CA2871058A1 - Cold weather hydrocarbon well cementing using surfaced mixed epoxy - Google Patents

Abstract

A cold weather cementing composition for cementing a well includes a polymeric component and an activator component, wherein the activator component is a mercaptan.
Optionally the composition may include a diluent provided to allow the composition to be pumped. This composition is then surface mixed in a method of cementing a well, and ultimately placed in the well at the desired location, where in situ it forms a cement plug.

Description

COLD WEATHER HYDROCARBON WELL CEMENTING USING SURFACED
MIXED EPDXY
[0001]BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to wells, well operations, to methods, apparatus and products for operating wells. In another aspect, the present invention relates to well cementing operations, and to compositions, methods, apparatus and products for cementing wells. In even another aspect, the present invention relates to primary and secondary well cementing operations, and to compositions, methods, apparatus and products for cementing wells. In still another aspect, the present invention relates to cold weather well operations, and to compositions, methods, apparatus and products therefore. In yet another aspect, the present invention relates to cold weather compositions for well cementing operations, such as, but not limited to sealing casing leaks, micro-annular gas migration, water shut off, gas shut off and zonal isolation for wells, including oil, gas, water, geothermal, or analogous wells..

[0004] 2. Description of the Related Art

[0005] Some embodiments of the present invention relate to wells residing in cold weather environments. Cold weather brings it own challenges for operating wells. In addition to the obvious harshness of the cold on human operators around a well site and cold on the physical equipment, the cold also affects all of the well chemicals around the well site. The obvious physical effects on the chemicals would include hardening of solid chemicals, viscosity changes of various liquids and gels, perhaps even a state change from liquid to a gel or a solid, perhaps less vaporization from liquids, and perhaps less pressure on gases. However, how this effects the well operation is not always so clear, what needs to be done (if anything) to correct for the effects of cold weather are also not always so clear, and finally, if weather/temperature corrective actions are taking, it is not clear that those corrective actions will help/hurt the operation. In some instances, the "cure" for the cold weather might be worse than the affect of the cold weather on the well operation.

[0006] In the present application, cold weather will generally mean ambient temperatures around the well site of less than 70 F, 60 F, 50 F, 45 F, 40 F, 35 F, 32 F, 30 F, 25 F, 20 F, 15 F, 10 F, 5 F, 0 F, -5 F, -10 F, -15 F, -20 F, or -30 F.

[0007] Cementing compositions are utilized in wells for both primary and secondary cementing operations.

[0008] U.S. Patent No. 7,748,455 to Burts, Jr., et al. issued July 6,2010 for surfaced mixed epoxy method for primary cementing of a well discloses a two part epoxy resin system is surface mixed in a method of primary cementing a well. This surface mixed epoxy resin is then placed in the annulus of the well. Finally, the mixture in situ forms a hard impermeable mass.

[0009] U.S. Patent No. 8,235,116 to Burts, Jr., et al. issued August 7, 2012 for a well remediation using surfaced mixed epoxy discloses a two part epoxy resin system is surface mixed in a method of remediating an active well. This surface mixed epoxy resin is then placed in the well at the desired remediation depth. Finally, the mixture in situ forms a cement plug.

[00010] In spite of the advances in the prior art, there is still a need in the art for cold weather well cementing compositions, methods, apparatus and products.

[00011] These and other needs in the art will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.

[00012] SUMMARY OF THE INVENTION

[00013] It is an object of the present invention to provide for compositions, methods, apparatus and products relating to well cementing operations.

[00014] These and other objects of the present invention will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.

[00015] According to one embodiment of the present invention, there is provided a method of cementing a well. The method may include providing an epoxy resin component, an activator component, wherein the activator component comprises a mercaptan.
The method may also include surface mixing the components to form a cementing system. And, the method may include placing the system in the well to be cemented.

[00016] According to even another embodiment of the present invention, there is provided a method of cementing a well. The method may include providing an epoxy resin component, an activator component, and a diluent component, wherein the activatory component comprises a mercaptan. The method may also include surface mixing the components to form a cementing system, wherein the diluent is selected to allow the cementing system to have working flowability at the surface. And, the method may include placing the system in the well to be cemented.

[00017] According to still another embodiment of the present invention, there is provided a well fluid composition comprising a well fluid, an epoxy resin component, and an activator component, wherein the activator component comprises a mercaptan.

