METHOD FOR IMPROVING COUNTERFLOW CONTROL OF PROPPING

Abstract

The techniques described in this disclosure relate to proppant backflow control. One method comprises coating resin in a proppant at a well site; pumping the coated proppant into a well during a fracturing operation; and pumping an activator for the resin into the well to displace the coated proppant in at least one fracture during the fracturing operation, wherein the step of pumping the coated proppant and the step of pumping the activator are performed separately.

Description

METHODOLOGY FOR CONSOLIDATING SAND OR PROPELLANT WITH RESIN IN TWO STAGES BACKGROUND

[0001] Hydrocarbon production wells can be stimulated by hydraulic fracturing treatments. In hydraulic fracturing treatments, a fracturing fluid is pumped into a production zone of a subterranean formation such that one or more fractures are formed in the zone. Proppant, such as sand, is suspended in the fracturing fluid to prop the fractures such that the proppant is deposited in the fractures.

[0002] Proppant in fractures prevents fractures from closing, resulting in conductive channels for producing formation fluid. However, many hydraulically fractured wells, especially unconventional wells, suffer from proppant backflow problems, which affect production and damage equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] These drawings illustrate certain aspects of some of the examples of the present disclosure and should not be used to limit or define the disclosure.

[0004] Figure 1A illustrates an example of a system that can be used to coat the proppant with resin, hydraulically fracture a subterranean formation with coated proppant, and activate the resin, in accordance with examples of the present disclosure;

[0005] Figure 1B illustrates the arrangement of a resin activator in a wellbore during a fracturing operation, in accordance with examples of the present disclosure;

[0006] Figure 2A illustrates a plug and perforation system for the arrangement of the activator in the well, in accordance with the examples of the present disclosure;

[0007] Figure 2B illustrates the placement of a plug during a plugging and drilling operation, in accordance with examples of the present disclosure;

[0008] Figure 3 illustrates the arrangement of the activator in the wellbore during a milling operation to remove the plug, in accordance with the examples of the present disclosure; and

[0009] Figure 4 illustrates an operating sequence for proppant backflow control, in accordance with examples of the present disclosure. 239009 2082383 of 13 DETAILED DESCRIPTION

[0010] The methods of the present disclosure generally relate to treating a well with a resin and its activator to reduce proppant flowback. The resin and activator can be pumped into the wellbore in two stages, allowing equipment (e.g., pumping / mixing equipment) to be kept free of cured resin. Therefore, cleaning of the equipment at the wellbore surface may not be necessary. While the methods can be used in a variety of formations, they may be particularly beneficial in unconventional formations, such as shale formations, to prevent proppant flowback.

[0011] The methods may be performed during fracturing, plug completion, and drilling and / or milling of a plug. The resin may be dry coated or wet coated onto the proppant (e.g., sand) at, for example, the well site. For example, dry coating may be performed in a sand washer screw through a sprayer. As the sand passes through the sand washer screw, the sand may be sprayed with the resin, and then the coated sand may pass into mixing equipment, such as, for example, a fracturing pipe may include a mixer that is used for fracturing.

[0012] Wet coating can be performed in mixing equipment. For example, the sand can be passed to mixing equipment where the sand is mixed with resin, producing coated sand. Following coating of the sand with resin through wet coating or coating therein, the coated sand can be pumped into the wellbore for hydraulic fracturing of a subterranean formation. The resin can be safely pumped without the risk of curing in the equipment. Then, toward the end of the hydraulic fracturing operation, the activator can be added to the mixing equipment to discharge / displace the coated sand from the wellbore into the fractures extending from the wellbore into the subterranean formation.For example, the N stage can be fractured with the coated sand and then the coated sand can be displaced / discharged from the wellbore into the N stage fracture clusters, with the activator, towards the end of the fracturing operation.

