CA1222933A - Method of determination of weighting materials and low gravity solids in drilling fluids - Google Patents
Method of determination of weighting materials and low gravity solids in drilling fluidsInfo
- Publication number
- CA1222933A CA1222933A CA000456172A CA456172A CA1222933A CA 1222933 A CA1222933 A CA 1222933A CA 000456172 A CA000456172 A CA 000456172A CA 456172 A CA456172 A CA 456172A CA 1222933 A CA1222933 A CA 1222933A
- Authority
- CA
- Canada
- Prior art keywords
- weighting agent
- settled
- developer liquid
- weighting
- drilling fluid
- 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.)
- Expired
Links
- 239000012530 fluid Substances 0.000 title claims abstract description 64
- 230000005484 gravity Effects 0.000 title claims abstract description 62
- 238000005553 drilling Methods 0.000 title claims abstract description 57
- 238000000034 method Methods 0.000 title claims abstract description 45
- 239000007787 solid Substances 0.000 title claims abstract description 40
- 239000000463 material Substances 0.000 title abstract description 13
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 88
- 239000007788 liquid Substances 0.000 claims abstract description 43
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 claims abstract description 29
- DIKBFYAXUHHXCS-UHFFFAOYSA-N bromoform Chemical compound BrC(Br)Br DIKBFYAXUHHXCS-UHFFFAOYSA-N 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 12
- 238000001035 drying Methods 0.000 claims description 6
- 238000005303 weighing Methods 0.000 claims description 6
- 229950005228 bromoform Drugs 0.000 claims description 4
- 239000003960 organic solvent Substances 0.000 claims description 4
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical group [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 claims description 2
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 claims description 2
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052794 bromium Inorganic materials 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- 150000002896 organic halogen compounds Chemical class 0.000 claims description 2
- 238000005065 mining Methods 0.000 claims 1
- 239000000203 mixture Substances 0.000 abstract description 4
- 239000000440 bentonite Substances 0.000 abstract description 3
- 229910000278 bentonite Inorganic materials 0.000 abstract description 3
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 abstract description 3
- 238000004821 distillation Methods 0.000 abstract description 2
- 239000000523 sample Substances 0.000 abstract 1
- 239000010428 baryte Substances 0.000 description 15
- 229910052601 baryte Inorganic materials 0.000 description 15
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- YZCKVEUIGOORGS-IGMARMGPSA-N Protium Chemical compound [1H] YZCKVEUIGOORGS-IGMARMGPSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052716 thallium Inorganic materials 0.000 description 1
- BKVIYDNLLOSFOA-UHFFFAOYSA-N thallium Chemical compound [Tl] BKVIYDNLLOSFOA-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/14—Investigating or analyzing materials by the use of thermal means by using distillation, extraction, sublimation, condensation, freezing, or crystallisation
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/06—Arrangements for treating drilling fluids outside the borehole
- E21B21/063—Arrangements for treating drilling fluids outside the borehole by separating components
- E21B21/065—Separating solids from drilling fluids
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mining & Mineral Resources (AREA)
- Geology (AREA)
- Immunology (AREA)
- Environmental & Geological Engineering (AREA)
- General Physics & Mathematics (AREA)
- Biochemistry (AREA)
- Pathology (AREA)
- Analytical Chemistry (AREA)
- Mechanical Engineering (AREA)
- General Health & Medical Sciences (AREA)
- Fluid Mechanics (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
METHOD OF DETERMINATION OF WEIGHTING MATERIALS AND LOW
GRAVITY SOLIDS IN DRILLING FLUIDS
ABSTRACT OF THE DISCLOSURE
Normally, concentration of weighting agents such as barium sulphate is calculated by retort distillation to dryness and by means of a relatively inaccurate mate-rial-balance equation. The present process utilizes the fact that weighting agents have a specific gravity higher than the specific gravity of the low gravity solids such as bentonite, etc. present in the drilling fluids. A sam-ple is mixed with a liquid known as a developer liquid which has a specific gravity higher than the low gravity solids which therefore float on the developer, but lower than the weighting agent which sinks in the developer.
