CA2148969A1 - Application of low density drilling muds - Google Patents
Application of low density drilling mudsInfo
- Publication number
- CA2148969A1 CA2148969A1 CA002148969A CA2148969A CA2148969A1 CA 2148969 A1 CA2148969 A1 CA 2148969A1 CA 002148969 A CA002148969 A CA 002148969A CA 2148969 A CA2148969 A CA 2148969A CA 2148969 A1 CA2148969 A1 CA 2148969A1
- Authority
- CA
- Canada
- Prior art keywords
- drilling
- density
- additive
- lbg
- drilling muds
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/02—Well-drilling compositions
- C09K8/03—Specific additives for general use in well-drilling compositions
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/02—Well-drilling compositions
- C09K8/03—Specific additives for general use in well-drilling compositions
- C09K8/032—Inorganic additives
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/02—Well-drilling compositions
- C09K8/04—Aqueous well-drilling compositions
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/02—Well-drilling compositions
- C09K8/32—Non-aqueous well-drilling compositions, e.g. oil-based
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Earth Drilling (AREA)
Abstract
Through the addition of light weight additives, it is possible to reduce the density of drilling muds down to a desired value that will permit faster rates of production than can be achieved with conventional drilling muds.
The LBG Additive series can produce an infinite density variation from 360 kg/m3 to 1000 kg/m3 to be used in drilling muds for under balanced development drilling of oil wells.
With the addition of a polymer compound and the LBG Additive, the drilling mud engineer can mix up the correct density so as to allow the drilling operation to proceed in an under balance manner.
There are large financial reasons for oil companies to reduce the density of their drilling muds to the point of under balanced operation.
The LBG Additives range in density from 0.02 g/cc to 0.9 g/cc and in diameter from 10 micro to 150 micron.
The applicability of the additive is directly related to various factors that are encountered during the drilling cycle. This patent explains the applicability of the additive to the drilling cycle.
The LBG Additive series can produce an infinite density variation from 360 kg/m3 to 1000 kg/m3 to be used in drilling muds for under balanced development drilling of oil wells.
With the addition of a polymer compound and the LBG Additive, the drilling mud engineer can mix up the correct density so as to allow the drilling operation to proceed in an under balance manner.
There are large financial reasons for oil companies to reduce the density of their drilling muds to the point of under balanced operation.
The LBG Additives range in density from 0.02 g/cc to 0.9 g/cc and in diameter from 10 micro to 150 micron.
The applicability of the additive is directly related to various factors that are encountered during the drilling cycle. This patent explains the applicability of the additive to the drilling cycle.
Description
~ 6 ~
DETAI1ED DESCRIPTION:
In oil well deyelopment drilling, the production rate obtained is directly related to the density of the drilling fluid used to remove the cuttings from the tool face. In every case, when the density is matched correctly to that required by the formation, substantial increases in production can be achieved.
These increases are in the order of two(2) times over otherwise "normal"
drilling rates. This potentially results in oil well drilling that can proceed .
:~ . - :
~, 2148969 at substantially higher rates, and thus project completions ahead of schedule resulting in saved money. The possibility of completing an oil well in half the "normal" time is well within the physical limitation of development drilling.
At present, the drilling companies use Nitrogen gas to displace the water and thus reduce the density. It is known how ineffective this method is, yet this was the only method available. There are several draw backs to using Nitrogen gas that makes its replacement, especially by techniques presented within the context of this patent, a very real eventuality.
The primary concern of the drilling companies up until very recently was the reduction of torque drag, removal of the cuttings and circulation within the hole. With the advent of horizontal drilling, the drilling companies soon realized that it was within their power to begin production of the reservoir while the final development phase was being completed. This resulted in the development of the under balanced drilling regime.
The critical nature in under balanced drilling is matching the hydrostatic and dynamic pressures with that of the pressure exerted by the formation. The largest single problem with this procedure is the difficulty in determining the exact formation pressure, and as a result mixing up the required density of the drilling mud to match both the hydrostatic and dynamic pressures.
Traditionally, over balanced drilling involves the drilling mud exerting pressure into the surrounding rock so as to prevent any migration of fluid and gases from the formation into the drilling mud. The problems associated with this type of drilling regime are:
The higher pressures within the hole cause the part~es within the hole to be forced into the surrounding rock formation's porosity. This leads to potential blockage of the zone by way of all the ~ines ~ 2148969 collecting within the porosity of the formation. This action can be potentially damaging to the formation leading to a reduction in ultimate production from the resevoir.
