MXPA96000313A - Base oil for fluids used in po - Google Patents

Abstract

A base oil for drilling fluids in wells such as drilling fluids comprising normal alkanes having from 11 to 16, carbon atoms, with no more than one trace of normal alkanes having more than 16 carbon atoms and having a pour point less than 2øC, as well as low toxicity and good biodegradability both aerobic and anaerobic

Description

ACE Tí) E [ASE PARA 7LUIDCS JSA3CS IN PCSCS OWNER: BAROIO TECHNOLOGY, INC, American Nationality Society, domiciled in; 300 N Sam Houston Park to East,, -uston, Texas 77032. E.U.A. INVENTORS: (i) THCMAS GREGORY SHUMATE, of British Nation, domiciled in; T! -. E ELMS, 32 ilanor Place Cú'ts, Aberdeen * Scotland, UK AB1 9QN, GREAT BRITAIN; (2). '. A CCLM EL1. ICE, of British Nationality, with a home in; THE RCV-'ANS. 27 Abbotshal 1 Roa Cu'ts, Aberdeen. Scotland, UK ABL 9JX, GREAT BRITAIN and (3) S. AND: EL: ', And, of British Nationality are C'OTÍ? cilio -an i "1 to 1 ^ 7 ort 3eeside Road Lie'dsice, Aberdeen, Scotland, UK ABl 9EA, GREAT BRITAIN.

DESCPyl PC ION OF THE INVENTION The present invention relates to base oils for use in well drilling fluids, such as drilling fluids, also to hole drilling fluids incorporating the base oil and to the use of such fluids. Well drilling fluids, for example drilling fluids are used in the recovery of oil and gas in gerothermic energy and in mineral extraction and extraction operations. The product performs various functions including the removal of the cut material during drilling and the sealing of the perforated surfaces of the well, so that the loss of fluid in the formation that is being drilled will be slight. minimum. The fluid also lubricates and cools the percorant tube during drilling. Fumidids have been used for approximately fifty years, to produce sub-terrestrial formations to obtain gas and oil; The oil-based fluids are preferred in systems and not the sgue-based formulations, especi agent when drilling underground formations very sensitive to water. In water-based fluids, it tends to migrate from the f? Uid to the formation being drilled. This destabilizes the formation and can lead to the disintegration of the drilling hole; In addition, water-based fluids tend to be unsuitable for use at elevated temperatures, and where highly deviated drill holes are required to achieve the formations sought. In view of the disadvantages of water-based fluids, the current trends have been to use fluids - oil-based drilling fluids, however, oil-based fluids, previously used containing base oils such as diesel oil, and crude oil, are toxic and only slightly biodegradable. This is, obviously, unsatisfactory with respect to environmental health and safety considerations, especially when the cuts of the percforation coated with or containing the fluid, are usually discharged to the seabed, when drilling off shore; the use of these kinds of oil-based fluids has a pernicious effect on marine organisms. It has been proposed to use mineral oils, base oil in drilling fluids, instead of other petroleum-derived oils, however, although less toxic, than those other petroleum-based drilling fluids, fluids based on mineral oil, are not very biodegradable. Investigations in the perforating cuts, in the bed of the sea of N.Sr del Norte, have confirmed the persistence of the mineral oils. • k- More recently, attention has been directed to the use of esters, ethers and white oils, as base oils; they have improved toxicity characteristics close to that of water, and have a reasonably good aerobic biodegradable capacity. However, with the exception of esters, they typically exhibit poor anaerobic biodegradation, which is required, for example, in e. floor of the sea. These base agents also tend to have highly kinematic viscosities and temperature limitations. In addition, with the exception of white oils, they are very expensive when compared to the mineral oil classes described above. The present invention seeks to provide a base oil for use in well drilling fluids, under oil, which benefits the disadvantages discussed above.; in particular, the present one seeks to provide a base oil - which has low toxicity, good biodegradability, both aerobic and anaerobic, and a combination of physical characteristics that are especially suitable for use as a drilling fluid. well, this is also an object to provide a base oil that is not expensive. According to the present invention, this is based on the use of base oil in a "well" drilling fluid with a mixture comprising 70% by weight of one or more normal alkanes, having 11 to 16 carbon atoms, wherein the mixture has a pour point of less than -2 C. The mixture typically comprises 30 s by weight or less of one or more branched or cyclic alkanes having from 11 to 16 carbon atoms. Since it is extremely important that the base oil biodegrade as quickly as possible, it is preferred that the mixture comprises a very high proportion of normal alkanes; that is, straight chain. The cyclic and branched hydrocarbons are not broken by bacteria as rapidly as normal hydrocarbons. According to the preferred embodiment, of the invention, the mixture comprises at least 90% by weight of one or more normal alkanes. The mixture preferably comprises at least about 93 by weight of one or more normal alkanes. Mixtures of normal hairs, which have 11 to 16 carbon atoms, are the most preferred; the -toxicity to the flora and fauna of the base oils used, in -the perforating fluids, is believed to be directly based on their aromatic content; therefore, to decrease the toxicity the aromatic content in the mixture should be kept as low as possible, with 0.1% by weight being the maximum allowed; the pour point of drilling fluids is a particularly important feature, since it is essential that the fluid be able to be pumped at the lowest temperature found during mixing, storage, transportation and use; the pour point of the fluid is basically influenced - by the pour point of the base oil that is used. In the PCT patent application 95/066 ° ^, published on March 9, 1995, there is an indication on page 1, 1, 12-16, that by using normal alkanes as a filler for a founder in a cold environment, You can use a depression agent to reduce the pour point (this is the point of COJI ge 'ation of' fluid). According to the present, the batch of oil has a pour point less than -2 C, preferably -9, or even less. However, this represents the point of conversion of the mixture without the addition of depressants.

