CN-119039953-B - Scale inhibitor capable of being attached and solidified on stratum and preparation method thereof

CN119039953BCN 119039953 BCN119039953 BCN 119039953BCN-119039953-B

Abstract

The invention provides an antiscaling agent capable of adhering and solidifying on a stratum and a preparation method thereof. The whole emulsion can deform according to the pore throat of the stratum, is not easy to block and can enter into a production layer, the antiscaling agent has lower ground viscosity, gradually thickens under the action of a cross-linking agent after staying in a porous medium, can stay in the stratum for a long time, is slowly degraded after meeting divalent cations, is slowly released and has long antiscaling period, and the defects of the traditional adsorption type or precipitation extrusion technology are overcome, and the antiscaling agent is used for preventing the well bore and the stratum for a long time after being used. The superfine silica particles suspended in the water-absorbent resin can ensure good conductivity among the resin particles, and the bactericide has antibacterial and bactericidal properties, so that the resin can be effectively prevented from being rapidly degraded, and the release period of the antiscaling agent can be prolonged.

Inventors

LI HUI
ZHANG ZHENYUN
LIU GUANGSHENG
WANG WEIJUN
LI QIONGWEI
YANG LIHUA
YUAN HUIYING
YANG HUILI
LIU AIHUA
LIU NING

Assignees

中国石油天然气股份有限公司

Dates

Publication Date: 20260508
Application Date: 20230529

Claims (6)

1. The scale inhibitor capable of being adhered and solidified on the stratum is characterized by comprising, by weight, 99-99.5% of a scale inhibition system and 0.5-1% of water-absorbent resin; the scale preventing system comprises, by mass, 50-60% of a scale inhibitor, 10-15% of a natural polymer material, 10% of barium sulfate, 1% of a regulator, 0.4-0.6% of ammonium sulfate and the balance of water; the water-absorbent resin is prepared by reacting, by mass, 0.3-0.6% of acrylic acid, 0.15-0.3% of alkali, 0.02-0.04% of bactericide, 0.01-0.02% of composite organic chromium cross-linking agent, 0.01-0.02% of superfine silicon dioxide and 0.01-0.02% of initiator, wherein the particle size of the superfine silicon dioxide is 2000-3000 meshes; the scale inhibitor is a compound of organic phosphorus and a multipolymer, the mass ratio is 1:1-2, and the multipolymer is polyacrylic acid, hydrolyzed polymaleic anhydride or sodium polyethylene sulfonate.
2. A scale inhibitor for use in the adhesion and solidification of a subterranean formation according to claim 1, wherein the modifier is diethylenetriamine hydrochloride or polymethacrylate.
3. A scale inhibitor according to claim 1, wherein the scale inhibitor is prepared by the following steps: Adding a certain amount of natural polymer material into a certain amount of water at 50-70 ℃, stirring until the natural polymer material is dissolved, then adding a certain amount of barium sulfate in batches, stirring uniformly, adding a certain amount of antiscaling agent, reducing the temperature to 40-60 ℃, stirring, adding a slow-release rate regulator, dissolving ammonium sulfate in the rest water, and stirring for 3-4 hours to obtain the natural polymer material.
4. A scale inhibitor for use in the adhesion and solidification of a subterranean formation according to claim 1, wherein the bactericide is acryloylmorpholine or dodecyldimethylbenzyl ammonium chloride and the initiator is potassium persulfate or sodium bisulfate.
5. A scale inhibitor for use in the adhesion and solidification of a subterranean formation according to claim 1, wherein the mass ratio of acrylic acid to potassium hydroxide is 2:1.
6. A method of preparing an anti-fouling agent which is attachable to and curable in a subterranean formation according to any one of claims 1 to 5, comprising the steps of: Step 1) preparing an anti-scaling system; Step 2) preparing water-absorbent resin, namely adding acrylic acid and alkali with the formula amount into a reactor for neutralization reaction, then adding a bactericide, a composite organic chromium crosslinking agent and superfine silicon dioxide, adding an initiator when the temperature is adjusted to 25-30 ℃, initiating polymerization reaction under the action of the initiator, initially forming a certain sticky shape, introducing nitrogen to remove oxygen for 20-30 min, and ending the reaction when the temperature is not increased; and 3) adding the scale preventing system and the water absorbing resin according to the formula ratio, and uniformly stirring to obtain the scale preventing agent.