The higher pressures exacerbate the problem when fractures are encountered. The higher pressure will force the drilling mud down the fracture and away from the well. This type of event typically is identified as a "loss in circulation". It is a very bad situation and companies will spend considerable amounts of money to plug these fractures once they have stolen the circulation.
The higher pressures force the oil and gas into the formation not allowing it to be extracted while the final stages of development are taking place. This is not always such a bad event, particularly in the event of sour gas or any other unwanted hazardous chemicals.
With the advent of more efficient drilling operations and reservoir recovery, it has been noted that by reducing the density, the company can reverse all the effects stated above. In such situations such as sour gas, for the safety of the rig, over balanced operations shall continue to keep the gas under control until such time as the company is prepared to handle it.
For the rf-~ining holes, the reduction in the density provides extremely good justification for its application.
The only other method currently available to the drilling companies is Nitrogen injection into the well to reduce the density. The reason for Nitrogen injection is pure functionality, it is readily available and does not provide (- 2148969 oxygen to a potentially explosive environment. Until recently, it was thought that the purity from Nitrogen systems was such that very small amounts of Oxygen was being pumped down the hole. This, however, is not the case from the portable, cheaper systems as the high level of Oxygen is leading to severe corrosion within the drill pipes and other metal surfaces coming in contact with the drilling muds. This unexpected short coming is curtailed application of this system.
The intension of this application is to introduce the addition of an ultra light density additive to the mud so as to reduce the total, overall density.
The LBG Additive series can be added to create virtually any density.
Due to the nature of the LBG Additive series, the total vertical depth of the well plays a critical factor in determining the ultimate potential density.
The reason for this is the higher the pressures, the tougher the additive needs be, and as a direct result, the particles by nature must be heavier.
The single largest feature of this application over the present Nitrogen process is the ability of the drilling company to recover the LBG Additive so a to move the system to drill another hole at another location. Nitrogen gas on the other hand, once it has been pumped into the hole and returned to the surface, it is released into the atmosphere never to be recovered again. This adds considerably to the cost of under balanced drilling. For this reason alone, many drilling companies are hesitant to proceed with under balanced drilling due to the cost of the Nitrogen gas.
- Compressibility Due to the hydrostatic head within the well, the Nitrogen gas readily decreases volume and thus effectiveness. To counter this, the company can on~
put more Nitrogen gas into the system. The draw badk this is the production of a foam for the top 100 metres ~ 2148969 or so of the well. This foam does not permit the operation of a standard drill tool survey tools, and thus forces the company rely on technology that is less than reliable. In addition, the volume of Nitrogen gas will reduce to approximately 1~ of initial value within the initial depth.
- Foaming As mentioned above, the top 100 metres section contains a very light foamy solution that does not permit the transmission of pressure waves. These pressure waves are presently used for the survey tools many of the companies employ. As a result of this failure, the companies are forced to rely upon other, much more unstable new technology which has proven not to be overly successful. In addition, these tools are more expensive than those used to pulse the fluid for data transmission.
- Limitation of Supply.
While there rely is no true limitation on supply for liquid Nitrogen gas, the amount that the company can physically force down a hole is limited. The deeper the well, the more Nitrogen gas must be injected.
- One time deal.
The Nitrogen gas is used only once and then released into the atmosphere. This is highly inefficient.
While there are all the benefits of under balanced drilling, the hassle and involvement with the nitrogen system makes it to complicated and expensive for oil companies to fully exploit.
L, 2l48969 The LBG Additive series gives the oil company a manner in which to perform under balanced drilling and not have to be concerned with all the complications of nitrogen gas. The additive series can be added directly to the drilling fluid much the same as other presently added additives.
Not being a gas, these additives, when added in the correct situation, will not crush or compress, thus pressure wave can pass through them allowing conventional survey tools to be utilized.
Presently, in the industry, there are two base components to drilling muds, fresh water and salt water. Typically, the company will then add an additives to effect lubrication, density, viscosity, formation interaction and chemical inertness. The use of mircospheres has been seen in the industry, but only as a method to increase the lubrication of the hole. This required small amounts of the microspheres and did not play a major role in effecting density.