The mixture is preferably centrifuged to force the weight-ing agent out of the drilling fluid and into the developer liquid after preferably lowering the viscosity of the dril-ling fluid. The settled heavy gravity solids (weighting agent) may then be removed, dried and weighed or prefer-ably the volume is read directly on a suitably graduated centrifuge tube in which the settling process has taken place. By calibration with fluids containing known con-centrations of the weighting agent, the volume readings can readily be converted into concentration units.
GRAVITY SOLIDS IN DRILLING FLUIDS
ABSTRACT OF THE DISCLOSURE
Normally, concentration of weighting agents such as barium sulphate is calculated by retort distillation to dryness and by means of a relatively inaccurate mate-rial-balance equation. The present process utilizes the fact that weighting agents have a specific gravity higher than the specific gravity of the low gravity solids such as bentonite, etc. present in the drilling fluids. A sam-ple is mixed with a liquid known as a developer liquid which has a specific gravity higher than the low gravity solids which therefore float on the developer, but lower than the weighting agent which sinks in the developer.
The mixture is preferably centrifuged to force the weight-ing agent out of the drilling fluid and into the developer liquid after preferably lowering the viscosity of the dril-ling fluid. The settled heavy gravity solids (weighting agent) may then be removed, dried and weighed or prefer-ably the volume is read directly on a suitably graduated centrifuge tube in which the settling process has taken place. By calibration with fluids containing known con-centrations of the weighting agent, the volume readings can readily be converted into concentration units.
Description
1~`22933 METHOD OF DETERMINATION OF WEIGHTING MATERIALS AND LOW
GRAVITY SOLIDS IN DRILLING FLUIDS
BACKGROUND OF THE INVENTION
This invention relates to new and useful improve-ments in processes or methods of determining the amount of solids of various kinds present in drilling fluids.
In order to impart the required density to drilling fluids, weighting agents are added and although several weighting agents can be used, the most widely used mate-rial for this purpose is barite, which is a naturally occurring barium sulphate (CHBr3). This barite is added to the drilling fluid in the form of a very fine powder, which is insoluble within the base of the drilling fluid. Che-mically pure barium sulphate has a specific gravity of 4.50 but the grade of barite used in drilling fluids has usually a specific gravity of approximately 4.2. Grades of barite with a lower specific gravity are less desirable because they contain larger amounts of impurities which may be de-trimental to the drilling operations in various ways.
In deep hole drilling, barite costs form a large part of the total cost of the drilling fluid materials and since deep hole drilling is becoming increasingly necessary, and good sources of barite are becoming scarce, a reliable and simple method to determine the actual concentration of the barite or other weighting material, present in drilling fluids, is required.
At the present time, the concentration of barite or other weighting material is calculated in an indirect way, frum the amount of total solids as determined by re-tort distillation to dryness. In this conventional retort method, the amount of total solids follows from the amount of liquid (water and oil) that is collected as distillate.
A material-balance equation, in which values for specific gravity of "low gravity solids" (comprised of bentonite or other viscosifying clays and drill solids and the like) and "high gravity solids" (weighting materials such as ba-rite) are assumed, thus allowing calculation of a value for the concentration of the weighting material from the total solids content and the density of the drilling fluid.
Utilizing these same data, the concentration of low gravi-ty solids is also calculated from a similar material-balance equation. It will be appreciated that these calculations suffer from inherent inaccuracies of the retort procedure inasmuch as the weighting material concentration is calcu-lated in an indirect way, based on values which are not known accurately.
~, , :
~, '':
.,,--~, .. ; .
. . , .. . .
::,. . .
, . , , SUMMARY OF TH_ INVENTION
The present invention overcomes these disadvantages and makes use of the fact that a weighting agent or material has a specific gravity that is larger or higher than the specific gravity of the low gravity solids, which is usually approximately 2.5 and lower or below the specific gravity of the high gravity solids consisting of the weighting agents.
In accordance with the invention there is provided a method for determining the amount of solids present in drilling fluids, particularly relatively high gravity so-lids used as weighting agents; consisting of the steps of taking a sample of the drilling fluid, mixing same with a quantity of a developer liquid having a specific gravity lower than the specific gravity of the weighting agent and being effectively non-immiscible with the base of the dril-ling fluid and in which the weighting agent is insoluble, then forcing the weighting agent out of the drilling fluid and into the developer liquid, allowing the weighting agent to settle by gravity and then determining the amount of settled weighting agent.