Description

Scale inhibitor capable of being attached and solidified on stratum and preparation method thereof Technical Field The invention belongs to the technical field of oilfield aids, and particularly relates to an anti-scaling agent capable of being attached to and solidified in a stratum and a preparation method thereof. Background Scaling of oil and gas field production systems is an important issue affecting production and development benefits, and may occur throughout the life of the field development, with formation and wellbore plugging caused by scaling, affecting production and final recovery. Among the numerous scale inhibition processes, the addition of scale inhibitors to oil and gas wells is a common and effective scale inhibition measure. (1) The liquid scale inhibitor is added, the added liquid scale inhibitor is easy to be carried out, the effective period is short, the liquid scale inhibitor is adhered to the wall of the oil pipe, the utilization rate of the medicament is low, and the addition requires to use ground equipment such as a high-pressure liquid injection pump, a container, a pump carrying vehicle and the like, so that the difficulty is high and the labor intensity is high. (2) The solid slow-release scale inhibitor is thrown, and the concentrated burst release and the effective period of the scale inhibitor caused by the dissolution of the polymer are too short. The deep extrusion antiscaling process for stratum is one of the most common antiscaling process for use in oil fields, including both domestic and offshore fields, and is one of the common well repairing techniques for preventing scale in stratum, shaft and ground. At present, the extrusion and precipitation extrusion processes of the adsorption type antiscaling agent mainly exist, however, the adsorption amount of the extrusion process of the antiscaling agent has multi-factor influence, such as formation water components and pH value, reservoir wettability and mineral composition, temperature and the like, the ground is thickened well, and cannot enter deep gaps of the stratum well, most products have a certain effective period, the length of the products depends on the type of the antiscaling agent, the adopted detention mode and the mineralogy and physical properties of the stratum, and the general effective period is 0.5-2 years, so that the antiscaling agent cannot scale for a shaft and the stratum for a long time. The national intellectual property office discloses a patent publication number CN114605979A at 6-10 of 2022, and the patent name is an invention patent of a calcium carbonate scale inhibitor for oil fields and a preparation method thereof, and the aggregation and later dispersion effects of aspartic acid are utilized to enable possible microcrystals with scale formation to be stably suspended in water, namely, the collision between crystal particles and the metal surface is blocked, so that the growth of scale layers is also inhibited. The scale inhibitor has good scale inhibition effect on calcium carbonate, but has short effective period, and can not prevent scale on a shaft and a stratum for a long time. Disclosure of Invention The invention aims to provide an anti-scaling agent which can be adhered and solidified on a stratum and overcome the technical problems in the prior art. It is another object of the present invention to provide a method for preparing an anti-fouling agent that can be set in a formation. Therefore, the technical scheme provided by the invention is as follows: An antiscaling agent capable of adhering and solidifying on a stratum is composed of, by weight, 99-99.5% of an antiscaling system and 0.5-1% of a water-absorbent resin. The scale preventing system comprises, by mass, 50-60% of a scale preventing substance, 10-15% of a natural polymer material, 10% of barium sulfate, 1% of a regulator, 0.4-0.6% of ammonium sulfate and the balance of water. The water-absorbent resin is prepared by reacting, by mass, 0.3-0.6% of acrylic acid, 0.15-0.3% of alkali, 0.02-0.04% of bactericide, 0.01-0.02% of composite organic chromium cross-linking agent, 0.01-0.02% of superfine silicon dioxide and 0.01-0.02% of initiator, wherein the particle size of the superfine silicon dioxide is 2000-3000 meshes. The scale inhibitor is a compound of organic phosphorus and a multipolymer, the mass ratio is 1:1-2, and the multipolymer is polyacrylic acid, hydrolyzed polymaleic anhydride or sodium polyethylene sulfonate. The regulator is diethylenetriamine hydrochloride or polymethacrylate. The preparation process of the scale preventing system is as follows: Adding a certain amount of natural polymer material into a certain amount of water at 50-70 ℃, stirring until the natural polymer material is dissolved, then adding a certain amount of barium sulfate in batches, stirring uniformly, adding a certain amount of antiscaling agent, reducing the temperature to 40-60 ℃, stirring, adding a slow-release rate regulator,