By adding the microspheres from 5% to 80% total volume, the density of the fluid can be drastically changed. The lower values than 5% do not effect the density substantially and therefor it would be wiser to other, less expensive additives to achieve these densities. Values higher that 80% by volume can be achieved, however, the problem of phase separation is encountered once the water has allowed to come to rest for more than 10 minutes, with potential hardening within 24 hours. At these volume concentrations, the pumpability also becomes a factor. It is possible to achieve higher concentrations is the conditions require it.
The second factor in the utilization of the mircospheres in a drilling environment is the expected pressures exerted on the microspheres during their voyage around the drilling cycle. Since these mircosphere are pressure dependant, the proper application it critical to their success.
In designing the system for the additive's use, one of the following 21~8969 outlined procedures must be ~ollowed.
XNO~N FORMA~ION PR~SSURS
1) Determinatlon o~ the ~ormation pressure.
~) Determination of the varlous depths for the di~ferent ~ormatlons.
~) In knowing the ~`ormation pressure and the depth, one can then calculate the density of the arilling mud so as to produce an under balance condition.
row = P~
w~lere:
row = desired density o~ the drllling mud P~ = formation pressure at depth H = rhe actual depth o~- the ~ormatlon This equation will yield the balance drilling condition ~or ~ormation. The intension now is to reduce the density to produce the under balanced condition. The exact amount of reductlon will depend on the formation, desired drilling rates and the ~unctionality o~ the microspheres. This calculation can be repeated to determine the drilling densities down the depth of the hole as the drllling passes through various formations.
4) Determination o~ the correct LB~ Additive to add to ~he drilling mud to produce the desired density. This is determined ln the ~ollowing equatlon:
~_, 21~8969 row(D) = X * row(A) + (1 - X)*row(W) some re-arranging and:
X = row(D) - row(W) (2) row(A) - row(W) where:
X = volume percent of additive to yield density row(D) = desired density from equation (1) row(W) = present fluid density before additive row(A) = density of LBG Additive [from supplier]
5) From equation (2), one obtains the percent required, by volume, to produce the desired density of drilling mud. Knowing the volume flow of drilling muds required, the volume flow of additive is simply:
Q(T) = Q(A) + Q(W) (3) where:
Q(T) = total volume flow required Q(A) = volume flow of additive Q(W) = volume flow of present drilling fluid and:
Q(A) = X ~ Q(T) (3A) Q(W) = (1 - X) * Q(T) (3B) where:
21~8969 X = volume percent flow of additive to yield density.
and the total mass flow is:
m.dot.(A) = Q(A) * row(A) (3C) m.dot.(W) = Q(W) * row(W) (3D) where:
m.dot.(A) = mass flow of additive m.dot.(W) = mass flow of present drilling fluid row(A) = density of LBG Additive row(W) = density of present drilling fluid 6) From knowing the mass flow into the system, it is a simple case of calculating cost to aid in the determination of the most effective additive to utilize.
$T = m.dot.(A) * $(A) (4) where:
$T = cost per unit time of additive m.dot.(A) = mass flow of LBG Additive per unit time $(A) = cost of LBG Additive per unit mass 7) The process is now iterative to determine the most cost effective method of reducing the density. Since the LBG Additives come in such a variety, the combination of density and cost of the additives play a major role in the price per unit drilling mud.
8) Once the hole has been reduce to the required density, it is simply a case of keeping the density at the target value. Since very few of the microspheres will be destroyed during a cycle, the task at hand is to replace the ones that are crushed. This is a low number and potentially even 0%. This factor depends on the depth, flow rate of mud, type of formation and strength of the mircosphere.
This is where the benefits of this system come into play. In the case of the nitrogen, the company is continuously adding nitrogen, yet here, they are simply replacing the missing spheres. This proves to be cheaper.
This technique will provide the drilling engineer with the rough calculations to purchase the initial amounts of the LBG Additives. There is however, the present method of determining the under balanced condition, and this is through trial and error. This involves adjusting the volume flow of the nitrogen into the system until the production rate increases and therefore this must be the under balanced condition.
This technique can be applied to the additives, yet an initial estimate of the amount and density must be made in order to ensure not running out while under drilling conditions.
In order to not contaminate the oil while under production with the additive in the system, the use of a polymer to adhere to the mircospheres to prevent them from becoming trapped in the oil. Once in the oil, it is difficult to remove them completely. Recovery is in the order of 95%, yet this is unacceptable since contamination of the oil has occurred. The rA ~;n;ng 5% is quite valuable and as such should be recovered if possible.
