SU1341183A1 - Drilling mud for opening permeable seams - Google Patents

Abstract

The invention relates to the drilling of oil and gas wells. The purpose of the invention is to preserve the reservoir properties of a low-permeable formation by reducing the infiltration zone of the filtrates. The solution contains the ingredients in their following ratio, wt%: sodium carbonate 10-20 clay 7-15; carboxymethylcellulose 0.7-2.0; aniline 0.3-0.7; sulfur 0.3-0.7; ut 10-40; water the rest. The solution is prepared by successively mixing clay, sodium carbonate, carboxymethylcellulose, aniline, sulfur, and yel iron. The carbonate content in the solution leads to a decrease in the filtration characteristics of the collector in the infiltration zone of the filtrate. When the filtrate penetrates into the reservoir, it adsorbs on the walls of the pore channels with the formation of solvation layers. The presence of CO - anion in the filtrate contributes to the thickening and hardening of these solvation films. In the near-well part of the well, a blockade zone with a low permeability coefficient is formed. 2 tab. § (L from 4:00 with

Description

The invention relates to the drilling of oil and gas squaldans, namely drilling fluids used for drilling wells and opening up production horizons.

The purpose of the invention is to preserve the collection properties of a low-permeable formation by reducing the penetration zone of filtrates

This goal is achieved by using a drilling fluid containing sodium carbonate, clay, carboxymethylcellulose, aniline sulfur, the desired agent and water at the following ratio of components, wt.%:

Clay

Carboxymethylcellulose

Aniline

Sulfur

Carbonate

on three

Ut uhelitel

 Water

7-15 0.7-2 „0

oz, o;

0.3-0 „7

10-20 10-40 Else

The drilling fluid is prepared by successive mixing of clay, sodium carbonate, carboxymethylcellulose lulose, sulfur anilineJ, and weaning within these ratios.

Table 1 shows the compositions and their technological parameters.,

Table 2 presents data illustrating the restoration of sample permeability after exposure of drilling mud filtrates.

Example: Prepare a clay solution by mixing 35 g

When carbonate filtrate penetrates into interlayers filled with formation water containing multivalent cations (for example, Ca

bentonite clay in 500 ml of water., za t, n), the permeability of these particles is successively introduced into a solution of 50 g of sodium carbonate, 3, 5 g of CMC-600, 1.5 g of sulfur, 1.5 g of aniline. , 50 g of barite. As a result, a solution is obtained, having co., Wt.% G

Sodium carbonate 7 clay 10

Carboxymethylcellulose / loza0,7

Anilin0,3

Sulfur Oj3

Barite10

WaterEverything

As can be seen from the tabular data, the filtrates of solutions mineralized with water-soluble carbonate reduce the permeability of the samples.

This effect is weakly detected in the area of low concentrations - 0.5-- 2.0%. A further increase in

45

50

55

stacks decrease more intensively from an increase in the volume of the tightly bound phase and also due to the salting out of carbonates in the mobile aqueous phase.

Claims (1)

Invention Formula The drilling fluid to open the permeable formations, including clay, carboxymethylcellulose, aniline, sulfur, salt, and water, is characterized in that, in order to preserve the reservoir properties of the low-permeability formation by reducing the infiltration zone of the filtrates, it also contains an alkali metal carbonate in the following ratio ingredients, wt.%: Sodium carbonate 10-20 clay 7-15 five 0 five 0 five Neither the filtrate of a water-soluble carbonate leads to an intensive decrease in the filtration characteristics of the collector in the infiltration zone of the filtrate. A decrease in the coefficient of permeability recovery is accompanied by an increase in the volume of the stationary aqueous phase in the pore space. The reduction in permeability is a result of the physicochemical interaction of the filtrate with the solid surface of the pore channels. When the filtrate penetrates into the reservoir, it adsorbs on the walls of the burrow channels, with the formation of solvation layers. The presence in the filtrate of the anion CO | contributes to the thickening and hardening of these solvate films, resulting in a decrease in the hydraulic radius C of permeable channels and the resulting permeability of the plate. one, In the near-wellbore part of the well, a blockade zone with a low permeability coefficient is formed, preventing filtration both from the formation into the well of formation fluids and from the well into the mud filtrate formation. So, when filtering highly brine water (brine) through samples filled with carbonate filtrate in the opposite direction, permeability is not restored. When carbonate filtrate penetrates into interlayers filled with formation water containing multivalent cations (for example, Ca  t, n,), permeability etiucha stacks decrease more intensively from an increase in the volume of the tightly bound phase and also due to the salting out of carbonates in the mobile aqueous phase. Invention Formula The drilling fluid to open the permeable formations, including clay, carboxymethylcellulose, aniline, sulfur, salt, and water, is characterized in that, in order to preserve the reservoir properties of the low-permeability formation by reducing the infiltration zone of the filtrates, it also contains an alkali metal carbonate in the following ratio ingredients, wt.%: Sodium carbonate 10-20 clay 7-15 Carboxymethylcellulose, 7-2.0 Aniline 0.3-0.7 Bentonite clay 7i KsjCO, 10; CMC-600 0.7; aniline 0.3; sulfur 0.3; barite 10; water the rest Bentonite clay 10; KaiCOj 15; CMC-600 1.5; aniline 0.5; sulfur 0.5; barite 20; water the rest Bentonite clay 15} MajCOj 20; CMC-600 2.0; aniline 0.7; sulfur 0.7; barite 40; water the rest Bentonite clay 7; NajCOj 7; CMC-600 0.7; aniline 0.3; sulfur 0.3; barite 10; water the rest Palygorskite clay (group I) 7; NajGOj 10; KNTS-600 0.7, aniline 0.3; sulfur 0.3; barite 10; water the rest Bentonite clay 7; NajCOj 10; KSC-600 0.7; aniline 0.3; sulfur 0.3; celestine ore 10; water the rest Bentonite clay 7 | ten; CMC-600 0.7; aniline 0.3; sulfur 0.3; barite 10; water the rest 0.3-0.7 10-40 Else Table t After thermostating a dream 1 min / 10 min dpa 15/20 20/25 40/70 15/20 10/15 15/20 15/20 5120020/25 4130025/35 4145045/808 5120020/25 5120012/20 5120020/25 6120020/25 ten Tvvl tsa2