CA1304163C - Steam injection profiling - Google Patents
Steam injection profilingInfo
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- CA1304163C CA1304163C CA000552702A CA552702A CA1304163C CA 1304163 C CA1304163 C CA 1304163C CA 000552702 A CA000552702 A CA 000552702A CA 552702 A CA552702 A CA 552702A CA 1304163 C CA1304163 C CA 1304163C
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- liquid
- injection well
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Abstract
ABSTRACT OF THE DISCLOSURE
An improved method and apparatus for determining injection profiles in a steam injection well is disclosed. The mass flow rate and quality of steam entering the well is measured. A
well logging tool is then used to measure temperature and/or pressure profiles within the perforated zone of the well. A
liquid phase tracer is then injected for a short time into the well with the steam. The well logging tool contains dual gamma ray detectors and is used to measure the transit time of the tracer slug. In the preferred embodiment, the liquid tracer is radioactive elemental iodine or sodium iodide. The procedure is repeated with a vapor phase tracer which is radioactive Krypton, Argon, or Zenon in the preferred embodiment. A vapor and liquid profile can then be calculated with simple mass balance equa-tions. In a second approach, a spinner survey and a single tracer survey are conducted. By combining the spinner and trac-er survey results, vapor and liquid rates can be determined and steam injection profiles can be calculated.
An improved method and apparatus for determining injection profiles in a steam injection well is disclosed. The mass flow rate and quality of steam entering the well is measured. A
well logging tool is then used to measure temperature and/or pressure profiles within the perforated zone of the well. A
liquid phase tracer is then injected for a short time into the well with the steam. The well logging tool contains dual gamma ray detectors and is used to measure the transit time of the tracer slug. In the preferred embodiment, the liquid tracer is radioactive elemental iodine or sodium iodide. The procedure is repeated with a vapor phase tracer which is radioactive Krypton, Argon, or Zenon in the preferred embodiment. A vapor and liquid profile can then be calculated with simple mass balance equa-tions. In a second approach, a spinner survey and a single tracer survey are conducted. By combining the spinner and trac-er survey results, vapor and liquid rates can be determined and steam injection profiles can be calculated.
Description
~ 30~1~3 ~ 1936-176 STEAM INJECTION PROFILING
E'IELD OF THE INVE~TIO~
.
This inven-tion relates generally to thermally enhan-ced oil recovery. More specifically, this invention provides a method and apparatus for accurately developing steam injection profiles in steam in~ection wells.
B~CKGROUND OF _HE INVENTION
In the production of crude oil, it is frequently found that the crude oil is sufficiently viscous to require the injection of steam into the petroleum reservoir. Ideally, the petroleum reservoir would be completely homogeneous and the steam would enter all portions of the reservoir evenly. How-ever, it is often found that this does not occur. Instead, steam selectively enters a small portion of the reservoir while effectively bypassing other portions of the reservoir. Eventu-ally, "steam breakthrough" occurs and most of the steam flows directly from an injection well to a production well, bypassing a large part of the petroleum reservoir.
It is possible to overcome this problem with various remedial measures, e.g., by plugging off certain portions of the injection well. For example, see U.S. Patent Nos.
4,470,462 and 4,501,329, assigned to the assignee of the pre-sent inven-tion. However, to institute these remedial measures, it is necessary to determine which portions oE the reservoir are selectively receiving the injected steam. This is often a difficult problem.
Various methods have been proposed for det~rmining how injected steam is being distributed in the wellbore.
Bookout ("Injection Profiles During Steam Injection", SPE Paper ~o. 801-43C, May 3, 1967) summarizes the known methods for determining steam in]ection profil~sO
The first and most widely used of these methods is Xnown as a "spinner survey"~ A tool containing a freely rota-ting impeller is placed in the wellbore. As steam passes the impeller, it rotates at a rate which s~
~3(~ 3 ~1 -2-depends on the velocity of the steam~ The rotation vf theimpeller is translated into an electrical signal which is 05 transmitted up the logging cable to the surface where it is recorded on a strip chart or other recording device.
As is well known to those skilled in the art, these spinners are greatly affected by -the quality of the steam injected into the well, leading to unreliable results or results which cannot be interpreted in any way~
Radioactive tracer surveys are also used in many situations. With this method methyl iodide (131) has been used to trace the vapor phase. Sodium iodide has been used to trace the liquid phase. The radioactive Iodine is injected into the steam between the injection well and the steam generator. The tracer moves down the tubing with the steam-until it reaches the formation, where the tracer is temporarily held on the face of the formation for several minutes. A typical yamma ray log is then run~
immediately followin~ the tracer injection. The recorded gamma ray intensity at any point in the well is then assumed to be proportional to the amount of ~team injectecl at that point.
