Limited entry liner for hydrocarbon reservoir stimulation with deep penetration capabilities

Abstract

The present disclosure relates to an apparatus (100) for hydrocarbon reservoir stimulation, comprising: a limited entry liner, LEE (110), comprising a plurality of stimulation ports, and configured to be inserted into a wellbore accessing a part of the hydrocarbon reservoir (102); and a plurality of stimulation needles (115) arranged inside the LEE (110) and configured to extend away from the LEE (110) to penetrate the hydrocarbon reservoir (102) in response to a stimulation fluid being pumped into the LEE (110).

Description

 December 27, 2023Abu Dhabi National Oil CompanyA170652WO MAJ / Bmn  Limited entry liner for hydrocarbon reservoir stimulation with deep penetration capabilities Technical field [1] The present invention relates to an apparatus, a system, and a method for stimulating a hydrocarbon reservoir with deep formation penetration capabilities. Technical background[2] Fossil fuels like hydrocarbons (e.g., crude oil, natural gas, etc.) or hydrogen gas (H2) are typically extracted from a hydrocarbon reservoir, i.e., a geologic formation that contains such hydrocarbons and / or their precursor materials (e.g. kerogen, bitumen, tar mats, liquid crude oil, etc.) via wells drilled into the hydrocarbon reservoir. It is known in the field that various well stimulation techniques (e.g., acid treatments / well acidizing, hydraulic fracturing, etc.) can be used to improve and / or recover well productivity. [3] For example, know acidizing techniques may involve pumping acid into a wellbore or a geologic formation that is capable of producing oil and / or gas. The purpose of any acidizing is to improve a well’s productivity or injectivity. Typically, there are three general categories of acid treatments: acid washing, matrix acidizing, and fracture acidizing. Typically, acid washing may be used for tubular and wellbore cleaning. Acid washing is most commonly performed with hydrochloric acid (HCl) mixtures to clean out scale (such as calcium carbonate), rust, and other debris restricting flow in the well. Matrix and fracture acidizing are both formation treatments. In matrix acidizing, the acid treatment typically is injected below the formation fracturing pressure. In fracture acidizing, acid is pumped above the formation fracturing pressure. The purpose of matrix or fracture acidizing is to restore or improve an oil and / or gas well’s productivity by dissolving material in the productive formation that is restricting flow, or to dissolve formation rock itself to enhance existing, or to create new flow paths to the wellbore. Two key factors dominate the treatment selection and design process when planning an acid job: (i) formation type – e.g., carbonate, sandstone, or shale, and (ii) formation permeability – the ability of fluid to flow through the formation in its natural state. Formation type determines the type(s) of acid necessary and formation permeability determines the pressure required for pumping the acid into the formation. [4] A common stimulation method for carbonate reservoirs is acid stimulation whereby the selected acid is allowed to chemically react with the reservoir rock, which leads to dissolution and enhanced productivity. For wells completed open-hole, a complicating factor is the acid placement, i.e. the ability to distribute acid across the entire reservoir section. Bull-heading acid from the surface typically results in a mediocre stimulation treatment because the majority of the acid is spent reacting at the heel of the well. A known solution to the acid placement challenge is addressed by the limited-entry liner (LEL) technique, also denoted as controlled-acid jetting. The key concept is to distribute small holes of varying sizes and frequency in the liner. These holes act as flow restrictions, which leads to mechanical diversion of flow along the liner. An appropriate hole size distribution design is capable of ensuring that the entire reservoir section is treated with acid.  [5] In this context, Applicant’s own EP 3 922 811 A1 (incorporated herein in it’s entirety) relates to a method for stimulation of a well in a material formation which includes a workflow for the design of optimum hole-size distribution in the liner of a LEL liner system is modelled, wherein a solution strategy for providing an initial estimate of the number of holes per segment honours the acid coverage per segment and the drop in pressure across the last hole, where the initial estimate can be found from the relationship between interstitial velocity, pump rate, and total cross-sectional hole area for a particular discharge coefficient and liner configuration.  [6] Further, horizontal well application is one of the key development strategies that can improve the sweep efficiency and hydrocarbon recovery while minimizing field development cost by reducing well counts. Long horizontal or highly deviated wells require lower completion liners to improve well productivity for carbonate reservoirs. Optimum well productivity requires effective stimulation, either hydraulic fracturing or matrix-acid stimulation. Traditionally, a complicating factor in matrix-acid stimulation treatments has been the poor control of the acid placement along the reservoir section.  [7] Bull-heading of acid into an open hole creates a uniform dissolution of reservoir rock at the heel while leaving the rest of the wellbore largely unstimulated. Coiled tubing stimulation imposes a significant limitation on the maximum pumping rate and thereby limits the ability of the acid to penetrate the formation. Use of chemical diverters is common practice but cannot ensure diversion along extended-reach laterals. The limited-entry liner (LEL) lower completion addresses the shortcomings of the previously mentioned stimulation techniques. It consists of a number of unevenly spaced holes with the purpose to distribute fluid, in this case acid, evenly along the reservoir section to be stimulated. Figure 1 shows a schematic of the concept. Without the need of a coiled tubing, acid is bull-headed from surface through the production tubing and enters the liner from the left. The liner does not have to be horizontal but very often is. When acid reaches the first hole, which typically has a size of 3 mm to 6 mm, the pressure drop across the hole is so large that only a small portion of the acid exits the liner through the hole; the remaining acid continues along the liner until it reaches the next hole where the same process is repeated. An appropriate hole-size design makes it possible to ensure that acid is distributed with a user-specified acid coverage, defined as barrels of acid per feet of reservoir section. It is often advantageous to segment the wellbore with open-hole swellable packers to isolate sections with different reservoir pressure and / or permeability and the LEL design can accommodate that. [8] Specifically, as discussed in detail in EP 3 922 811 A1, Fig. 1 shows a schematic cross-sectional view of a well-bore 12. The well-bore 12 includes a wall 14 created by the drilling process, a leading end 16, which extends into the formation 18, and a trailing end 20 for accessing the well-bore. An LEL 20 is introduced into the well-bore 12. The LEL 20 has an open end 22 and opposed sealed end 24. An annulus 22 is formed between the wall 14 and outer surface 26 of the LEL and the LEL 20 is provided with a number of pre-formed holes 28 (also designate as injection ports or stimulation ports herein) that form flow passages between the interior of the LEL 20 and the annular space 22. The holes 28 have a shape and location that comply with particular, pre-defined specifications. Typically, the distances between adjacent holes 28 along the LEL 20 decrease towards the end 24 of the LEL 20. Typically, acid is pumped into the LEL 20 and exits holes 28 at high velocities resulting in jetting into the formation 18.  [9] By limiting the number and size of holes, a choke effect is obtained and a significant pressure drop occurs between the inside and the outside of the LEL 20 during stimulation. A non-uniform geometric distribution of the holes may be used to compensate for the friction pressure drop along the LEL section. The open annulus 22 outside the LEL in combination with the overpressure on the inside of the LEL ensures that the acid eventually reaches the bottom of liner, and the well is thus stimulated along its full length. As mentioned above, typically, acid is bull-headed from the surface and enters the LEL 20 in the direction of arrows 30. The liner does not have to be horizontal but very often is. When acid reaches the first hole 28, which typically has a size of 4mm to 7 mm, the pressure drop across the hole is so high that only a small portion of the acid exits the LEL 20 through the hole. The remaining portion continues along the LEL until it reaches the next hole where the same process is repeated.  

