TECHNICAL FIELD
The present invention relates to a lubricating formulation for oil and gas well.
The present invention further relates to the application of the lubricating formulation in reduction of torque and drag in drilled of oil and gas wells.
BACKGROUND
Drilling fluids are used in oil well drilling to provide various functions. One of the functions of drilling fluid is to lubricate bit and drill string. Manifestation of friction between the drill string and the borehole is as old as drilling itself. Frictional resistance to rotation of the drill string is called torque, and frictional resistance to hoisting and lowering the drill string is called drag.
An important function of drilling fluid is to provide lubrication to bit and drill string. If lubricating properties of the drilling fluid are not adequate, considerable pressure losses are generated due to friction when string is being rotated or is being pulled out and rurming in against the wellbore. With growing orientation towards drilling of Multilateral wells, side tracks. Extended Reach Drilling (ERD) wells and horizontal wells with open hole completions use of non damaging drilling fluids with adequate lubricating properties to reduce torque and drag is essentially being felt. The lubricity, or drill string to borehole wall drag, of drilling fluid is a property of special importance in drilling directional wells.
The frictional resistance generated by rotating the drill string against the formation or casing may require extra torque if the hole is crooked or directional. Considerable frictional resistance to raising and lowering the drill string may also occur. Under certain conditions, such as in highly deviated holes, holes with different changes in direction, under gauge holes or poor drill string dynamics, increased torque and drag entail a high risk of lost rig time, expensive pipe recovery operations and limitations in well developments. Extensive torque required to rotate the pipe generates greater strain on the drill pipe with the danger of twist -off.
Sometimes, another problem occurs when drill pipe sticks to the wall of borehole. This may be caused by ruiming or pulling pipe into the under gauge section of the hole, a key seat or a bridge of caving. Under certain circumstances differential pressure sticking may also occur when the drill pipe becomes motionless against a permeable formation and a portion of the contact area of the pipe is isolated by the filter cake. To overcome these difficulties, drilling fluids are treated with mud lubricants.
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Different types of lubricants are in use worldwide to improve lubricating properties of the drilling muds.
In oil industry, Graphite, asphalt, HSD and / or crude oil, fine mica and ground nut hulls Drilling detergent and EP (Extreme Pressure) lubricants are being used for the purpose of lubrication. Extreme pressure lubricants were developed for adding better lubricating characteristics to drilling fluids and to increase the life of bit bearings. Their effectiveness in providing lubricating properties deteriorates rapidly with time due to certain emulsification properties or separation from vibrating screens. HSD oil is a poor lubricant and looses its lubricating properties as soon as it makes a tight emulsion with water in presence of mud additives.
United States patent 6,806,235 discloses a process for imparting lubricity to an aqueous drilling fluid used in geological exploration involving: (a) providing an aqueous drilling fluid; (b) providing a lubricant component containing a partial glyceride of predominantly unsaturated fatty acids having from about 16 to 24 carbon atoms; and (c) introducing the partial glyceride into the aqueous drilling fluid. The process claims from about 0.5 to 5% by weight of the lubricant component, based on the weight of the drilling fluid, is introduced into the drilling fluid.
United States patent 5,344,817 discloses a method for lubricating a down hole well drilling operation comprising the steps of: (a) mixing a spotting fluid concentrate composition comprising water soluble glycerophosphoric acid ester prepared as the reaction product of glycerin and phosphoric acid, an optional viscosifying agent and an optional sealing agent with drilling mud; and (b) Circulating said mud mixture through the well.
United States patent 5,869,434 discloses the use of linear hydrocarbon compounds, unsaturated in the alpha position, as the oil phase or as part of the oil phase in drilling fluid formulations. Emulsifiers are used in these water-based formulations.
United States patents 5,851,958 and 5,605,879 disclose the use of olefinic hydrocarbons as lubricants, rate of penetration enhancers, and spotting fluids in water-based drilling fluids. Spotting fluids preferably include functional additives, such as emulsifiers, viscosifiers, surfactants, and / or brine. United States patent 5,837,655 discloses the use of purified paraffins, selected from the group consisting of white oils and food grade paraffins, as lubricants, rate of penetration enhancers, and spotting fluids in water-based drilling fluids. When used in spotting fluids, paraffins are supplemented with additives such as emulsifiers, viscosifiers, surfactants, and / or brine. When used as lubricants and / or rate of penetration enhancers, the paraffins are preferably used alone or in combination with surfactants.
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United States patent 5,707,940 relates to oil-in-water drilling fluid formulations comprising brine, at least one triglyceride, at least one alcohol, at least one emulsifier, and at least on sulfiirized composition. United States Patent 5,700,767 discloses a lubricant system comprising surfactant (preferably aluminum Stearate), Viscosifier (oil-compatible Bentonite or polyacrylamide), filming amine, activator (petroleum solvent, coconut oil, terpene, zylene, mineral oil, turpentine, d-limonene or mixtures thereof), and diluents (diesel fuel, fuel oil, gasoline, naphtha, kerosene, or jet fuel). When the lubricant formulation is dispersed in the drilling fluid, the filming amine coats the metal; and friction associated with the drilling operation causes formation of a lubricious emulsion.