The vapor phase tracers have variously been described as alkyl halides (methyl iodide, methyl bromide, and ethyl bromide) or elemental iodine. It has been found that the above materials undergo chemical reactions that dramatically affect the accuracy of the results of the survey.
3~ It is, therefore, desirable to devise a highly accurate method of developing steam profiles in steam injection wells.
SUMMARY OF THE INVENTION
Field trials with the most common radioactive tracer, methyl iodide, were run to determine its effec-tiveness as a vapor tracer. It was Eound that a si~nifi-cant percentage of methyl iodide decomposes into liquid soluble components shortly after injection.
It is also believed that significant errors in measurement will occur when elemental iodine is used, as ~1 3~ i3 well a~ the alkyl halides other than methyl iodide. Further errors in the use of prior art tracers result from the assump-tion that tracers "plate o~t" in the formation and the assumption that gamma ray intensity is proportional to flow at a given depth.
Therefore, we have devised a method of determining the steam profile in a steam injection well using improved tracers and actual liquid and vapor velocities. A logging tool with temperature and/or pressure measurement devices and dual gamma ray detectors is placed in the injection well. Temperature and/or pressure logs are then run to determine vapor and liquid densities. The dual gamma ray logging tool is then placed in the formation at a known depth. After determining the mass flow rate and quality of steam entering the well, liquid phase tracers and thermaly stable, irradiated vapor phase tracers are injected into the flowing steam at the wellhead and detector outputs are recorded to calculate transit time between the detectors. This procedure is repeated at different positions ln the wellbore tQ
obtain an injection profile.
Alternatively~ the improved liyuid phase tracer or vapor phase tracer can be uqed in conjunction with a traditional spinner survey to determine both liquid and vapor profiles.
Accordingly, in one aspect the present invention provides a method of determining liquid and vapor phase steam profiles in a steam injec~tion well comprising the steps of:
(a) inserting a well logging tool into a steam injection well at a first Iocation, said logging tool further comprising dual gamma ray detectors;
(b) mea~uring a ma~s flow rate and quality of steam entering the steam injection well:
(c) injecting an irradiated, liquid phase tracer into the ~3~41~
-3a- 61936 1762 steam injection well;
(d) determining a liquid transit time with said logging tool;
(e~ injecting an irradiated, thermally stable vapor phase tracer into the steam injection well;
(f) determining a vapor transit time with said logging tool;
(g) moving said logging tool to a second location;
(h) repeating steps (c), (d), (e), and (f); and (i) calculating an amount of vapor and an amount of liquid entering a formation between said first location and said second location~
In another aspect the invention provides a method of determining liquid and vapor phase steam profiles in a steam injection well comprising the steps of:
(a) inserting a well logging tool into a steam injection well;
(b) measuring a mass flow rate and quality of ~team entering the injection well;
(c) performing a spinner survey of a perforatQd zone of the steam injection well to determine a mass flow rate of ~team at a first station;
(d) injecting a thermally stable vapor phase tracer into the steam injection well;
(e) determining a vapor transit time at a first station;
(f) repeating steps (c)l (d), and (e) for a second station:
and (g) calculating an amount of vapor and an amount of liquid entering a formation at various locations in said perforated zone based on ~aid mass flow rate at said first and said second station of steam entering the well; said mass flow rate, and -3b- 61936-1752 said vapor transit time at said first and said second ~tation.
In yet another aspect the inven~ion provides a method of determining liquid and vapor phase steam profiles in a steam injection well comprising the steps of:
(a) inserting a well logging tool into a steam injection well (b) measuring a mass flow rate and quality of steam entering the injection well;
(c) performing a spinner survey of a perforated zone of the steam injection well to determine a mass flow rate of steam at a first station ~ d) injecting an irradiated liquid phase tracer into said steam injection well;
(e) determining a vapor tran~it time at a first station:
(f) repeating steps (c), (d), and (e) for a second station; and (g) calculating an amount of vapor and an amount of liquid entering a formation at various locations in said perforated zone based on said mass flow rate at said first and aid ~econd station of 3team entering the well, said mass flow rate, and said vapor tran~it time at said first and said second station.
D~r~l~r~o~ Cu~b FIG. l is a plot showing the gamma ray detector outputs for a methyl iodide survey.
FIG. 2 schematically illustrates the method and appara-tus used ~n the first preferred e~bodiment.