[0013] In some examples, the activator may be pumped into the wellbore during a plug and drill operation. Plug and drill refers to a cased hole completion procedure that pumps a plug and drill gun to a desired stage in a wellbore. Once the plug is set, the drill gun 239009 2082383 of 13 drills into the casing and penetrates the underground section between the plugs. Hydraulic fracturing then occurs, and fracturing fluid is pumped into this section.

[0014] The process is repeated for each stage, until all stages have been hydraulically fractured. Plugs are then drilled or milled. For example, after fracturing with the coated sand, the activator may be pumped into the wellbore followed by a plug, such as a frac plug or bridge plug, for example, attached to the drilling rig. The drilling rig may be pumped down the wellbore to displace the activator into the fracture clusters in the subterranean formation.

[0015] The activator can be moved slightly into the formation. Once the plug is in place, the drilling rig can be removed from the plug to drill another stage (e.g., N+1) for subsequent hydraulic fracturing with the resin-coated proppant. For example, the drilling rig can be pulled uphole to drill N+1. The process can be repeated for any number of stages.

[0016] In other examples, the activator may be pumped into the wellbore during plug milling, for example, through coiled tubing (CT), hydraulic workover (HWO), or a drilling rig. Non-limiting examples of the resin include, but are not limited to, a two-component epoxy resin; a novolak resin; a polyepoxide resin; a phenol-aldehyde resin; a urea-aldehyde resin; a urethane resin; a phenolic resin; a furan resin; a furan / furfuryl alcohol resin; a phenolic / latex resin; a phenol-formaldehyde resin; a polyester resin; a hybrid polyester resin; a polyester copolymer resin; a polyurethane resin; a hybrid polyurethane resin; a polyurethane copolymer resin; an acrylate resin; and any combination thereof.

[0017] Non-limiting examples of the resin activator include an acid such as hydrochloric acid, citric acid, malic acid, tartaric acid, acetic acid, phosphoric acid, maleic acid, lactic acid, ascorbic acid, acetic acid, carbonic acid, succinic acid and / or benzoic acid. In some examples, an ester may be used as the activator.

[0018] Figure 1A illustrates an example of a fracturing system 100, in accordance with examples of the present disclosure. The system 100 may be used to coat sand with resin and pump the coated sand into a well and then 239009 2082383 of 13 pumping the activator into the wellbore during a fracturing operation. The system 100 includes a proppant source 101 (e.g., a container) for providing (e.g., via gravity feed, valve) a proppant 102 (e.g., sand) into a conveying system 103 (e.g., a roller conveyor) for transporting the proppant 102 to a sand washer screw 104.

[0019] Coating of the proppant 102 may be performed by dry coating or wet coating. During dry coating of the proppant 102, a spray unit 105 (e.g., nozzles, pump, and resin source) may spray resin 106 into the proppant 102 to encapsulate the proppant 102 as the proppant 102 passes through the sand washer screw 104. The system may further include mixing equipment 107 (e.g., fracturing tubing) coupled to pumping equipment 108 and wellbore supply conduit 110 coupled to a wellbore 112 extending into a subterranean formation 113. Alternatively, during wet coating of the proppant 102, the resin 106 may be delivered to the mixing equipment 107 from a container 114, e.g., through valves or gravity feed. Each particle of proppant 102 can be completely coated with resin 106.

[0020] Non-limiting examples of the resin include, but are not limited to, a two-component epoxy resin; a novolak resin; a polyepoxide resin; a phenolaldehyde resin; a urea-aldehyde resin; a urethane resin; a phenolic resin; a furan resin; a furan / furfuryl alcohol resin; a phenolic / latex resin; a phenol-formaldehyde resin; a polyester resin; a hybrid polyester resin; a polyester copolymer resin; a polyurethane resin; a hybrid polyurethane resin; a polyurethane copolymer resin; an acrylate resin; and any combination thereof.