The use of the method of the present invention will therefore result in an accurate determination of the actual concentration of the weighting agent or material ~'' ' ' ~
present in the drilling fluids so that the necessary ad-justments (if any) can be made readily and easily and with-out wastage occurring of the weighting agent.
A further advantage of the present method is that it is simple in operation, economical in use and otherwise well suited to the purpose for which it is designed.
With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which the invention relates as this specification proceeds, the invention is herein described by reference to the accompany-ing drawings forming a part hereof, which includes a des-cription of the method of the principles of the present invention, in which:
DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic view of a centrifuge tube showing an example of the separation occurring by use of the method.
Figure 2 is a representation of a graph showing the preferred method of ascertaining the percentage of weiyhting agents.
In the drawings like characters of reference in-dicate corresponding parts in the different figures.
DETAILED DESCRIPTION
Before proceeding to describe the method in detail, .. ..
:
'-;
`';
, ~. ' ' , ; .' ' ' ' ' ' ' ' ' , ' ' it will be noted that the examples utilized barite as a weighting agent so that the developer is known as a "barite developer". However, as will become apparent from a reading of the specification and claims, other weighting agents can be used and of course suitable developer li-quids will be required.
As mentioned previously, the present invention makes use of the fact that the weighting agents such as barite or any practical weighting agent, has a specific gravity that is larger than the gravity of the low gravity solids which is usually approximately 2.5, and below or lower than the specific gravity of the high gravity solids consisting principally of the weighting agent used. The low gravity solids normally consist of bentonite or other clays which are added to the drilling fluids to provide the necessary viscosity to same, together with drilled solids which are obviously present in the drilling fluid after some use.
Briefly, a sample of the drilling fluid is brought into contact with a liquid called a weighting agent develop-er, of a well defined composition with the specific gravity of the developer being such that low gravity solids will float on top of the liquid and that the high gravity solids consisting primarily of the weighting agent, will sink in 1~22933 the liquid. The high gravity solids or weighting agent is thus separated conveniently from the o~her components of the drilling fluid so that the amount of the weighting agent can be determined.
It will be appreciated that the developer liquid must satisfy the following specifications:
1. The liquid must have a specific gravity lar-ger than that of the low gravity solids usually encoun-tered in drilling fluids, so that its specific gravity should be higher than approximately 2.5 up to approxima-tely 3.0 or at least lower than the specific gravity of the viscosifying clay utilized.
GRAVITY SOLIDS IN DRILLING FLUIDS
BACKGROUND OF THE INVENTION
This invention relates to new and useful improve-ments in processes or methods of determining the amount of solids of various kinds present in drilling fluids.
In order to impart the required density to drilling fluids, weighting agents are added and although several weighting agents can be used, the most widely used mate-rial for this purpose is barite, which is a naturally occurring barium sulphate (CHBr3). This barite is added to the drilling fluid in the form of a very fine powder, which is insoluble within the base of the drilling fluid. Che-mically pure barium sulphate has a specific gravity of 4.50 but the grade of barite used in drilling fluids has usually a specific gravity of approximately 4.2. Grades of barite with a lower specific gravity are less desirable because they contain larger amounts of impurities which may be de-trimental to the drilling operations in various ways.
In deep hole drilling, barite costs form a large part of the total cost of the drilling fluid materials and since deep hole drilling is becoming increasingly necessary, and good sources of barite are becoming scarce, a reliable and simple method to determine the actual concentration of the barite or other weighting material, present in drilling fluids, is required.
At the present time, the concentration of barite or other weighting material is calculated in an indirect way, frum the amount of total solids as determined by re-tort distillation to dryness. In this conventional retort method, the amount of total solids follows from the amount of liquid (water and oil) that is collected as distillate.
A material-balance equation, in which values for specific gravity of "low gravity solids" (comprised of bentonite or other viscosifying clays and drill solids and the like) and "high gravity solids" (weighting materials such as ba-rite) are assumed, thus allowing calculation of a value for the concentration of the weighting material from the total solids content and the density of the drilling fluid.
Utilizing these same data, the concentration of low gravi-ty solids is also calculated from a similar material-balance equation. It will be appreciated that these calculations suffer from inherent inaccuracies of the retort procedure inasmuch as the weighting material concentration is calcu-lated in an indirect way, based on values which are not known accurately.
~, , :
~, '':
.,,--~, .. ; .
