CA1189300A - Balanced-activity improved inverse emulsion to inhibit brittle lutite hydration in oil fields - Google Patents
Balanced-activity improved inverse emulsion to inhibit brittle lutite hydration in oil fieldsInfo
- Publication number
- CA1189300A CA1189300A CA000403344A CA403344A CA1189300A CA 1189300 A CA1189300 A CA 1189300A CA 000403344 A CA000403344 A CA 000403344A CA 403344 A CA403344 A CA 403344A CA 1189300 A CA1189300 A CA 1189300A
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- CA
- Canada
- Prior art keywords
- weight
- emulsion
- brine
- oil
- agent
- 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.)
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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
- C09K8/32—Non-aqueous well-drilling compositions, e.g. oil-based
- C09K8/36—Water-in-oil emulsions
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S507/00—Earth boring, well treating, and oil field chemistry
- Y10S507/901—Organically modified inorganic solid
Abstract
A BALANCED-ACTIVITY IMPROVED INVERSE EMULSION
TO INHIBIT BRITTLE LUTITE HYDRATION IN OIL FIELDS
ABSTRACT OF THE DISCLOSURE
This invention refers to an improved inverse emulsion that allows the adjustment of the dispersed-phase activity, when used as a drilling fluid or a fluid to repair oil fields in order to inhibit brittle lutite hydration, or else when it is used as packing fluid to drag or suspend cuttings made by the drilling bit in said wells. The emulsion comprises the following components: heavy oil, brine, viscosity agent, with thermostabilizing properties in addition to being the main controller of filtration properties, as well as secondary emulsifier, main emulsifying agent; thickening agent; gelatinizing additive; and an alkaline earth metal hydroxide. The balanced-activity feature consists of feasibility to equal inverse emulsion brine activity with that pertaining to the formation to be drilled, in such a way as to avoid hole collapsing, causing improved well gage stability.
TO INHIBIT BRITTLE LUTITE HYDRATION IN OIL FIELDS
ABSTRACT OF THE DISCLOSURE
This invention refers to an improved inverse emulsion that allows the adjustment of the dispersed-phase activity, when used as a drilling fluid or a fluid to repair oil fields in order to inhibit brittle lutite hydration, or else when it is used as packing fluid to drag or suspend cuttings made by the drilling bit in said wells. The emulsion comprises the following components: heavy oil, brine, viscosity agent, with thermostabilizing properties in addition to being the main controller of filtration properties, as well as secondary emulsifier, main emulsifying agent; thickening agent; gelatinizing additive; and an alkaline earth metal hydroxide. The balanced-activity feature consists of feasibility to equal inverse emulsion brine activity with that pertaining to the formation to be drilled, in such a way as to avoid hole collapsing, causing improved well gage stability.
Description
3 )t~
BACKGROUND OF THE IN~FNTION
According to the present invention, the impro~ed inverse emulsion is made up of the following elements. special-type diesel oil; viscosity agent; thermostabilizer, main controller of filtration properties and secondary emulsifier; a main emulsifying agent and dampener with thickening solids oil; calcium chloride brine; thickening agentl gelatinizing agent, and hydrated calcium hydroxide.
Universally, a drilling fluid whose consistency resembles that of a lubricating oil, is used in a circulating system with rotary drilling mechanisms pumping it into the well through the drilling bit, which it lubricates and cools, and then returning it to a hydraulic-fill dam on the surface.
In this way it drags hole cuttings and carries them out from the well to the surface, where thick particles or cuttings are removed, leaving the fluid in good condition to be used again in a continuous-circulation process.
Reasons to use drilling fluids are ~ariedand complex. One of the main reasons of their use i~. the desire to exert an adequate hydrostatic pressure in order to prevent gas leaks and thus avoid well fires.
Taking into consideration that hydrostatic pressure depends, to a large extent, on the fluid's specific gravity, the same may be increased, as ~ 2 --indicated in the present invention, through the addition of a heavy material such as barite. On the other hand, drilling fluid should have an adequate viscosity, i.e., it should be viscous enough to drag cuttings. However, at the same time, it should be practical from the standpoint of pumping, and allow heavy particle settling in the hydraulic-fill dams, in such a way that it may be used again.
An important property of the drilling fluid is that in case of a temporary shutdown, the fluid's gelling capabilities should be enough to prevent settling of suspended-cuttings sincel otherwise, those cuttings when settling would stick to the well's shaft and obstruct operations restarting or their final removal from same. Therefore, it is obvious that both fluid viscosity and the fluid's gelling capability or gelatinousness in case of drilling or repair work shutdown are of paramount importance.
Consequently, the fluid should maintain cuttings 2Q suspended while flowing when work is resumed. This is known as the fluid's thixotropic property or gel intensity. Such property may be enhanced through the addition of a bentonite-type clay or similar substances, as in the present invention where ~5 bentonite, previously reacted with ammonium quaternary salts, is used.
During oil well drilling, the drill frequently encounters brittle lutites or water-base muds that hydrate when they are in contact with water, causing landslides or hole instability. This is why fluids that act as agents to i.nhibit brittle lutite hydration have been developed, ha~ing observed that the use of inverse emulsions provide the best results, as is the case with the balanced activity improved lnverse emulsïon that is the object of the present invention.
