DE1232896B - Emulsion drilling fluid - Google Patents

Description

Emulsion drilling fluid The invention relates to an emulsion drilling fluid, which is also used as a packer fluid when completing boreholes Can be found.

When drilling deep, it is desirable to use a low viscosity mud to be used to lower pump pressures, increase drilling progress, to facilitate the discharge of the cuttings and the ease of handling as well to improve the retention of the flush. You can use thin rinses of this type however, do not suspend heavy material adequately, which often leads to constipation leads. But when such low viscosity rinses are made thixotropic can, it can be achieved that they heavy material to a sufficient extent suspend.

A drilling fluid must also have only a slight loss of fluid have at elevated temperature. In many previously developed drilling fluids Oil base became a low fluid loss through the addition of large amounts of Colloids dispersible in oil, such as soaps or materials containing asphalt, as well as achieved by the addition of clay or the like; but all this depends on the generation a high viscosity, which is unfavorable, especially when the conditioner should be given a greater density by adding heavy material.

An ideal drilling fluid should have a low viscosity, a low one Have fluid loss even at elevated temperatures and have sufficient thixotropy, to be able to suspend heavy material. Is the flush a Water-in-oil emulsion, the emulsion must be used over the entire temperature range it is exposed to remain stable.

The main purpose of the invention is to provide an emulsion rinse To create the type mentioned at the beginning with low viscosity, which is sufficiently thixotropic is to suspend heavy material and low fluid loss has at both elevated and low temperatures, even in the absence of filter cake-forming materials, such as. B. Asphalt.

An emulsion drilling fluid is already known which, in addition to oil and Water in combination with alkaline earth soaps of fatty acids and tall oil with a high resin content and alkaline earths to increase the pH of the water, especially in Use of fatty acid and abietic acid soaps, the latter being the main ingredient represent. 32 to 65% of the total acids present are abietic acids. Also the use of partially polymerized fatty acids is for the production known from drilling fluids, but only in connection with violently oxidizing fluids Agents such as sodium dichromate. The oxidizing agent changes the unsaturated ones Compounds of fatty acids and brings them into the form of aldehydes, which in turn are polymerized and give compounds which are less oil-soluble than the original fatty acid polymers. It becomes the alkali metal soaps of the oxidized Acids used.

The invention relates to an emulsion drilling fluid of the initially mentioned called type, which consists of a water-in-oil emulsion with alkaline earth soaps of fatty acids and tall oils with high resin content and alkaline earths to increase the pH of the Water, and is characterized according to the invention by 2 to 65% of an aqueous Phase with dissolved alkaline earths in it to raise the pH to above 9, 3.5 to 53 g / 1 of an alkaline earth soap of a fatty acid residue with a content of polymerized Fatty acids and 1.75 to 35 g / 1 of an alkaline earth soap of a purified dew oil with a content of 15 to 45% resin acids, which between 3 and 304 / o- of the total make up organic acids present in the soaps. The invention is based on the surprising finding that an emulsion with such a composition is very stable, characterized by pronounced gel formation and good Has load-bearing capacity. These properties are extraordinary for an emulsion drilling fluid important. Liquid Phases Any type of oil can be used, including Crude oils and purified petroleum products such as diesel fuel, carburetor fuel and heating oils. The oil is always in the outer or continuous phase.

The aqueous inner phase should be in an amount of at least 2% and may be present in amounts of up to 65% in some cases. The aqueous phase can be pure water, but it can also contain one or more electrolytes in solution, like sodium or calcium chloride. Such salts can be used in amounts up to saturation to be present. They serve as a means of increasing the density and improving the Stability of the liquid without the addition of solid particles. Polymerized acid residue Sufficiently polymerized acid residues are those from purification distillation are formed by fatty acids at temperatures above 70 ° C. The food supply for the The still should contain essentially unsaturated fatty acids, which preferably have 16 to 18 carbon atoms. Resin acids should not exceed 4%; accordingly tall oil is unsuitable as a food supply. The food supply can also contain color bodies, Contain glycerides, unsaponifiables, and minor amounts of soaps, some of which may be of a heavy metal type.