Surprisingly, it has been found that up to 89 percent of the methyl iodide injected into a steam injection well hydrolyzes within 10 seconds exposure to typical injection well conditions~ In a field trial, methyl iodide was injected into -3c- 61936-1762 the well and travelled into the formation in about 10 seconds.
Gamma ray detector outputs (as shown in FIG. 1~ show two distinct peaks ~3~
01 _4_ characteristic of methyl iodide in the vapor phase (peak A) and decomposition products in the liquid phase 05 (peak B). Calculations of the area under these two curves show that 8g percent of the methyl iodide is found in the liquid. Note that peak B shows strong dispersion charac-teristic of a liquid signal.
Methyl iodide and other alkyl halide tracers are believed by the inventors herein to degrade according to the following reactions in a steam injection well within the time required for the tracers to reach the formation:
Methyl iodide: CH3I ~ H20 -> CH30H + HI
Ethyl iodide: C2H5I ~ H20 > C2H50H + HI
(with a possible side reaction:
-- C2H5I > C2H4 + HI) Methyl bromide: CH3Br + H20 - > CH30H ~ HBr Ethyl bromide: c2H5sr + H20 - > C2H50H ~ HBr Due to the high solubility and low vapor pressure oE HX
and HBr, the reaction products will virtuaLly totally equilibrate into the liquid phase oE the steam. Alsol HI
and HBr are strong acids while the liquid phase of t:he steam is very basic, so once the HI or HBr e~uilibrates into the liquid phase, they will be converted to salts which are totally water-soluble. Therefore, when a por-tion of an alkyl halide vapor phase tracer thermally degrades (hydrolyzes) within the wellbore, the liquid phase of the steam will also be traced. When all of the vapor phase tracer has hydrolyzed, virtually only the `liquid phase will be traced. These problems make it vir-tually impossible to formulate an accurate injection pro-file.
Therefore, an improved method and means of determining the steam injection profile of a steam injec-tion well has been devised. FIG. 2 schematically illus-trates the method and apparatus of the first preEerred ~3~ 3 ~1 -5-embodiment Steam is yenerated in steam generator 1 and injected into steam injection well 2 khrough tubing 3 and 05 perforations 5 into petroleum formation 6. It is impor-tant in the practice of the present invention that the steam rate and quality be maintained at a relatively con-stant level, so conditions should be stabilized bef~e the me-thod is carried out. The steam mass flow rate and quality is determined at the wellhead with flow rate and quality measurement equipment 12.
Initially, a well logging tool 4 is used to develop temperature and/or pressure profiles which enable the determination of vapor and liquid densities from steam l~ tables. Well logging tool 4 i5 then returned to the ..... . . .
bottom of perforated zone 5. A slug of liquid phase tracer 7 is then injected into steam line 9. In the pre-ferred embodiment, liquid phase tracer 7 is elemental iodine 131 or sodium iodide. A sufficient quantity is injected to permit easy detection at the gamma ray detec-tor~. This quantity will vary radically depending on the steam flow rate and steam quality, but can readily be calculated by one skilled in the art.
L,ogging tool 4 is of a type well known in the art and contains gamma ray detectors 10. Instrumentation and recording equipment 11 is used ~o record the tran~it time for the passing slug oE tracer between the detec-kors 10. ~ogying tool 4 ls then moved upward in the well-bore and the above procedure is repeated.
After da~a have been gathered using the liquid phase tracer 7, logging tool 4 is returned to tha bottom of the perforated zone and the above procedure is repeated using thermally stable vapor phase tracer 8. In the pre ferred embodiment, vapor phase tracer 8 i5 Krypton 85, 3~ Argon, Xenon 133, or other irradiated, thermally s~able gases.
The vapor and liquid flow rates at each location in the perforated zone can now be determined respectively with the equations:
~ ~30~3 VV TV (1 ~5 VL TL (2) where.
VV = Vapor velocity;
VL = L.iquid veIocity;
L = The distance between detectors 10;
TV = Vapor transit time; and TL = Liquid transit time.
From a simple mass balan~e, it is also found that:
~PVVV + PL(l ~ a)VL]A
where:
~U W= The mass flow rate measured at each -tool location;
= The wellbore cross~sectional area corrected Eor the presence of the logging tool~
PV and PL = The vapor and liquid phase densities (determined rom the temperctture log~, the pressure loys, or Erom both); and ~ = The downhole void Eraction.