[0021] Well 112 may include unconventional and / or conventional wells including horizontal, vertical, inclined, curved, and / or other types of wellbore geometries and orientations. In some examples, coiled tubing may be used to fracture the wellbore. System 100 may be deployed offshore or onshore. Well 112 may include casing 116 which may be cemented within well 112 by a cement sheath 122. Perforations 120 may extend from casing 116, through cement sheath 122, into formation 113. Pumping equipment 108 may be fluidly coupled with the wellbore 112. 239009 2082383 of 13 mixing equipment 107 and well supply conduit 110 for communicating various fluids / materials to the well 112.

[0022] Proppant 102 (e.g., sand) may be mixed with a fluid such as, for example, a water-based fluid by mixing equipment 107, whereby a treatment fluid such as, for example, a fracturing fluid is formed that may be pumped by pumping equipment 108 from mixing equipment 107 downhole 112 to a fracture gradient of subterranean formation 113 or above to create (or enhance) at least one fracture (e.g., clusters 126) extending from perforations 120.

[0023] Stage N may refer to the present stage in well 112 for treatment. Stage N-1 may refer to the previously treated stage, and stage N+1 may refer to the next stage of treatment. Plugs 128 may separate each stage. Plugs 128 may include fracturing plugs or bridge plugs.

[0024] Wellbore 112 may include dozens or hundreds of stages, where each stage may include 6-12 clusters, for example. Each stage may extend 200 feet along wellbore 112 from plug to plug, for example. Each cluster 126 may be separated by about 20 feet in some examples and may include a cluster width of about 1 foot for each cluster.

[0025] Figure 1B illustrates an addition of an activator 130 to the system 100, toward the end of the fracturing operation, in accordance with examples of the present disclosure. The activator 130 may be added to mixing equipment 107 (e.g., a fracturing tubing) to discharge / displace the proppant 102 from the wellbore 112 into the clusters 126 extending from the wellbore 112 into the subterranean formation 113.

[0026] Activator 130 may be dispensed from a container 132 through a valve, for example, to mixing equipment 107. Other components such as liquids may be added to mixing equipment 107. Non-limiting examples of other components include friction reducers and / or water. Non-limiting examples of activator 130 include an acid such as hydrochloric acid, citric acid, malic acid, tartaric acid, acetic acid, phosphoric acid, maleic acid, lactic acid, ascorbic acid, acetic acid, carbonic acid, succinic acid, and / or benzoic acid. In some examples, an ester may be used as the activator. 239009 2082383 of 13

[0027] Figure 2A illustrates a pumping system 200 including a drilling rig 201 for a plug and drill method, in accordance with examples of the present disclosure. The system 200 may be deployed offshore or onshore. The drilling rig 201 may include a spool / reel and / or controller to raise / lower and trip the drilling apparatus 204 as desired via a conveyance 206 such as, for example, wireline, slickline, or coiled tubing.

[0028] The pumping system 200 further includes a fluid handling system 208, which may include a fluid supply 210, mixing equipment 212, pumping equipment 214, and wellbore supply conduit 216 coupled to the wellbore 112 extending into a subterranean formation 113. The activator 130 may be added to the pump downstream of the system 200 (e.g., via the fluid supply 210 or the mixing equipment 212) to be placed in the wellbore 112 prior to plugging and drilling. The system 200 may be unique to the system 100 of Figures 1A and 1B.

[0029] For example, after fracturing stage N with proppant 102, activator 130 (e.g., any suitable acid or ester) may be pumped into wellbore 112 via pump downstream of system 200. For example, activator 130 may be added to fluid supply 210 or mixing equipment 212 to be placed in wellbore 112. Then, a plug 128a (e.g., a frac plug or bridge plug) coupled to drilling apparatus 204 may be pumped downstream into wellbore 108 with fluid E (e.g., brine). Plug 128a and / or drilling apparatus 204 may be used to displace activator 130 in clusters 126. The amounts of activator 130 (or other components that are pumped into the wellbore) may vary and may be adjusted as desired. The volume depends on the degree of consolidation and the number of perforations. For example, 500 gallons of activator 130 can be used.E is the displacement fluid which may be equal to at least the volume of the wellbore above the plug 128a at the placement location.