SUMMARY OF THE INVENTION
The present invention refers to a balanced activity improved inverse emulsion where diesel oil stands for the continuous phase and calcium chloride bri.ne for the dispersed phase, in a diesel oil/water proportion of 60-90/40 10% in volume with densities of 1.0 to 2.2 g/cm , calcium chloride concentrations in brine equivalent to 15-32% in weight (approximately 250,000 to 320,000 ppm) and a chemical activity of 0~50 to 0.80. The elements that make up this emulsion, intervene in the following weight percentages, referred to tne total weight of prepared e~ulsion;
water-oil emulsion 25 to 90%, a viscosity additive 2.0 to 5.0%; a main emulsifier 0O5 to 2.0%; a thickening agent up to 72%; a gelatinizing additive up to 0.23%;
and an alkaline earth metal hydroxide up to 0.47%.
The present invention, therefore, provides an inverse emulsion that inhibits brittle lutite hydration comprising a heavy-oil/brine emulsion of heavy oil as the oily phase and an alkaline earth r1 .,~ j ,. ..
3~
metal brine, having a concentra~tion of from 2.5 X
105 to 3.2 X 105 ppm, as the aqueous phase, the ratio of heavy oil to brine being from 90-60~10-40% by volume and the oil~brine emulsion comprising from 25 to 90% by weight based on the total weight of the inverse emulsion; from 2.0 to 5.0% by weight of a viscosity and thermostabilizing agent; from 0.5 to
BACKGROUND OF THE IN~FNTION
According to the present invention, the impro~ed inverse emulsion is made up of the following elements. special-type diesel oil; viscosity agent; thermostabilizer, main controller of filtration properties and secondary emulsifier; a main emulsifying agent and dampener with thickening solids oil; calcium chloride brine; thickening agentl gelatinizing agent, and hydrated calcium hydroxide.
Universally, a drilling fluid whose consistency resembles that of a lubricating oil, is used in a circulating system with rotary drilling mechanisms pumping it into the well through the drilling bit, which it lubricates and cools, and then returning it to a hydraulic-fill dam on the surface.
In this way it drags hole cuttings and carries them out from the well to the surface, where thick particles or cuttings are removed, leaving the fluid in good condition to be used again in a continuous-circulation process.
Reasons to use drilling fluids are ~ariedand complex. One of the main reasons of their use i~. the desire to exert an adequate hydrostatic pressure in order to prevent gas leaks and thus avoid well fires.
Taking into consideration that hydrostatic pressure depends, to a large extent, on the fluid's specific gravity, the same may be increased, as ~ 2 --indicated in the present invention, through the addition of a heavy material such as barite. On the other hand, drilling fluid should have an adequate viscosity, i.e., it should be viscous enough to drag cuttings. However, at the same time, it should be practical from the standpoint of pumping, and allow heavy particle settling in the hydraulic-fill dams, in such a way that it may be used again.
An important property of the drilling fluid is that in case of a temporary shutdown, the fluid's gelling capabilities should be enough to prevent settling of suspended-cuttings sincel otherwise, those cuttings when settling would stick to the well's shaft and obstruct operations restarting or their final removal from same. Therefore, it is obvious that both fluid viscosity and the fluid's gelling capability or gelatinousness in case of drilling or repair work shutdown are of paramount importance.
Consequently, the fluid should maintain cuttings 2Q suspended while flowing when work is resumed. This is known as the fluid's thixotropic property or gel intensity. Such property may be enhanced through the addition of a bentonite-type clay or similar substances, as in the present invention where ~5 bentonite, previously reacted with ammonium quaternary salts, is used.
During oil well drilling, the drill frequently encounters brittle lutites or water-base muds that hydrate when they are in contact with water, causing landslides or hole instability. This is why fluids that act as agents to i.nhibit brittle lutite hydration have been developed, ha~ing observed that the use of inverse emulsions provide the best results, as is the case with the balanced activity improved lnverse emulsïon that is the object of the present invention.
SUMMARY OF THE INVENTION
The present invention refers to a balanced activity improved inverse emulsion where diesel oil stands for the continuous phase and calcium chloride bri.ne for the dispersed phase, in a diesel oil/water proportion of 60-90/40 10% in volume with densities of 1.0 to 2.2 g/cm , calcium chloride concentrations in brine equivalent to 15-32% in weight (approximately 250,000 to 320,000 ppm) and a chemical activity of 0~50 to 0.80. The elements that make up this emulsion, intervene in the following weight percentages, referred to tne total weight of prepared e~ulsion;
water-oil emulsion 25 to 90%, a viscosity additive 2.0 to 5.0%; a main emulsifier 0O5 to 2.0%; a thickening agent up to 72%; a gelatinizing additive up to 0.23%;
and an alkaline earth metal hydroxide up to 0.47%.
The present invention, therefore, provides an inverse emulsion that inhibits brittle lutite hydration comprising a heavy-oil/brine emulsion of heavy oil as the oily phase and an alkaline earth r1 .,~ j ,. ..