The polymer traps the microspheres before they have a chance to interact with the oil, and as such are almost 100% recoverable from the oil.
At the completion of the drilling program, the polymer and additive are ~ 2148969 then stripped from the system using a separator and loaded into holding trucks.
Now the additives and polymer can be transported to the next well site for use there.
Tests have been performed to determine the effectiveness of this procedure on drilling fluids and presented below are some results.
ADDITIVE:
LBG Additive-HS
Density : 0.6 g/cc Diameter : 20 to 150 micron Hydrostatic collapse strength = 124 MPa (18,000 psi) DRILLING MUD
Density : 1.11 g/cc WATER
Density : 1.0 g/cc Mixed 1 part MUD, 1 part WATER and 2 parts ADDITIVE
Density = 0.85 g/cc - from Laboratory using APHA,AWWA,WPCF 16TH Edition method 213E
214896~
Calculated density =0.82 ~/cc This shows excellent agreement between actual and theoretical.
Mixed 1 part WATER and 2 parts ADDITIVE
Density = 0.755 - from Laboratory usin~ APHA, AWWA, WPCF, 16TH Edition -method 213E
Calculated density = 0.733 Again this show excellent agreement between actual and theoretical.
1~
DETAI1ED DESCRIPTION:
In oil well deyelopment drilling, the production rate obtained is directly related to the density of the drilling fluid used to remove the cuttings from the tool face. In every case, when the density is matched correctly to that required by the formation, substantial increases in production can be achieved.
These increases are in the order of two(2) times over otherwise "normal"
drilling rates. This potentially results in oil well drilling that can proceed .
:~ . - :
~, 2148969 at substantially higher rates, and thus project completions ahead of schedule resulting in saved money. The possibility of completing an oil well in half the "normal" time is well within the physical limitation of development drilling.
At present, the drilling companies use Nitrogen gas to displace the water and thus reduce the density. It is known how ineffective this method is, yet this was the only method available. There are several draw backs to using Nitrogen gas that makes its replacement, especially by techniques presented within the context of this patent, a very real eventuality.
The primary concern of the drilling companies up until very recently was the reduction of torque drag, removal of the cuttings and circulation within the hole. With the advent of horizontal drilling, the drilling companies soon realized that it was within their power to begin production of the reservoir while the final development phase was being completed. This resulted in the development of the under balanced drilling regime.
The critical nature in under balanced drilling is matching the hydrostatic and dynamic pressures with that of the pressure exerted by the formation. The largest single problem with this procedure is the difficulty in determining the exact formation pressure, and as a result mixing up the required density of the drilling mud to match both the hydrostatic and dynamic pressures.
Traditionally, over balanced drilling involves the drilling mud exerting pressure into the surrounding rock so as to prevent any migration of fluid and gases from the formation into the drilling mud. The problems associated with this type of drilling regime are:
The higher pressures within the hole cause the part~es within the hole to be forced into the surrounding rock formation's porosity. This leads to potential blockage of the zone by way of all the ~ines ~ 2148969 collecting within the porosity of the formation. This action can be potentially damaging to the formation leading to a reduction in ultimate production from the resevoir.
The higher pressures exacerbate the problem when fractures are encountered. The higher pressure will force the drilling mud down the fracture and away from the well. This type of event typically is identified as a "loss in circulation". It is a very bad situation and companies will spend considerable amounts of money to plug these fractures once they have stolen the circulation.
The higher pressures force the oil and gas into the formation not allowing it to be extracted while the final stages of development are taking place. This is not always such a bad event, particularly in the event of sour gas or any other unwanted hazardous chemicals.
With the advent of more efficient drilling operations and reservoir recovery, it has been noted that by reducing the density, the company can reverse all the effects stated above. In such situations such as sour gas, for the safety of the rig, over balanced operations shall continue to keep the gas under control until such time as the company is prepared to handle it.
For the rf-~ining holes, the reduction in the density provides extremely good justification for its application.
The only other method currently available to the drilling companies is Nitrogen injection into the well to reduce the density. The reason for Nitrogen injection is pure functionality, it is readily available and does not provide (- 2148969 oxygen to a potentially explosive environment. Until recently, it was thought that the purity from Nitrogen systems was such that very small amounts of Oxygen was being pumped down the hole. This, however, is not the case from the portable, cheaper systems as the high level of Oxygen is leading to severe corrosion within the drill pipes and other metal surfaces coming in contact with the drilling muds. This unexpected short coming is curtailed application of this system.