[0030] Figure 2B illustrates the placement of plug 128a and the drilling of stage N+1, in accordance with examples of the present disclosure. Plug 128a may be positioned between stages N and N+1, and drilling apparatus 204 may be disengaged (e.g., via an electrical signal) from plug 128a and pulled uphole to a target location. While Figure 2B illustrates stage N+1 as a proximal uphole stage of stage N, the 6 239009 2082383 of 13 embodiments also encompass N+1 as a further distal stage downhole relative to stage N.

[0031] In some examples, a placement tool may dislodge plug 128a from drilling apparatus 204. Once plug 128a is dislodged, drilling apparatus 204 may then drill stage N+1 of well 112, for example, in 30 foot increments. The activator may be moved slightly into the formation surrounding stage N and any previously discussed stages.

[0032] The aforementioned plugging and drilling process may be repeated for any number of stages. For example, stage N-1 was discussed above in accordance with techniques of the present disclosure. Each stage may be soaked in the activator, and the activator may be slightly displaced into the formation. The resin may consolidate the proppant 102 and harden during activation. This provides mitigation of proppant backflow in the wellbore 112.

[0033] Figure 3 illustrates a system 300 for pumping activator 130 into wellbore 112 during milling of a plug 128, in accordance with examples of the present disclosure. A milling bit 302 may be positioned in wellbore 112 via a conveyance 304 such as, for example, coiled tubing (CT) or a drill string. In some examples, milling may be performed via hydraulic workover (HWO). System 300 further includes a fluid handling system 308, which may include a fluid supply 310, pumping equipment 314, and wellbore supply conduit 316 coupled to wellbore 112 extending into a subterranean formation 113.

[0034] Activator 130 may be added to system 300 via fluid supply 310. For example, activator 130 may be placed in supply 310 to pump through bit 302 during milling operation to remove plug 128. Activator 130 may contact / activate proppant 102 in aggregates 126, for sand consolidation.

[0035] Figure 4 illustrates an operational sequence for proppant backflow control, in accordance with examples of the present disclosure. In step 400, the resin may be dry coated or wet coated onto the proppant (e.g., see Figure 1A). For example, dry coating may be performed in a sand washer screw through a sprayer. For example, as the sand passes through the sand washer screw, the sand may be sprayed with the resin, and then the coated sand may pass to mixing equipment from the screw. 239009 2082383 of 13 sand washer. Wet coating can be performed in mixing equipment. For example, the sand can be passed to mixing equipment where it is mixed with resin, producing coated sand. Other components such as water and / or friction reducers may be present in the mixing equipment.

[0036] In step 402, following coating of the sand with the resin via wet coating or coating therein, the coated sand may be pumped into the wellbore for hydraulic fracturing of a subterranean formation. For example, proppant may be disposed in the wellbore during fracturing in step N (e.g., see Figure 1A). The proppant may be mixed with a fluid such as, for example, a water-based fluid by mixing equipment, whereby a treatment fluid such as, for example, a fracturing fluid is formed which may be pumped by pumping equipment from the fluid supply down the wellbore to a fracture gradient of the subterranean or upper formation to create (or enhance) at least one fracture (e.g., clusters 126) extending from the perforations.

[0037] In step 404, toward the end of the hydraulic fracturing operation (call flush), the activator may be added to the mixing equipment to flush / displace coated sand from the wellbore into the fracture clusters extending from the wellbore into the subterranean formation. For example, coated sand may be displaced / flushed from the wellbore into the fracture clusters of stage N, with the activator, toward the end of the fracturing operation (e.g., see Figure 1B). The activator may be pumped with a liquid such as, for example, water.