3~
metal brine, having a concentra~tion of from 2.5 X
105 to 3.2 X 105 ppm, as the aqueous phase, the ratio of heavy oil to brine being from 90-60~10-40% by volume and the oil~brine emulsion comprising from 25 to 90% by weight based on the total weight of the inverse emulsion; from 2.0 to 5.0% by weight of a viscosity and thermostabilizing agent; from 0.5 to
2.0% by weight of a calcium salt of a suifonic aromatic C10-Cl8 alkyl acid as an emulsifying agent;
up to 72% by weight of a thickening agent; up to 0.5%
by weight of a gelatinizing agent; and up to 0.50%
by weight of an alkaline earth metal hydroxide.
The invention further provides an inverse emulsion that inhibits brittle lutite hydration comprising:
a) a heavy-oil/brine emulsion of diesel oil having a low sulfur content as the oily phase; and calcium chloride brine, having a concentration of 2.5 X 105 to 3.2 X 105 ppm as the aqueous phase, the ratio of oil to brine being from 80-60/ - 20-40% by volllme and the oil/brine emulsion comprising from 25-90% by weight of the emulsion;
b) from 2.8 to 4.6% by weight of a viscosity agent comprising blown asphalt and gilsonite;
c) from 0.8 to 1.6% by weïght of a calcium salt of a sulfonic aromatic C10-Cl8 alkyl acid as an emulsifier~
d) from 0.07 to 0.23% by weight of the q~
reaction product of a bentonite clay with ammonium dialkyl-dimethyl chloride as a gelatinizing agent;
e) up to 72% by weight of barite as a thickening ayent; and f) from 0.07 to 0.47% by weight of calcium hydroxide.
According to the present invention, the balanced-activity improved inverse emulsion is characteri~ed by the use of a non-saturated calcium chloride brine, in concentrations that vary according to features of formations to be drilled, and that accept adjustments in the dispersed-phase activity, as well as for the use of a viscosity agent and thermostabilizer that controls filtration properties and is a secondary emulsifier. ~his agent~s effects, combined with those of the water-diesel oil emulsion and other agents, make the emulsion's balanced activity feasible, obtaining a stabiliz.ed hole when drilling and a more uniform wel.l gage.
Therefore, one of the objectives of the present in~ention is to provide a balanced activity improved inverse emulsion, ade~uate to be used as an oil well repairing and drilling fluid, in order to inhibit brittle lutite hydration.
Another objective of this inyention is to provide a balanced activity improved inverse emulsion, capable of accepting brine concentration adjustments, in such a way that it may be equalized to that of 33~
-- 6 ~
formations to be drilled, obtaining stabiliz.ed holes while drilling.
~ third objective of the present invention is to provide a balanced activity improved inverse emul.sion with all the necessary qualities to serve as a packing fluid, suspending heavy materials such as barite and drilled formations cuttings, having an improved stability at high temperatures and against fresh and salt water pollution, and controlling formation fluid loss.
DETAILED DESCRIPTION OF THE INVENTION
The balanced activity improved inverse emulsion is made up of a series of agents and additives that form an inverse emulsion system when mixed,where diesel or heavy oil stands for the continuous phase and calcium chloride brine for the dispersed phase, and where each element has a definite and specific function. In addition to special type diesel oil and non-saturated calcium chloride brine, the improved inverse emulsion which is the object of the present invention, contains the following elements~ a gilsonite and blown asphalt-based thermostabilizer and viscosity agent; a main emulsifying agent having as basic ingredient the calcium salt of a sulfonic aromatic C10-Cl8 alkyl acidi a barite based thickening agent, an organophyllous-clay gelatinizing agent and, finally, - hydrated calcium hydroxide as auxiliary agent to ~3
up to 72% by weight of a thickening agent; up to 0.5%
by weight of a gelatinizing agent; and up to 0.50%
by weight of an alkaline earth metal hydroxide.
The invention further provides an inverse emulsion that inhibits brittle lutite hydration comprising:
a) a heavy-oil/brine emulsion of diesel oil having a low sulfur content as the oily phase; and calcium chloride brine, having a concentration of 2.5 X 105 to 3.2 X 105 ppm as the aqueous phase, the ratio of oil to brine being from 80-60/ - 20-40% by volllme and the oil/brine emulsion comprising from 25-90% by weight of the emulsion;
b) from 2.8 to 4.6% by weight of a viscosity agent comprising blown asphalt and gilsonite;
c) from 0.8 to 1.6% by weïght of a calcium salt of a sulfonic aromatic C10-Cl8 alkyl acid as an emulsifier~
d) from 0.07 to 0.23% by weight of the q~
reaction product of a bentonite clay with ammonium dialkyl-dimethyl chloride as a gelatinizing agent;
e) up to 72% by weight of barite as a thickening ayent; and f) from 0.07 to 0.47% by weight of calcium hydroxide.
According to the present invention, the balanced-activity improved inverse emulsion is characteri~ed by the use of a non-saturated calcium chloride brine, in concentrations that vary according to features of formations to be drilled, and that accept adjustments in the dispersed-phase activity, as well as for the use of a viscosity agent and thermostabilizer that controls filtration properties and is a secondary emulsifier. ~his agent~s effects, combined with those of the water-diesel oil emulsion and other agents, make the emulsion's balanced activity feasible, obtaining a stabiliz.ed hole when drilling and a more uniform wel.l gage.
Therefore, one of the objectives of the present in~ention is to provide a balanced activity improved inverse emulsion, ade~uate to be used as an oil well repairing and drilling fluid, in order to inhibit brittle lutite hydration.