[10] A further approach to reservoir stimulation is the so-called Fishbone Stimulation Technology (e.g., described in WO 2022 / 255883 A1, and US 10,174,557) which essentially is an uncemented liner rig deployed completion stimulation system. The liner includes fishbone subsections at fixed intervals and each subsection typically comprises four needles that will facilitate to connect reservoir sublayers by penetrating into the geologic formation. Further prior art discussing the general background of the present disclosure is provided by US 2023 / 0228188, US 2023 / 0160292, US 2022 / 0412198, US 2023 / 0296008, US 11,591,871, US 11,719,074, US 11,149,499, US 11,346,181, US 11,499,423.  Summary

[11] While limited entry liner technology and Fishbone stimulation technologies are both under implementation, currently, these technologies can merely be implemented separately at differently wells respectively and cannot be implemented both at the same well during the well operation period. For instance, conventionally, only one of both technologies can be used for each well and it is typically not possible to apply them together or at the same well. Aspects of the present disclosure relate to ways how to efficiently and effectively combine both technologies into combined stimulation apparatuses and systems to further enhance well productivity and / or injectivity.  

[12] Specifically, aspects of the present disclosure relate to an apparatus for hydrocarbon reservoir stimulation, comprising a limited entry liner, LEL, comprising a plurality of stimulation ports, and configured to be inserted into a wellbore accessing a part of the hydrocarbon reservoir; and a plurality of stimulation needles arranged inside the LEL and configured to extend away from the LEL to penetrate into the hydrocarbon reservoir in response to a stimulation fluid being pumped into the LEL.For instance, the LEL may comprise a plurality of interconnected segments (also called LEL subs herein), wherein a first segment comprises a portion of the plurality of stimulation ports, and a second segment comprises a portion of the stimulation needles, and, optionally, a further portion of the plurality of stimulation ports. For instance, the stimulation needles may be Fishbone stimulation needles as discussed above. In this manner, the advantages of LEL-technology and of Fishbone stimulation technology may be combined into a single stimulation apparatus such that each well may be stimulated using both stimulation technologies. 

[13] In some implementations, such stimulation apparatus may further comprise a plurality of removable knock-off pins arranged inside the LEL and sealing a portion or all of the plurality of stimulation ports in an initial configuration of the LEL. The apparatus may further comprise a cutting tool arranged inside the LEL and configured to be retracted from the LEL after the stimulation needles are extended from the LEL inside the reservoir, wherein the cutting tool may be configured to remove non-extended portions of the stimulation needles and / or knock-off pins when being retracted from the LEL. Additionally or alternatively, a portion of the knock-off pins may be formed from a dissolvable material, e.g., a material that dissolves during an initial acid treatment injected into the LEL. In this manner it can be ensured that a pressure drop caused by the stimulation ports of the LEL is reduced during initial stimulation which causes extension of the stimulation needles thereby increasing penetration depth into the reservoir. 

[14] Further, in some implementations, the LEL may comprises a plurality of essentially identical segments, each comprising a portion of the plurality of injection ports and exit holes for a portion of the injection needles. In some aspects, some of the segments, preferably every second segment, may not comprise injection needles. Further, the exit holes of such segments that do not comprise injection needles may also be sealed by knock-off pins in the initial configuration of the LEL. Further, in some aspects, the stimulation ports may be arranged essentially perpendicular to a longitudinal direction of the wellbore, and / or the exit holes may be arranged at an angle in a forward pointing direction with respect to the longitudinal direction of the wellbore. In this manner, LEL stimulation and needle penetration may be enhanced simultaneously. 

[15] Further, in some aspects, e.g., to further improve LEL-stimulation, the plurality of injection ports may comprises two or more types of injections ports having a different effective diameter. For example, injection ports may comprise customized sizes, e.g. with an effective diameter of 2, 3, or 4 mm with suitable knock-off pins covering the ports in the initial configuration. Further, e.g., to enhance reservoir penetration, the injection needles may comprise or be connected to a tube configured for a reservoir penetration depth of >4 meters, preferably of > 10 meters, and more preferably of > 15 meters. 

[16] Aspects of the present disclosure also relate to a system for hydrocarbon reservoir stimulation comprising a high-pressure stimulation fluid pump, and an apparatus as described above that is connected to the high-pressure stimulation fluid pump. 