. . , .. . .
::,. . .
, . , , SUMMARY OF TH_ INVENTION
The present invention overcomes these disadvantages and makes use of the fact that a weighting agent or material has a specific gravity that is larger or higher than the specific gravity of the low gravity solids, which is usually approximately 2.5 and lower or below the specific gravity of the high gravity solids consisting of the weighting agents.
In accordance with the invention there is provided a method for determining the amount of solids present in drilling fluids, particularly relatively high gravity so-lids used as weighting agents; consisting of the steps of taking a sample of the drilling fluid, mixing same with a quantity of a developer liquid having a specific gravity lower than the specific gravity of the weighting agent and being effectively non-immiscible with the base of the dril-ling fluid and in which the weighting agent is insoluble, then forcing the weighting agent out of the drilling fluid and into the developer liquid, allowing the weighting agent to settle by gravity and then determining the amount of settled weighting agent.
The use of the method of the present invention will therefore result in an accurate determination of the actual concentration of the weighting agent or material ~'' ' ' ~
present in the drilling fluids so that the necessary ad-justments (if any) can be made readily and easily and with-out wastage occurring of the weighting agent.
A further advantage of the present method is that it is simple in operation, economical in use and otherwise well suited to the purpose for which it is designed.
With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which the invention relates as this specification proceeds, the invention is herein described by reference to the accompany-ing drawings forming a part hereof, which includes a des-cription of the method of the principles of the present invention, in which:
DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic view of a centrifuge tube showing an example of the separation occurring by use of the method.
Figure 2 is a representation of a graph showing the preferred method of ascertaining the percentage of weiyhting agents.
In the drawings like characters of reference in-dicate corresponding parts in the different figures.
DETAILED DESCRIPTION
Before proceeding to describe the method in detail, .. ..
:
'-;
`';
, ~. ' ' , ; .' ' ' ' ' ' ' ' ' , ' ' it will be noted that the examples utilized barite as a weighting agent so that the developer is known as a "barite developer". However, as will become apparent from a reading of the specification and claims, other weighting agents can be used and of course suitable developer li-quids will be required.
As mentioned previously, the present invention makes use of the fact that the weighting agents such as barite or any practical weighting agent, has a specific gravity that is larger than the gravity of the low gravity solids which is usually approximately 2.5, and below or lower than the specific gravity of the high gravity solids consisting principally of the weighting agent used. The low gravity solids normally consist of bentonite or other clays which are added to the drilling fluids to provide the necessary viscosity to same, together with drilled solids which are obviously present in the drilling fluid after some use.
Briefly, a sample of the drilling fluid is brought into contact with a liquid called a weighting agent develop-er, of a well defined composition with the specific gravity of the developer being such that low gravity solids will float on top of the liquid and that the high gravity solids consisting primarily of the weighting agent, will sink in 1~22933 the liquid. The high gravity solids or weighting agent is thus separated conveniently from the o~her components of the drilling fluid so that the amount of the weighting agent can be determined.
It will be appreciated that the developer liquid must satisfy the following specifications:
1. The liquid must have a specific gravity lar-ger than that of the low gravity solids usually encoun-tered in drilling fluids, so that its specific gravity should be higher than approximately 2.5 up to approxima-tely 3.0 or at least lower than the specific gravity of the viscosifying clay utilized.
2. The developer liquid must have a specific gravity lower than that of the weighting agent and if this weighting agent is barite, it should be lower than approximately 4.2. Needless to say, if other weighting agents with different specific gravities are used, this requirement must be changed accordingly.
3. The liquid should preferably not be miscible with water in the case of water-based drilling fluids.
Miscibility with water will lead to a decrease of specific gravity of the liquid by dilution with water from the drilling fluid. This requirement can be circumvented by ad3ustment of the relative amounts of drilling fluid sam-, . . .
ple and weighted agent developer liquid used in the deter-mination, or by increasing the specific gravity of the de-veloper liquid above the limits set by the previous requi-rements.
Miscibility with water will lead to a decrease of specific gravity of the liquid by dilution with water from the drilling fluid. This requirement can be circumvented by ad3ustment of the relative amounts of drilling fluid sam-, . . .
ple and weighted agent developer liquid used in the deter-mination, or by increasing the specific gravity of the de-veloper liquid above the limits set by the previous requi-rements.
