HU203125B - Bentonite-based boring liquide inhibiting dispersion of clay minerals for deep drilling - Google Patents

Abstract

Bentonite based rinse to impede mineral clay dispersion during deep drilling, consists of (all kg/m3): 2-40 ammonium lignin sulphonate and/or 2-40 ammonium salt of oxidised lignin sulphonate and/or 2-40 ligninsulphonate and sulphonated phenol-novolak resin-formaldehyde condensate-ammonium salt, and possibly 1-40 humic acid salt, pref. potassium- or ammonium humate, and/or 0.1-20 polysaccharide-derivates and/or 0.01-0.2 acrylate polymer, pref. sodiumpolyacrylate or partially hydrolysed polyacrylamide.

Description

BACKGROUND OF THE INVENTION The present invention relates to bentonite-based organic rinse fluids for use in boreholes to inhibit the dispersion of clay minerals.

One of the most important factors in the exploration and exploration of hydrocarbon deposits and solid mineral sources is the flushing fluid used. For reasons of economy, bentonite-based compositions are most often used, since bentonite clay mineral provides the desired theological properties (viscosity, thixotropy) and is also suitable for controlling water discharge (dehydration). However, during drilling, a significant amount of solids, especially clay minerals, is introduced into the flushing fluid, where it is fractured, hydrated and undesirably increases the viscosity. Strong dispersants (polyphosphates, ferro-chromium lignosulfonate, etc.) are used to counteract this effect (Gray, G.R. et al., Composition and Properties of Oilwell Drilling Fluids, Gulf Publishing Co., 1980).

However, the hatching and swelling of the clay minerals also occurs in the rocks that make up the hole wall, thus losing the physical stability of a given rock layer and being pressed into the borehole as a plastic mass or disintegrated to disintegrate to a few millimeters.

In both cases, a lengthy, costly and uncertain liquidation operation is required. This problem is particularly dangerous in the so-called. For continuous core drilling, where the nature of the technology is extremely long, sometimes several months, the contact time between the layer prone to hydration and the flushing liquid.

The reason for the instability of the perforated wall is the water uptake of the clay minerals. This process can occur by surface or osmotic hydration (CHENEVERT, M.E .: Shale alteration by water adsorption, Journal of Petroleum Technology, September 1970, 1141-1148). At shallow depths, mainly at the surface, at greater depths (2000 m), osmotic hydration is predominant. Organic and inorganic potassium compounds are mainly used to solve these problems because potassium ions are adsorbed specifically on clay minerals and thus have an extremely inhibitory effect on their hydration and swelling (O'BRIEN, D. - CHENEVERT, M. drilling fluids, Journal of Petroleum Technology, September 1973, 1089-1100). Among the compositions used in practice are potassium humate and KC1, as well as partially hydrolyzed polyacrylamide and KC1 based systems (Clark, R. Ik. Et al., Polyacrylamide (Potassium chloride artificial drilling water sensitive shales, Journal of Petroleum Technology). , June 1976, 719-727).

However, potassium ion-containing flushing liquids have the disadvantage that their theological properties are extremely difficult to control and require a high degree of technical skill.

It is also known in the literature that, like potassium ions, ammonium ions are capable of stabilizing clay minerals and suppressing their hydration. They can be used to create a compact, less dispersible form. Of course, like any electrolyte, ammonium salts promote the coagulation of clay mineral suspensions. Our aim was to eliminate this process in the case of rinsing fluids.

In the course of our work it was found that bentonite-based flushing fluids provide stability of clay mineral suspensions in the presence of ammonium lignosulfonate additives.

BACKGROUND OF THE INVENTION The present invention relates to a bentonite-based flushing liquid comprising 2-40 kg / m ³ - preferably 2-25 kg / m ³ - of ammonium lignosulfonate and / or ammonium salts of modified lignosulfonates and / or 2-40 kg / m ^{3 of} lignosulfonate and phenol / novolac. ammonium salt of its formaldehyde condensate resin and optionally furthermore 1-40 kg / m ³ , preferably 10-25 kg / m ³ potassium and / or ammonium humate and 0.1-20 kg / m ³ polysaccharide derivative as excipients (e.g., carboxymethylcellulose, carboxymethylstarch, etc.) and / or 0.01-0.2 kg / m ³ polyacrylate or partially hydrolyzed polyacrylamide.

Laboratory studies have shown that NH4-lignosulfonate in the aqueous suspension is highly capable of increasing the stability and inhibiting the dispersion of clay minerals by its NH4 ⁺ ions.

In addition to the NH4 ⁺ ions specifically adsorbed on clay particles, electrostatic bonding lignosulfonate anions (polyelectrolytes) further increase stability while reducing interactions between particles, thus regulating theological properties.

By increasing the degree of dispersion of the system, the water discharge is thereby reduced, especially under the dynamic conditions of the borehole.

Modified lignosulfonates include lignosulfonates treated with various oxidizing agents (hydrogen peroxide, hypochlorite, peroxydisulfate, permanganate, etc.) and formaldehyde condensed products of lignosulfonate and sulfonated phenol / novolac resin or phenolsulfonic acid. Thus, by increasing the number of anionic groups as well as the molecular weight, the amount of NH ⁺ 4 ions that can be introduced into the system advantageously increases and the adsorption characteristics of the polyelectrolyte molecule are also improved.

We have shown in previous studies that there is a synergistic interaction between lignosulfonate and humate-based additives (Dormán, J.-Hingl, J. Technological problems of leaching fluid for geothermal drilling, Geological Survey, April, 1981, 3-10).

Our current experiments have shown that this effect also occurs with ammonium lignosulfonate. It is therefore preferable to use the ammonium salts of the lignosulfonates together with ammonium or optionally potassium humate. If it is necessary to drain the water further-21

In order to reduce 125 Β bi, polysaccharide derivatives or acrylic polymers may be used.