[17] Aspects of the of the present disclosure also relate to a method for stimulating a hydrocarbon reservoir, comprising injecting a stimulation fluid into the hydrocarbon reservoir using an apparatus and / or system as described above. Further aspects of the present disclosure and some related benefits are described in the following with reference to the appended drawings. Brief description of the drawings 

[18] Fig. 1 is a schematic illustration showing an LEL as described in EP 3 922 811 A1 paced inside a hydrocarbon wellbore; 

[19] Fig. 2 is a schematic illustration showing an apparatus for hydrocarbon reservoir stimulation according to the present disclosure inside a wellbore with extended stimulation needles; 

[20] Fig. 3 is a schematic illustration showing a portion of an apparatus for hydrocarbon reservoir stimulation according to the present disclosure with non-extended stimulation needles in an initial configuration; 

[21] Fig. 4 is a schematic illustration showing an apparatus for hydrocarbon reservoir stimulation according to the present disclosure inside a wellbore with extended stimulation needles; 

[22] Fig. 5 is a schematic illustration showing an apparatus for hydrocarbon reservoir stimulation according to the present disclosure; 

[23] Fig. 6 is a schematic illustration showing a cut through a segment of an apparatus for hydrocarbon reservoir stimulation according to the present disclosure; 

[24] Fig. 7 is a schematic illustration showing a cut through a segment of an apparatus for hydrocarbon reservoir stimulation according to the present disclosure before and after removal of knock-off pins; 

[25] Fig. 8 is a schematic process flow diagram of a method for hydrocarbon reservoir stimulation according to the present disclosure; 

[26] Fig. 9 is a schematic illustration of a system for hydrocarbon reservoir stimulation according to the present disclosure. Detailed description of illustrative examples 

[27] In the following, some exemplary embodiments of the present disclosure described in more detail, with reference to exemplary hydrocarbon stimulation apparatuses, systems and methods. While specific feature combinations are described in the following paragraphs with respect to the exemplary embodiments of the present disclosure, it is to be understood that not all features of the discussed embodiments have to be present for realizing the disclosure, which is defined by the subject matter of the claims. The disclosed embodiments may be modified by combining certain features of one embodiment with one or more technically and functionally compatible features of other embodiments. Specifically, the skilled person will understand that features, components, processing steps and / or functional elements of one embodiment can be combined with technically compatible features, processing steps, components and / or functional elements of any other embodiment of the present disclosure as long as covered by the subject matter as specified by the appended claims. 

[28] Fig. 2 is a schematic illustration showing an apparatus 100 for reservoir stimulation according to the present disclosure. The apparatus 100 is placed inside a wellbore and comprises a limited entry liner, LEL, 110 comprising a plurality of stimulation ports, and configured to be inserted into the wellbore accessing a part of a hydrocarbon reservoir 102. The apparatus 100 further comprises a plurality of stimulation needles 115 which (initially) are arranged inside the LEL 110 and which are configured to extend away from the LEL 110 to penetrate the hydrocarbon reservoir 102 in response to a stimulation fluid being pumped into the LEL 110. Fig. 2 shows the apparatus 100 after the stimulation fluid has already been pumped into the LEL 110 such that stimulation needles 115 have already penetrated into the hydrocarbon reservoir 102. The dashed curve 120 illustrates a typical stimulation volume accessible via the stimulation ports of the LEL 110. The extended stimulation needles substantially increase the volume that can be stimulated. This technology typically yields one or more of the following advantages:Connection of multi-layered reservoirs with poor vertical permeability. Typically, the needles 115 can penetrate into the formation up to 40 ft and thereby can establish a connection to layers located around the wellbore.Significantly larger reservoir exposure and reduced drawdown: While the increased connection length is a direct contributor to the reduced draw down, the laterals also create access to higher reservoir pressures in previously isolated layers.Connections to naturally producing fractures: the needles 115 serve as part of penetration process, and they can intersect with the present fractures at multiple points allowing production from much deeper points in the reservoir natural fracture network,Bypass near wellbore damage: the laterals created by the needles 115 allow a flow pathway to bypass any skin and effectively eliminate any contribution of the near wellbore damage to choking the flow during hydrocarbon extraction and / or injection of fluids, e.g., of a reservoir stimulation acid.Improved conformance: The needles 115 mechanically improves the conformance by spacing the laterals along the entire wellbore, helping to improve conformance along the horizontal section.Reduced risk: Compared to hydraulic fracturing, where control on fractures is limited and chances of percolating the fracture to water and gas bearing zone exists. 