[00018] These and other embodiments of the present invention will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.
DETAILED DESCRIPTION OF THE INVENTION

[00019] T The methods of the present invention relate to the operation of a well, more specifically to various cementing operations. While the present invention may be discussed in terms of well cementing operations, such as, but not limited to sealing casing leaks, micro-annular gas migration, water shut off, gas shut off and zonal isolation, the present invention is not to be so limited and in fact is believed to be applicable to any primary, secondary and/or other cementing operation. The present invention is also believed to have applicability to any type of well, including but not limited to, oil, gas, water, geothermal, or analogous wells.

[00020] The method of the present invention for cementing a well involves the use of a two part cementing composition, which is incorporated into known cementing methods. While the present invention is illustrated mainly with respect to "active wells", the present invention is believed to have applicability to non-active wells also. As used herein "active well" refers to any well that is not an abandoned well or one that is not undergoing abandonment.
As examples, a well during the process of drilling, a producing well, and the like.

[00021] In particular, the two part cementing composition of the present invention comprises a two part polymeric cementing system comprising a polymeric component and an activator component. The polymeric component will in the presence of an activator component be set up, reacted, hardened, cured, catalyzed or crosslinked into a cementing plug. Some embodiments of the present invention further include a diluent component as a third component.

[00022] The polymeric component utilized in the present invention may be any material suitable polymeric material for forming a cementing plug that will adequately plug the well in the manner as desired, for the specific cementing operation as desired.
Examples of suitable polymeric systems include those described in U.S. Patent Nos. 7,748,455 and 8,235,116 and patents recited therein. This polymeric component may comprise a thermoplastic or thermoset, that is water soluble or insoluable. Preferably, this polymeric component is an epoxy resin.
Commercially available examples of suitable epoxy resins include Epon 862 or 863-resin, available from Momentive.

[00023] In the present invention, the polymeric system not only contains the polymeric material and activator, but may optionally include additives to improve thermal stability, control set time, generate expansion, and control fluid loss. The additives may be incorporated into the system directly, or into one or both of the components.

[00024] Any suitable polymeric system may be utilized, with epoxy systems being preferred. In selecting a suitable polymeric system, it is desired that the system exhibit one or more, preferably several if not all, of the following characteristics: liquid system that is solid free, no shrinkage upon set up, maintains (or causes an increase in) the wellhole pressure;
hydrophobic; density allows it to fall thru the well fluid at a suitable rate;
and non-gas generating (so as not to cause micro channels).

[00025] As utilized in the present invention, the activator component may serves not only to activate, set up, crosslink and/or cure the polymeric compound, but may also serve to accelerate such, so as to reduce the wait on cement (WOC) time. The activator causes the sealant to set under downhole temperature and pressure conditions at an accelerated rate. Of course, this activator component will have to be carefully selected depending upon the material utilized as the first component. Commercially available activators include Epicure 3046 and Epicure W, available from Momentive.

[00026] Some non-limiting embodiments of the present invention employ a mercaptan terminated polymer as part/all of the activator component. Some non-limiting embodiments of the present invention utilize an activator component comprising a mercaptan terminated polymer and a non-mercaptan activator, with the mercaptan terminated polymer comprising in the range of from/to or between any two of the following numbers 0.25, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50 parts by weight based on 100 parts of the polymer.
As non-limiting examples, a range from 1 to 50 or a range between 2 and 30. It should be noted that any desired range can be constructed with any two listed numbers depending upon the application desired.

[00027] Non-limiting examples of commercially available mercaptan activators include, Capcuret 40 SECHV Polyamine-Polymercaptan Epoxy curing agent from BASF, and and GPM-800L0, both mercaptan terminated polymers, both from Gabriel Perfomance Products.

[00028] In the present invention, accelerated set times are generally less than 12 hours, preferably less than 10 hours, more preferably less than 8 hours, even more preferably less than 6 hours, still more preferably less than 4 hours, and yet more preferably less than 2 hours.

[00029] The activator will cause the polymeric sealant to set under downhole conditions to cause the sealant to bond to the casing and or other formation surfaces in the well. The pipe may have coating of oil or water based drilling mud.

[00030] The activator component may be selected to not only accelerate cement set, but may optionally be selected to also alter slurry density, clean downhole surfaces, and/or improve bond.

[00031] The activator will be selected for its known property for accelerating the setup, activation, cure, crosslinking, of the polymeric material. For the preferred epoxy resin system, activators for epoxies are well known, and any suitable one may be utilized.
In many instances paired resin-activator systems are commercially available.

[00032] For some non-limiting embodiments, based on 100 parts by weight of polymer, the present invention anticipates utilizing 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 parts by weight of total activator component(s), or any amount in the range between or from/to any two of the foregoing listed numbers.

[00033] However, for some other non-limiting embodiments, based on 100 parts by weight of polymer, the present invention anticipates utilizing greater than 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by weight of total activator component(s). For even other non-limiting embodiments, based on 100 parts by weight of polymer, the present invention anticipates using greater than 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by weight of total activator component(s). Preferably, based on 100 parts by weight of polymer, the present invention anticipates using greater than 45, 46, 47, 48, 49, 50, 60, 70, 80, 90 or 100 parts by weight of activator components. More preferably, based on 100 parts by weight of polymer, the present invention anticipates using greater than 50, 51, 52, 53, 54, 55, 60, 70, 80, 90 or 100 parts by weight of activator components. It should be understood that this "greater than" refers to the total weight of all of the activator components.

[00034] The cementing composition of the present invention may include a third component, a diluent. In some non-limiting embodiments, the cementing composition will arrive at the well site already comprising a polymeric component, an activator component, and optionally a diluent. The present invention contemplates adding (at the surface) diluent to this cementing composition (whether is already has diluent or not). In other non-limiting embodiment, the various polymeric component, activator component and diluent component are all surface mixed at the well site. Non-limiting examples of suitable diluents include functional glycidyl esters and ethers. Non-limiting examples of suitable commercially available diluents include any of the "Heloxy" family of diluents (a non-limiting example of which is Heloxy 7) or CarDura E 1 OP high-temp diluent a glycidyl ester.

[00035] If present, the diluent will comprise in the range of from/to or between any two of the following numbers 0.25, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 parts by weight based on 100 parts of the polymer.
An amount of diluent may also be selected to provide for the cementing system to have workable flowability at the surface, meaning that at the ambient temperature at the well site surface, the flowability of the system allows it to be pumped in the desired well operation.

[00036] Examples of commercially available materials follows and possible formulations follow. Concentrations are parts by weight.

[00037] Materials: Epon 862 or 863-resin, Epicure 3046 low-temp hardener, Epicure W
high temp hardener, Heloxy 7-primary reactive diluent, CarDura El OP-secondary, high-temp diluent. Formulations: (1) 100 Epon 862 or 863+ greater than 40 Epicure 3046 good 50 F to 100 F (downhole temperature); (2) 100 Epon 862 or 863+20 to 50 parts Heloxy 7+
greater than 40 parts Epicure 3046 good 70 F to 125 F (downhole temperature; (3) 100 Epon 862 or 863+20 to 50 parts Heloxy 7+ greater than 40 parts combined of Epicure 3046 and Epicure W good 125 to 175 F (downhole temperature); (4) 100 parts Epon 862 or 863+0 to 50 parts Heloxy 7+greater than 40 parts Epicure W good from 175 to 250 F (downhole temperature); (5) 100 parts Epon 862 04 863+30 to 50 parts Heloxy 7+ greater than 40 parts Epicure W+0 to 20 parts CarDura El OP good from 250 to 350 F.

[00038] The present invention also contemplates the optional use of two or more activator systems, generally selected to operate at various temperatures to assist in controlling any set, activation, curing, or crosslinking. A blend of polymeric material may also be utilized.

[00039] The method of the present invention for cementing of wells, includes any of the known cementing methods in which is utilized the multi-component plugging composition of the present invention as the cementing material.

[00040] The cementing compositions of the invention are useful in any type of cementing operation, including primary, secondary and other cementing operations., including, but not limited to sealing casing leaks, micro-annular gas migration, water shut off, gas shut off and zonal isolation

[00041] Generally in the practice of the method of the present invention, the various components of the composition are mixed at the surface ("surface mixed") and then placed downhole at a desired location allowed to form into a plug.

[00042] Sealing casing leaks is a non-limiting example of the cementing operation possible with the present invention. Such an operation may include identifying the casing leak through diagnostic work. Once the casing leak is identified, the operation may also include positioning a packer below the casing. The operation may also include testing the pump and mixing equipment. The operation may also include surface batch mixing the polymeric component, activator component and any diluent component (if not pre mixed in either/both components). The operation may also include the addition of weighting agent:
light weight beads, silica flour, barite, hematite, micro max, etc). The operation may also include adding a determined amount of low temperature additive designed through lab testing for fluid time, and pumping it through drill pipe, tubing, or coil tubing as a balanced plug. The operation may also include pulling the end of the work string above top of the plug and squeezing the plug through the casing leak leaving an amount of plug in the casing while allowing the plug to solidify or cure. Finally, the operation may include drilling the plug left in the casing and applying a positive or negative pressure test as desired.

[00043] Sealing micro annular gas migration in casing is another non-limiting example of the cementing operation possible with the present invention. For failed cement gas migration in casing such an operation may include identifying the gas migration through diagnostic work, and once leak is identified it is recommended to run in hole, and test pump and mixing equipment.
The operation may also include surface batch mixing the polymeric component, activator component and any diluent component (if not pre mixed in either/both components). The operation may also include the addition of weighting agent: light weight beads. silica flour, barite, hematite, micro max, etc). The operation may also include adding a determined amount of low temperature additive as determined through lab testing for fluid time, and pumping it through drill pipe, tubing, or coil tubing as a balanced plug. The operation may also include pulling the end of the work string above top of the plug and squeeze/ apply positive pressure (generally 250 psi > shut in casing pressure) to the plug while allowing the plug to solidify or cure. Finally, the operation may include applying a positive or negative pressure test or bubble test as desired.

[00044] Sealing micro annular gas migration in the casing annulus is another non-limiting example of the cementing operation possible with the present invention. For failed cement in casing annulus, this operation may include identifying the gas migration through diagnostic work, and once leak is identified, to run in hole with perforating assembly and perforate the casing above top of cement in annulus, and test pump and mixing equipment. The operation may also include surface batch mixing of the polymeric component(s), the activator component(s), and any desired diluent if not pre mixed in either of the components. The operation may include the addition of weighting agent: light weight beads, silica flour, barite, hematite, micro max, etc.
The operation may also include adding an amount of low temperature additive as determined through lab testing for fluid time and pumping through casing annulus valve taking returns on casing, and once the plug is in place above failed cement in annulus, close casing valve and apply positive psi (generally 250 psi > shut in casing pressure) to the plug while allowing the plug to solidify or cure. The operation may also include applying positive or negative pressure test or bubble test as desired.

[00045] Zonal isolation (water, gas, etc.) is another non-limiting example of the cementing operation possible with the present invention. Such an operation may include identifying the casing leak through diagnostic work. Once the casing leak is identified, the operation may also include positioning a packer below the casing. The operation may also include testing the pump and mixing equipment. The operation may also include surface batch mixing the polymeric component, activator component and any diluent component (if not pre mixed in either/both components). The operation may also include the addition of weighting agent:
light weight beads, silica flour, barite, hematite, micro max, etc). The operation may also include adding a determined amount of low temperature additive designed through lab testing for fluid time, and pumping it through drill pipe, tubing, or coil tubing as a balanced plug. The operation may also include pulling the end of the work string above top of the plug and squeezing the plug through the casing leak leaving an amount of plug in the casing while allowing the plug to solidify or cure. Finally, the operation may include drilling the plug left in the casing and applying a positive or negative pressure test as desired.

[00046] Preferably, in the practice of the present invention, the epoxy system is heavier than the well fluid to allow gravity flow thru the well fluid to the plug location.

[00047] Any suitable apparatus and method for the delivery of the components may be utilized. As non-limiting examples, suitable delivery systems may utilize a dump bailer, coiled tubing and jointed tubing. They require a base to stack up against such as a packer, petal basket or sand plug. The compositions of the present invention may be directly stacked up against the packer or petal basket. While any suitable delivery mechanism can be utilized, more specific non-limiting examples of suitable delivery mechanisms include: dump bailer run on electric line or slick line; pumping through tubing, drillpipe, work strings or any tubulars; allowing fall through fluids via gravity; and pumping into an annullas or pipe without displacing (i.e., "bull heading").