A preferred fatty acid food supply is formed from a raw soap supply, which is produced by the cleaning treatment of raw vegetable oils with an aqueous alkali solution, such an aqueous soap supply containing fatty acid soaps, pigments and some glycerides. After separation from the oil , the soap stock is neutralized with sulfuric acid or the like; the non-aqueous product then contains essentially fatty acids along with some unsaponifiables, coloring matter and glycerides.

Another satisfactory fatty acid food supply is derived from the fatty acid product that results from the high-pressure steam stripping of fatty oils originates from, whereby the glycerine is separated and a fatty acid product remains, the essentially free, monomeric acids with minor amounts of glycerides and Contains unsaponifiables.

Any of these acid feed stocks or mixtures thereof will be or will be then subjected to purification distillation to produce purified fatty acids, leaving a dark-colored residue, the monomeric monocarboxylic fatty acids, contains polymeric polycarbonate fatty acids, color bodies, glycerides and unsaponifiables. Residues of this type are disclosed as one of the components of the emulsion drilling fluid of the invention usable.

Tall oil fraction The polymerized in conjunction with the remaining Acids used according to the invention tall oil acids must be derived from tall oil, which by Acid upgrading or preferably purified by distillation derived will. This purified tall oil must contain between 15 and 45% resin acids, whereby the remaining acids are highly unsaturated fatty acids of the oleic-linoleic acid type. This purified product should not have more than 16% unsaponifiable and preferably contain less than 6% of it. The acid number of this product is normally between 1..50 and 190 and the iodine number between 130 and 180.

Method of making the emulsion drilling fluid in manufacture The emulsion drilling fluid will normally remove the polymerized acid residues and the purified tall oil acids added to the oil phase. The amount of used Acid residue is in the range from 3.5 to 53 g / l based on the final volume the drilling fluid. The amount of tall oil acids is in the range from 1.75 to 35 g / l. The acid residues and tall oil acids can, if desired, be mixed together before they are added to the drilling fluid.

The aqueous phase is added to the oil phase after initially in it any salts to be added are dissolved. Then, order the alkaline earth soap to form an excess of an alkaline earth base to the union of the oil and aqueous Phase added. Vigorous stirring is necessary to form the emulsion.

Alkaline earth bases such as calcium hydroxide, calcium oxide, magnesium oxide and the like. The like. Are suitable for producing the alkaline earth soap in the liquid. It should enough base can be added to completely convert all acidic components to soap and to raise the pH of the aqueous phase to at least 9. An excess of Base beyond this minimum is beneficial. Mixtures of bases can also be used will.

If desired, the acidic components can first be added to alkaline earth soaps are converted, which is done by adding the bases directly to the acids. the resulting soaps can then later be added to the drilling fluid during its manufacture can be added. In this case, you should add a small extra amount of conditioner Alkaline earth base can be added in order to ensure an excess of the alkaline earth metal ion.

If desired, the alkaline earth base in the drilling fluid can through the Addition of a water-soluble alkaline earth salt, such as calcium chloride, can be generated, whereupon an alkali metal base such as sodium hydroxide is added.

The amount of acidic components added to the conditioner depends on the desired setpoints for the fluid loss of the irrigation and their viscosity, it should be noted that larger amounts of soaps are smaller Fluid losses, but also a higher viscosity result, especially when there is a lot of water. In general, smaller amounts of acidic Components added when there is a lot of water or when the amount of solid heavy material is great. It was found that a ratio of one part Tall oil acids give satisfactory results to two parts of acid residues, but this ratio can be changed within fairly wide limits to the thixotropic property and the fluid loss of the emulsion drilling fluid to change.

In the preparation of the emulsion drilling fluid, the components can be added in any order, but is the order given above to prefer.

Scoring methods The viscosities of all drilling fluids were with the Tests described here either with a Stormer viscometer or with a Marsh funnel determined at a temperature of 49 ° C. All fluid losses were determined at a pressure of 35 at, using a baroid filter press (High Pressure Wall Building Tester) was used. The fluid losses were over measured for a period of 30 minutes at a temperature between 70 and 120 ° C, since the fluid losses of oil-based drilling fluids, measured at room temperature, are often irrelevant. In some cases, the emulsion stability was determined by measuring the voltage of 60 Hz alternating current determined that was required to generate a current between electrodes immersed in the emulsion drilling fluid at a distance of 12.5 mm to let flow. Any water left in the Filtrate occurs, indicates instability of the emulsion.

Example 1 To the synergistic effect of a calcium soap of purified Tall oil on a rinse containing calcium soap from polymerized acid residues To explain, a series of experiments with rinsing according to the above-mentioned method was carried out carried out in diesel fuel with a density of 0.8448 (at 15 ° C) and a content of 47 0/0 of a saturated salt water solution and weighed to 1350 g / 1 with bargt. Lime was added to make the alkaline earth soaps.

In these experiments, the polymerized acid residues were derived from the distillation purification of an acidified soap supply. The tall oil used was purified by distillation and contained 28% resin acids. Acid tall oil emulsion Stormer values 30 'fluid loss at 35 at residue stability viscosity 0 'gel 10' gel temperature g / 1 g / 1 V CP gg ml io C remarks 12.2 0 350 24 0 tracks 1.8 95 settles 1.9 135 settles 0 12.2 170 28 2 3 3.0 *) 95 8.8 3.5 440 25 0 7 1.5 95 1.4 135 *) Emulsion breakup (water in the filtrate). As can be seen, those emulsion drilling fluids containing only the acid residue side or only the tall oil acid soap were significantly inferior to fluids containing both of these soaps. When the residual acid soap was used alone, Bargt settled in the high temperature cell, and when the tall oil acid soap was used alone, the thixotropy was poor; the fluid loss was high and the emulsion was weak and broke open at the comparatively low temperature of 95 ° C. If, on the other hand, the soaps of both acids were present, the emulsion was particularly stable, the fluid loss was extremely low, and the thixotropy was itself excellent at 135 ° C.

In a fourth experiment an emulsion was prepared as above with 90 g / 1 of a tall oil acid residue and 3.5 g / 1 of distilled tall oil acid, as previously described. The tall oil acid residue used contained 10% fatty acids, 24%. Resin acids and 28% unsaponifiables and was obtained from fractional distillation purification extracted from tall oil. The resulting emulsion drilling mud had emulsion stability of 170 volts, a viscosity of 26 centipoise, a gel strength of 1 and 6 g, respectively, and a fluid loss of 3.3 ml at 95 ° C with a significant amount of water in the filtrate as an indication of emulsion breakdown in the cell. So it is can be seen that tall oil residue soaps are unsatisfactory for emulsion drilling fluids are. Example 2 A concentrate containing 2 parts of residual acid was obtained and 1 part of distilled tall oil acids, the acids being the same were as in the first three attempts in Example 1. This is hereinafter referred to as Concentrate A is called.

A Coalinga crude oil drilling fluid with a density of 0.9440 (at 15 ° C) produced, and the aqueous phase contained 5% of a 4% Solution of sodium chloride. The drilling fluid contained 28 g / l of concentrate A and 35 g / 1 lime. It was weighed with calcium carbonate to a weight of 265 g / l. After circulating in a borehole for one day, the drilling fluid had a Marsh funnel viscosity of 116 seconds with fluid loss over 30 minutes of 0 ml at 35 at and 70 ° C. Solid did not settle in the cell.

Example 3 A drilling fluid was produced from Ventura crude oil with a density of 0.8789 (at 15 ° C.) and a content of 25% fresh water, 28 g / l of concentrate A and 35 g / l lime. It was weighed to 1280 g / l with Bargt. The finished emulsion drilling fluid had a Marsh funnel viscosity of 70 seconds and a fluid loss over 30 minutes of 1.0 ml at 35 atm and 115 ° C. Solids did not settle in the cell. Example 4 A drilling fluid was prepared from Canadian diesel fuel with a density of 0.8275 (at 15 ° C.) and a content of 55% fresh water. It was treated with 28 g / l of concentrate A and 28 gil of lime and was weighed with barite to 1180 g / l. The rinse had a Marsh funnel viscosity of 70 seconds and a fluid loss over 30 minutes of 0.5 ml at 35 atm and 76 ° C. Solid does not settle in the cell. Example 5 A drilling fluid was prepared containing 30% of a heating oil with a density of 0.8109 (at 15 ° C.), 20% of a saturated salt solution and 30% of a 30% strength calcium chloride solution. It did not contain any heavy solid material. It was treated with 18 g / l of concentrate A and 35 g / l of lime. Although it did not contain solids, it weighed 1080 g / l. It had a Marsh funnel viscosity of 53 seconds and a 30 minute fluid loss of 0.5 ml at 35 atm and 70 ° C. These properties were measured after the emulsion drilling fluid had been used in a well for several days. Concentrates For convenience, it is desirable to prepare a drilling fluid concentrate containing both fatty acid residues and purified tall oil acids. These acids must be present in the correct weight ratio; oil can be added to lower the viscosity and thereby facilitate handling. Usually a mineral oil is used. A ratio of 2 parts of residual acid and 1 part of tall oil acids has been found to be satisfactory in most cases, but this ratio can vary considerably depending on the chemical characteristics of the acids and the properties desired in drilling fluids in which the concentrate is to be used . The ratio of fatty acid residues to tall oil acids can vary from 0.5 to 10.0. In use, an amount of the liquid concentrate is added to a major portion of the drilling fluid, ensuring that an excess of an alkaline earth base remains in the fluid after the addition and reaction of the concentrate.

If a dry concentrate is desired, the fatty acid residues can and tall oil acids mixed in the above ratio and of a finely divided one Solid absorption carriers are absorbed by using enough carrier material to ensure a free flowing product. Satisfactory carrier materials are z. B. clay, diatomaceous earth, aluminum silicates, sawdust or calcium carbonate in one of its various forms. There can be lime or alkaline earth bases in the dry concentrate. Applications of the emulsion drilling fluids The emulsion drilling fluids According to this invention can be used for drilling, as a completion fluid or for Probe reprocessing can be used. Since the emulsion is stable, only touches oil the formation, thereby avoiding a loss of oil permeability of the layer, as it often occurs when aqueous rinses are used.

Claims (5)

Claims: 1. Emulsion drilling fluid, also known as a packer fluid in the completion of boreholes can be used, consisting of a Water-in-oil emulsion with alkaline earth soaps of fatty acids and tall oils with high Resin content and alkaline earths to increase the pH value of the water d u r c h 2 to 65 percent by weight of an aqueous phase with alkaline earths dissolved therein, to raise the pH to above 9, 3.5 to 53 g / 1 of an alkaline earth soap of a fatty acid residue with a content of polymerized fatty acids and 1.75 to 35 gll of an alkaline earth soap a purified tall oil with a content of 15 to 45% resin acids, which between Make up 3 and 30% of the total organic acids present in the soaps. 2. Additive for the production of an emulsion drilling fluid according to Claim 1, characterized through a mixture of fatty acid residues and purified dew oils, whereby the Dew oils have a content of 15 to 45% rosin acids (resin acids). 3. Additive according to Claim 2, characterized by an additional mineral oil content. 4. Additive according to claims 2 and 3, characterized by a mixture from fatty acid residues and purified dew oils, which from a finely divided Absorbents, e.g. B. diatomaceous earth, are absorbed. 5. Additive according to claim 4, characterized by an additional content of an alkaline earth base. Into consideration Drawn pamphlets: U.S. Patent Nos. 2,793,996, 3,044,959.