The intension of this application is to introduce the addition of an ultra light density additive to the mud so as to reduce the total, overall density.
The LBG Additive series can be added to create virtually any density.
Due to the nature of the LBG Additive series, the total vertical depth of the well plays a critical factor in determining the ultimate potential density.
The reason for this is the higher the pressures, the tougher the additive needs be, and as a direct result, the particles by nature must be heavier.
The single largest feature of this application over the present Nitrogen process is the ability of the drilling company to recover the LBG Additive so a to move the system to drill another hole at another location. Nitrogen gas on the other hand, once it has been pumped into the hole and returned to the surface, it is released into the atmosphere never to be recovered again. This adds considerably to the cost of under balanced drilling. For this reason alone, many drilling companies are hesitant to proceed with under balanced drilling due to the cost of the Nitrogen gas.
- Compressibility Due to the hydrostatic head within the well, the Nitrogen gas readily decreases volume and thus effectiveness. To counter this, the company can on~
put more Nitrogen gas into the system. The draw badk this is the production of a foam for the top 100 metres ~ 2148969 or so of the well. This foam does not permit the operation of a standard drill tool survey tools, and thus forces the company rely on technology that is less than reliable. In addition, the volume of Nitrogen gas will reduce to approximately 1~ of initial value within the initial depth.
- Foaming As mentioned above, the top 100 metres section contains a very light foamy solution that does not permit the transmission of pressure waves. These pressure waves are presently used for the survey tools many of the companies employ. As a result of this failure, the companies are forced to rely upon other, much more unstable new technology which has proven not to be overly successful. In addition, these tools are more expensive than those used to pulse the fluid for data transmission.
- Limitation of Supply.
While there rely is no true limitation on supply for liquid Nitrogen gas, the amount that the company can physically force down a hole is limited. The deeper the well, the more Nitrogen gas must be injected.
- One time deal.
The Nitrogen gas is used only once and then released into the atmosphere. This is highly inefficient.
While there are all the benefits of under balanced drilling, the hassle and involvement with the nitrogen system makes it to complicated and expensive for oil companies to fully exploit.
L, 2l48969 The LBG Additive series gives the oil company a manner in which to perform under balanced drilling and not have to be concerned with all the complications of nitrogen gas. The additive series can be added directly to the drilling fluid much the same as other presently added additives.
Not being a gas, these additives, when added in the correct situation, will not crush or compress, thus pressure wave can pass through them allowing conventional survey tools to be utilized.
Presently, in the industry, there are two base components to drilling muds, fresh water and salt water. Typically, the company will then add an additives to effect lubrication, density, viscosity, formation interaction and chemical inertness. The use of mircospheres has been seen in the industry, but only as a method to increase the lubrication of the hole. This required small amounts of the microspheres and did not play a major role in effecting density.
By adding the microspheres from 5% to 80% total volume, the density of the fluid can be drastically changed. The lower values than 5% do not effect the density substantially and therefor it would be wiser to other, less expensive additives to achieve these densities. Values higher that 80% by volume can be achieved, however, the problem of phase separation is encountered once the water has allowed to come to rest for more than 10 minutes, with potential hardening within 24 hours. At these volume concentrations, the pumpability also becomes a factor. It is possible to achieve higher concentrations is the conditions require it.
The second factor in the utilization of the mircospheres in a drilling environment is the expected pressures exerted on the microspheres during their voyage around the drilling cycle. Since these mircosphere are pressure dependant, the proper application it critical to their success.
In designing the system for the additive's use, one of the following 21~8969 outlined procedures must be ~ollowed.
XNO~N FORMA~ION PR~SSURS
1) Determinatlon o~ the ~ormation pressure.
~) Determination of the varlous depths for the di~ferent ~ormatlons.
~) In knowing the ~`ormation pressure and the depth, one can then calculate the density of the arilling mud so as to produce an under balance condition.
row = P~
w~lere:
row = desired density o~ the drllling mud P~ = formation pressure at depth H = rhe actual depth o~- the ~ormatlon This equation will yield the balance drilling condition ~or ~ormation. The intension now is to reduce the density to produce the under balanced condition. The exact amount of reductlon will depend on the formation, desired drilling rates and the ~unctionality o~ the microspheres. This calculation can be repeated to determine the drilling densities down the depth of the hole as the drllling passes through various formations.