4. The developer liquid should preferably not be miscible with oil in the case of oil-based drilling fluids for similar reasons as mentioned in (3). However, this requirement can be circumvented by similar measures.
5. The liquid should have miscibility properties chosen in accordance with one of the two previous require-ments in the case of emulsion-based drilling fluids con-taining approximately equal amounts of water and oil.
6. The liquid should not dissolve the weighting material present in the drilling fluid.
The majority of drilling fluids are water-based and water-immiscible liquids that are suitable according to the specifications required generally belong to the class of halogenated organic compounds containing at least two bromine or iodine atoms. Such organic compounds are liquid and stable at between approximately 10C and 35C.
The example used in the present specification is bromoform, (CHBr3), having a specific gravity of 2.89.
However, it will be appreciated that solutions of solids w1th high specific gravity in organic solvents are not '~ , ~ , '' . ~ .
i222933 excluded. Water-miscible liquids can be made from aqueous solutions of salts of heavy metals such as thallium and lead.
Because of the viscous nature of drilling fluids, energy is needed to force the weighting agent out of the fluid in which it is suspended, and thence into the deve-loper liquid where it can settle. A convenient way of effecting this separation is centrifugation of the test mixture. It is advantageous to decrease the viscosity of the drilling fluid by one or more of the following techniques:
(a) dilution with water (or the relevant base of the drilling fluid);
(b) addition of chemicals such as acids that will decrease the viscosity and;
(c) oxidation of the organic polymers that are often present in drilling fluids.
The actual determination of the amount of the weighting agent can be accomplished most accurately by removing the weighting agent that has settled in the developer liquid phase and then drying same and weighing the dried weighting agent. More conveniently, the volume thereof can be read directly on a suitably graduated cen-` ~ trifuge tube 10 in which the settling process has taken . , .
"`;~ , ~":
., '; , ' ' ~
. , .:
. "~ , ~ ' ` .
' .
g place. By calibration with fluids containing known con-centrations of the weighting agent, the volume readings can be converted into concentration units by use of a graph similar to that illustrated schematically in Figure 2 in which the base shows the percentage of the weighting agent and the vert~ical,the volume with the necessary reading being taken along the graph line.
An example of a procedure in which the above principles are embodied is as follows:
A 2.5 ml sample of water-base drilling fluid was placed in a l5 ml graduated centrifuge tube, such as that shown schematically by reference character 10 in Figure 1.
To the sample was added ml of 3% hydrogen peroxide and 1 ml of 0.2 M hydrochloric acid. The tube 10 was sha-ken and heated in a hot water bath for approximately 15 minutes. After cooling to room temperature, lml of bromo-form was added and the mixture was shaken.
The tube was then centrifuged at high speed in a conventional centrifuge for five minutes and after centri-fugation, the barite had settled to the bottom of the cen-trifuge tube in the area identified 11 whereupon the volume was read directly from the tube which was marked with the necessary graduations (not illustrated). When one parti-cular type of centrifuge was used, the factor to convert .
. ' .
, 12i~2933 the volume (ml) of barite to concentration in the drilling fluid (kg/m3) was found to be 777.
If the density, W, of the drilling fluid is known in kg/m3, the amount of insoluble low gravity solids, LGS, may be calculated in kg/m3 from the following formula:
LGS = 1.667 W - 1.296 B - 1667 Where B is concentration of barite (kg/m ) as de-termined by the procedure forming a part of this invention and described in the example above. If sodium chloride and potassium chloride are also present, either alone or together, the value of LGS must be decreased by the amount:
(2.675 x 10-4 K+ + 17. 716 x 10-4 Cl~) Where K+ and Cl are the concentrations (mg/L) of the potassium and chloride ions, respectively.
Since various modifications can be made in our in-vention as hereinabove described, and many apparently wide-ly different embodiments of same made within the spirit and scope of the claims without departing from such spirit and scope, it is intended that all matter contained in the ac-companying specification shall be interpreted as illustra-tive only and not in a limiting sense.
The majority of drilling fluids are water-based and water-immiscible liquids that are suitable according to the specifications required generally belong to the class of halogenated organic compounds containing at least two bromine or iodine atoms. Such organic compounds are liquid and stable at between approximately 10C and 35C.