Solvin~ for a from Equation (3) yields:
W
= A L ~L _ ~ PVVV ~ PL VL (4) The downhole steam quality above the top perforated zone, i.e., at the tubing tail, can then be calculated from the equation:
PV Vv x . . . . ~
pyaVv -~ pL(l - ~VL
~0 )4~ 3 where:
X= s-team quality above -the perforated zone;
~ is given by equation 4 where W is the steam flow;
Ta measured at the well bed 05Beginning at the top of the perEorations, the vapor and liquid profiles can now be determined. Since the total mass f:Low rate into the well is known, the vapor and liquid flow rates at the top of the perforated inter-val (designated station "l") can be calculated from the equations:
Wv1 = (W)(x) (6) WLl = (W)(l - x) where:
Wvl = The vapor mass flow rate at station l~
WL2 = The liquid mass flow rate at station l.
The amount of vapor and liquid leaving the wellbore ~o between station l and station 2 is now givQn by the equa-tions:
wwvl = wvl L [1 TV21 ] ; (8) WWLl WLl [1 [( ~ ( 9 ) The vapor and liquid mass Elow rates at station 2 are now given by the equations:
WV2 = ~Vl W~Vl WL2 = WLl ~ ~WLl The above calculations can now be p~rformed at every location in the wellbore where data have been taken.
In general, the amount of vapor and liquid entering the formatlon between station i:and station (i -~ l) will be given by the equations:
~ 3~4~3 ~1 -8-~ai -~ 1 rVl ~ :1 ( 10 ) -(1 - a(i + 1)) TLi _ WwLi VLi 1 - (1 - ai) TL(i + 1) _ (11) As an alternative to the above procedure, a single tracer can be used ~for either the vapor or liquid phase, as described above) in combination with a spinner survey of the type well known to one skilled in the art.
In this method, the spinner can be used to extract the total mass flow rate at any given point within the per-forated zone. Simple mass balance equations can then beused to develop a profile along the perforated zone. In this app~oach, the spinner response is represented by the following'"equationsO
rps = flWv~ WL~ X) (12) where:
~U
rps = the spinner response WV ~ the vapor flow rate WL = the liquid 10w rate X = the steam quality The tracer surve~ results are used to calculate the flow rate of one phase (Wv or WL). E-luation ~12) is then used ~o caLculate the other flow r.ate ~WL or Wv~.
The above-descrlbed vapor or liquid tracers are used.
It is to be understood that the above-described embodiments are intended to be illustrative and not restrictive. For~example, the order of the above-described steps could readily be varied. For that reason, the scope of the~invention is not to be limited by the above~described embodiments, but instead by the appended claims along with the full range of equivalents th~retoO
E'IELD OF THE INVE~TIO~
.
This inven-tion relates generally to thermally enhan-ced oil recovery. More specifically, this invention provides a method and apparatus for accurately developing steam injection profiles in steam in~ection wells.
B~CKGROUND OF _HE INVENTION
In the production of crude oil, it is frequently found that the crude oil is sufficiently viscous to require the injection of steam into the petroleum reservoir. Ideally, the petroleum reservoir would be completely homogeneous and the steam would enter all portions of the reservoir evenly. How-ever, it is often found that this does not occur. Instead, steam selectively enters a small portion of the reservoir while effectively bypassing other portions of the reservoir. Eventu-ally, "steam breakthrough" occurs and most of the steam flows directly from an injection well to a production well, bypassing a large part of the petroleum reservoir.
It is possible to overcome this problem with various remedial measures, e.g., by plugging off certain portions of the injection well. For example, see U.S. Patent Nos.
4,470,462 and 4,501,329, assigned to the assignee of the pre-sent inven-tion. However, to institute these remedial measures, it is necessary to determine which portions oE the reservoir are selectively receiving the injected steam. This is often a difficult problem.
Various methods have been proposed for det~rmining how injected steam is being distributed in the wellbore.
Bookout ("Injection Profiles During Steam Injection", SPE Paper ~o. 801-43C, May 3, 1967) summarizes the known methods for determining steam in]ection profil~sO
The first and most widely used of these methods is Xnown as a "spinner survey"~ A tool containing a freely rota-ting impeller is placed in the wellbore. As steam passes the impeller, it rotates at a rate which s~
~3(~ 3 ~1 -2-depends on the velocity of the steam~ The rotation vf theimpeller is translated into an electrical signal which is 05 transmitted up the logging cable to the surface where it is recorded on a strip chart or other recording device.
As is well known to those skilled in the art, these spinners are greatly affected by -the quality of the steam injected into the well, leading to unreliable results or results which cannot be interpreted in any way~
Radioactive tracer surveys are also used in many situations. With this method methyl iodide (131) has been used to trace the vapor phase. Sodium iodide has been used to trace the liquid phase. The radioactive Iodine is injected into the steam between the injection well and the steam generator. The tracer moves down the tubing with the steam-until it reaches the formation, where the tracer is temporarily held on the face of the formation for several minutes. A typical yamma ray log is then run~
immediately followin~ the tracer injection. The recorded gamma ray intensity at any point in the well is then assumed to be proportional to the amount of ~team injectecl at that point.