United States patent 5,593,954 describes drilling fluid compositions containing a mixture of brine, an oil soluble friction modifier, and an emulsifier. An oil carrier may be used in combination with the friction modifier and emulsifier to form the final oil phase. United States patent 5,587,354 discloses a drilling fluid additive comprising a monocyclic terpene (e.g., d-limonene) and oil, such as mineral oil or vegetable oil. The additive is mixed into a water-based drilling fluid in the range of 1-8% by volume and provides improved rate of penetration, high lubricity and low toxicity.
United States patent 5,248,664 describes water-based drilling fluid formulations that contain an alcohol such as glycerol to depress the freezing point of the formulation, to inhibit the formation of gas hydrates, to prevent shale dispersion, and to reduce drilling fluid loss. Oil is added to the formulation to increase lubricity, and emulsifiers are used to keep the water-insoluble oil uniformly suspended in the water phase. United States patent 4,517,100 discloses a water-based drilling fluids containing a lubricant composition comprised of a chlorinated component (chlorinated normal paraffin, chlorinated esters of fatty acids, chlorinated waxes, chlorinated olefins, or mixtures thereof) and a sulfurized component (sulfiirized fatty acid, sulfurized olefins, or mixture thereof).
United States patent 4,409,108 describes lubricants for water-based drilling fluids that contain up to about 5% (by weight) of an additive comprising a mixture of an odor-masking agent, a low molecular weight alcohol, and an ester of oleic acid.
United States patent 3,761,410 discloses the additive composition which increases the lubricity of the water based drilling fluids. This document also discloses that the lubricating additives may be selected from vegetable oils, animal fats, fatty acids, fatty acid esters etc. United States patent 4,064,056 discloses clay based drilling fluid containing an oil based additive composition for reduction in torque. United States patent 5,945,386 discloses the use of spotting fluid as a lubricating additive for drilling fluids (drilling muds).
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For more than last a decade or so drilling and reservoir engineers worldwide are engaged in dialogue for the purpose of utilizing drilling and production techniques which suitably match reservoir needs. With depleting reservoir pressures due to continuous production of oil and gas operators are placing increased emphasis on reservoir entry techniques. One reason for this change is growing number of side tracks, LDST wells, muhilaterals and horizontal wells wdth open hole completions. These hi-tech drilling techniques have a great demand for high performance lubricating formulations. To fulfill this requirement there is a need to identify lubricating formulations with additives as alternate to existing lubricants. There is a need for a lubricating formulation containing less amount of additive fluids to reduce friction as manifested by reduction of torque and drag in directional wells with special reference to Extended Reach Directional (ERD) wells drilled for oil and gas.
SUMMARY
The present invention relates to a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 35% to 55% (wt/wt) of a Fatty acid; and optionally 15 % to 30% (wt/wt) of an aromatic solvent.
The present invention also relates to the application of lubricating formulation in reduction of torque and drag in drilled of oil and gas wells.
These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
DETAILED DESCRIPTION
The present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (v^wt) of an Acid oil; and 35% to 55% (wt/wt) of a Fatty acid.
An embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to
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0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; and 35% to 55% (wt/wt) of oleic acid.
Still another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; and 35% to 55% (wt/wt) of linoliec acid.
Yet another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; and 35% to 55% (wt/wt) of ricinoliec acid.
Further an embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; and 35% to 55% (wt/wt) of tallow fatty acid.
Another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; and 35% to 55% (wt/wt) of lauric acid.
Yet another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; and 35% to 55% (wt/wt) of mixture of fatty acids.
Another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 15% to 25% of oleic acid; and 20% to 30% (wt/wt) of other fatty acid.
An embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of rapseed oil; and 35% to 55% (wt/wt) of a Fatty acid.
Yet another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of rice bran oil; and 35% to 55% (wt/wt) of a Fatty acid.
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An embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 35% to 55% (wt/wt) of a Fatty acid; and 15 % to 30% (wt/wt) of an aromatic solvent.
Further an embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (v^wt) of rapseed oil; 35% to 55% (wt/wt) of a Fatty acid; and 15 % to 30% (wt/wt) of an aromatic solvent.
Another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of rice bran oil; 35% to 55% (wt/wt) of a Fatty acid; and 15 % to 30% (wt/wt) of an aromatic solvent.
An embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 35% to 55% (vrt/wt) of oleic acid; and 15 % to 30% (wt/wt) of an aromatic solvent.
Still another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 35% to 55% (wt/wt) of linoliec acid; and 15 % to 30% (wt/wt) of an aromatic solvent..
Yet another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 35% to 55% (wt/wt) of ricinoliec acid; and 15 % to 30% (wl/wt) of an aromatic solvent.
Further an embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 35% to 55% (wt/wt) of tallow fatty acid; and 15 % to 30% (wt/wt) of an aromatic solvent.
Another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 35% to 55% (wt/wt) of lauric acid; and 15 % to 30% (wt/wt) of an aromatic solvent.
Yet another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and
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0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 35% to 55% (wt/wt) of mixture of fatty acids; and 15 % to 30% (wt/wt) of an aromatic solvent.
Another embodiment of the present disclosure provides a lubricating formulation for drilling of oil and gas wells, comprising: 99.4% to 99.9% (v/v) of a drilling fluid; and 0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 15% to 25% of oleic acid; 20% to 30% (v^vv4) of fatty acid other than oleic acid; and 15 % to 30% (wt/wt) of an aromatic solvent.
