RU2675650C1 - Polymerclay mud solution - Google Patents

Abstract

FIELD: drilling soil or rock.SUBSTANCE: invention relates to the field of drilling oil and gas wells, in particular to drilling fluids, and may find its application in the drilling of unstable clay rocks. Polymer clay drilling mud contains, wt%: bentonite clay 5; polyvinylpyrrolidone PVP 6.3–10; sodium formate 5.3–9.2; liquid potassium glass 3; antifoam 0.1; the rest being water.EFFECT: high inhibiting properties and low values of mud filtration rate.1 cl, 2 tbl

Description

The invention relates to the field of drilling oil and gas wells, in particular, to drilling fluids and can find application in the drilling of unstable clay rocks.

Known drilling fluid (RF patent No. 2445336, publ. March 20, 2012), including an aqueous solution of polyhydric alcohol, a biopolymer, a salt-electrolyte, an anionic emulsion (for example, ROSFLOK PV), a bactericide, dispersed chalk

A disadvantage of the known composition is the low inhibitory ability with respect to clays.

Known drilling fluid (RF patent 2208035, publ. 07/10/2003), including synthetic fatty acid, sodium hydroxide, weighting agent and structure former, which use atactic polypropylene and paraffin.

A disadvantage of the known solution is the use of fire hazardous diesel fuel as the hydrocarbon base?

Known drilling fluid (RF patent 2492208, publ. 09/10/2013), including water, clay powder and a filter reducing agent polyelectrolyte VPK-402.

A disadvantage of the known composition is the low inhibitory properties of the solution.

A well-known drilling fluid (patent of the Russian Federation 2184756, publ. 07/10/2002) containing bentonite clay powder, a water-soluble polymer and water, in which the polymer contains Praestol grades 2510, or 2515, or 2530, or 2540.

A disadvantage of the known mud composition is its low clay inhibitory capacity.

Known drilling fluid for drilling in crumbling rocks (RF patent No. 2163248, publ. 02.20.2001), adopted as a prototype, including clay, polyglycol, stabilizing reagent, liquid potassium glass (K ₂ SiO ₃ ), potassium chloride and water.

The disadvantages of this solution are the high values of the filtration rate under dynamic conditions and the low water-repellent ability of the mud filtrate.

The technical result of the invention is the development of a water-based drilling fluid for drilling in unstable clay rocks with high inhibitory properties and low values of the filtration rate.

The technical result is achieved by the fact that it additionally contains bentonite clay, polyvinylpyrrolidone PVP, antifoam, glycerin and sodium formate in the following ratio of ingredients, wt. %:

bentonite clay 5 polyvinylpyrrolidone PVP 6.3-10 sodium formate 5,3-9,2 liquid potassium glass 3 glycerol 5 antifoam 0.1 water rest

The inventive polymer clay drilling mud includes the following reagents and commercial products containing them:

- bentonite clay 5%;

- polyvinylpyrrolidone PVP 6.3-10%, manufactured according to GOST 12.1.044-89;

- sodium formate 5.3-9.2%;

- liquid potassium glass 3%, produced according to GOST 18958-71;

- glycerin 5%;

- antifoam 0.1%;

- water the rest.

If necessary, the weighting of the solution can be carried out with barite concentrate in an amount that provides a given density of the drilling fluid.

In the proposed drilling fluid can be used bentonite clay powder grades PBMA, PBMB, PBMV, PBMG, which is produced in accordance with TU 2164-004-0013836-2006 "Clay powder". The brand of clay powder does not significantly affect the technological parameters of the solution, but characterizes its consumption.

Liquid glass is produced in accordance with GOST 18958-71, is available. Potassium liquid glass, in addition to fastening and inhibitory properties, can reduce the filtration rate, i.e. It has a stabilizing effect.

Polydone is a water-polymer system based on high molecular weight polyvinylpyrrolidone (PVP), a viscous, transparent, colorless or slightly colored liquid, produced in accordance with GOST 12.1.044-89 "Polydon", manufactured by the factory.

Octanol is used as an antifoam, Penta 463A antifoam for clay drilling fluids, and Penta 465 universal antifoam for drilling fluids that are available can also be used.

Clay stability is ensured by the use of sodium or potassium polyacrylates in the drilling fluid when combined with glycerin or with sodium formate. The preliminary depolymerization of water glass by dissolving glycerin in it helps to increase the inhibitory ability to clay rocks. Polyvinylpyrrolidone (PVP) is prone to complexation and binds to low molecular weight compounds. The introduction of water-based polyvinylpyrrolidone (PVP) into the drilling fluid helps reduce the activity of the dispersion medium of the solution, inhibits the growth of pore pressure in the rocks that make up the walls of the well, and thereby increases the stability of the well when drilling in clay rocks.

The proposed drilling fluid can be prepared as follows. A predetermined amount of water is mixed with clay powder for 1.5 to 2 hours, providing dispersion, then sodium formate is added, after its complete dissolution, PVP is introduced. The necessary filtration indicators are achieved by treating the solution with liquid glass, in which glycerol is previously dissolved.

Table 1 shows the results of studies on the impact of the proposed drilling fluid on the stability of clays in comparison with known solutions. The inhibitory ability of the solution was estimated by the amount of absorbed water in clay samples: the smaller the amount of absorbed water in the sample, the higher the inhibitory ability of the solution and vice versa. For research, we used dry clay samples made from bentonite clay powder by pressing under a load of 6 MPa to obtain tablets with an initial weight of 12.0 g.

Experimentally, the results of a study of the drilling fluid were obtained, which are shown in the Table. When the content of sodium formate is not more than 3% according to the table. 1 and PVP no more than 5% according to the table. 1 clay samples swell and disperse. When the content of sodium formate is 5.3–9.2% and PVP 6.3–10%, clay samples remain stable and are not destroyed (Table 1). An increase in the sodium formate content of more than 9.2% leads to the destruction of the clay sample (Table 1).

Table 2 shows the results of studies on the effect of sodium formate and PVP in the solution on the filtration rate. With a sodium formate content of 5.3–9.2% and a PVP of 6.3–10%, the minimum value of the filtration index is ensured (Table 2).

Claims (2)

Polymer clay mud, including water, clay, liquid potassium glass, characterized in that it further contains bentonite clay, polyvinylpyrrolidone PVP, antifoam, glycerin and sodium formate in the following ratio of ingredients, wt.%: bentonite clay 5 polyvinylpyrrolidone PVP 6.3-10 sodium formate 5,3-9,2 liquid potassium glass 3 glycerol 5 antifoam 0.1 water rest