Another objective of this inyention is to provide a balanced activity improved inverse emulsion, capable of accepting brine concentration adjustments, in such a way that it may be equalized to that of 33~
-- 6 ~
formations to be drilled, obtaining stabiliz.ed holes while drilling.
~ third objective of the present invention is to provide a balanced activity improved inverse emul.sion with all the necessary qualities to serve as a packing fluid, suspending heavy materials such as barite and drilled formations cuttings, having an improved stability at high temperatures and against fresh and salt water pollution, and controlling formation fluid loss.
DETAILED DESCRIPTION OF THE INVENTION
The balanced activity improved inverse emulsion is made up of a series of agents and additives that form an inverse emulsion system when mixed,where diesel or heavy oil stands for the continuous phase and calcium chloride brine for the dispersed phase, and where each element has a definite and specific function. In addition to special type diesel oil and non-saturated calcium chloride brine, the improved inverse emulsion which is the object of the present invention, contains the following elements~ a gilsonite and blown asphalt-based thermostabilizer and viscosity agent; a main emulsifying agent having as basic ingredient the calcium salt of a sulfonic aromatic C10-Cl8 alkyl acidi a barite based thickening agent, an organophyllous-clay gelatinizing agent and, finally, - hydrated calcium hydroxide as auxiliary agent to ~3
3~
control filtration properties. ~11 these eiements, as a whole, have coordinated effects that provide the emulsion with certain characteristics, such aso a) Capability to suspend heavy material such as barite and cuttings from drilled Eormations, or grinding materials in case of repair work.
b) Viscosity values that make it possihle to drag or transport formation cuttings and do not allow their settling when emulsion circulation stops.
c) Properties maintenance when the emulsion is subject to high temperatures i.e.
approximately 130~C.
d) Resistance to breakage or separation in its two phases, when foreign solids such as formation cuttings exceeding 10% of emulsion volume are incorporated.
e~ Resistance to breakage when 30% water -either the formation's water or fresh water - is incorporated into the emulsion.
f) High resistance to electric current flow.
The complex additives or agents that form part of the balanced activity improved inverse emulsion, according to the present invention, have special properties that confer to this emulsion the above mentioned charateristics.
Such complex additives are:
A) Thermostabilizing and viscosity agent.
This additive is a dark gray powder which ~..~,~
3~
is the product of the interaction of blown asphalt, gilsonite, sulfuric acid and triethanolamine, all neutralized with calcium hydroxide. It is partially dispersable in diesel oil and provides emulsions with viscosity, stability at high temperatures and filtration properties control. It is the emulsion's basic additive and has secondary effects as an emulsifier. This additive is obtained as follows:
The reactor is loaded with asphalt at a temperature of 180-270C, starting stirring and heating. Gilsonite is melted in a separate container and then it is fed into the reactor; slow addition of sulfuric acid is started, taking care that the mixture temperature is kept constant; when finishing said addition, stirring and heating is continued for some minutes more, slowly adding thereinafter triethanolamine unti~
its total incorporation, homogenizing the mixture.
Immediately afterwards, hydrated lime is slowly added, controlling the foam formed. Stirxing and heating is continued for an additional hour, in order to complete reaction. The product is unloaded on trays to wait for solidification. Finally, grind ing is carried out mixing the previously fractured solidified product with hydrated lime.
B) Main emulsifying agent.
It is a dark brown liquid with a density of approximately 1.0 g/cm . It is an anïonic emuIsifier, whose basic ingredient is the calcium salt of a sulfonic aromatic Cl0-Cl8 alkyl acid, very effec~ive for calcium chloride emulsion, that facilitates oil-water mixture, preventing dispersed particle agglomeration through particles physical division, suspendin~ them colloidally. It also acts as a thickening-solids dampening agent.
C) Gelatinizing Agent This additive is a white fine powder that consists of an organophyllous clay, which is the product of the reaction of a bentonite with an ammonium quaternary salt pertaining to ammonium dialkyl-dimethyl chloride. It is a diesel oil-dispersable non-ionic character additive. It acts in the emulsion as a gelatinizing agent allowing suspension of thickening solids.
Other elements that contribute to form inverse emulsions are:
diesel oil/ preferring a special-type diesel oil because of its low sulfur content (0.5~) which allows aniline points above 60C. (ASTM-D-611-77) and lesser damage to the drilling equipment rubber devices, due to its maximum creepage temperature (ASTM D-97-66)(1971) of 0~C from March to October and -5C from November to February, as well as for its higher ignition point -52~C., (ASTM D-93-77)i calcium chloride, used in concentrations that vary from 250,000 to 320,000 ppm., depending on the characteristics of formations to be drilledO This ~i~3 ,~.J
special property causes the system to have a balanced activity~ i.e. it makes possible the equalization of the brine activity with that of the formation, thus obtaining a stabilized hole while drilling; hydrated calcium hydroxide, used as an auxiliary element in controlling emulsions filtering; water, industrial water is generally used when the emulsion is prepared in mud p]ants, however, when the same are required to be prepared in the well, there is no inconvenience in 10 using other types of wa-ter, lacking txeated water characteristicsi and barite as thickening agent~ used to provide emulsions with the xequired specific .
gra~ity.