In an embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: bentonite suspension in water; and cellulosic material in the range of 0.2% to 0.4% by weight of bentonite suspension.
In an embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: bentonite suspension in water; and 0.3% by weight of bentonite suspension cellulosic material.
, In an embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: bentonite suspension in water; and Polyanionic cellulose in the range of 0.2% 0.4% by weight of bentonite suspension.
In an embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: bentonite suspension in water; cellulosic material in the range of 0.2% to 0.4% by weight of bentonite suspension; and polyol in the range of 2 to 5% by weight of bentonite suspension.
In another embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: bentonite suspension in water; Polyanionic cellulose in the range of 0.2% to 0.4% by weight of bentonite suspension; and polyol in the range of 2 to 5% by weight of bentonite suspension.
In an embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: bentonite suspension in water; cellulosic material in the range of 0.2% to 0.4% by weight of bentonite suspension; and ethylene glycol in the range of 2 to 5% by weight of bentonite suspension.
In an embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: bentonite suspension in water; cellulosic material in the range of 0.2% to 0.4% by weight of bentonite suspension; and propanediol in the range of 2 to 5% by weight of bentonite suspension.
In another embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: bentonite suspension in water;
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cellulosic material in the range of 0.2% to 0.4% by weight of bentonite suspension; and butanediol in the range of 2 to 5% by weight of bentonite suspension.
In yet another embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: bentonite suspension in water; cellulosic material in the range of 0.2% to 0.4% by weight of bentonite suspension; and pentanediol in the range of 2 to 5% by weight of bentonite suspension.
In another embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: a clay free suspension; xanthum gimi in the range of 0.4% to 0.5% by weight of clay free suspension; starch in the range of 2% to 4% by weight of clay free suspension; and a micronized weighting agent in the range of 5% to 7% by weight of clay free suspension.
In an embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: a clay free suspension; xanthum gum in the range of 0.4% to 0.5% by weight of clay free suspension; starch in the range of 2% to 4% by weight of clay free suspension; and calcium carbonate in the range of 5% to 7% by weight of clay free suspension.
In yet another embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: a clay free suspension; xanthum gum in the range of 0.4% to 0.5% by weight of clay free suspension; starch in the range of 2% to 4% by weight of clay free suspension; and bariiun sulphate in the range of 5% to 7% by weight of clay free suspension.
In another embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: a clay free suspension; xanthum gum in the range of 0.4% to 0.5% by weight of clay free suspension; starch in the range of 2% to 4% by weight of clay free suspension; and dolomite in the range of 5% to 7% by weight of clay free suspension.
In an embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: a clay free suspension; xanthum gum in the range of 0.4% to 0.5% by weight of clay free suspension; starch in the range of 2% to 4% by weight of clay free suspension; and limenite in the range of 5% to 7% by weight of clay free suspension.
In yet another embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: a clay free suspension; xanthum gum in the range of 0.4% to 0.5% by weight of clay free suspension; starch in the range of
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2% to 4% by weight of clay free suspension; and hematite in the range of 5% to 7% by weight of clay free suspension.
In another embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosxire comprising: a clay free suspension; xanthum gum in the range of 0.4% to 0.5% by weight of clay free suspension; starch in the range of 2% to 4% by weight of clay free suspension; and manganese oxide in the range of 5% to 7% by weight of clay free suspension.
In another embodiment of the present disclosure the drilling fluid use in the lubricating formulation of the present disclosure comprising: a clay free suspension; xanthum gum in the range of 0.4% to 0.5% by weight of clay free suspension; starch in the range of 2% to 4% by weight of clay free suspension; and strontium sulphate in the range of 5% to 7% by weight of clay free suspension.
In an embodiment of the present disclosure the aromatic solvent used in the lubricating formulation of the present disclosure is selected from xylene, ethylbenzene, propylbenzene, ethyltoluene, diethylbenzene, and propyholuene.
An embodiment of the present disclosure provides a lubricating formulation with less amount of additive fluid (0.1% to 0.6% (v/v)) which is cost efficient. The lubricating formulation of the present disclosure is economical, since the additive fluid is required in less quantity to achieve the desired lubricating properties.
The term "Bentonite" as used herein means a fine grained clay that contains not less than 85% montmorrilonite. Montmorrilonite group of clays are having high swelling properties and are used for preparation of drilling fluid in oil well drilling. These clays provide number of fimctions like cutting suspension and transport, control of filtration and seepage, form an impermeable filter cake on the wall of the wellbore and to control mud loss and hole instability. Clays have sheet structure and are basically Alluminosilicates. Clay minerals carry charge due to isomorphous substitution of some atoms in their structure by other atoms of different valence.
The term "Cellulosic material" or PAC(R) as used herein means semi synthetic gums produced by the chemical modification of Cellulose. These polymers are characterized by degree of substitution (DS) and degree of polymerization (DP). A variety of products can be made by controlling these two parameters. Chemically purified cellulose is treated with caustic soda solution to form alkali cellulose. The addition of monochloroacetic acid or sodium monochloroacetate to form sodium carboxymethyl cellulose is next step. PAC(R) is
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high viscosity grade Polyanionic cellulose. This chemical is used in drilling fluids to control filtration loss.