The vapor phase tracers have variously been described as alkyl halides (methyl iodide, methyl bromide, and ethyl bromide) or elemental iodine. It has been found that the above materials undergo chemical reactions that dramatically affect the accuracy of the results of the survey.
3~ It is, therefore, desirable to devise a highly accurate method of developing steam profiles in steam injection wells.
SUMMARY OF THE INVENTION
Field trials with the most common radioactive tracer, methyl iodide, were run to determine its effec-tiveness as a vapor tracer. It was Eound that a si~nifi-cant percentage of methyl iodide decomposes into liquid soluble components shortly after injection.
It is also believed that significant errors in measurement will occur when elemental iodine is used, as ~1 3~ i3 well a~ the alkyl halides other than methyl iodide. Further errors in the use of prior art tracers result from the assump-tion that tracers "plate o~t" in the formation and the assumption that gamma ray intensity is proportional to flow at a given depth.
Therefore, we have devised a method of determining the steam profile in a steam injection well using improved tracers and actual liquid and vapor velocities. A logging tool with temperature and/or pressure measurement devices and dual gamma ray detectors is placed in the injection well. Temperature and/or pressure logs are then run to determine vapor and liquid densities. The dual gamma ray logging tool is then placed in the formation at a known depth. After determining the mass flow rate and quality of steam entering the well, liquid phase tracers and thermaly stable, irradiated vapor phase tracers are injected into the flowing steam at the wellhead and detector outputs are recorded to calculate transit time between the detectors. This procedure is repeated at different positions ln the wellbore tQ
obtain an injection profile.
Alternatively~ the improved liyuid phase tracer or vapor phase tracer can be uqed in conjunction with a traditional spinner survey to determine both liquid and vapor profiles.
Accordingly, in one aspect the present invention provides a method of determining liquid and vapor phase steam profiles in a steam injec~tion well comprising the steps of:
(a) inserting a well logging tool into a steam injection well at a first Iocation, said logging tool further comprising dual gamma ray detectors;
(b) mea~uring a ma~s flow rate and quality of steam entering the steam injection well:
(c) injecting an irradiated, liquid phase tracer into the ~3~41~
-3a- 61936 1762 steam injection well;
(d) determining a liquid transit time with said logging tool;
(e~ injecting an irradiated, thermally stable vapor phase tracer into the steam injection well;
(f) determining a vapor transit time with said logging tool;
(g) moving said logging tool to a second location;
(h) repeating steps (c), (d), (e), and (f); and (i) calculating an amount of vapor and an amount of liquid entering a formation between said first location and said second location~
In another aspect the invention provides a method of determining liquid and vapor phase steam profiles in a steam injection well comprising the steps of:
(a) inserting a well logging tool into a steam injection well;
(b) measuring a mass flow rate and quality of ~team entering the injection well;
(c) performing a spinner survey of a perforatQd zone of the steam injection well to determine a mass flow rate of ~team at a first station;
(d) injecting a thermally stable vapor phase tracer into the steam injection well;
(e) determining a vapor transit time at a first station;
(f) repeating steps (c)l (d), and (e) for a second station:
and (g) calculating an amount of vapor and an amount of liquid entering a formation at various locations in said perforated zone based on ~aid mass flow rate at said first and said second station of steam entering the well; said mass flow rate, and -3b- 61936-1752 said vapor transit time at said first and said second ~tation.
In yet another aspect the inven~ion provides a method of determining liquid and vapor phase steam profiles in a steam injection well comprising the steps of:
(a) inserting a well logging tool into a steam injection well (b) measuring a mass flow rate and quality of steam entering the injection well;
(c) performing a spinner survey of a perforated zone of the steam injection well to determine a mass flow rate of steam at a first station ~ d) injecting an irradiated liquid phase tracer into said steam injection well;
(e) determining a vapor tran~it time at a first station:
(f) repeating steps (c), (d), and (e) for a second station; and (g) calculating an amount of vapor and an amount of liquid entering a formation at various locations in said perforated zone based on said mass flow rate at said first and aid ~econd station of 3team entering the well, said mass flow rate, and said vapor tran~it time at said first and said second station.
D~r~l~r~o~ Cu~b FIG. l is a plot showing the gamma ray detector outputs for a methyl iodide survey.