The example used in the present specification is bromoform, (CHBr3), having a specific gravity of 2.89.
However, it will be appreciated that solutions of solids w1th high specific gravity in organic solvents are not '~ , ~ , '' . ~ .
i222933 excluded. Water-miscible liquids can be made from aqueous solutions of salts of heavy metals such as thallium and lead.
Because of the viscous nature of drilling fluids, energy is needed to force the weighting agent out of the fluid in which it is suspended, and thence into the deve-loper liquid where it can settle. A convenient way of effecting this separation is centrifugation of the test mixture. It is advantageous to decrease the viscosity of the drilling fluid by one or more of the following techniques:
(a) dilution with water (or the relevant base of the drilling fluid);
(b) addition of chemicals such as acids that will decrease the viscosity and;
(c) oxidation of the organic polymers that are often present in drilling fluids.
The actual determination of the amount of the weighting agent can be accomplished most accurately by removing the weighting agent that has settled in the developer liquid phase and then drying same and weighing the dried weighting agent. More conveniently, the volume thereof can be read directly on a suitably graduated cen-` ~ trifuge tube 10 in which the settling process has taken . , .
"`;~ , ~":
., '; , ' ' ~
. , .:
. "~ , ~ ' ` .
' .
g place. By calibration with fluids containing known con-centrations of the weighting agent, the volume readings can be converted into concentration units by use of a graph similar to that illustrated schematically in Figure 2 in which the base shows the percentage of the weighting agent and the vert~ical,the volume with the necessary reading being taken along the graph line.
An example of a procedure in which the above principles are embodied is as follows:
A 2.5 ml sample of water-base drilling fluid was placed in a l5 ml graduated centrifuge tube, such as that shown schematically by reference character 10 in Figure 1.
To the sample was added ml of 3% hydrogen peroxide and 1 ml of 0.2 M hydrochloric acid. The tube 10 was sha-ken and heated in a hot water bath for approximately 15 minutes. After cooling to room temperature, lml of bromo-form was added and the mixture was shaken.
The tube was then centrifuged at high speed in a conventional centrifuge for five minutes and after centri-fugation, the barite had settled to the bottom of the cen-trifuge tube in the area identified 11 whereupon the volume was read directly from the tube which was marked with the necessary graduations (not illustrated). When one parti-cular type of centrifuge was used, the factor to convert .
. ' .
, 12i~2933 the volume (ml) of barite to concentration in the drilling fluid (kg/m3) was found to be 777.
If the density, W, of the drilling fluid is known in kg/m3, the amount of insoluble low gravity solids, LGS, may be calculated in kg/m3 from the following formula:
LGS = 1.667 W - 1.296 B - 1667 Where B is concentration of barite (kg/m ) as de-termined by the procedure forming a part of this invention and described in the example above. If sodium chloride and potassium chloride are also present, either alone or together, the value of LGS must be decreased by the amount:
(2.675 x 10-4 K+ + 17. 716 x 10-4 Cl~) Where K+ and Cl are the concentrations (mg/L) of the potassium and chloride ions, respectively.
Since various modifications can be made in our in-vention as hereinabove described, and many apparently wide-ly different embodiments of same made within the spirit and scope of the claims without departing from such spirit and scope, it is intended that all matter contained in the ac-companying specification shall be interpreted as illustra-tive only and not in a limiting sense.
Claims
WHAT WE CLAIM AS OUR INVENTION IS:
(1) A method for determining the amount of solids present in drilling fluids, particularly relatively high gravity solids used as weighting agents; consisting of the steps of taking a sample of the drilling fluid, mixing same with a quantity of a developer liquid having a specific gravity lower than the specific gravity of the weighting agent and being effectively non-immiscible with the base of the drilling fluid and in which the weighting agent is insoluble, then forcing the weighting agent out of the drilling fluid and into the developer liquid, allowing the weighting agent to settle by gravity and then deter-mining the amount of settled weighting agent.
(2) The method according to Claim 1 which inclu-des the additional step of lowering the viscosity of the drilling fluid.
(3) The method according to Claim 1 in which the amount of relatively light gravity solids is determined al-so, particularly such solids as clays, drill solids and the like and in which the developer liquid has a specific gra-vity larger than the specific gravity of the light gravity solids.