4) Determination o~ the correct LB~ Additive to add to ~he drilling mud to produce the desired density. This is determined ln the ~ollowing equatlon:
~_, 21~8969 row(D) = X * row(A) + (1 - X)*row(W) some re-arranging and:
X = row(D) - row(W) (2) row(A) - row(W) where:
X = volume percent of additive to yield density row(D) = desired density from equation (1) row(W) = present fluid density before additive row(A) = density of LBG Additive [from supplier]
5) From equation (2), one obtains the percent required, by volume, to produce the desired density of drilling mud. Knowing the volume flow of drilling muds required, the volume flow of additive is simply:
Q(T) = Q(A) + Q(W) (3) where:
Q(T) = total volume flow required Q(A) = volume flow of additive Q(W) = volume flow of present drilling fluid and:
Q(A) = X ~ Q(T) (3A) Q(W) = (1 - X) * Q(T) (3B) where:
21~8969 X = volume percent flow of additive to yield density.
and the total mass flow is:
m.dot.(A) = Q(A) * row(A) (3C) m.dot.(W) = Q(W) * row(W) (3D) where:
m.dot.(A) = mass flow of additive m.dot.(W) = mass flow of present drilling fluid row(A) = density of LBG Additive row(W) = density of present drilling fluid 6) From knowing the mass flow into the system, it is a simple case of calculating cost to aid in the determination of the most effective additive to utilize.
$T = m.dot.(A) * $(A) (4) where:
$T = cost per unit time of additive m.dot.(A) = mass flow of LBG Additive per unit time $(A) = cost of LBG Additive per unit mass 7) The process is now iterative to determine the most cost effective method of reducing the density. Since the LBG Additives come in such a variety, the combination of density and cost of the additives play a major role in the price per unit drilling mud.
8) Once the hole has been reduce to the required density, it is simply a case of keeping the density at the target value. Since very few of the microspheres will be destroyed during a cycle, the task at hand is to replace the ones that are crushed. This is a low number and potentially even 0%. This factor depends on the depth, flow rate of mud, type of formation and strength of the mircosphere.
This is where the benefits of this system come into play. In the case of the nitrogen, the company is continuously adding nitrogen, yet here, they are simply replacing the missing spheres. This proves to be cheaper.
This technique will provide the drilling engineer with the rough calculations to purchase the initial amounts of the LBG Additives. There is however, the present method of determining the under balanced condition, and this is through trial and error. This involves adjusting the volume flow of the nitrogen into the system until the production rate increases and therefore this must be the under balanced condition.
This technique can be applied to the additives, yet an initial estimate of the amount and density must be made in order to ensure not running out while under drilling conditions.
In order to not contaminate the oil while under production with the additive in the system, the use of a polymer to adhere to the mircospheres to prevent them from becoming trapped in the oil. Once in the oil, it is difficult to remove them completely. Recovery is in the order of 95%, yet this is unacceptable since contamination of the oil has occurred. The rA ~;n;ng 5% is quite valuable and as such should be recovered if possible.
The polymer traps the microspheres before they have a chance to interact with the oil, and as such are almost 100% recoverable from the oil.
At the completion of the drilling program, the polymer and additive are ~ 2148969 then stripped from the system using a separator and loaded into holding trucks.
Now the additives and polymer can be transported to the next well site for use there.
Tests have been performed to determine the effectiveness of this procedure on drilling fluids and presented below are some results.
ADDITIVE:
LBG Additive-HS
Density : 0.6 g/cc Diameter : 20 to 150 micron Hydrostatic collapse strength = 124 MPa (18,000 psi) DRILLING MUD
Density : 1.11 g/cc WATER
Density : 1.0 g/cc Mixed 1 part MUD, 1 part WATER and 2 parts ADDITIVE
Density = 0.85 g/cc - from Laboratory using APHA,AWWA,WPCF 16TH Edition method 213E
214896~
Calculated density =0.82 ~/cc This shows excellent agreement between actual and theoretical.
Mixed 1 part WATER and 2 parts ADDITIVE
Density = 0.755 - from Laboratory usin~ APHA, AWWA, WPCF, 16TH Edition -method 213E
Calculated density = 0.733 Again this show excellent agreement between actual and theoretical.
