RU2461600C1 - Loaded drilling mud - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: loaded drilling mud includes the following, wt %: sodium carbonate 0.3 - 0.5, sodium hydroxide 0.2 - 0.3, bentonite 3-5, poly-anionic cellulose PATS-SV 0.6 - 0.8, amylase Fito-RK 1- 2, lignosulfonate FHLS 0.5 - 1.5, anti-foaming agent PES-1 0.1 - 0.5, lubricating additive Lurioil 0.5 - 0.8, potassium muriate 3-5, organosiloxane GKZH-PN 0.3 - 0.5, baryte 45 - 65, Givpan 0.3 - 0.5, bactericide LPE-32 0.2 - 0.3, water is the rest.

EFFECT: reduction of filtration, improvement of lubricating properties.

3 ex, 2 tbl

Description

The invention relates to the oil and gas industry, in particular to drilling fluids used when drilling in difficult conditions, namely when drilling deviated and horizontal wells under conditions of abnormally high pressures, temperatures and gas showings.

Known drilling fluids containing clay, mineral salt, fluid loss and viscosity regulator, water. Derivatives of cellulose and sulphite-alcohol stillage of SSB are used as a regulator of water loss and viscosity (US Pat. RF No. 2323725, IPC C09K 8/20, publ. 06/27/08; US Pat. RF No. 1678048, IPC C09K 7/02, publ. 10.11. 96). However, these drilling fluids cannot be used under conditions of abnormally high pressures, since their maximum density reaches 1.18 and 1.28 g / cm ^3, respectively.

The closest technical solution is drilling mud containing clay, stabilizer reagent KMTS-900, mineral salt - KCl, flocculant - Uniflock, Praestol, lubricant additive DSB-4TPP, pH regulator - potassium hydroxide KOH, protective reagent KSSB-2M, weighting agent - barite (US Pat. RF No. 2235751, IPC C09K 7/02, publ. 10.09.04).

The proposed drilling fluid has several disadvantages: high clay content (5-10%), which can adversely affect the quality of opening of reservoirs and contributes to the formation of a thick filter cake on the walls of the well, which is especially dangerous when drilling inclined and horizontal shafts; high values of the filtration rate (5-9 cm ³ ), which also contribute to the formation of thick filtering crusts and, as a result, sticking; the composition of the solution lacks special reagents designed to bind polyvalent metal ions, which limits its use, on the one hand, and makes the use of flocculants incompatible with polyvalent metal ions ineffective; the solution includes deficient potassium hydroxide; there is no antifoam to prevent foaming when using lignosulfonates and gas manifestations; high values of the coefficient of friction of the crust (CPC).

The objective of the invention is to provide a drilling fluid for drilling inclined and horizontal shafts with a low clay content with sufficient carrying and holding ability, having a low filtration rate, a thin clay cake with a low coefficient of friction.

The solution to the problem is achieved by the fact that a weighted drilling fluid containing clay, barite, a stabilizer reagent, potassium chloride, metal hydroxide, a lignosulfonate reagent, a lubricant additive, an acrylic reagent, according to the invention, contains PAC-SV polyanionic cellulose, metal hydroxide as a stabilizer reagent sodium hydroxide NaOH, lignosulfonate reagent - FHLS, lubricant additives - Lubriol, acrylic reagent - Givpan, and also additionally contains phyto-RK starch reagent, antifoam PES-1, guide Rofobizator - organosiloxane - GKZH-IIH, bactericide LPE-32, in the following ratio of ingredients, wt.%:

Soda ash - 0.3-0.5

Sodium hydroxide - 0.2-0.3

Bentonite - 3-5

PAC-SV - 0.6-0.8

Fito-RK starch - 1-2

FHLS lignosulfonate - 0.5-1.5

Defoamer PES-1 - 0.1-0.5

Lubriol lubricant additive - 0.5-0.8

Potassium Chloride - 3-5

GKZH-IIH - 0.3-0.5

Barite - 45-65

Givpan - 0.3-0.5

Bactericide - 0.2-0.3

Water - the rest

A comparative analysis with the prototype allows us to conclude that the inventive drilling fluid differs from the known one in that it additionally contains other components.

Thus, the claimed technical solution meets the criterion of "novelty."

The proposed technical solution improves the quality of the drilling fluid by reducing the clay content in the drilling fluid, reducing the filtration rate, using cheaper sodium hydroxide, preventing the negative effect of polyvalent ions on polymers, as well as improving lubricating properties.

When preparing the inventive solution, the following order is used: sodium hydroxide is added to fresh or mineralized water to create an alkaline environment and soda ash is used to bind salts of polyvalent metals, which contributes to a more complete clay peptization and increase its activity; then bentonite clay is added and the clay suspension is mixed for 20-30 minutes until it is completely dispersed. Then, lignosulfonate, PAC, starch, antifoam, a bactericide and a lubricant are sequentially introduced into the clay suspension. After that, barite and potassium chloride are introduced into the solution. The viscosity of the solution is adjusted by entering GKZh-IIH and Givpan.

Example 1. In tap water, 0.3% of soda ash and sodium hydroxide are dissolved, then 3% of bentonite is added to the solution, and the solution is mixed on a Voronezh mixer until the clay is completely dispersed. 1% lignosulfonate is added to the resulting clay suspension and the solution is stirred until they are completely dissolved. Then gradually with constant stirring, 0.7% PAC-SV (TU 2231-010-50277563-03) and 1% FITO-RK starch (TU 10 RF1039 - 92) are introduced. 0.5% PES-1 (TU 2458-012-20672718-2001), 0.2% LEC-32 bactericide (TU 2458-039-00209295-02), 0.5% Lubriol lubricant (TU) are added to the stabilized solution 2458-001-74138808-06). After thorough mixing, 50% barite and 5% KCl are added to the solution. Then, 0.5% of Givpan (TU 2216-001-04698227-99) and GKZh-IIH (TU 6-02-696-76) are introduced into the solution. After thorough mixing, the solution is considered ready.

Example 2. In tap water, 0.3% of soda ash and sodium hydroxide are dissolved, then 5% of bentonite is introduced into the solution and the solution is mixed on a Voronezh mixer until the clay is completely dispersed. 1% lignosulfonate is added to the resulting clay suspension and the solution is stirred until they are completely dissolved. Then gradually with constant stirring, 0.7% PAC-CB is introduced. 0.5% PES-1, 0.5% Lubriol lubricant is introduced into the stabilized solution. After thoroughly mixing, 50% barite and 3% KCl are added to the solution. Then, 0.5% of Givpan and GKZh-IIH are introduced into the solution. After thorough mixing, the solution is considered ready.

Example 3. In tap water, 0.3% of soda ash and sodium hydroxide are dissolved, then 3% of bentonite is added to the solution and the solution is mixed on a Voronezh mixer until the clay is completely dispersed. 1% lignosulfonates are added to the resulting clay suspension and the solution is stirred until they are completely dissolved. Then, with constant stirring, 0.7% PAC-CB and 1.5% FITO-RK starch are introduced. 0.5% PES-1, 0.2% bactericide LPE-32, 0.5% lubricant Lubriol are added to the stabilized solution. After thorough mixing, 65% barite and 5% KCl are added to the solution. Then, 0.5% of Givpan and GKZh-IIH are introduced into the solution. After thorough mixing, the solution is considered ready.

The compositions and properties of the solutions are given in tables 1 and 2.

In the specified drilling fluid, bentonite clay powder is used in the range of 3-5%. A decrease in the clay content leads to a solution with low values of structural and mechanical properties, which leads to the loss of weighting agent from the solution, an increase in the clay component contributes to an increase in the viscosity of the solution, which leads to an increase in the thickness of the crust, adhesions, poor passability.

To ensure the stability of the wellbore, the inhibitory ability of the solution is regulated by introducing KCl mineral salt into the solution, the concentration of which is determined by the mineralization of pore water in the drilled formations. In the inventive solution, the most optimal concentrations are proposed, based on drilling practice and literature data. In addition, the addition of mineral salt to the drilling fluid increases the heat resistance of the fluid.

To regulate the filtration properties, polyanionic cellulose of medium and low viscosity PAC-SV in the range of 0.6-0.8% is introduced into the drilling fluid. A decrease in the PAC content to 0.4% leads to high values of the filtration rate, a further increase in concentration to 1% is impractical because contributes to the thickening of the solution.

Also, to regulate the filtration, Fito-RK starch is additionally introduced into the solution, the effectiveness of which is especially increased in solutions with a high degree of mineralization. As shown by experimental data, the optimal starch additives are in the range of 1-2%.

To prevent biodegradation of polysaccharides, it is proposed to introduce an addition of the bactericide LPE-32 into the solution, the concentration of which is recommended by the manufacturer in the range 0.2-0.3%.

To control the rheological and filtration properties, it is recommended to introduce lignosulfonate FHLS within the range of 0.5-1.5%. However, the introduction of lignosulfonate in the solution promotes its foaming, therefore, antifoam PES-1 should be added to the solution.

Additives to Givpan's solution can further control the filtration and rheological properties of the solution, as well as prevent the enrichment of the solution with drill cuttings.

GKZH-IIH contributes to a significant decrease in the viscosity of the solution and increase its heat resistance.

As shown by experimental data, the combined use of antifoam PES-1 with a lubricant additive Lubriol contributes to a solution with sufficiently high lubricating properties, while the optimal concentrations of PES-1 lie in the range of 0.1-0.5, and Lubriol - 0.5-0 ,8%.