The term "Polyglycol" or "Polyol gd-2" means a generic group of compound which in true sense contain two hydroxyl (-0H) end groups. Polyglycol are formed when these groups are condensated between glycols to form ether links (i.e. C-O-C bonds). Some materials which are presently finding widespread use only contain one hydroxyl groups and are actually initiated from alcohols (e.g. butanol), fatty acids or fatty amines which are condensated with ethylene oxide (EO) or propylene oxide (PO) or butylenes oxide. Most of them are non ionic surfactant which combines in a single molecule a hydrophobic group (e.g. the alkyl chain that originated from the initiator) and a hydrophilic group (the EO - or EO/PO chain). It is a clouding Polyglycol. Clouding Polyglycol (Polyol) or thermally activated mud emulsion (TAME) Polyglycols are typically soluble/ miscible in water at lower temperatures, when heated will eventually separate into 2 distinct liquid phases as the Polyglycols become partially insoluble in aqueous phase. Polyglycols (polyols) are well known in the drilling industry for their use in controlling troublesome shale. Typical shale problems experienced with many other types of water based muds when drilling high clay content massive shales have been eliminated by using these additives. Polyglycols have become established as cost effective, enviroimiental friendly additive for water base muds in addition to HPHT stability of drilling fluids.
The temperature, known as 'cloud point' or cloud point temperature (CPT) may be defined as the point (temperature) where the molecule has lost sufficient water solubility so that phase separation starts to occur. As a result, surfactant properties (if any) of glycols also begin to change. At this temperature micelle formation may or may not take place depending upon the concentration and conformation of the molecule. The phenomenon is reversible as the separated phase re dissolves once the temperature is lowered below CPT. The exact CPT of a polyglycol is a function of the specific polyglycol used, its concentration and the presence of other dissolved materials especially electrolytes. Clouding Glycol (Named Polyglycol or Polyol- gd 2) have parameters like pH, Surface Tension, Hydroxyl value. Iodoform test and Cloud Point in its specification.
The term "additive fluid" as used herein means the compounds or the compoistion which are used in stuck breaking pill for spotting in weighted and non weighted drilling fluids and have parameters like Miscibility with HSD Oil, Interfacial Tension with Distilled Water - HSD Oil, Lubricity Coefficient with Bentonite Suspension, Mud Cake Cracking Test, Sticking Test and stability (emulsion and weight) test in their specification. These
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additives are basically used in 2- 3% concentration by weight of diesel or crude oil in stuck breaker pill.
The term "Apparent Viscosity" as used herein means half of the 600 rpm dial reading of the formulation in Fann V G meter.
The term "Plastic Viscosity" as used herein means the difference of 600 rpm dial reading and 300 rpm dial reading of the formulation in Fann V G meter.
The term "Yield Point" as used herein means the difference of 300 rpm dial reading and Plastic Viscosity of the formulation in Fann V G meter.
The term "lubricity coefficient (L.C.)" defined as the ratio of frictional force parallel to the contact siirface to the load acting normal to the contact surface. In general engineering practice, friction between two solid samples (in present case between drill string/Tubular and borehole or between drill string/Tubular and casing) is reduced by interposing a film of oil or any other lubricant between moving solid /metal parts. These lubricants are evaluated by their effect on the coefficient of friction, which mathematically is:
^ = F/W
^ = Coefficient of friction
F = Force parallel to the surface
W = Force normal to the surface
To evaluate lubricant for torque reduction Fan Make Lubricity and E.P. tester was used.
The coefficient of fiiction is measured under standard conditions of 60 rpm for test ring and 150 inch pounds (720 psi) load by a torque arm, which are judged to be representations of field conditions. Lubricity coefficient can be calculated by the evaluation given below.
Mud lubricity coefficient (n) = Meter Reading /100
EXAMPLES
The following examples are given by way of illustration of the present disclosure and should not be construed to limit the scope of present disclosure. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide fiirther explanation of the claimed subject matter.
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Experiments were carried out to evaluate the lubricating properties of the lubricating formulation of the present disclosure in terms of lubricity coefficient and pH value. Following formulations were designed and studied as demonstrated in Tables 1 to 7.
Formulation 1: Bentonite suspension in water + Polyanionic cellulose - 0.3% w/v + Polyol (gd-2) - 5%w/v.
Formulation 2: Bentonite suspension in water + Polyanionic cellulose - 0.3% w/v + Polyol (gd 2) - 5%w/v + Additive fluid-A- 0.1 % v/v.
Formulation 3: Bentonite suspension in water + Polyanionic cellulose - 0.3% w/v+ Polyol (gd-2) - 5%w/v + Additive fluid-A- 0.1-0.2% v/v.
Formulation 4: Bentonite suspension in water + Polyanionic cellulose - 03% w/v+ Polyol (gd-2) - 5%w/v + Additive fluid-A- 0.3% v/v.
Formulation 5: Bentonite suspension in water + Polyanionic cellulose - 0.3% w/v+ Polyol (gd-2) - 5%w/v + Additive fluid-A- 0.6% v/v.
Formulation 6: Bentonite suspension in water + Polyanionic cellulose - 0.3% w/v+ Polyol (gd-2) - 5%w/v + Additive fluid-A- 0.7% v/v.