These can be used, but tend to be of little effect in mixtures of pure normal alkanes; in fact its addition can lead to undesirable side effects such as increased toxicity and a point of ignition; Depressants, too, can cause decreased stability of the fluid used in well drilling with inverted emulsion. In order to minimize the risk of fire or explosion, the oil-based fluids for drilling must have an ignition point that is greater than the circulating surface temperature of the fluid during drilling. well drill. Preferably, the base oil used in the present invention has an ignition point of at least 65, more preferably at least 30 C. An important characteristic of oil ba is its kinematic viscosity, this is crucial as far as it is concerned. the capacity of the drilling fluid to tolerate solids and water, either aggregated as integral or aqueous components during the drilling mechanism in the formations or in formation with the entry of water, Generally, the lower the kinematic viscosity of the oil base, the higher the tolerance of the fluid; from practical experience, it has been found that the oil should have a kinematic viscosity of 1 to 10 cSt, more preferably 1 to 6 cSt, at 0 C, and this is a thermal side of the base oil of the present invention. The base oils have a viscosity of about 1 cSt at -0 C, and are believed to be the most tolerant of solids and water. The difficulty in pumping tends to be found when using base oils that have a viscosity at 0 C, greater than 6 cSt. The base oils that can be used in the present invention are readily available, and tend to be produced by "cracking", rectification, reaction and distillation processes. The present invention also provides a well-drilling fluid comprising as a base oil the mixture as described above in combination with an emulsifier, an oil wetting agent, an additive filter additive, a modifier rheology, thinner or, agent for the weight. There are conventional additives, such as those that are used in fluids for well drilling, and whose combustion depends on the desired characteristics of the fluid that is formulated. Emulsifiers that can be used include fatty acids, fatty acid soaps and fatty acid derivatives and amidoamines, polyaids, polyamines, esters - such as polyethoxylate, monooleate, sorbitan, and polyethoxylate, sorbitan dioleate and midaxolines and alcohols. Wetting agents, typical oils that can be used are lecithin, fatty acids, crude wood oil, crude oil of oxidized wood, organic phosphate esters, my dazol inas, amidoamines, euiphatic, aromatic alkyl, sulfonates, aromatic alkyl and esters Hydrophobic organic alcohols, typical viscosifiers include organophosphoric alcohols (eg, hectorite, bentonite, alumina), oil-soluble polymers in polymers and polymers such as polypropylene terephthalate. sulphonated ethylene oxide (EPDf.) and copolymers of styrene butadiene its 1 pouted. Filtration control additives which may be used are asphalt and derivatives thereof, glycol, lignite treated with amines and polymers such as EPD.hi terpolymers, copolymers, styrene butadiene and copolymers. styrene acri. The typical rheology is that they include fatty acids and polymeric fatty acids. Thinners that may be used include petroleum sulfonate, aminoamides, alkaryl sulfonate and polyals. Examples of agents for weight include barite, iron oxide, iron carbonate, carbonate carbonate and galena. It is possible to use the base oils alone, this is, without the use of the conventional additives described, only, however, additives are required to fix the properties of the fluid so as to meet specific requirements. The fluid for the hole borehole can be an oil-based fluid or an inverted solution (this is a water-in-oil emulsion), formed using water, brine or a polar organic liquid, which is insoluble in oil. base, preferably, polar organic liquid, is methanol glycerol or propylene carbonate; When the wellbore fluid is an inverted emulsion, the phase of the fluid typically represents 1 to 70% by volume of the fluid.

The use of the fluid that is an inverted emulsion allows reducing the total cost by reducing the volume of base oil that is needed; the water activity of the inverted emulsion can be adjusted by the addition of inorganic salts to balance the water activity of the formulations used in the drilling; Examples of inorganic salts that can be used include sodium chlorides, potassium calcium, magnesium, cesium and zinc, sodium bromides, calcium and zinc, sodium, potassium and cesium formats, sodium and potassium acetates, and calcium nitrates. and ammonium. The typical proportion of these aaititvos in the fluids for the drilling of wells in the present, are shown in the following table: TíltHCO i 'typical SAY oil, volume% 20-100 50-90 emulsifier, 1 b / bb 1 1-20 4-16 oil wetting agent 0-10 0.5-4 viscosifying agent, Ib / bbl 0-15 1-6 control additive of filt.lb/bbl 0.5-25 1-10 rheology modifier, 1b / bb1 0-4 rr thinner, 1 b / bb 1 0-10 0.5-4 agent for weight, 1b / bb1 0-700 0-500 water, olume% 0-60 20-50 chloride of le io, 1b / bb1 0-150 2-100 (to adjust water activity) In this table lb / bbl, represents pounds per barrel of the United States of America. Filuidas of the present invention are prepared according to conventional techniques mixing the constituents. The preparation of the oil-based drilling fluid can take place in a landfill facility or at the wellsite, mixing typically takes place in tanks equipped with centrifugal circulation pumps and dewatering agitation equipment. Although, described basically as a perforating fluid, the base oil described herein is suitable for general use as a fluid in well drilling; The base oil can be used, for example, in a pay zone drilling fluid, as a fluid to complete a kill fluid, a packaging fluid, a signal fluid or a spacer, the invention also provides , a method of drilling using a fluid according to the invention as described above The following examples illustrate the present invention, unless otherwise indicated we refer to gallons and barrels according to the use of the United States of America. EJEÜPLG 1 A 350ml laboratory barrel of drilling fluid was prepared by mixing the different ones shown in the following table using a Silverson mixer at a speed of 6,000rpm, using a square hole integrating head, the total mixing time was one hour, and the ingredients were added in the order of the list, there being a period of 5min, between each addition of each ingredient, a water bath was used to maintain the temperature below. or of the 65 TAELA 1 nqredient Amount Func t ion Base oil A 136 my base oil 1 EZ ML 2F 10 ge ú 1 sif icator 1 GELTONE II '2.5 g viscos icator cal ** g cont, of alkalinity 1 DURATONE HT 4 g filtration control fresh water 136 m emulsified phase barite 163 g agent for weight c loride calcium (purity 32% 60 g balance of act.egu 1 RM-63 modifier reo logia -obtainable from Laroid Limited The fluid formed has the following properties: Density 1.33kg / m oil / water ratio 50/50 salinity aqueous phase 250, 000 ppmc ca l ion cycle Base oil A, has the following composition and properties: / or weight nC 9., 1 11 nC 21 .7 12 nC 36 > .2 13 nC 31 .3 14 nC 1. 15 nC 0., 04 16 strike 1 as 16 aromatics 0.1 pour point = -9 C firing point = 91 * C kinematic viscoeity 40 C = 1.75 cSt The base oil properties A, in comparison with some base oils used in the commercially available source of the North, is illustrated in Table 2.

TAI LA 2 It can be seen from this table that base A compares very favorably with the other oils that are used to formulate fluids for drilling wells, with respect to the combination of characteristics that it possesses. EXAMPLE 2 The properties of a laboratory barrel (350ml), of the fluid of Example 1, were measured in accordance with API RP 13E-2. The properties were also measured when contaminated with 35g Mymod clay, 10% by volume of seawater and 10% by volume of carnal brine. The results are shown in the following table 3: TAC LA This table shows that the fluid for the preparation of potos of the invention is very stable to contaminants, it should be noted that the fluid has very good rheological properties, this is low when the water content of the fluid is 50% volume, This shows how low n-alkane mixture base oil viscosity contributes to the fluid capacity to tolerate high concentrations of water and water aggregation as a contaminant. EXAMPLE 3 Following the same procedure as in Example 1, a 350ml laboratory barrel of well drilling fluid was prepared; the ingredients were mixed in the order indicated in the following table 4. The base oil A was the same as that used in example 1: TABLE 4 nc rediente Amount Func onon base oil A 147 my base oil 1 The MU 2? 20 g emuls i Picador 1 DU? ATO E MT 11 g cont.fi 1 trac. 1 XP-10 (producexperim.) 3.5 g cont. i 1 trac, : ENTCNE 3 C5 g viscos i fíc. 1 SUSGENTONE ** 9 v¡scos¡ f ¡c. cal cont.elcal.

It's cool 23 my emulsif phase. bar ta 589 g calcium chloride moisturizing agent 9.7 g balance of activity (32% purity) water 1 1 RM-63 0.75 g rheology modifier 1- obtainable from Cariod Lime 2 - obtainable from Puieox E lfluido formed ti ene l as if prop i eca l gu id es '3 Density: 2.24 kg / density oil / water: 85/15 sa1ity of the aqueous phase 250,000 mg / L calcium chloride EXAMPLE 4 Example 2 was repeated using a barrel of the liquid borehole drilling fluid. Example 3, the contaminants used were Mymod clay (35g), and seawater (10 * .volume). The fluid was heated to the temperatures shown in the following table 5. This table shows the properties of the fluid. Their results confirm the stability of the fluids of the invention in exposing themselves with high temperature to contaminants.

TADLA i

Claims (1)

NOVELTY OF THE INVENTION Having described the invention as above, the content of the following is claimed as property: CLAIMS 1.- A base oil to be used in a fluid for drilling wells of a mixture comprising at least 70% by weight of one or more normal cardan having from 11 to 16 carbon atoms, with no more than one trace of the normal alkanes having more than 16 carbon atoms, in which the mixture has a lower pour point -2 C, without having a depressant of the pour point. 2. The base oil according to claim 1, wherein the mixture comprises up to 0.1% by weight of aromatics. 3.- The base oil according to claims

1-2, wherein the mixture contains 30% by weight or less of one or more branched or cyclic alkanes having from 11 to 16 carbon atoms. 4. The base oil according to claims 1 to 3, wherein the mixture comprises at least 90% by weight of one c plus normal alkanes. 5. The base oil according to claim 4, wherein the mixture comprises at least about -93% by weight of one or more normal alkanes. 6. The base oil according to any of the claims wherein the mixture has a pour point of -9 or less. 7. The base oil according to any of the preceding claims, wherein the mixture has an ignition point of at least 65. The base oil according to claim 7, wherein the mixture has a starting point of when 9. The base oil according to any of the preceding claims, wherein the mixture has a kinematic viscosity of 40 * from 1 to 10 cSt. 10.- The base oil according to claim or 9, wherein the mixture has a kinematic viscosity at 40 from 1 to 6 cSt. 11. A fluid for drilling wells comprising a mixture of base oil as defined in any of claims 1 to 10, in combination with one or more agents such as emulsifier, oil moistener, viscometer, filtration control additive, rheology modifier modifier, weight agent and other fluid additive for well drilling. 12. A fluid according to claim 11, comprising from 20 to 100% by weight of a base oil mixture, based on the total weight of the fluid. 13. A fluid according to claim 11 or 12, which is an oil-based fluid. 14. A fluid according to claims 11, 12, which is an inverted emulsion with water, brine or a polar organic liquid that is insoluble in the mixture of the base oil. 15. A fluid according to claim 14, wherein the polar organic liquid is glycerol methanol or propylene carbonate. 16. A method for drilling a well comprising using a drilling fluid that: is the drilling fluid according to any of claims 11 to 15. SUMMARY OF THE INVENTION A base oil for well drilling fluids such as drilling fluids comprising normal alkanes having from 11 to 16 carbon atoms, with no more than one trace of normal alkanes having more than 16 carbon atoms and having a point of less discharge of less than 2 C, as well as low toxicity and good biodegradability both aerobic and anaerobic. Under protest to tell the truth, the best known method for putting the present invention into practice is the one described in the description of this application. In testimony of which we sign the present in: Mexico, D.F., on January 19, 1996. BAROID TECHNOLOGY, INC.