E X A M P L E S
PXEP~RATION OF THE INVERSE EMULSION
Percentages mentioned in the following examples relate to weight and are referred to prepared inverse emulsion total weight.
EXAMPLE 1.
_ 23-24% diesel oil and 4-5% of a thermostabilizing and viscosity agent are mixed -stirring - at room temperature, in a container, after stirring for 75 minutes, 1.0 - 1~5% of the main emulsifier is added and stirring is continued for 15 minutes more; then 18-I9% of 32% weight calcium chloride brine is added, stirring the mixture for 120 minutes. 51-52~ of a thickening agent is added to the resultant mixture and after stirring for 60 ~inutes, B
the balanced activity improved inverse emulsion is obtained, with a dens~ty of 1.7 g/~cm3. It is laboratory assessed, adjusting both its thixotropy with the addition of 0.1 - 0.2~ of gelatinizing additive and its filtration capacity with the addition of 0.2 - 0.3% of hydrated calcium hydroxide.
As a result of the above preparation, a balanced activity improved inverse emulsion is obtained, with the following characteristics:
Diesel oil/water ratio ~vol). 70/30 Density g/cm3 1.70 Brine concentration (weight) 32~
Chemical activity (aw) 0.58 EXAMPLE 2.
Following the technique of Example 1 an inverse emulsion is prepared in such a way that the elements used agree with the following percentages:
diesel oil 24-25~; thermostabilizing and viscosity additive 4.0 - 5.0%; main emulsifier 1.0 - 2.0%, 20 14 - 15~ of 30% by weight calcium chloride brine;
55 56% thickening agent, 0.1 - 0.2~ gelatinizing additive; and 0.20 - 0.25~ hydrated calcium hydroxide.
- The inverse emulsion obtained, as per this example, has the following characteristics:
Diesel oil/water ratio (vol). 74/26 Density g/cm 1.75 Brine concentration (weight) 30%
Chemical activity (aw) 0.63 ~J
3~
EXAMPLE 3.
Following the technique of Example l, an inverse emulsion is prepared, including elements in agreement with the following amounts:
diesel oil 21 22~, thermostabilizing and viscosity additive 3 - 4~; main emulsifier 1 - 2~; 8 ~ 9~ by weight calcium chloride brine 25%; t.hickening agent 65 - 66~; gelatinizing additive 0.1 - 2.0%; and hydrat~d calcium hydroxide 0.1 0.2~.
1~ The inverse emulsion obtained, in agreement with this example, has the following characteristics:
Diesel oil/water ratio ~vol). 80/20 Density g/cm3 2.0 Brine concentration (weight) 25%
Chemical activity (aw) 0.74 According to the described examples, Table 1 provides a more ample characteriz.ation of the prepared inverse emulsions.
PROPERTIES OF THE BALANCED ACTI~ITY IMPRO~ED
INVERSE EMULSION AS PER EXAMPLES PRESENTED
Inverse Emulsion Example Example Example Diesel oil/water ratio volume ~ 70~30 74/2680/20 Brine concentration,ppm 320 000 300 000 250 000 Apparent viscosity cp 60 67 88 Plastic ~iscosity cp 44 50 68 Yield point dynes/cm2 153 163 229 3~1 Initial gelatinousness 5 to 10 minO 53-72 53-77 67-91 dynes/cm2 Electric stability, volts 400 900 B40 High temperature/pressure filtrate 2 (150C and 35 kg/cm .ml.) 4.0 2 0 3.0 The following results were obtained when using the inverse emulsion, prepared in agreement 10 with the present invention, in drilling a well in the area of Tabasco.
Drilled Depth Well's diameter (meters) (centimeters) Eormation 3000 24.13 Deposit 3200 24.13 3300 24.13 3400 24.13 3500 24.55 3600 24.13 Oligocene 3700 25.40 3800 24.97 3900 24.13 4000 24.13 4100 24.97 4200 24.13 4300 24.13 Eocene 4400 24.13 4500 24.13 4600 24.13 3~
- ~4 -The above Table shows that the hole diameter in the drilling interval from 3000 to 4600 is essentially equal to that pertaining to the drilling bit used, i.e. 24.13 cm. (9.5 inches). This demonstrates that inverse emulsion actually contributes to Deposit, Oligocene and Eocene formations drilling, with a good well gage stability.
control filtration properties. ~11 these eiements, as a whole, have coordinated effects that provide the emulsion with certain characteristics, such aso a) Capability to suspend heavy material such as barite and cuttings from drilled Eormations, or grinding materials in case of repair work.
b) Viscosity values that make it possihle to drag or transport formation cuttings and do not allow their settling when emulsion circulation stops.
c) Properties maintenance when the emulsion is subject to high temperatures i.e.
approximately 130~C.
d) Resistance to breakage or separation in its two phases, when foreign solids such as formation cuttings exceeding 10% of emulsion volume are incorporated.
e~ Resistance to breakage when 30% water -either the formation's water or fresh water - is incorporated into the emulsion.
f) High resistance to electric current flow.
The complex additives or agents that form part of the balanced activity improved inverse emulsion, according to the present invention, have special properties that confer to this emulsion the above mentioned charateristics.
Such complex additives are:
A) Thermostabilizing and viscosity agent.