[29] In some implementations the LEL 110 may comprise a plurality of interconnected segments, wherein a first segment comprises a portion of the plurality of stimulation ports, and a second segment comprises a portion of the stimulation needles, and optionally, a further portion of the plurality of stimulation ports. For instance, Fig. 3 is a schematic illustration showing a portion of a segmented apparatus for reservoir stimulation according to the present disclosure in an initial configuration with non-extended stimulation needles 115. For example, a first type of segment / LEL sub 210 may comprise stimulation ports 215 that may also be used for hydrocarbon extraction. In the illustrated example, the first type of segment 210 does not comprise any stimulation needles. A second type of segment 220 comprises a portion of the stimulation needles 115 which initially are arranged on the inside of the second type of segment 220. The needles 115 are arranged such that they can exit the second type of segment 220 via exit holes 224 to penetrate into the reservoir formation (cf. Fig. 2). 

[30] In some implementations, the apparatus disclosed herein may comprise a plurality of removable knock-off pins arranged inside the LEL, and sealing a portion of the plurality of stimulation ports in an initial configuration, e.g., prior to pumping the stimulation fluid into the LEL. 

[31] The apparatus disclosed herein may also comprise: a cutting tool (not shown) arranged inside the LEL and configured to be retracted from the LEL after the stimulation needles are extended from the LEL, wherein the cutting tool may be configured to remove non-extended portions of the stimulation needles and / or a portion of the knock-off pins when being retracted from the LEL 110. In some implementations, the LEL 110 may comprises a plurality of essentially identical segments, each comprising a portion of the plurality of injection ports 215 as well as exit holes 224 for a portion of the injection needles 115. For example, some of the segments, preferably every second segment, may not comprise injection needles 115, and, optionally, the exit holes 224 of such segments that do not comprise injection needles 115 may also be sealed by knock-off pins in the initial configuration of the LEL 110. Additionally or alternatively, a portion of the knock-off pins may be formed from a dissolvable material, e.g., a material that dissolves during an initial acid treatment injected into the LEL. In this manner it can be ensured that a pressure drop caused by the stimulation ports of the LEL is reduced during initial stimulation which causes extension of the stimulation needles thereby increasing penetration depth into the reservoir. 

[32] As illustrated in Fig. 3 some of the stimulation ports 215 may be arranged essentially perpendicular to a longitudinal direction of the wellbore. Alternatively or additionally the exit holes 224 may be arranged at an angle in a forward pointing direction with respect to the longitudinal direction of the wellbore, e.g., to facilitate reservoir formation penetration. In some implementations, the plurality of injection ports 215 may comprise two or more types of injections ports having a different effective diameter. Further, each injection needle 115 may be connected to or comprise a flexible tube configured for a reservoir penetration depth of >4 meters, preferably of > 10 meters, and more preferably of > 15 meters. 

[33] As shown in Fig. 4, the apparatus disclosed herein allows to stimulate the hydrogen reservoir in a first volume within a distance of approximately 10 ft (~10 m) surrounding the LEL, and in a second volume within a distance of approximately 80 ft (~24 m) via the stimulation needles 115. Thus, the apparatus disclosed herein allows to combine LEL stimulation with Fishbone stimulation to improve reservoir stimulation as well as hydrocarbon extraction performance. Since Fishbone stimulation aims at connecting sublayers within the reservoir to maximize the productivity and LEL stimulates the reservoir as per the design at intended sections for deep worm holing to improve the productivity. Combing both technologies enhance the stimulation both deep into reservoir as well as large worm holing from the wellbore. The present disclosure allows to apply both stimulation techniques sequentially or simultaneously within the same wellbore for maximizing the reservoir contact area and improve vertical communication for enhancing the productivity and / or injectivity of the well. 