FIG. 2 schematically illustrates the method and appara-tus used ~n the first preferred e~bodiment.
Surprisingly, it has been found that up to 89 percent of the methyl iodide injected into a steam injection well hydrolyzes within 10 seconds exposure to typical injection well conditions~ In a field trial, methyl iodide was injected into -3c- 61936-1762 the well and travelled into the formation in about 10 seconds.
Gamma ray detector outputs (as shown in FIG. 1~ show two distinct peaks ~3~
01 _4_ characteristic of methyl iodide in the vapor phase (peak A) and decomposition products in the liquid phase 05 (peak B). Calculations of the area under these two curves show that 8g percent of the methyl iodide is found in the liquid. Note that peak B shows strong dispersion charac-teristic of a liquid signal.
Methyl iodide and other alkyl halide tracers are believed by the inventors herein to degrade according to the following reactions in a steam injection well within the time required for the tracers to reach the formation:
Methyl iodide: CH3I ~ H20 -> CH30H + HI
Ethyl iodide: C2H5I ~ H20 > C2H50H + HI
(with a possible side reaction:
-- C2H5I > C2H4 + HI) Methyl bromide: CH3Br + H20 - > CH30H ~ HBr Ethyl bromide: c2H5sr + H20 - > C2H50H ~ HBr Due to the high solubility and low vapor pressure oE HX
and HBr, the reaction products will virtuaLly totally equilibrate into the liquid phase oE the steam. Alsol HI
and HBr are strong acids while the liquid phase of t:he steam is very basic, so once the HI or HBr e~uilibrates into the liquid phase, they will be converted to salts which are totally water-soluble. Therefore, when a por-tion of an alkyl halide vapor phase tracer thermally degrades (hydrolyzes) within the wellbore, the liquid phase of the steam will also be traced. When all of the vapor phase tracer has hydrolyzed, virtually only the `liquid phase will be traced. These problems make it vir-tually impossible to formulate an accurate injection pro-file.
Therefore, an improved method and means of determining the steam injection profile of a steam injec-tion well has been devised. FIG. 2 schematically illus-trates the method and apparatus of the first preEerred ~3~ 3 ~1 -5-embodiment Steam is yenerated in steam generator 1 and injected into steam injection well 2 khrough tubing 3 and 05 perforations 5 into petroleum formation 6. It is impor-tant in the practice of the present invention that the steam rate and quality be maintained at a relatively con-stant level, so conditions should be stabilized bef~e the me-thod is carried out. The steam mass flow rate and quality is determined at the wellhead with flow rate and quality measurement equipment 12.
Initially, a well logging tool 4 is used to develop temperature and/or pressure profiles which enable the determination of vapor and liquid densities from steam l~ tables. Well logging tool 4 i5 then returned to the ..... . . .
bottom of perforated zone 5. A slug of liquid phase tracer 7 is then injected into steam line 9. In the pre-ferred embodiment, liquid phase tracer 7 is elemental iodine 131 or sodium iodide. A sufficient quantity is injected to permit easy detection at the gamma ray detec-tor~. This quantity will vary radically depending on the steam flow rate and steam quality, but can readily be calculated by one skilled in the art.
L,ogging tool 4 is of a type well known in the art and contains gamma ray detectors 10. Instrumentation and recording equipment 11 is used ~o record the tran~it time for the passing slug oE tracer between the detec-kors 10. ~ogying tool 4 ls then moved upward in the well-bore and the above procedure is repeated.
After da~a have been gathered using the liquid phase tracer 7, logging tool 4 is returned to tha bottom of the perforated zone and the above procedure is repeated using thermally stable vapor phase tracer 8. In the pre ferred embodiment, vapor phase tracer 8 i5 Krypton 85, 3~ Argon, Xenon 133, or other irradiated, thermally s~able gases.
The vapor and liquid flow rates at each location in the perforated zone can now be determined respectively with the equations:
~ ~30~3 VV TV (1 ~5 VL TL (2) where.
VV = Vapor velocity;
VL = L.iquid veIocity;
L = The distance between detectors 10;
TV = Vapor transit time; and TL = Liquid transit time.
From a simple mass balan~e, it is also found that:
~PVVV + PL(l ~ a)VL]A
where:
~U W= The mass flow rate measured at each -tool location;
= The wellbore cross~sectional area corrected Eor the presence of the logging tool~
PV and PL = The vapor and liquid phase densities (determined rom the temperctture log~, the pressure loys, or Erom both); and ~ = The downhole void Eraction.