[00048] In some instances epoxy system will not have suitable density, specifically, the density may not be greater than that of the well fluid.

[00049] Some non-limiting embodiments of the present invention provide for the utilization of weighting agent additives to the first component or the second component, or to the resultant combined system, to change the density of the mixed system. Suitable additives to change the density include metal salts, preferably calcium chloride. Other examples of weighting agents include sand, barite, hemitite, calcium carbonate, FeO. MgO, and manganese ore. Sufficient amounts of the additive are utilized to achieve the desired density. Other non-limiting embodiments of the present invention provide for no weighting agents in the cementing composition, that is, they are "neat" (without weighting agents).

[00050] In some well operations of the present invention, the desired cement components are surface mixed. The mixed components are then introduced into the well fluid at a position above, or directly on top of (i.e. touching) the sand/petal basket to allow for in-situ formation of the cement plug to plug the well.

[00051] It should be appreciated that at some point, the density differential between the polymeric system and the well fluid is so low as to result in too slow of displacement.

[00052] On the other hand, it should further be appreciated that at some point, the density differential between the system and the well fluid is so great as to result in problems.

[00053] Thus, the density differential should be selected so as to provide suitable gravity feed of the system thru the well fluid to the desired location.

[00054] Typical densities for the well fluid will be in the range of about 8.33 ppg up to about 20.0 ppg, with typical densities for the activator in the range of about 8.33 ppg up to about 21.0 ppg, and with typical densities for the sealant system in the range of about 8.54 up to about 22.0 ppg.

[00055] It should be understood that other well fluid additives as are well known in the art may be incorporated into the first and/or second component, or added before, along with, or after the introduction of the first and/or second component, non-limiting examples of which include surfactants, surface bond enhancers (non-limiting examples include styrene butadiene latex, polyvinal alcohols, resins, other adhesives), emulsifiers, ph control agents, fluid loss additives, gas prevention additive, dispersants, expanding agents, and wetting agents.

[00056] Although the present invention has been illustrated by preferred reference to epoxy systems, it should be understood that any remediation composition having two or more components can be utilized in the present invention.

[00057] U.S. Patent Nos. 7,748,455 and 8,235,116, and any patents, publications, articles, books, journals, brochures, cited therein, are herein incorporated by reference.

[00058] While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those skilled in the art to which this invention pertains.

Claims (11)

1. A method of cementing a well, the method comprising:
(A) providing an epoxy resin component, an activator component, wherein the activator component comprises a mercaptan;
(B) surface mixing the components to form a cementing system; and, (C) placing the system in the well to be cemented.

2. The method of claim 1 further comprising (D) adding diluent to the surface mixed cementing system.

3. The method of claim 1, wherein the mercaptan comprises a mercaptan terminated polymer.

4. A method of cementing a well, the method comprising:
(A) providing an epoxy resin component, an activator component, and a diluent component;
(B) surface mixing the components to form a cementing system, wherein the diluent is selected to allow the cementing system to have working flowability at the surface; and, (C) placing the system in the well to be cemented.

5. The method of claim 3 further comprising before step (C) adding an additional amount of diluent to the surface mixed cementing system.

6. The method of claim 3, wherein the mercaptan comprises a mercaptan terminated polymer.

7. A well fluid composition comprising:
a well fluid;
an epoxy resin component; and, an activator component, wherein the activator component comprises a mercaptan.

8. The well fluid composition of claim 7, wherein the mercaptan comprises a mercaptan terminated polymer

9. A method of cementing a well, the method comprising:
(A) providing an epoxy resin component, an activator component, and a diluent component;
(B) surface mixing the components to form a cementing system, wherein the diluent is selected to allow the cementing system to have working flowability at the surface;
(C) adding an additional amount of diluent to the surface mixed cementing system; and, (D) placing the system in the well to be cemented.

10. A method of cementing a well, the method comprising:
(A) providing a premixed cementing system comprising an epoxy resin component, an activator component, and a diluent component;
(B) adding an additional amount of diluent to the surface mixed cementing system; and, (C) placing the system in the well to be cemented.

11. A method of cementing a well, the method comprising:
(A) providing an epoxy resin component, and an activator component;
(B) surface mixing the components to form a cementing system;
(C) adding an amount of diluent to the surface mixed cementing system; and, (D) placing the system in the well to be cemented.