[34] Fig. 5 shows a further exemplary stimulation apparatus design with 40 LEL subs 510, 7 anchors 515 and a shoe 520. In this example, each LEL sub 510 includes 4 stimulation needles (40 ft. each), 2 production ports (7 mm), as well as 2 two-way ports (7 mm). As part of the implementation after the liner run in hole an acid job can be conducted to penetrate the stimulation needles into the formation while the production and injection port will be covered with knock-off pins to keep the LEL as a closed system to allow the acid jetting to happen through needles at each sub. Subsequently left out needles will be removed by running a cutting tool, e.g., a fish basket along with removing knock-off pins at injection and production ports. 

[35] LEL installation may include an RIH liner with pre-drilled holes at each segment based on design requirements. An acid job can be conducted post rig release at high volumes to achieve a desired velocity across the holes for creating worm holing deep into the formation up to 5 to 6 ft. In some implementations, production and injection ports can be customized with sizes from 2 mm to 8 mm with knock-off pins covering the ports while RIH and place them according to LEL design. This customization of port sizes and fishbone subs will allow first to complete Fishbone liner RIH and acid job to penetrate the needles inside the formation. After properly removing the knock-off pins during the cleaning of the liner with the cutting tool, (e.g., a fish basket run) allows the LEL stimulation post rig release. The present disclosure thus provides the combined advantage to place the fishbone needles deep inside the reservoir to connect the sublayers, whereas limited entry liner stimulation for deep penetration from the wellbore. 

[36] Fig. 6 is a schematic illustration showing a cut through a segment 210 of an apparatus for reservoir stimulation according to the present disclosure. The segment 210 comprises stimulation ports 215 pointing radially outwards and exit holes 224 for the stimulation needles pointing at an angle into the forward direction. As shown in Fig. 7 the stimulation ports 215 and, optionally, exit holes 224 that are not used for stimulation needles can be sealed via knock-off pins 710 in an initial configuration of the LEL. After the stimulation fluid is pumped into the LEL to extend the needles into the reservoir, the knock-off pins can be removed to start LEL stimulation via the stimulation ports 215, and optionally, exit holes 224 that are not used for stimulation needles. 

[37] Fig. 8 is a schematic process flow diagram of a method for hydrocarbon reservoir stimulation according to the present disclosure. The method comprises a step 810 of inserting an apparatus for reservoir stimulation as disclosed herein into a wellbore, and a step 820 of injecting a stimulation fluid into the hydrocarbon reservoir using the inserted apparatus. In some implementations, injecting the stimulation fluid into the hydrocarbon reservoir comprises: injecting the stimulation fluid into the hydrocarbon reservoir using a subset of the plurality of stimulation needles; and injecting the stimulation fluid into the hydrocarbon reservoir using a subset of the plurality of stimulation ports. In some implementations, the method may further comprise one or more of: extending a subset of the plurality of stimulation needles via an initial stimulation run, cleaning a subset of the plurality of stimulation needles after the initial stimulation run, removing a plurality of knock-off pins after the initial stimulation run, and injecting the stimulation fluid into the hydrocarbon reservoir after removing the plurality of knock-off pins.  

[38] Fig. 9 shows a system for hydrocarbon reservoir stimulation comprising a high-pressure stimulation fluid pump 910; and an apparatus 920 for reservoir stimulation as disclosed herein that is operably connected to the high-pressure stimulation fluid pump 910. For instance, such a system may be used to execute a method for hydrocarbon reservoir stimulation as disclosed herein.  