Solvin~ for a from Equation (3) yields:
W
= A L ~L _ ~ PVVV ~ PL VL (4) The downhole steam quality above the top perforated zone, i.e., at the tubing tail, can then be calculated from the equation:
PV Vv x . . . . ~
pyaVv -~ pL(l - ~VL
~0 )4~ 3 where:
X= s-team quality above -the perforated zone;
~ is given by equation 4 where W is the steam flow;
Ta measured at the well bed 05Beginning at the top of the perEorations, the vapor and liquid profiles can now be determined. Since the total mass f:Low rate into the well is known, the vapor and liquid flow rates at the top of the perforated inter-val (designated station "l") can be calculated from the equations:
Wv1 = (W)(x) (6) WLl = (W)(l - x) where:
Wvl = The vapor mass flow rate at station l~
WL2 = The liquid mass flow rate at station l.
The amount of vapor and liquid leaving the wellbore ~o between station l and station 2 is now givQn by the equa-tions:
wwvl = wvl L [1 TV21 ] ; (8) WWLl WLl [1 [( ~ ( 9 ) The vapor and liquid mass Elow rates at station 2 are now given by the equations:
WV2 = ~Vl W~Vl WL2 = WLl ~ ~WLl The above calculations can now be p~rformed at every location in the wellbore where data have been taken.
In general, the amount of vapor and liquid entering the formatlon between station i:and station (i -~ l) will be given by the equations:
~ 3~4~3 ~1 -8-~ai -~ 1 rVl ~ :1 ( 10 ) -(1 - a(i + 1)) TLi _ WwLi VLi 1 - (1 - ai) TL(i + 1) _ (11) As an alternative to the above procedure, a single tracer can be used ~for either the vapor or liquid phase, as described above) in combination with a spinner survey of the type well known to one skilled in the art.
In this method, the spinner can be used to extract the total mass flow rate at any given point within the per-forated zone. Simple mass balance equations can then beused to develop a profile along the perforated zone. In this app~oach, the spinner response is represented by the following'"equationsO
rps = flWv~ WL~ X) (12) where:
~U
rps = the spinner response WV ~ the vapor flow rate WL = the liquid 10w rate X = the steam quality The tracer surve~ results are used to calculate the flow rate of one phase (Wv or WL). E-luation ~12) is then used ~o caLculate the other flow r.ate ~WL or Wv~.
The above-descrlbed vapor or liquid tracers are used.
It is to be understood that the above-described embodiments are intended to be illustrative and not restrictive. For~example, the order of the above-described steps could readily be varied. For that reason, the scope of the~invention is not to be limited by the above~described embodiments, but instead by the appended claims along with the full range of equivalents th~retoO
Claims (5)
1. A method of determining liquid and vapor phase steam profiles in a steam injection well comprising the steps of:
(a) inserting a well logging tool into a steam injection well at a first location, said logging tool further comprising dual gamma ray detectors;
(b) measuring a mass flow rate and quality of steam entering the steam injection well;
(c) injecting an irradiated, liquid phase tracer into the steam injection well;
(d) determining a liquid transit time with said logging tool;
(e) injecting an irradiated, thermally stable vapor phase tracer into the steam injection well:
(f) determining a vapor transit time with said logging tool;
(g) moving said logging tool to a second location;
(h) repeating steps (c), (d), (e), and (f); and (i) calculating an amount of vapor and an amount of liquid entering a formation between said first location and said second location.
(a) inserting a well logging tool into a steam injection well at a first location, said logging tool further comprising dual gamma ray detectors;
(b) measuring a mass flow rate and quality of steam entering the steam injection well;
(c) injecting an irradiated, liquid phase tracer into the steam injection well;
(d) determining a liquid transit time with said logging tool;
(e) injecting an irradiated, thermally stable vapor phase tracer into the steam injection well:
(f) determining a vapor transit time with said logging tool;
(g) moving said logging tool to a second location;
(h) repeating steps (c), (d), (e), and (f); and (i) calculating an amount of vapor and an amount of liquid entering a formation between said first location and said second location.
2. The method as recited in Claim 1 wherein said thermally stable vapor phase tracer is selected from the group irradiated Argon, irradiated Krypton or irradiated Xenon.
3. A method of determining liquid and vapor phase steam profiles in a steam injection well comprising the steps of:
(a) inserting a well logging tool into a steam injection well;
(b) measuring a mass flow rate and quality of steam entering the injection well;
(c) performing a spinner survey of a perforated zone of the steam injection well to determine a mass flow rate of steam at a first station;
(d) injecting a thermally stable vapor phase tracer into the steam injection well;
(e) determining a vapor transit time at a first station;
(f) repeating steps (c), (d), and (e) for a second station;
and (g) calculating an amount of vapor and an amount of liquid entering a formation at various locations in said perforated zone based on said mass flow rate at said first and said second station of steam entering the well; said mass flow rate, and said vapor transit time at said first and said second station.