Formulation 7: Bentonite suspension in water + Polyanionic cellulose - 0.3% w/v+ Polyol (gd-2) - 5%w/v + Additive fluid-A- 0.8% v/v.
Formulation 8: Bentonite suspension in water + Polyanionic cellulose - 0.3% w/v
Formulation 9: Bentonite suspension in water + Polyanionic cellulose - 0.3% w/v + Additive fluid-A- 0.1% v/v.
Formulation 10: Bentonite suspension in water + Polyanionic cellulose - 0.3%) w/v + Additive fluid-A- 0.1 to 0.2% v/v.
Formulation 11: Bentonite suspension in water + Polyanionic cellulose - 0.3%) w/v + Additive fluid-A- 0.3% v/v.
Formulation 12: Bentonite suspension in water + Polyanionic cellulose - 0.3%) w/v+ Additive fluid-A- 0.6% v/v.
Formulation 13: Bentonite suspension in water + Polyanionic cellulose - 0.3%) w/v + Additive fluid-A- 0.7% v/v.
Formulation 14: Bentonite suspension in water + Polyanionic cellulose - 0.3%) w/v + Additive fluid-A- 0.8% v/v.
Formulation 15: Bentonite suspension in water + Polyanionic cellulose - 0.3%) w/v+ Polyol (gd-2) - 5%w/v + E P Lub.- 0.3% v/v
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Formulation 16: Bentonite suspension in water + Polyanionic cellulose - 0.3% w/v+ Polyol (gd-2) - 5%w/v + E P Lub.- 0.6% v/v
Formulation 17: Bentonite suspension in water + Polyanionic cellulose - 0.3% w/v+ Polyol (gd-2)—5% + Additive fluid-B- 0.3% v/v.
Formulation 18: Bentonite suspension in water + Polyanionic cellulose - 0.3%) w/v + Polyol (gd-2)—5% + Additive fluid-B- 0.6% v/v.
Formulation 19: Bentonite suspension in water + Polyanionic cellulose - 0.3%) w/v+ Additive fluid-B- 0.3% w/v or v/v.
Formulation 20: Bentonite suspension in water + Polyanionic cellulose - 0.3%) w/v+ Additive fluid-B - 0.6% w/v or v/v.
Formulation 21: Clay free water suspension + Xanthan Polymer-0.5%) + PAC( R)-0.3% w/v + PAC(L)-1.2% w/v+ MCC(Micronized Calcium Carbonate) -6%w/v + Polyol (gd-2)-5%w/v.
Formulation 22: Clay free water suspension + Xanthan Polymer-0.5% + PAC( R)-0.3% w/v + PAC(L)-1.2% w/v+ MCC(Micronized Calcium Carbonate) -6%w/v + Polyol (gd-2) - 5%w/v+ Additive fluid-A - 0.6% v/v.
Formulation 23: Clay free water suspension + Xanthan Polymer-0.5%) + PAC( R)-0.3% w/v + PAC(L)-1.2% w/v+ MCC(Micronized Calcium Carbonate) -6%w/v + Polyol (gd-2) - 5%w/v+ Additive fluid-A - 0.7% v/v.
Formulation 24: Clay free water suspension + Xanthan Polymer-0.5% + PAC( R)-0.3%) w/v + PAC(L)-1.2%) w/v+ MCC(Micronized Calcium Carbonate) -6%)w/v + Polyol (gd-2) - 5%w/v+ Additive fluid-A - 0.8% v/v.
Formulation 25: Clay free water suspension + Xanthan Polymer-0.5%) + PGS-3%) w/v + MCC (Micronized Calcium Carbonate) -6%)w/v + Polyol (gd-2) - 5%)w/v.
Formulation 26: Clay free water suspension + Xanthan Polymer-0.5%) + PGS-3%) w/v + MCC (Micronized Calcium Carbonate) -6%w/v + Polyol (gd-2) - 5%)w/v+ Additive fluid-A - 0.6% v/v.
Formulation 27: Clay free water suspension + Xanthan Polymer-0.5%) + PGS-3%) w/v + MCC (Micronized Calcium Carbonate) -6%w/v + Polyol (gd-2) - 5%)w/v+ Additive fluid-A - 0.7% v/v.
Formulation 28: Clay free water suspension + Xanthan Polymer-0.5%) + PGS-3%) w/v + MCC (Micronized Calcium Carbonate) -6%w/v + Polyol (gd-2) - 5%ow/v+ Additive fluid-A - 0.8% v/v.
14

The Additive Fluid-A as used herein means an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 35% to 55% (wt/wt) of a Fatty acid; and 15 % to 30% (wt/wt) of an aromatic solvent.
The Additive Fluid-B as used herein means an additive fluid comprising: 30% to 50%) (wt/wt) of an Acid oil; and 35% to 55%) (wt/wt) of a Fatty acid.
The conditions of measurement of lubricity coefficient in lab are representative of conditions of torque and drag in field. The adverse lubricating properties can lead to a typical hole problem known as stuck pipe.