This additive is a dark gray powder which ~..~,~
3~
is the product of the interaction of blown asphalt, gilsonite, sulfuric acid and triethanolamine, all neutralized with calcium hydroxide. It is partially dispersable in diesel oil and provides emulsions with viscosity, stability at high temperatures and filtration properties control. It is the emulsion's basic additive and has secondary effects as an emulsifier. This additive is obtained as follows:
The reactor is loaded with asphalt at a temperature of 180-270C, starting stirring and heating. Gilsonite is melted in a separate container and then it is fed into the reactor; slow addition of sulfuric acid is started, taking care that the mixture temperature is kept constant; when finishing said addition, stirring and heating is continued for some minutes more, slowly adding thereinafter triethanolamine unti~
its total incorporation, homogenizing the mixture.
Immediately afterwards, hydrated lime is slowly added, controlling the foam formed. Stirxing and heating is continued for an additional hour, in order to complete reaction. The product is unloaded on trays to wait for solidification. Finally, grind ing is carried out mixing the previously fractured solidified product with hydrated lime.
B) Main emulsifying agent.
It is a dark brown liquid with a density of approximately 1.0 g/cm . It is an anïonic emuIsifier, whose basic ingredient is the calcium salt of a sulfonic aromatic Cl0-Cl8 alkyl acid, very effec~ive for calcium chloride emulsion, that facilitates oil-water mixture, preventing dispersed particle agglomeration through particles physical division, suspendin~ them colloidally. It also acts as a thickening-solids dampening agent.
C) Gelatinizing Agent This additive is a white fine powder that consists of an organophyllous clay, which is the product of the reaction of a bentonite with an ammonium quaternary salt pertaining to ammonium dialkyl-dimethyl chloride. It is a diesel oil-dispersable non-ionic character additive. It acts in the emulsion as a gelatinizing agent allowing suspension of thickening solids.
Other elements that contribute to form inverse emulsions are:
diesel oil/ preferring a special-type diesel oil because of its low sulfur content (0.5~) which allows aniline points above 60C. (ASTM-D-611-77) and lesser damage to the drilling equipment rubber devices, due to its maximum creepage temperature (ASTM D-97-66)(1971) of 0~C from March to October and -5C from November to February, as well as for its higher ignition point -52~C., (ASTM D-93-77)i calcium chloride, used in concentrations that vary from 250,000 to 320,000 ppm., depending on the characteristics of formations to be drilledO This ~i~3 ,~.J
special property causes the system to have a balanced activity~ i.e. it makes possible the equalization of the brine activity with that of the formation, thus obtaining a stabilized hole while drilling; hydrated calcium hydroxide, used as an auxiliary element in controlling emulsions filtering; water, industrial water is generally used when the emulsion is prepared in mud p]ants, however, when the same are required to be prepared in the well, there is no inconvenience in 10 using other types of wa-ter, lacking txeated water characteristicsi and barite as thickening agent~ used to provide emulsions with the xequired specific .
gra~ity.
E X A M P L E S
PXEP~RATION OF THE INVERSE EMULSION
Percentages mentioned in the following examples relate to weight and are referred to prepared inverse emulsion total weight.
EXAMPLE 1.
_ 23-24% diesel oil and 4-5% of a thermostabilizing and viscosity agent are mixed -stirring - at room temperature, in a container, after stirring for 75 minutes, 1.0 - 1~5% of the main emulsifier is added and stirring is continued for 15 minutes more; then 18-I9% of 32% weight calcium chloride brine is added, stirring the mixture for 120 minutes. 51-52~ of a thickening agent is added to the resultant mixture and after stirring for 60 ~inutes, B
the balanced activity improved inverse emulsion is obtained, with a dens~ty of 1.7 g/~cm3. It is laboratory assessed, adjusting both its thixotropy with the addition of 0.1 - 0.2~ of gelatinizing additive and its filtration capacity with the addition of 0.2 - 0.3% of hydrated calcium hydroxide.
As a result of the above preparation, a balanced activity improved inverse emulsion is obtained, with the following characteristics:
Diesel oil/water ratio ~vol). 70/30 Density g/cm3 1.70 Brine concentration (weight) 32~
Chemical activity (aw) 0.58 EXAMPLE 2.
Following the technique of Example 1 an inverse emulsion is prepared in such a way that the elements used agree with the following percentages:
diesel oil 24-25~; thermostabilizing and viscosity additive 4.0 - 5.0%; main emulsifier 1.0 - 2.0%, 20 14 - 15~ of 30% by weight calcium chloride brine;
55 56% thickening agent, 0.1 - 0.2~ gelatinizing additive; and 0.20 - 0.25~ hydrated calcium hydroxide.
- The inverse emulsion obtained, as per this example, has the following characteristics:
Diesel oil/water ratio (vol). 74/26 Density g/cm 1.75 Brine concentration (weight) 30%
Chemical activity (aw) 0.63 ~J
3~
EXAMPLE 3.
Following the technique of Example l, an inverse emulsion is prepared, including elements in agreement with the following amounts:
diesel oil 21 22~, thermostabilizing and viscosity additive 3 - 4~; main emulsifier 1 - 2~; 8 ~ 9~ by weight calcium chloride brine 25%; t.hickening agent 65 - 66~; gelatinizing additive 0.1 - 2.0%; and hydrat~d calcium hydroxide 0.1 0.2~.