(a) inserting a well logging tool into a steam injection well;
(b) measuring a mass flow rate and quality of steam entering the injection well;
(c) performing a spinner survey of a perforated zone of the steam injection well to determine a mass flow rate of steam at a first station;
(d) injecting a thermally stable vapor phase tracer into the steam injection well;
(e) determining a vapor transit time at a first station;
(f) repeating steps (c), (d), and (e) for a second station;
and (g) calculating an amount of vapor and an amount of liquid entering a formation at various locations in said perforated zone based on said mass flow rate at said first and said second station of steam entering the well; said mass flow rate, and said vapor transit time at said first and said second station.
4. The method as recited in Claim 2 wherein said thermally stable vapor phase tracer is selected from the group irradiated Argon, irradiated Krypton, or irradiated Xenon.
5. A method of determining liquid and vapor phase steam profiles in a steam injection well comprising the steps of:
(a) inserting a well logging tool into a steam injection well;
(b) measuring a mass flow rate and quality of steam entering the injection well;
(c) performing a spinner survey of a perforated zone of the steam injection well to determine a mass flow rate of steam at a first station;
(d) injecting an irradiated liquid phase tracer into said steam injection well;
(e) determining a vapor transit time at a first station;
(f) repeating steps (c), (d), and (e) for a second station;
and (g) calculating an amount of vapor and an amount of liquid entering a formation at various locations in said per-forated zone based on said mass flow rate at said first and said second station of steam entering the well, said mass flow rate, and said vapor transit time at said first and said second station.
(a) inserting a well logging tool into a steam injection well;
(b) measuring a mass flow rate and quality of steam entering the injection well;
(c) performing a spinner survey of a perforated zone of the steam injection well to determine a mass flow rate of steam at a first station;
(d) injecting an irradiated liquid phase tracer into said steam injection well;
(e) determining a vapor transit time at a first station;
(f) repeating steps (c), (d), and (e) for a second station;
and (g) calculating an amount of vapor and an amount of liquid entering a formation at various locations in said per-forated zone based on said mass flow rate at said first and said second station of steam entering the well, said mass flow rate, and said vapor transit time at said first and said second station.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US93566286A | 1986-11-26 | 1986-11-26 | |
| US935,662 | 1986-11-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1304163C true CA1304163C (en) | 1992-06-23 |
Family
ID=25467487
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000552702A Expired - Fee Related CA1304163C (en) | 1986-11-26 | 1987-11-25 | Steam injection profiling |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN1012092B (en) |
| BR (1) | BR8702452A (en) |
| CA (1) | CA1304163C (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1044286C (en) * | 1994-07-15 | 1999-07-21 | 西安石油勘探仪器总厂 | Radioactive energy spectrum tracing water uptake section well logging method |
| CN102322254A (en) * | 2011-06-01 | 2012-01-18 | 陕西华晨石油科技有限公司 | Downhole steam entry profile monitoring method |
| CN103541708A (en) * | 2012-07-11 | 2014-01-29 | 中国石油化工股份有限公司 | Method for improving super-heavy oil steam flooding recovery efficiency |
| CN107939379A (en) * | 2017-11-03 | 2018-04-20 | 中国石油天然气股份有限公司 | Method and system for detecting steam absorption and water absorption conditions of heavy oil thermal recovery steam injection well |
| CN113324777B (en) * | 2021-04-26 | 2024-01-23 | 中国辐射防护研究院 | Polymorphic radioactive iodine environment simulation and equipment comprehensive evaluation equipment |
| CN113586036B (en) * | 2021-09-09 | 2023-07-14 | 中国石油大学(华东) | A device and method for early monitoring of well kick based on dual density measurement of downhole overflow type and invasion amount |
| CN116892387B (en) * | 2023-07-10 | 2024-05-24 | 河南省科学院同位素研究所有限责任公司 | Preparation method of radioactive isotope tracer for oilfield gas flooding monitoring |
-
1987
- 1987-05-13 BR BR8702452A patent/BR8702452A/en not_active IP Right Cessation
- 1987-11-25 CA CA000552702A patent/CA1304163C/en not_active Expired - Fee Related
- 1987-11-25 CN CN 87108005 patent/CN1012092B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN87108005A (en) | 1988-08-03 |
| CN1012092B (en) | 1991-03-20 |
| BR8702452A (en) | 1988-07-05 |
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