[0038] Alternatively, in step 405, the activator may be pumped into the wellbore during a plug and drill operation (e.g., see Figures 2A and 2B). Plug and drill refers to a cased hole completion procedure that pumps a plug and drill gun to a desired stage in a wellbore. Once the plug is set, the drill gun is fired into the casing and penetrates the underground section between the set plugs. Hydraulic fracturing then occurs, and fracturing fluid is pumped into this section. The process is repeated for each stage, until all stages have been hydraulically fractured. The plugs are then drilled or milled.

[0039] For example, after fracturing with the sand encased, the activator can be pumped into the well followed by a plug, such as a sand plug. 239009 2082383 of 13 fracturing or a bridge plug, for example, attached to the drilling rig. The drilling rig can be pumped down the wellbore to displace the activator in the fracture clusters in the underground formation. The activator can be moved slightly into the formation. Each stage can be soaked in the activator (e.g., an acid or ester), and the activator can be moved slightly into the formation.

[0040] Once the plug is in place, the drilling apparatus may be stripped from the plug to drill another stage (e.g., N+1) for subsequent hydraulic fracturing with the resin-coated proppant. For example, the drilling apparatus may be pulled uphole to drill N+1. The plug may be positioned between stages N and N+1, and the drilling apparatus may be stripped (e.g., via an electrical signal) from the plug and pulled uphole to a target location. In some embodiments, a setting tool may strip the plug 1 from the drilling apparatus.

[0041] Once the plug is removed, the drilling rig may then drill stage N+1 of the well, for example, in 30-foot increments. The activator may be moved slightly into the formation surrounding stage N and any previously treated stages. The process may be repeated for any number of stages.

[0042] Alternatively, in step 406, the activator may be pumped into the wellbore during plug milling (e.g., see Figure 3). Milling may be performed, for example, by coiled tubing (CT), hydraulic workover (HWO), or a drilling rig. The activator may be added to a circulating fluid through, for example, the bit. In other examples, steps 404 through 406 may be performed consecutively.

[0043] Accordingly, the methods of the present disclosure improve proppant backflow control and can be performed during fracturing, plug completion, and drilling and / or milling of a plug. The methods may include any of the various features disclosed herein, including one or more of the following statements.

[0044] Statement 1. A method comprises coating resin onto a proppant at a well site; pumping the coated proppant into a wellbore during a fracturing operation; and pumping an activator for the resin into the wellbore to displace the coated proppant in at least one fracture during the fracturing operation, wherein the step of pumping the coated proppant and the step of 239009 2082383 of 13 pumping the activator is done separately.

[0045] Statement 2. The method according to statement 1, further comprising pumping a drilling apparatus coupled to a plug, into the well.

[0046] Statement 3. The method according to any of the preceding statements, further comprising placing the plug such that the coated proppant and activator are contained in a stage of the well.

[0047] Statement 4. The method according to any of the preceding statements, further comprising drilling a subsequent stage of the well.

[0048] Statement 5. The method according to any of the preceding statements, further comprising milling the plug.

[0049] Statement 6. The method according to any of the preceding statements, wherein the coating step comprises dry coating the resin in the proppant.

[0050] Statement 7. The method according to any of the preceding statements, wherein the coating step comprises wet-coating the resin onto the proppant.

[0051] Statement 8. A method comprising: coating resin onto a proppant at a well site; pumping the coated proppant into at least one fracture extending from a wellbore; wherein the step of pumping the coated proppant and the step of pumping the activator are performed separately; and moving the activator from the wellbore toward the at least one fracture with a drilling apparatus coupled to a plug.

[0052] Statement 9. The method according to statement 8, further comprising placing the plug such that the coated proppant and activator are contained in a stage of the well.

[0053] Statement 10. The method according to statement 8 or statement 9, further comprising drilling a subsequent stage of the well.

[0054] Statement 11. The method according to any of statements 810, further comprising milling the plug.

[0055] Statement 12. The method according to any of statements 811, wherein the coating step comprises coating the resin onto the proppant during a fracturing operation.

[0056] Statement 13. The method according to any of statements 812, wherein the coating step comprises coating the resin in the proppant 239009 2082383 of 13 being placed on a sand washer screw during a fracturing operation.