The rinsing fluid of the present invention has been tested under operating conditions and the results have been consistent with laboratory experiments.

The composition, preparation and application technology of the compositions of the present invention are described in detail in the following examples, without limiting their scope.

Example 1

72 g of bentonite were dispersed in 1200 cm ^{3 of} water with vigorous stirring and the resulting slurry was allowed to stand for 1624 hours. Subsequently, for the suspension divided into four equal portions, 0, 1.5, 3.0 and

4.5 g NH4 lignosulfonate (M - 2000-20000, M 5000) was added. The liquids so prepared had good theological properties and water retention. The dispersion inhibitory effect of the samples was measured on water-sensitive clay ore, and it was found to be 36.1% for 59%, 70.7% and 73.3% for the doped bentonite sample, respectively.

Example 2

48 g of bentonite were dispersed in 1200 cm ^{3 of} water with vigorous stirring and the resulting slurry was allowed to stand for 16-24 hours. The suspension of properly hydrated bentonite was divided into three equal portions, one portion containing 4 g of NH4-lignosulfonate (M - 2000-20000, M - 5000) and the other 4 g of ammonium salt of lignosulphonate oxidized with NaOCl (100 parts by weight of lignosulphate NaOCL was used). Compared to the untreated sample (36.1%), the dispersing effect increased to 67.4% and 78.6%, respectively.

Example 5

1200 cm ³ of the untreated clay suspension formed during drilling were divided into four equal parts. For the first, 3 g of ferro-chromium lignosulfonate (M - 200020000, M - 5000), for the third 3 g of 2 parts by weight of sulfonated phenol / novolac resin and 10 parts by weight of ammonium salt of product lignosulfonate condensed with formaldehyde (M - 5000-40000, M 15000). We added. The fourth sample was the untreated clay suspension. With practically the same rheological properties and water retention, the anti-dispersion effect in the untreated sample was 37.9% and this effect was reduced to 30.5% when using ferro-chromium lignosulfonate, but to 64.2% when using NH4-lignosulfonate. and increased to 78.6% with the modified product. ^{4 * * * *}

Example 4

1200 cm ³ of untreated clay suspension formed during drilling were divided into four equal parts; one gram of NH4 lignosulfonate (M - 2000-20000,

M to 5000), to the other 3 g of NH4 lignosulfonate (M-2000-20000, M to 5000) and 3 g of K-humate (M 10000-100000, M to 20000) and finally to the third 6 g of K-humate (M) M - 10,000-100,000, M - 20,000) were left untreated. The anti-dispersion activity was 37.9% for the sample without additive, 64.2% for NH4-lignosulfonate and 59.2% for K-humate. However, the antiperspirant effect of the sample containing NH4 lignosulfonate and K-humate was 80.3%.

Example 5

56 g of bentonite were suspended in 1200 cm ^{3 of} water and left for 16-24 hours. The suspension was divided into four equal parts and treated with the following additives:

A - 3 g NH4 Lignosulfonate (ALS) (M - 200020000, M - 5000)

B - 3 g ALS + 4.5 g carboxymethylcellulose (CMC) C - 3 g ferro-chromium lignosulfonate (M - 2000-20000,

M - 5000) + 4.5 g CMC

D - 3G ALS + 1.5g CMC + 0.015g Na-polyacrylate (M - 1000-10000, M - 1500)

The dispersion inhibitory activity mentioned in the Examples was determined as follows. The pre-selected water-sensitive, deep-water (drilled) rock sample was crushed to particles between 2.0 and 3.15 mm in size. The rock particles were placed in a lockable steel bomb containing the liquid to be evaluated (heat treated and dispersed in autoclave at 10 g / 100 cm ³ and 373 K for 5 hours. After examination (leaching, drying), particles larger than 2.0 mm were weighed back ratio directly indicated the anti-dispersion effect.

The technological characteristics of the rinsing fluid of the above samples are shown in Table I (after 5 hours heat treatment at 430 K):

Table I: Technological characteristics of rinsing fluids

Characteristics of the sample Pattern sign THE B C D Apparent viscosity, mPa.s 17.5 33.5 27.5 25 Plastic viscosity, mPa.s 13 26.5 18 17.5 River Boundary, Pa 4.6 7.2 8.4 7.7 Motion resistance (10 ”) Pa 1.0 1.3 2.8 1.5 Motion resistance (10 ') Pa 3.6 5.9 14.8 6.6 n 0.67 0.74 0.58 0.64 (In the Ostwald-de Vaele formula dimensionless exponent) K, Pa.s ¹¹ 0.17 0.19 0.47 0.29 consistency index Water discharge, cm ³ 20 9.0 15.5 13 PH 8.36 7.54 8.38 3.11

HU 203 125 Β

Claims (2)

PATENT CLAIMS 1. Bentonite-based flushing fluids for inhibiting the dispersion of clay minerals, characterized in that: - 2-8% bentonite; - 0.1 to 1% by weight of ammonium lignosulfonate of molecular weight 2000 to 20000 or of lignosulfonate ammonium salt oxidised by alkali hypochlorite of 2000 to 20000 and lignosulfonate and sulfonated phenol / novolac resin (10: 1) - ( 10: 3) an ammonium salt of a condensation product of formaldehyde having a molecular weight of 5000-40000 in a weight ratio; and optionally 0.1 to 1% by weight of alkali metal humate or carboxymethyl cellulose; and optionally Containing from 0.001 to 0.005% by weight of N-polyacrylate having a molecular weight of 1000 to 10,000. Rinse fluids according to claim 1, characterized in that they contain potassium humate as the alkali metal humate.