Table-1 ^_^
SI. Formulation Apparent Plastic Yield Lubricity pH
No. viscosity - viscosity point - coefficient
AV (Cp) -PV Cp) Yp(lbs/1
OOsq.ft)
JLI Formulation 1 _41^5 23 37 022 8,91
_Z After hot rolling at 100 "C fori6 hrs 40 21 38 023
^ Formulation 2 41.5 23 37 013 7.84-8.1
_4. After hot rolling at 100 "C fori6 hrs 40 21 38 013
_5. Formulations _4L5 23 37 012-013 7.84-7.86
6. After hot rolling at 100 "C fori6 hrs 40 21 38 0.09-OlO
T. Formulation 4 4L5 23 37 OTI 7.84-7.86
~8. After hot rolling at 100 "C forl6 hrs ~40 21 38 007
~9. Formulation 5 45^5 25 41 0.03 - 0.04 7.41-7.50
lO After hot rolling at 100 "C for 16 hrs 45.5 25 41 0.3 - 0.04
IT Formulation 6 35 20 30 0.04 - 0.05 7.25-7.30
12. After hot rolling at 100 "C for 16 hrs lO 20 20 0.04 - 0.05
13. Formulation 7 32l 22 2\ 0.04 - 0.05 7.20-7.25
~U. After hot rolling at 100 "C fori 6 hrs 28.5 20 17 0.04 - 0.05
Formulation 1 having no additive fluid possesses high lubricity coefficient of 0.22 which is not desirable. The pH value of Formulation 1 is 8.91 which is a desired value, hoverer the high lubricity coefficient of the formulation 1 makes this formulation undesirable for use in lubricating purposes.
Formulation 2 having 0.1% v/v of additive fluid A possesses a lubricity coefficient of 0.13 at ambient temperature and pH of 7.84-8.1.
Formulation 3 having 0.1-0.2% v/v of additive fluid A possesses a lubricity
coefficient of 0.12 - 0.13 at ambient temperature and pH of 7.84 - 7.86.
Formulation 4 having 0.3% v/v of additive fluid A without polyol possesses a lubricity coefficient of 0.11 at ambient temperature and pH of 7.84 - 7.86.
15

Formulation 5 having 0.6% v/v of additive fluid A without polyol possesses a lubricity coefficient of 0.03 - 0.04 at ambient temperature and pH of 7.41- 7.50.
Formulation 6 having 0.7% v/v of additive fluid A possesses a lubricity coefficient of 0.04 - 0.05 at ambient temperature and pH of 7.25 - 7.30.
Formulation 7 having 0.8% v/v of additive fluid A possesses a lubricity coefficient of 0.04 - 0.05 at ambient temperature and pH of 7.20 - 7.25.
Hence, it can conclude from Table 1 that the lubricating formulation without additive fluid possesses a high lubricity coefficient, which is not desirable. On the other hand, the lubricating formulations of the present disclosure possess a low lubricity coefficient of at ambient temperature as well as after hot rolling at 100°C for 16 hours. Further, the formulations having additive fluid more than 0.6% on one hand possess low lubricity coefficient on the other hand having low pH value. The low value of pH is not desired as the low value of pH adversely affects the rheological properties of the lubricating formulation. Thus the lubricating formulation with additive fluid in the range of 0.1% to 0.6% (v/v) shows the desired lubricating property in terms of lubricity coefficient as well as pH value.
Table-2
SI. Formulation Apparent Plastic Yield Lubricity pH
No. viscosity - viscosity point - coefficient
AV (Cp) -PV Cp) Yp(lbs/1
; OOsq.ft)
J, Formulation 8 ^4,5 13 23 025 8.82
2. After hot rolling at 100 "C fori 6 24.5 13 23 0.25
hrs
^ Formulation9 ^4,5 13 23 0J3 8.13-8.15
•
After hot rolling at 100 "C forl6 24.5 13 23 0.13
, _hrs
^ Formulation 10 _24^5 13 23 OB 7.6-7.8
6. After hot rolling at 100 "C fori6 24.5 13 23 0.10
hrs
7. Formulation 11 27.5 14 27 0.11 7.60-7.8
'J. After hot rolling at 100 "C forl6 263 14 25 007
hrs
9. Formulation 12 27.5 14 27 0.04 7.60-7.7
lo After hot rolling at 100 "C fori6 253 14 27 O04
hrs
11. Formulation 13 24.5 14 21 004-005 7.50
IZ After hot rolling at 100 "C fori6 24 U 16 0.03 0 0.04
hrs
13. Formulation 14 23 10 26 0.04-O05 He
16

14. I After hot rolling at 100 "C forl6 I 22 p p6 I 0.03 - 0.04 I
hrs I I I [_
Formulation 8 having no polyol and no additive fluid possesses high lubricity coefficient of 0.25 which is not desirable.
Formulation 9 having 0.1% v/v of additive fluid A without polyol possesses a lubricity coefficient of 0.13 at ambient temperature and 0.13 after hot rolling at 100°C.
Formulation 10 having 0.1-0.2% v/v of additive fluid A without polyol possesses a lubricity coefficient of 0.13 at ambient temperature and 0.13 even after hot rolling at lOO^C.
Formulation 11 having 0.3% v/v of additive fluid A without polyol possesses a lubricity coefficient of 0.11 at ambient temperature and 0.07 after hot rolling at 100°C.
Formulation 12 having 0.6% v/v of additive fluid A without polyol possesses a lubricity coefficient of 0.04 at ambient temperature and 0.04 even after hot rolling at 100°C.