1~
Claims (2)
1) Any drilling fluid that is to be used in the application of under balance drilling can be reduced in density by using microsphere additives that range in true average particle densities of about 0.02 g/cc to 0.9 g/cc and size less than 500 microns.
2) Any fluid to be utilized in the application of drilling a well, for the purposes of exploration, development or experimentation can in using the light weight additive to improve drilling times by increasing the rate of penetration
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002148969A CA2148969A1 (en) | 1995-05-09 | 1995-05-09 | Application of low density drilling muds |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002148969A CA2148969A1 (en) | 1995-05-09 | 1995-05-09 | Application of low density drilling muds |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2148969A1 true CA2148969A1 (en) | 1996-11-10 |
Family
ID=4155809
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002148969A Abandoned CA2148969A1 (en) | 1995-05-09 | 1995-05-09 | Application of low density drilling muds |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2148969A1 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6571873B2 (en) | 2001-02-23 | 2003-06-03 | Exxonmobil Upstream Research Company | Method for controlling bottom-hole pressure during dual-gradient drilling |
| WO2004016707A1 (en) * | 2002-08-14 | 2004-02-26 | 3M Innovative Properties Company | Drilling fluid containing microspheres and use thereof |
| US6802379B2 (en) | 2001-02-23 | 2004-10-12 | Exxonmobil Upstream Research Company | Liquid lift method for drilling risers |
| US7767629B2 (en) | 2002-08-14 | 2010-08-03 | 3M Innovative Properties Company | Drilling fluid containing microspheres and use thereof |
| US7972555B2 (en) | 2004-06-17 | 2011-07-05 | Exxonmobil Upstream Research Company | Method for fabricating compressible objects for a variable density drilling mud |
| US8076269B2 (en) | 2004-06-17 | 2011-12-13 | Exxonmobil Upstream Research Company | Compressible objects combined with a drilling fluid to form a variable density drilling mud |
| US8088717B2 (en) | 2004-06-17 | 2012-01-03 | Exxonmobil Upstream Research Company | Compressible objects having partial foam interiors combined with a drilling fluid to form a variable density drilling mud |
| US8088716B2 (en) | 2004-06-17 | 2012-01-03 | Exxonmobil Upstream Research Company | Compressible objects having a predetermined internal pressure combined with a drilling fluid to form a variable density drilling mud |
-
1995
- 1995-05-09 CA CA002148969A patent/CA2148969A1/en not_active Abandoned
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6571873B2 (en) | 2001-02-23 | 2003-06-03 | Exxonmobil Upstream Research Company | Method for controlling bottom-hole pressure during dual-gradient drilling |
| US6802379B2 (en) | 2001-02-23 | 2004-10-12 | Exxonmobil Upstream Research Company | Liquid lift method for drilling risers |
| WO2004016707A1 (en) * | 2002-08-14 | 2004-02-26 | 3M Innovative Properties Company | Drilling fluid containing microspheres and use thereof |
| US6906009B2 (en) | 2002-08-14 | 2005-06-14 | 3M Innovative Properties Company | Drilling fluid containing microspheres and use thereof |
| CN1329472C (en) * | 2002-08-14 | 2007-08-01 | 3M创新有限公司 | Drilling fluid containing microspheres and use thereof |
| US7767629B2 (en) | 2002-08-14 | 2010-08-03 | 3M Innovative Properties Company | Drilling fluid containing microspheres and use thereof |
| NO338581B1 (en) * | 2002-08-14 | 2016-09-12 | 3M Innovative Properties Co | Drilling fluid containing microspheres and their use |
| US7972555B2 (en) | 2004-06-17 | 2011-07-05 | Exxonmobil Upstream Research Company | Method for fabricating compressible objects for a variable density drilling mud |
| US8076269B2 (en) | 2004-06-17 | 2011-12-13 | Exxonmobil Upstream Research Company | Compressible objects combined with a drilling fluid to form a variable density drilling mud |
| US8088717B2 (en) | 2004-06-17 | 2012-01-03 | Exxonmobil Upstream Research Company | Compressible objects having partial foam interiors combined with a drilling fluid to form a variable density drilling mud |
| US8088716B2 (en) | 2004-06-17 | 2012-01-03 | Exxonmobil Upstream Research Company | Compressible objects having a predetermined internal pressure combined with a drilling fluid to form a variable density drilling mud |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |