SU885244A1 - Drilling mud - Google Patents

Description

The invention relates to water drilling fluids used for drilling oil and gas wells in intervals composed of interbedded terrigenous and chemogenic species represented by salts one (sodium, potassium} and bivalent (MAI, calcium) metals prone to disruption stability, dissolution and plastic flow. A saline saturated drilling mud is known, in which the prevention of stabilization dilution is achieved by thickening with active fillers (clay, palygorskite, asbestos, etc.) 1. However Clay thickening does not give positive results due to the inhibitory effect of the saline medium, is short-lived and causes large amounts of clay and reagents. Asbestos additives provide intensive thickening of the polyvalent metals in the salt medium containing asbestos, is difficult due to the clogging of the cleaning devices, the well-known salt-saturated clay solution with a high degree of stabilization has not found practical application. There is also known a method for regulating the properties of aqueous SALT-saturated drilling muds, in which the composition of a drilling fluid containing clay, a water loss reducer, a thinner — lignosulfonate, sodium chloride — is implemented, and oxidized petrolatum (SMAD-1) is used to improve the structural and mechanical properties: 2. However, oxidized petrolatum related to higher fatty acids and containing a carboxyl group, working in saline clay solutions, is unstable in solutions containing salts of polyvalent metals, for example calcium and magnesium measures. In addition, the addition of oxidized petrolatum, which is sensitive to the action of calcium and magnesium ions, causes liquefaction and foaming of the solution. The purpose of the invention is to improve the quality of the solution by increasing its salt resistance under conditions of calcium-magnesium aggression, which are maintained at bottomhole temperatures from 4-5 ° C to 160 ° C.

To achieve this goal, as a structurant, the solution contains gossypol resin and additionally potassium chloride in the following ratios of components, May,%:

Clay3-10

Thinner, for example, cob, oxyl 1-3 chlorium potassium 3-5 gossipolova

resin 0,5-2

Stabilizer2-3

Sodium Chloride 20.3-23.9 Water Else

Gossypol resin is a substance whose main component is gossypol (polyphenol} is a yellow pigment contained in cotton.

Structural formula of gossypol

dHo ON: he too

Uh

(iH3 bNz YNz SNZ

The presence in the structure of a polymer of hydroxyl groups gives it resistance to calcite and α-magnesium aggression.

To compare the proposed drilling mud with the known, two types of initial saline-saturated (according to N aC-Bj mud are prepared: treated with 3% starch (type 1) and 3% CMC (type 2).

After thermostatting the initial solutions at 120 and, respectively, both solutions, despite the excessively high viscosity, the values of the static shear stress are very low (Tables 1 and 2, Test 1). To increase the strength of the structure, 0.5 and 2% gossypol resin was added to the initial solution (the proposed solution). ,

In order to obtain a known drilling fluid, SMAD-1 was added to the initial solutions in an amount of 0.5-3% (boundary conditions). Both (known and suggested) types of solution are prepared

as in the presence of Calcium-Magnesium aggression due to the addition of carnalite to the initial solutions to obtain 600-800 mg / l of magnesium and gypsum ions to obtain calcium ions in the filtrate of 1000-1200 mg / and without it.

The results of the analyzes after thermostating the prepared samples under the same conditions are given in Tables 1 and 2.

Compared the data of these tables, it should be noted that the additives of SMAD-1 in the amount of 0.5-3.0% (Table 1 and 2, experiment 2 and 3) provide an increase in the strength of the structure of highly stabilized saline-saturated clay solution to the required limits. However, in the presence of calcium-magnesium aggression, the additive Smad-1 does not allow to obtain a structured system (experiment b and -7) both when using starch (Table 1) and when using CMC-BLO (Table 2)

As can be seen from experiments 4 and 5 (Table 1 and 2), Gossipol resin, added in the amount of 0.5-2.0%, both in the presence of calcium-magnesium aggression (experiments 8 and -9), and without it ( experiments 4 and 5), provides. getting quite high values of structure strength.

Thus, it follows from the data obtained that in clay solutions saturated with salt (NaCE) treated with polysaccharides (starch, CMC). Using SMAD-1 as a structure-forming additive in the presence of calcium-magnesium aggression does not prevent stabilization liquefaction.

Using for this purpose gossypolovoy resin in the amount of 0.5 g-2.0 allows you to increase the structural and mechanical characteristics of the proposed solution.

In the absence of calcium-magnesium aggression, additives of gossypol resin allow to obtain higher strength characteristics of the salt-saturated (by N aCl) drilling mud as compared to solutions, worked by Smad-1

Table 1

. Saline-saturated (NaCBj drilling mud stabilized with 2% starch Sample 1 + 0.5% SMYD-1. Sample 1 + 3.0% SMAD-1 Sample 1 + 0.5% gossypolova Sample 1 + 2.0% gossypolova Sample 2 + GIPS + 1000-1200 600-800 carnalit Sample 3 + GIPS + 1000-1200 600-800 carnalit Sample 4 + GIPS + 1000-1200 600-800 carnale Sample 5 + GIPS + 1000-1200 600-800 carnalite

 saturated drilling mud stabilized 3.0% KSHCH-600

Sample 1 + 0.5% SMAD-1

Sample 1 + 3.0% SMAD-1

table 2

1.50 140 0.3 3.0 1.0

1.49 85 12/38 3.0 1.0

1.47 70 39/67 3.0 1.0 1.50 120 3/6 3.0 1.0 1.50 80 15/43 3.0 1.0 1.48 60 47/92 3.0 1 , 0 1.50 75 23/54 2.0 Oj5 1.48 60 45/114 2.0 0.5 1.49 130 3/7 4.5 1.5, 1.47 140 4/12 4.0 1.0 1.50 65 48/102 3.0 1.0 1.48 63 69/162 2.5 0.5

Sample 1 + 0.5% gossypolovoy resin

Sample 1 + 2.0% gossypolovoy resin

Sample 2 + GIPS +

1000-1200 600-800 carnalite

Sample 3 + GIPS +

1000-1200 600-800 carnalite

Test 4 + GIPS +

1000-1200 600-800 carnalite

Test 5 + GIPS +

1000-1200 600-800 carnalite

Claims (2)

1. WORKS VNIIBT, M., vyh.HHUI, 1971, p.20. 2. USSR Author's Certificate No. 202027, cl. From 09 to 1/04, 1971 {prototype).