1~ The inverse emulsion obtained, in agreement with this example, has the following characteristics:
Diesel oil/water ratio ~vol). 80/20 Density g/cm3 2.0 Brine concentration (weight) 25%
Chemical activity (aw) 0.74 According to the described examples, Table 1 provides a more ample characteriz.ation of the prepared inverse emulsions.
PROPERTIES OF THE BALANCED ACTI~ITY IMPRO~ED
INVERSE EMULSION AS PER EXAMPLES PRESENTED
Inverse Emulsion Example Example Example Diesel oil/water ratio volume ~ 70~30 74/2680/20 Brine concentration,ppm 320 000 300 000 250 000 Apparent viscosity cp 60 67 88 Plastic ~iscosity cp 44 50 68 Yield point dynes/cm2 153 163 229 3~1 Initial gelatinousness 5 to 10 minO 53-72 53-77 67-91 dynes/cm2 Electric stability, volts 400 900 B40 High temperature/pressure filtrate 2 (150C and 35 kg/cm .ml.) 4.0 2 0 3.0 The following results were obtained when using the inverse emulsion, prepared in agreement 10 with the present invention, in drilling a well in the area of Tabasco.
Drilled Depth Well's diameter (meters) (centimeters) Eormation 3000 24.13 Deposit 3200 24.13 3300 24.13 3400 24.13 3500 24.55 3600 24.13 Oligocene 3700 25.40 3800 24.97 3900 24.13 4000 24.13 4100 24.97 4200 24.13 4300 24.13 Eocene 4400 24.13 4500 24.13 4600 24.13 3~
- ~4 -The above Table shows that the hole diameter in the drilling interval from 3000 to 4600 is essentially equal to that pertaining to the drilling bit used, i.e. 24.13 cm. (9.5 inches). This demonstrates that inverse emulsion actually contributes to Deposit, Oligocene and Eocene formations drilling, with a good well gage stability.
Claims (8)
1. An inverse emulsion that inhibits brittle lutite hydration comprising a heavy-oil/
brine emulsion of heavy oil as the oily phase and an alkaline earth metal brine, having a concentration of from 2.5 X 105 to 3.2 X 105 ppm, as the aqueous phase, the ratio of heavy oil to brine being from 90-60/10-40% by volume and the oil/brine emulsion comprising from 25 to 90% by weight based on the total weight of the inverse emulsion; from 2.0 to 5.0% by weight of a viscosity and thermostabilizing agent, from 0.5 to 2.0% by weight of a calcium salt of a sulfonic aromatic C10-C18 alkyl acid as an emulsifying agent; up to 72% by weight of a thickening agent; up to 0.5% by weight of a gelatinizing agent; and up to 0.50% by weight of an alkaline earth metal hydroxide.
brine emulsion of heavy oil as the oily phase and an alkaline earth metal brine, having a concentration of from 2.5 X 105 to 3.2 X 105 ppm, as the aqueous phase, the ratio of heavy oil to brine being from 90-60/10-40% by volume and the oil/brine emulsion comprising from 25 to 90% by weight based on the total weight of the inverse emulsion; from 2.0 to 5.0% by weight of a viscosity and thermostabilizing agent, from 0.5 to 2.0% by weight of a calcium salt of a sulfonic aromatic C10-C18 alkyl acid as an emulsifying agent; up to 72% by weight of a thickening agent; up to 0.5% by weight of a gelatinizing agent; and up to 0.50% by weight of an alkaline earth metal hydroxide.
2. The inverse emulsion of claim 1 wherein the heavy oil is diesel oil having a low sulfur content and the brine is calcium chloride brine.
3. The inverse emulsion of claim 1 wherein the thermostabilizing and viscosity agent comprises blown asphalt and gilsonite.
4. The inverse emulsion of claim 1 wherein the gelatinizing agent is an organophyllous clay resulting from the reaction of a bentonite with ammonium dialkyl-dimethyl chloride.
5. The inverse emulsion of claim 1 wherein the thickening agent is barite.
6. The inverse emulsion of claim 1 wherein the alkaline earth metal hydroxide is hydrated calcium hydroxide.
7. The inverse emulsion of claim 1 wherein the heavy-oil/brine emulsion is in a ratio of from 80-60/20-40% by volume and the oil/brine emulsion comprising from 25 to 90% by weight based on the total weight of the inverse emulsion; from 2.8 to 4.6% of the thermostabilizing and viscosity agent; from 0.8 to 1.6% by weight of the emulsifying agent; from 0.07 to 0.23% of the gelatinizing agent; up to 72% by weight of a thickening agent and from 0.07 to 0.47% of the alkaline earth metal hydroxide.