Hence it can be concluded that the formulation of the present disclosure possess superior lubricity properties and these superior lubricity properties are stable even at a temperature of 100°C. Further, the formulations having additive fluid more than 0.6% (formulation 13 and formulation 14) on one hand possess low lubricity coefficient on the other hand having low pH value. The low value of pH is not desired as the low value of pH adversely affects the rheological properties of the lubricating formulation. Thus the lubricating formulation with additive fluid in the range of 0.1% to 0.6% (v/v) shows the desired lubricating property in terms of lubricity coefficient as well as pH value.
Table-3
SI. Formulation Apparent Plastic Yield Lubricity pH
No. viscosity - viscosity point - coefficient
AV(Cp) -PVCp) Yp(lbs/10
Osq.ft)
1. Formulation 15 37 21 34 003 8.9-8.3
2^ After hot rolling at 100 "C " 37 21 34 014
J. Formulation 16 J7^ 20 35 0T2 8.5-8.2
~4. I After hot rolling at 100 "C | 37.5 120 | 35 | 0.12 |
Formulation 15 having 0.3% v/v of E P Lubricant, which is currently used in drilling fluids for improvement of lubricity has a lubricity coefficient of 0.14 at ambient temperature and 0.15 after hot rolling at 100°c.
Formulation 16 having 0.6% v/v of E P Lubricant in place of additive fluid has a lubricity coefficient of 0.12 at ambient temperature and 0.12 after hot rolling at lOO^c.
17

Hence it can be concluded from Table 3 that the use of conventional additive in less amount will not give desired results.
Table-4
SI. Formulation Apparent Plastic Yield point- Lubricity pH
No. viscosity- viscosity- Yp(lbs/100sq.f coefficient
AV (Cp) PV Cp) t)
1. Formulation 17 27.5 18 19 0.11 7.84-7.86
~2. After hot rolling at 275 18 \9 0^07
100°Cforl6hrs
3. Formulation 18 31.5 20 23 0.07-0.06 7.6-7.7
~A. After hot rolling at 3L5 20 23 0.07- 0.06
I 100"Cforl6hrs | \ \ | \
Formulation 17 having 0.3% v/v of additive fluid-B and polyol possesses a lubricity coefficient of 0.11 at ambient temperature and 0.07 after hot rolling at 100°C for 16 hrs. The pH value of formulation is 7.84 - 7.86.
Formulation 18 having 0.6% v/v of additive fluid-B and polyol possesses a lubricity coefficient of 0.06 - 0.07 at ambient temperature and 0.06 - 0.07 even after hot rolling at 100°C for 16 hrs. The pH value of formulation is 7.6 - 7.7.
Hence it can be concluded that the formulation of the present disclosure possess superior lubricity properties and these superior lubricity properties are stable even at a temperature of 100°C.
Table-5
SI. Formulation Apparent Plastic Yield Lubricity pH
No. viscosity - AV viscosity - point - coefficient
•
(Cp) PVCp) Yp(lbs/1
; OOsq.ft)
1. Formulation 19 24.5 13 23 0.05 7.8-7.9
~2. After hot rolling at 26^5 \5 23 004
100 °C for 16 hrs
3. Formulation 20 26 14 24 0.04 7.7-7.8
T After hot rolling at 27 15 24 003
I 100 °C for 16 hrs | \ | \ \
Formulation 19 having 0.3% v/v of additive fluid-B has a lubricity coefficient of 0.05 at ambient temperature and 0.04 after hot rolling at 100°C for 18-24 hrs. The pH value of formulation is 7.8 - 7.9.
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Formulation 20 having 0.6% v/v of additive fluid-B has a lubricity coefficient 0.04 at ambient temperature and 0.03 after hot rolling at lOO^C for 18-24 hrs. The pH value of formulation is 7.7 - 7.8.
Hence it can be concluded that the formulation of the present disclosure possess superior lubricity properties and these superior lubricity properties are stable even at a temperature of 100*'C. Table-6
~Sr I Formulation I Av(Cp) I PV(Cp) I Yp(lbs/100sq.ft) I Lubricity TpH
No. coefficient
1. Formulation 21 57.5 29 57 020 8.31
2. Formulation 22 57.5 29 57 0.05-0.08 7.63
^ After hot rolling at 100 "C 54 27 54 0.05-0.08
4. Formulation 23 50 20 60 0.05-0.08 7.3-7.4
After hot rolling at 100 "C 49.5 19 61 0.05-0.08
5. Formulation 24 47.5 19 57 0.05-0.08 7.2-7.3
I After hot rolling at 100 "C 147 | 19 [56 | 0.05-0.08 |
It can be concluded from table 6 that the Formulation 21, having no additive fluid possesses a high lubricity coefficient (0.20) which is not desired. The formulation 22, which is the formulation of the present disclosure, possesses a lubricity coefficient in the range of 0.05 - 0.08. Further the formulation of the present disclosure (formulation 22) possesses the desirable lubricity coefficient even after hot rolling at lOO^C for 18-24 hours. Formulation 23 and formulation 24 having additive fluid 0.7% and 0.8% (v/v) respectively possess low lubricity coefficient as well as low pH values. The formulations having additive fluid more than 0.6% on one hand possess low lubricity coefficient on the other hand having low pH value. The low value of pH is not desired as the low value of pH adversely affects the rheological properties of the lubricating formulation. Thus the lubricating formulation with additive fluid in the range of 0.1% to 0.6% (v/v) shows the desired lubricating property in terms of lubricity coefficient as well as pH value.