[0057] Statement 14. A method comprising: coating resin onto a proppant at a well site; pumping a coated activator into at least one fracture extending from a wellbore; placing a plug in the wellbore; and pumping an activator for the resin into the wellbore during an operation to mill the plug, wherein the step of pumping the coated proppant and the step of pumping the activator are performed separately.

[0058] Statement 15. The method according to statement 14, wherein the coating step comprises applying a furan resin on the proppant.

[0059] Statement 16. The method according to statement 14 or statement 15, wherein the coating step comprises applying a furan resin on the sand.

[0060] Statement 17. The method according to any of statements 1416, wherein the coating step comprises adding the resin into the mixing equipment during a fracturing operation.

[0061] Statement 18. The method according to any of statements 1417, wherein the coating step comprises coating the resin on the proppant that is placed in a sand washer screw during a fracturing operation.

[0062] Statement 19. The method according to any of statements 1418, wherein the step of pumping the activator comprises passing the activator through the milling equipment.

[0063] Statement 20. The method according to any of statements 1419, wherein the step of pumping the activator comprises pumping an acid or ester into the well.

[0064] It should be understood that while the compositions and methods are described in terms of comprising, containing, or including various components or steps, the compositions and methods may also consist essentially of or consist of the various components and steps. Furthermore, the indefinite article "a" or "an," as used in the claims, means, as defined herein, one or more than one of the elements it introduces.

[0065] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to mention a range not explicitly mentioned, and ranges from any lower limit may be combined with 239009 2082383 of 13 any other lower limit to mention a range not explicitly mentioned; likewise, ranges from any upper limit may be combined with any other upper limit to mention a range not explicitly mentioned. Furthermore, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range that falls within the range is specifically disclosed. In particular, it should be understood that each range of values ​​(of the form from about a to about b, or, equivalently, from about a to b, or, equivalently, from about a to b) disclosed herein sets forth each number and range encompassed within the broader range of values ​​even if not explicitly mentioned.Thus, each individual point or value can serve as its own lower or upper bound combined with any other individual point or value or any other lower or upper bound, to enumerate a range not explicitly enumerated.

[0066] Therefore, the present embodiments are well adapted to achieve the aforementioned purposes and advantages, as well as those inherent therein. The particular embodiments disclosed above are illustrative only, as the present embodiments may be modified and practiced in different, but equivalent, manners. Although individual embodiments are discussed, all combinations of each embodiment are contemplated and covered by the disclosure. Furthermore, no limitation is intended on the details of construction or design shown herein, except as described in the following claims. Furthermore, terms in the claims have their plain and ordinary meaning unless explicitly and clearly defined otherwise by the patentee.Therefore, it is evident that the particular illustrative embodiments disclosed above may be altered or modified, and that all such variations are considered within the scope and spirit of this disclosure. If there is any conflict between the uses of a word or term in this specification and one or more patents or other documents that may be incorporated herein by reference, the definitions consistent with this specification should be adopted. 239009 2082383 of 13 20225952036 CRISTIAN DANIEL BITTEL - 20225952036 Digitally signed by PORTALTRAMITES - INPI Date: 2022.12.13 14:32:55 -03:00 Reason: Digitally signed by the INPI Location: Buenos Aires, Argentina 2082383

Claims

1. A method for improving proppant backflow control, characterized in that it comprises: coating resin on a proppant at a well site to provide coated proppant; pumping the coated proppant into a well during a fracturing operation; pumping an activator for the resin into the well, the activator being configured to harden the resin to consolidate loose particles; discharging the coated proppant into at least one fracture with the activator during the fracturing operation, wherein the pumping of the coated proppant and the pumping of the activator are performed separately; running a plug and a drilling apparatus into the well, wherein the plug is coupled to the drilling apparatus; pumping the plug and the drilling apparatus down the well; and displacing the activator to the bottom of the well together with the plug. 14 Claims follow