(4) The method according to Claim 2 in which the amount of relatively light gravity solids is determined al-so, particularly such solids as clays, drill solids and the like and in which the developer liquid has a specific gra-vity larger than the specific gravity of the light gravity solids.
(5) The method according to Claim 1 in which the weighting agent consists of powdered barium sulphate (bari-te).
(6) The method according to Claim 2 in which the weighting agent consists of powdered barium sulphate (bari-te).
(7) The method according to Claim 3 in which the weighting agent consists of powdered barium sulphate (bari-te).
(8) The method according to Claim 4 in which the weighting agent consists of powdered barium sulphate (bari-te).
(9) The method according to Claim 1 in which the drilling fluid base is water and the developer liquid is water-immiscible and is a high specific gravity solid dis-solved in an organic solvent.
(10) The method according to Claim 9 in which the developer liquid is selected from the class of halogenated organic compounds having two bromine or two iodine atoms.
(11) The method according to Claim 10 in which the developer liquid is bromoform (CHBr3) having a specific gravity of approximately 2.89.
(12) The method according to Claim 5 in which the drilling fluid base is water and the developer liquid is water-immiscible and is a high specific gravity solid dissolved in an organic solvent.
(13) The method according to Claim 12 in which the drilling fluid base is water and the developer liquid is water-immiscible and is a high specific gravity solid dissolved in an organic solvent.
(14) The method according to Claim 13 in which the developer liquid is bromoform (CHBr3) having a speci-fic gravity of approximately 2.89.
(15) The method according to Claims 1, 2 or 3 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of removing the settled weighting agent, drying same and then weighing the dried weighting agent.
(16) The method according to Claims 4, 5 or 6 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of removing the settled weighting agent, drying same and then weighing the dried weighting agent.
(17) The method according to Claims 7, 8 or 9 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of removing the settled weighting agent, drying same and then weighing the dried weighting agent.
(18) The method according to Claims 10, 11 or 12 in which the weighting agent is forced out of the dril-ling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weight-ing agent includes the steps of removing the settled weight-ing agent, drying same and then weighing the dried weighting agent.
19) The method according to Claims 13 or 14 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of removing the settled weighting agent, drying same and then weighing the dried weighting agent.
(20) The method according to Claims 1, 2 or 3 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of first reading the volume of the settled weighting agent and then calibrating same with fluids containing known concentrations of weighting agents and then converting the volume readings into concentration units.
(21) The method according to Claims 4, 5 or 6 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of first reading the volume of the settled weighting agent and then calibrating same with fluids containing known concentrations of weighting agents and then converting the volume readings into concentration units.
(22) The method according to Claims 7, 8 or 9 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of first reading the volume of the settled weighting agent and then calibrating same with fluids containing known concentrations of weighting agents and then converting the volume readings into concentration units.
(23) The method according to Claims 10, 11 or 12 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of first reading the volume of the settled weighting agent and then calibrating same with fluids containing known concentrations of weighting agents and then converting the volume readings into concentration units.
(24) The method according to Claims 13 or 14 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of first reading the volume of the settled weighting agent and then calibrating same with fluids containing known concentrations of weighting agents and then converting the volume readings into concentration units.
(1) A method for determining the amount of solids present in drilling fluids, particularly relatively high gravity solids used as weighting agents; consisting of the steps of taking a sample of the drilling fluid, mixing same with a quantity of a developer liquid having a specific gravity lower than the specific gravity of the weighting agent and being effectively non-immiscible with the base of the drilling fluid and in which the weighting agent is insoluble, then forcing the weighting agent out of the drilling fluid and into the developer liquid, allowing the weighting agent to settle by gravity and then deter-mining the amount of settled weighting agent.
(2) The method according to Claim 1 which inclu-des the additional step of lowering the viscosity of the drilling fluid.
(3) The method according to Claim 1 in which the amount of relatively light gravity solids is determined al-so, particularly such solids as clays, drill solids and the like and in which the developer liquid has a specific gra-vity larger than the specific gravity of the light gravity solids.
(4) The method according to Claim 2 in which the amount of relatively light gravity solids is determined al-so, particularly such solids as clays, drill solids and the like and in which the developer liquid has a specific gra-vity larger than the specific gravity of the light gravity solids.
(5) The method according to Claim 1 in which the weighting agent consists of powdered barium sulphate (bari-te).
(6) The method according to Claim 2 in which the weighting agent consists of powdered barium sulphate (bari-te).
(7) The method according to Claim 3 in which the weighting agent consists of powdered barium sulphate (bari-te).
(8) The method according to Claim 4 in which the weighting agent consists of powdered barium sulphate (bari-te).
(9) The method according to Claim 1 in which the drilling fluid base is water and the developer liquid is water-immiscible and is a high specific gravity solid dis-solved in an organic solvent.
(10) The method according to Claim 9 in which the developer liquid is selected from the class of halogenated organic compounds having two bromine or two iodine atoms.
(11) The method according to Claim 10 in which the developer liquid is bromoform (CHBr3) having a specific gravity of approximately 2.89.
(12) The method according to Claim 5 in which the drilling fluid base is water and the developer liquid is water-immiscible and is a high specific gravity solid dissolved in an organic solvent.
(13) The method according to Claim 12 in which the drilling fluid base is water and the developer liquid is water-immiscible and is a high specific gravity solid dissolved in an organic solvent.
(14) The method according to Claim 13 in which the developer liquid is bromoform (CHBr3) having a speci-fic gravity of approximately 2.89.
(15) The method according to Claims 1, 2 or 3 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of removing the settled weighting agent, drying same and then weighing the dried weighting agent.
(16) The method according to Claims 4, 5 or 6 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of removing the settled weighting agent, drying same and then weighing the dried weighting agent.
(17) The method according to Claims 7, 8 or 9 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of removing the settled weighting agent, drying same and then weighing the dried weighting agent.
(18) The method according to Claims 10, 11 or 12 in which the weighting agent is forced out of the dril-ling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weight-ing agent includes the steps of removing the settled weight-ing agent, drying same and then weighing the dried weighting agent.
19) The method according to Claims 13 or 14 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of removing the settled weighting agent, drying same and then weighing the dried weighting agent.
(20) The method according to Claims 1, 2 or 3 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of first reading the volume of the settled weighting agent and then calibrating same with fluids containing known concentrations of weighting agents and then converting the volume readings into concentration units.
(21) The method according to Claims 4, 5 or 6 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of first reading the volume of the settled weighting agent and then calibrating same with fluids containing known concentrations of weighting agents and then converting the volume readings into concentration units.
(22) The method according to Claims 7, 8 or 9 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of first reading the volume of the settled weighting agent and then calibrating same with fluids containing known concentrations of weighting agents and then converting the volume readings into concentration units.
(23) The method according to Claims 10, 11 or 12 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of first reading the volume of the settled weighting agent and then calibrating same with fluids containing known concentrations of weighting agents and then converting the volume readings into concentration units.
(24) The method according to Claims 13 or 14 in which the weighting agent is forced out of the drilling fluid and into the developer liquid by centrifugal force and the determination of the amount of settled weighting agent includes the steps of first reading the volume of the settled weighting agent and then calibrating same with fluids containing known concentrations of weighting agents and then converting the volume readings into concentration units.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000456172A CA1222933A (en) | 1984-06-08 | 1984-06-08 | Method of determination of weighting materials and low gravity solids in drilling fluids |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000456172A CA1222933A (en) | 1984-06-08 | 1984-06-08 | Method of determination of weighting materials and low gravity solids in drilling fluids |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1222933A true CA1222933A (en) | 1987-06-16 |
Family
ID=4128062
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000456172A Expired CA1222933A (en) | 1984-06-08 | 1984-06-08 | Method of determination of weighting materials and low gravity solids in drilling fluids |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1222933A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0316985A1 (en) * | 1987-11-14 | 1989-05-24 | Services Petroliers Schlumberger | A method of monitoring the drilling operations by analysing the circulating drilling mud |
| US5140527A (en) * | 1988-12-15 | 1992-08-18 | Schlumberger Technology Corporation | Method for the determination of the ionic content of drilling mud |
-
1984
- 1984-06-08 CA CA000456172A patent/CA1222933A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0316985A1 (en) * | 1987-11-14 | 1989-05-24 | Services Petroliers Schlumberger | A method of monitoring the drilling operations by analysing the circulating drilling mud |
| US5140527A (en) * | 1988-12-15 | 1992-08-18 | Schlumberger Technology Corporation | Method for the determination of the ionic content of drilling mud |
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