Table-7
SI. I Formulation I Av(Cp) I PV(Cp) I Yp(lbs/100 I Lubricity T^H
No. sq.ft) coefficient
1 Formulation 25 27.5 to 33 11 to 13 33 to 40 0.25 8.15
~2 Formulation 26 27.5 to 33 11 to 13 33 to 40 0.05-0.08 7.8-7.9
"3 After hot rolling at 100 "C 25-30 Tri2 28-36 0.05-0.08 ~"
_4^ Formulation 27 25-31 10-13 30-36 0.05-0.08 7.04-7.22
After hot rolling at 100 "C ~ 24 10 28 0.05-0.08
_5^ Formulation 28 ^3 10 26 0.05-0.08 7.04-7.22
I After hot rolling at 100 "C | 22.5 | 11 123 [0.05-0.08 |
19

It is evident from table 7 that the Formulation 25, having no additive fluid possesses a high lubricity coefficient (0.25) vv^hich is not desired. The formulation 26, which is the formulation of the present disclosure, possesses a lubricity coefficient in the range of 0.05 -0.08. Further the formulation of the present disclosure (formulation 26) possesses the desirable lubricity coefficient even after hot rolling at 100°C for 18-24 hours. Further, the formulations having additive fluid more than 0.6% on one hand possess low lubricity coefficient on the other hand having low pH value. The low value of pH is not desired as the low value of pH adversely affects the rheological properties of the lubricating formulation. Thus the lubricating formulation with additive fluid in the range of 0.1% to 0.6% (v/v) shows the desired lubricating property in terms of lubricity coefficient as well as pH value.
The lubricating formulation has improved lubricating properties which is evident from reduction in lubricity coefficient in all cases.
pH is an important property of lubricating formulation that is responsible for homogeneous dispersion of lubricating formulation and their solubility. It is observed in the above examples that the addition of additive beyond 0.6% (v/v) bring down pH. Reduction in pH is more as the concentration of additive is increased. This increase in pH is not desirable as it adversely affect the rheological properties with time. Hence it can be concluded from the examples above that the lubricating formulation having additive in the range of 0.1% to 0.6% (v/v) shows desirable lubricating properties and the lubricating formulation having more than 0.6% (v/v) of additive does not possess desirable lubricating properties.
Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.
20

WE CLAIM;
1. A lubricating formulation for drilling of oil and gas wells, comprising:
99.4% to 99.9% (v/v) of a drilling fluid; and
0.1% to 0.6% (v/v) of an additive fluid comprising: 30% to 50% (wt/wt) of an Acid oil; 35% to 55% (wt/wt) of a Fatty acid; and optionally 15 % to 30% (wt/wt) of an aromatic solvent.
2. The lubricating formulation as claimed in claim 1, wherein the drilling fluid comprises:
bentonite suspension in water;
cellulosic material in the range of 0.2% to 0.4% by weight of bentonite suspension; and
optionally polyol in the range of 2 to 5% by weight of bentonite suspension.
3. The lubricating formulation as claimed in claim 2, wherein the cellulosic material is Polyanionic cellulose.
4. The lubricating formulation as claimed in claim 2, wherein the polyol is selected from the group consisting of ethylene glycol, propanediol, butanediol, pentanediol, Poly ethylene Glycol, Polypropylene Glycol, Alcohol Ethoxylates and Glycol Ether.
5. The lubricating formulation as claimed in claim 1, wherein the drilling fluid comprises:
a clay free suspension;
xanthum gum in the range of 0.4% to 0.5% by weight of clay free suspension;
starch in the range of 2% to 4% by weight of clay free suspension; and
a micronized weighting agent in the range of 5% to 7% by weight of clay free suspension.
6. The lubricating formulation as claimed in claim 5, wherein the micronized weighting
agent is selected from the group consisting of calcium carbonate, barium sulpahte,
21

dolomite, limenite, hematite, manganese oxide, calcium Carbonate , dolomite, trimangnese tetreoxide and strontium sulphate.
7. The lubricating formulation as claimed in claim 1, wherein the acid oil is selected from rapeseed oil or rice bran oil.
8. The lubricating formulation as claimed in claim 1, wherein the fatty acid is selected from the group consisting of oleic acid, linoleic acid, ricinoliec acid, tallow fatty acid, and lauric acid or mixture thereof.
9. The lubricating formulation as claimed in claim 1, wherein the fatty acid contains at least 15% to 25% (wt/wt) of oleic acid.
10. The lubricating formulation as claimed in claim 1, wherein the aromatic solvent is selected from xylene, ethylbenzene, propylbenzene, ethyholuene, diethylbenzene, propyltoluene.
11. The lubricating formulation as claimed in claim 1, wherein the additive fluid consisting of:
30% to 50% (wt/wt) of an Acid oil;
35% to 55% (wt/wt) of a Fatty acid; and
15 % to 30% (wt/wt) of an aromatic solvent.
Dated this 29"" day of March, 2012
AVIGARe
IN/PA-1522
Agent for the Applicant
To,
The Controller of Patents,
The Patent Office,
At New Delhi.
22