When combined with the introduction of antifoam PES-1 and the lubricating additive Lubriol, a synergistic effect is also observed with respect to the lubricating action of the crust, characterized by the coefficient of friction of the CPC. This can be seen from Table 3, where the separate introduction of PES-1 and Lubriol in the total amount does not provide the drilling fluid with the necessary lubricating properties. Polyethylsiloxane PES-1 is a hydrophobizing agent with respect to the clay peel, preventing it from swelling, and Lubriol creates an additional lubricating layer on the surface of the peel, and reduces stickiness.

The inventive composition of the drilling fluid with an optimal ratio of reagents (pos. 2 and 3, table 3) in comparison with the prototype has lower filtration values (2-2.5 times), contains less clay. In a solution of the claimed composition with an optimal ratio of reagents, an improvement in the lubricating properties of the peel is observed than in the prototype (1.4-1.6 times).

When using the inventive composition, the use of expensive and scarce caustic potassium is excluded.

The use of an effective antifoam PES-1 helps to prevent foaming of the solution during gas manifestations and to keep the density of the solution at the required level without accidental emissions.

Due to the reduced filtration and low clay content, the solution forms a thin crust with a low coefficient of friction, which reduces the risk of sticking and accident rate, increases the overall drilling speed; also less filtrate and solid phase penetrates into the reservoir, which ultimately will lead to a reduction in development time and to obtain a greater influx of oil or gas from the reservoir.

The use of the proposed drilling fluid in difficult geological conditions, for example, when drilling deviated and horizontal (especially gas) wells with abnormally high pressures and temperatures, will help to avoid accidents and thereby increase the speed of penetration and productivity of the well.

table 2 Solution parameters at 20 ° C Structure Density, g / cm ³ Conditional viscosity, s PF, cm ³ SNA, dPa pH Note in 1 min in 10 min one 2 3 four 5 6 7 8 one 1.83 29th 16 3.3 13,2 8.3 Barite partially drops out of solution 2 1.90 40 14.5 16.5 33 8.3 3 1.90 75 13 26,4 36.3 8.2 four 1.91 92 eleven 29.7 49.5 8.2 5 1.90 68 twenty 42.9 42.9 7.9 6 1.90 33 19.5 17,2 28.1 8.4 7 1.90 46 17 15.1 31.3 8.3 8 1.90 52 13 28,2 35.7 8.3 9 1.90 64 eleven 35.3 48.1 8.1 10 1.91 56 6 23.1 39.6 7.6 eleven 1.91 52 3 19.8 36.3 7.5 12 1.91 54 2 20.1 36.3 7.3 13 1.91 55 2 20.1 39.6 7.1 fourteen 1.90 45 2.5 17.3 29.1 8.0 fifteen 1.90 39 14.5 17 31.3 8.1 16 1.90 36 fourteen 15.1 26.3 7.8 17 1.90 32 13.5 10.1 21.3 7.5 eighteen 1.86 28 13 6.6 15.1 7.1 Barite partially drops out of solution 19 1.90 45 14.5 15.8 31.3 8.0 twenty 1.90 42 fifteen 12.1 26.1 8.2 21 1.85 24 fifteen 9.9 11.3 8.5 Barite partially drops out of solution 22 1.90 48 16 17.0 31.3 7.8 23 1.90 41 fifteen 14.8 30.9 8.1 24 1.87 32 13 13,2 23.1 8.5 Barite partially drops out of solution 25 1.83 40 3 16.5 33.3 7.4 26 2.12 55 2 21.3 45.1 7.4

Claims (1)

Weighted drilling fluid containing clay - bentonite, barite, soda ash, stabilizing reagent, potassium chloride, metal hydroxide, lignosulfonate reagent, water, lubricant, acrylic reagent, characterized in that it contains PAC-polyanionic cellulose as a stabilizing reagent CB, metal hydroxide - sodium hydroxide NaOH, lignosulfonate reagent - FHLS, lubricant - Lubriol, acrylic reagent - Givpan, and also additionally contains Phyto-RK starch reagent, antifoam PES-1, hydrophobization torus - organosiloxane - GKZH-IIH, bactericide LPE-32, in the following ratio of ingredients, wt.%:
Soda ash 0.3-0.5 Sodium hydroxide 0.2-0.3 Bentonite 3-5 PAC-SV 0.6-0.8 Fito-RK starch 1-2 FHLS lignosulfonate 0.5-1.5 Defoamer PES-1 0.1-0.5 Lubricant Lubriol 0.5-0.8 Potassium chloride 3-5 GKZH-IIH 0.3-0.5 Barite 45-65 Givpan 0.3-0.5 Bactericide 0.2-0.3 Water Rest