8. An inverse emulsion that inhibits brittle lutite hydration comprising:
a) a heavy-oil/brine emulsion of diesel oil having a low sulfur content as the oily phase;
and calcium chloride brine, having a concentration of 2.5 X 105 to 3.2 X 105 ppm. as the aqueous phase, the ratio of oil to brine being from 80-60/20-40%
by volume and the oil/brine emulsion comprising from 25-90% by weight of the emulsion;
b) from 2.8 to 4.6% by weight of a viscosity agent comprising blown asphalt and gilsonite;
c) from 0.8 to 1.6% by weight of a calcium salt of a sulfonic aromatic C10-C18 alkyl acid as an emulsifier;
d) from 0.07 to 0.23% by weight of the reaction product of a bentonite clay with ammonium dialkyl-dimethyl chloride as a gelatinizing agent;
e) up to 72% by weight of barite as a thickening agent; and f) from 0.07 to 0.47% by weight of calcium hydroxide.
a) a heavy-oil/brine emulsion of diesel oil having a low sulfur content as the oily phase;
and calcium chloride brine, having a concentration of 2.5 X 105 to 3.2 X 105 ppm. as the aqueous phase, the ratio of oil to brine being from 80-60/20-40%
by volume and the oil/brine emulsion comprising from 25-90% by weight of the emulsion;
b) from 2.8 to 4.6% by weight of a viscosity agent comprising blown asphalt and gilsonite;
c) from 0.8 to 1.6% by weight of a calcium salt of a sulfonic aromatic C10-C18 alkyl acid as an emulsifier;
d) from 0.07 to 0.23% by weight of the reaction product of a bentonite clay with ammonium dialkyl-dimethyl chloride as a gelatinizing agent;
e) up to 72% by weight of barite as a thickening agent; and f) from 0.07 to 0.47% by weight of calcium hydroxide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| MX187401A MX156325A (en) | 1981-05-20 | 1981-05-20 | AN IMPROVED REVERSE EMULSION OF BALANCED ACTIVITY TO INHIBIT THE HYDRATION OF DELEZNABLE PASSES IN OIL WELLS |
| MX187401 | 1981-05-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189300A true CA1189300A (en) | 1985-06-25 |
Family
ID=19747619
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000403344A Expired CA1189300A (en) | 1981-05-20 | 1982-05-19 | Balanced-activity improved inverse emulsion to inhibit brittle lutite hydration in oil fields |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4474666A (en) |
| AR (1) | AR241229A1 (en) |
| BR (1) | BR8202977A (en) |
| CA (1) | CA1189300A (en) |
| FR (1) | FR2506319B1 (en) |
| GB (1) | GB2099485B (en) |
| MX (1) | MX156325A (en) |
| NO (1) | NO156091C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| USRE36066E (en) * | 1988-12-19 | 1999-01-26 | Henkel Kgaa | Use of selected ester oils in drilling fluids and muds |
| WO2000037774A1 (en) * | 1998-12-21 | 2000-06-29 | Gennady Nikolaevich Pozdnyshev | Composition for eor and method of its preparation |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2599752A (en) * | 1949-02-03 | 1952-06-10 | Union Oil Co | Drilling fluids |
| US3252903A (en) * | 1958-09-08 | 1966-05-24 | Socony Mobil Oil Co Inc | Emulsion drilling fluid |
| US3533941A (en) * | 1967-05-23 | 1970-10-13 | John W Freeland | Oil base drilling fluid |
| US3622518A (en) * | 1968-09-27 | 1971-11-23 | Armour Ind Chem Co | Water-in-oil invert emulsions |
| FR2056177A5 (en) * | 1969-07-07 | 1971-05-14 | Witco Chemical Corp | |
| US3642623A (en) * | 1969-10-10 | 1972-02-15 | Oil Base | Oil base well drilling fluid composition and method |
| US3852201A (en) * | 1970-12-23 | 1974-12-03 | J Jackson | A clay free aqueous drilling fluid |
| US3827497A (en) * | 1973-02-01 | 1974-08-06 | Sun Oil Co | Oil recovery process using aqueous surfactant compositions |
| US3811504A (en) * | 1973-02-09 | 1974-05-21 | Texaco Inc | Surfactant oil recovery process usable in formations containing water having high concentrations of polyvalent ions such as calcium and magnesium |
| US4306980A (en) * | 1979-12-03 | 1981-12-22 | Nl Industries, Inc. | Invert emulsion well-servicing fluids |
| US4381241A (en) * | 1981-02-23 | 1983-04-26 | Dow Corning Corporation | Invert emulsions for well-drilling comprising a polydiorganosiloxane and method therefor |
-
1981
- 1981-05-20 MX MX187401A patent/MX156325A/en unknown
-
1982
- 1982-05-17 US US06/378,904 patent/US4474666A/en not_active Expired - Fee Related
- 1982-05-18 NO NO82821639A patent/NO156091C/en unknown
- 1982-05-18 AR AR82289430A patent/AR241229A1/en active
- 1982-05-19 CA CA000403344A patent/CA1189300A/en not_active Expired
- 1982-05-19 FR FR8208767A patent/FR2506319B1/en not_active Expired
- 1982-05-20 GB GB8214699A patent/GB2099485B/en not_active Expired
- 1982-05-20 BR BR8202977A patent/BR8202977A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| NO156091B (en) | 1987-04-13 |
| MX156325A (en) | 1988-08-10 |
| GB2099485B (en) | 1985-02-27 |
| BR8202977A (en) | 1983-05-03 |
| US4474666A (en) | 1984-10-02 |
| NO156091C (en) | 1987-07-22 |
| AR241229A1 (en) | 1992-02-28 |
| GB2099485A (en) | 1982-12-08 |
| NO821639L (en) | 1982-11-19 |
| FR2506319B1 (en) | 1986-11-14 |
| FR2506319A1 (en) | 1982-11-26 |
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