CN1103130A - Bentonite gel plugging agent - Google Patents

Abstract

The component of the invented agent consists of (by weight percentage) bentonite 4-10, polyacrylamide 0.1-1, sodium silicate 2.5-10, sulfonated phenolic resin 0.1-9 and water residue. The advantages of said invention are high blocking strength (break through pressure over 0.48 MP/cm), good blocking result (permiability decreasing degree up to 99.92%) and wide range of application (capable of using at reservoir temp. 20-150 deg.C).

Description

Bentonite gel plugging agent

The present invention relates to a kind of sealing agent that is used for the oilfield oil well shutoff.

The swell soil sealing agent of Shi Yonging mainly adopts hydrolyzed polyacrylamide and swell soil reaction in the prior art, produces floccule and stop up the shutoff exhalant canal in oil reservoir.Provide a kind of polymer-swell soil drilling fluid that is used for the oil gas well as the patent SU1574619 of the former Soviet Union.This drilling fluid contains polyacrylamide (as polymer), swell soil, carbamide resin, NaOH and water.It consists of (by Wt%): polyacrylamide 0.05-0.75, and swell soil 1-6 contains the carbamide resin 1-5 of the carboxymethyl group of 30-40%, and NaOH 0.1-0.5, water are remaining quota.This drilling fluid only produces floccule, can not produce into glue, so plugging effect is bad.And for example the patent of patent No. SU160103 provides a kind of drilling well mud liquid that is used to wash exploratory well, contains swell soil, hydrolyzed polyacrylamide, silicate of soda, urea formaldehyde resin and water.Its component (by Wt%) is: swell soil 2-3; The hydrolyzed polyacrylamide 0.01-0.09 of 3-10%; Silicate of soda 0.2-2; The Lauxite 10-15 of 30-34% carboxymethyl group (pH value is 8.5); Water is remaining quota.The bonding strength of the floccule that above-mentioned mud produces is all lower, under the impact of injecting water, and the loose very granule that resolves into of cotton-shaped agglomerate, the intensity of shutoff exhalant canal is lower.

It is simple and convenient to the purpose of this invention is to provide a kind of construction, and gelation time is short, and core breakthrough pressure height can produce the swell soil sealing agent of gel shutoff.

The present invention contains swell soil, silicate, hydrolyzed polyacrylamide, sulfonated phenol formaldehyde resin and water, and its component (Wt% meter) is: swell soil 4-10; Polyacrylamide 0.1-1; Silicate of soda 2.5-10; Sulfonated phenol formaldehyde resin 0.1-9; The surplus quota is a water.

The negative electrical charge of bentonite clay particle band is more, the aquation peptizaiton is strong, the decentralization height, hydration shell is thicker, in bentonite slurry, add a certain amount of sulfonated phenol formaldehyde resin, an adsorption group and an aquation group are arranged on the sulfonated phenol formaldehyde resin strand, make bentonite clay particle hydration shell thickening, repulsion weakens between particle and the particle.Bentonite slurry system stable performance this moment.This system is with after polyacrylamide solution mixes, polyacrylamide strand amide group and swell soil surface produce the effect of hydrogen-oxygen bonding force, multiple spot absorption takes place on bentonite clay particle, polyacrylamide is obeyed the Langmuir equation in adsorbance on the bentonite clay particle in polyacrylamide finite concentration scope, increase with concentration of polyacrylamide, polyacrylamide adsorbance on bentonite clay particle increases gradually, form stable bridge chain structure until the saturated back of absorption, form the gel state of stable flocculation.In order to improve the gel strength of this gel rubber system, in gel rubber system, introduce silicate, generate branched silica long-chain and form net structure, formed net structure and above-mentioned gel rubber system have synergy, make the gel strength of system increase.

The invention has the advantages that: gelation time had plugging strength height (breakthrough pressure is at 0.48MPa/cm) at 8-16 hour; 2, plugging effect is good, and the permeability reduction degree can reach 99.92%; 3, the scope of application is wide, can be in reservoir temperature 20-150 ℃ use; 4, simple, the health of job practices of the present invention, nontoxic and non-stimulated smell.Can improve water injection profile effectively.

Embodiment (by Wt%):

Project	Embodiment 1	Embodiment 2	Embodiment 3
				Swell soil	10	25	40
Sulfonated phenol formaldehyde resin	0.50	1.5	10
				Silicate of soda	4.00	6.00	10
Polyacrylamide	0.1	0.5	1
				The surplus quota	Water	Water	Water
Gel strength	121	0	0
				Gelation time	18h	8h	2h
The core breakthrough pressure	0.32	0.45	0.65

In an embodiment, gel strength is that penetrometer is measured; The unit of core breakthrough pressure is Mpa/cm.

With an embodiment manufacture craft of the present invention is described below: 1, mud preparation: the bentonite slurry that the ratio preparation in 25% is 150 cubic metres, and make it abundant dissolving, stir, and then in this mud, add 1.5% sulfonated phenol formaldehyde resin and fully stir well evenly, be pulled to usefulness such as construction well site.2, mixed liquor is prepared: the hydrolysis of polyacrylamide solution that the concentration preparation by 0.5% is 45 cubic metres, fully after the dissolving, add 15 cubic metres silicate of soda again, and mix, usefulness such as scene are arrived in roping.By two pump trucks two kinds of liquid are pumped into well head threeway place respectively when 3, constructing and mix, clamp-on the construction well.

Claims (1)

1, a kind of bentonite gel plugging agent that is used for the oilfield oil well shutoff, its component is (by Wt%):

Swell soil: 4-10;

Polyacrylamide: 0.1-1;

Silicate of soda: 2.5-10;

Sulfonated phenol formaldehyde resin: 0.1-9;

Remaining quota is: water.