to the state of the Technique: The orientation of the horizontal portion (6) of the production well (2) is in the opposite direction or opposite to the injection well (1). In addition to what has been described so far with respect to the injector (1) and producer (2) well, it is contemplated, when the multilaterality described in this paragraph is presented, that said wells will preferably be of short or medium length, in order to optimize The distribution of media injected into the reservoir, the extraction of hydrocarbon and the control of the combustion front.

Additionally, the invention contemplates a scheme of arrangement of several wells such as that proposed from Figure 6. In said figure a general arrangement of multiple producing wells (2) according to the technique described in any of the previous figures is observed. The invention is capable of being carried out under any arrangement of wells, linear, with distribution around an injector well, or without a defined arrangement, being able to have a certain amount of wells and injectors and which in practice, will be conditioned by the conditions of the reservoir.

The invention contemplates being able to have multiple variable sensors arranged along part of the horizontal portion (6) of the horizontal production well (2) in order to monitor and control the combustion front. On the other hand, the present invention can contemplate installing a series of control sensors both at the surface and at the bottom of the wells, in order to control the combustion front in real time and at a distance. The description presents the invention in a referential manner by which, it contemplates and must be broadly understood by someone with knowledge of the art and techniques related thereto. Similarly, the drawings are referential representations to facilitate the visualization of the principles and contributions to the state of the art and, in this sense, should be interpreted in a broad and non-restrictive manner.

Claims

1. Procedure for the extraction of hydrocarbon from an underground reservoir comprising,

- providing at least one injector well (1) comprising a pipe assembly adapted to inject the necessary means to initiate and / or maintain the combustion reaction inside the reservoir (100);

- providing at least one production well that comprises a substantially horizontal portion (6), and which has a suitable set of pipes to fulfill its function of extracting the hydrocarbon that enters inside said production well (2) a through the substantially horizontal portion (6), wherein said substantially horizontal portion (6) comprises a first end (7), and a second end (8), the horizontal portion being

(6) the production well (2) positioned so that the end (8) is in a relative position closer to the injector well (1) than the end (7);

- Starting the combustion reaction inside the reservoir by injecting oxidizing gas through the set of pipes present inside the injection well (1) that generates a combustion front that in its path, will first meet the end (8) of The horizontal portion (6) and, subsequently, with the end (7);

- extract from the inside of the reservoir, through the assembly of pipes inside the production well (2), the hydrocarbon that enters the horizontal portion (6).

2. Method according to claim 1, wherein the injector well (1) presents, along or in part of the section submerged in the reservoir (100), a plurality of openings through which the gases enter and / or liquid fluids inside the reservoir.

3. Method according to any one of the preceding claims, wherein the injector well (1) has at least 2 pluralities of openings on the section submerged in the reservoir, preferably a relatively high one, close to the roof of the reservoir, and another, relatively low, very close to the lower end.

4. Method according to claim (3), wherein the openings extend along the section submerged in the reservoir of the injector well (1), being able to occupy 100% of the length thereof, preferably between 10 % and 60% of the length, more preferably, between 10% and 35% of the length.

5. Method according to any one of the preceding claims, wherein between the means initiating and / or maintaining the combustion reaction are air, oxygen enriched air, oxygen, or other oxidizing agent suitable for combustion and / or mixtures thereof.

6. Method according to claim (5), wherein among other means that can be injected into the reservoir with the oxidation gas, either simultaneously or sequentially, are agents that assist in combustion such as; carbon dioxide, hydrogen donor agents, water vapor, water, aqueous solutions containing chemical compounds and / or mixtures thereof.

7. Method according to any one of the preceding claims, wherein the horizontal portion (6) can have at least a plurality of openings that can extend along the horizontal portion (6), preferably, being in a position close to the end (7).

8. Method according to claim (5), wherein the plurality of openings can be extended along the horizontal portion (6) occupying the 100% of the length thereof, preferably between 10% and 60% of the length, more preferably, between 10% and 35% of the length.

9. Procedure for the extraction of hydrocarbon from an underground reservoir comprising,

- providing at least one injector well (1) comprising a pipe assembly adapted to inject the necessary means to initiate and / or maintain the combustion reaction inside the reservoir (100) and comprising multiple lateral shunts;

- providing at least one production well that comprises a substantially horizontal portion (6), and which has a suitable set of pipes to fulfill its function of extracting the hydrocarbon that enters inside said production well (2) a through the substantially horizontal portion (6), wherein said substantially horizontal portion (6) comprises a first end (7), and a second end (8), the horizontal portion (6) being the production well (2) placed so that the end (8) is in a relative position closer to the injector well (1) than the end (7), where said production well (2). It comprises multiple lateral leads;

10. Method according to claim 10, wherein the injector well (1) presents, along or in part of the section submerged in the reservoir (100), a plurality of openings through which gases and / or media enter into the reservoir.

11. Method according to any one of claims 9 or 10, wherein the injector well (1) has at least 2 pluralities of openings on the section submerged in the reservoir, preferably a relatively high one, close to the roof of the reservoir, and another, relatively low, very close to the lower end.

12. Method according to claim 11, wherein the openings extend along the section submerged in the reservoir of the injector well (1), being able to occupy 100% of the length thereof, preferably between 10% and 60% of the length, more preferably, between 10% and 35% of the length.

13. Method according to any one of claims 9 to

12, where among the means to initiate and / or maintain the combustion reaction are air, oxygen enriched air, oxygen, or other oxidizing agent suitable for combustion and / or mixtures thereof.

14. Method according to any one of claims 13, wherein among other means that can be injected into the reservoir with the oxidation gas, either simultaneously or sequentially, are agents that assist in combustion such as; carbon dioxide, hydrogen donor agents, water vapor, water, aqueous solutions containing chemical compounds and / or mixtures thereof.

15. A method according to any one of claims 9 to 14, wherein the horizontal portion (6) can have at least a plurality of openings that can extend along the horizontal portion (6), preferably, being in a position near the end (7).

16. Method according to claim 15, wherein the plurality of openings can be extended along the horizontal portion (6) occupying 100% of the length thereof, preferably between 10% and 60% of the length , more preferably, between 10% and 35% of the length.

17. Method according to any one of the preceding claims, wherein the use of multiple variable sensors arranged along part of the horizontal portion (6) of the horizontal production well (2) is contemplated in order to monitor and control the combustion front.

18. Method according to any one of the preceding claims, wherein it is contemplated to install a series of control sensors both at the surface and at the bottom of the wells, in order to control the combustion front in real time and at a distance.