[39] Generally, the apparatus, system and method disclosed herein allow for application of limited entry liner and fishbone stimulation simultaneously at same well without any additional CAPEX. This yields a double advantage with two techniques in a single application that aims at addressing near well bore productivity improvement and improving communication across the layers deep in the formation. The present disclosure therefore allows for a multifold advantage for longer term production sustainability. The smart liner techniques disclosed herein also provide a backup option in case of a decline in the productivity from fishbone stimulation application. In some cases, e.g. of long horizontal wells combining both technologies will allow to simulate the entire well bore and overcome the coverage of each technology in limited sections. 

[40] While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results.       

Claims

 1. An apparatus for hydrocarbon reservoir stimulation, comprising: a limited entry liner, LEL, comprising a plurality of stimulation ports, and configured to be inserted into a wellbore accessing a part of the hydrocarbon reservoir; and a plurality of stimulation needles arranged inside the LEL and configured to extend away from the LEL to penetrate the hydrocarbon reservoir in response to a stimulation fluid being pumped into the LEL.  2. The apparatus according to claim 1, wherein the LEL comprises a plurality of interconnected segments (LEL subs), wherein a first segment comprises a portion of the plurality of stimulation ports, and a second segment comprises a portion of the stimulation needles.  3. The apparatus according to claim 2, wherein the second segment comprises a further portion of the plurality of stimulation ports. 4. The apparatus of according to claim 1, further comprising a plurality of removable knock-off pins arranged inside the LEL and sealing a portion of the plurality of stimulation ports in an initial configuration of the LEL.  5. The apparatus according to claim 1, further comprising: a cutting tool arranged inside the LEL and configured to be retracted from the LEL after the stimulation needles are extended from the LEL, wherein the cutting tool is configured to remove non-extended portions of the stimulation needles or a portion of the knock-off pins when being retracted from the LEL.  6. The apparatus according to claim 1, wherein the LEL comprises a plurality of identical segments, each comprising a portion of the plurality of injection ports and exit holes for a portion of the injection needles.  7. The apparatus according to claim 6, wherein some of the segments do not comprise injection needles.  8. The apparatus according to claim 7, wherein every second segment does not comprise injection needles. 9. The apparatus according to claim 8, wherein the exit holes of such segments that do not comprise injection needles are sealed by knock-off pins in the initial configuration of the LEL. 10. The apparatus according to claim 1, wherein the stimulation ports are arranged perpendicular to a longitudinal direction of the wellbore; orwherein the exit holes are arranged at an angle in a forward pointing direction with respect to the longitudinal direction of the wellbore. 11. The apparatus according to claim 1, wherein the plurality of injection ports comprises several types of injections ports having a different effective diameter.  12. The apparatus according to claim 1, wherein each injection needle is connected to a flexible tube configured for a reservoir penetration depth of >4 meters.  13. The apparatus according to claim 1, wherein each injection needle is connected to a flexible tube configured for a reservoir penetration depth of > 10 meters. 14. The apparatus according to claim 1, wherein each injection needle is connected to a flexible tube configured for a reservoir penetration depth of > 15 meters. 15. A system for hydrocarbon reservoir stimulation comprising a high-pressure stimulation fluid pump; and the apparatus according to any one of claims 1 to 14 operably connected to the high-pressure stimulation fluid pump.   16. A method for stimulating a hydrocarbon reservoir, comprising: injecting a stimulation fluid into the hydrocarbon reservoir using the apparatus according to any one of claims 1 to 14.  17. The method according to claim 16, wherein injecting the stimulation fluid into the hydrocarbon reservoir comprises: injecting the stimulation fluid into the hydrocarbon reservoir using a subset of the plurality of stimulation needles; andinjecting the stimulation fluid into the hydrocarbon reservoir using a subset of the plurality of stimulation ports. 18. The method according to claim 17, wherein injecting the stimulation fluid into the hydrocarbon reservoir further comprises: cleaning the subset of the plurality of stimulation needles.  

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