CN-121991655-A - Degradable temperature-control type water-absorption-expansion-delaying plugging agent and preparation method and application thereof

Abstract

The invention discloses a degradable temperature-control type water-absorption-delayed expansion plugging agent and a preparation method thereof, belonging to the technical field of well drilling plugging in petroleum industry. Raw materials for preparing the active ingredients of the plugging agent comprise hydroxyethyl acrylate, acrylamide, starch, bentonite, a cross-linking agent, an initiator and a rigid inert material. Wherein, the rigid inert material adopts aluminate coupling agent surface modification, greatly improving the gel linkage mechanical property between rigid material and polymer molecules. The elastic gel is prepared by uniformly mixing the raw materials and then carrying out crosslinking reaction, and the degradable temperature-control type water-absorption-delaying expansion plugging agent is obtained. The invention solves the problems of excessively high water expansion speed, no delay characteristic, low compressive strength and no degradation of the plugging agent, and is suitable for plugging operations of permeability leakage, crack leakage, cave type leakage and the like.

Inventors

• PU LIANGCHUN
• WEI WEI
• YANG XITIAN
• LIU JIANGUANG
• YANG XUEWEI
• Yuan Zongling
• HUANG JIAN
• XU JUNYANG
• LIU WENCHAO
• CHENG LIN
• YAN WENHUA
• HAN JINGYI
• WANG XIANZHOU
• CONG SHAN
• ZHANG WEI

Assignees

• 中国石油集团渤海钻探工程有限公司
• 中国石油天然气集团有限公司

Dates

Publication Date

20260508

Application Date

20241104

Claims (9)

1. 1. The degradable temperature-control type water-swelling-delaying plugging agent is characterized in that raw materials for preparing effective components of the plugging agent comprise, by weight, 8-18 parts of hydroxyethyl acrylate, 2-12 parts of acrylamide, 0.5-8 parts of starch, 1-9 parts of bentonite, 0.01-0.4 part of a cross-linking agent, 0.01-0.2 part of an initiator and 0-8 parts of a rigid inert material; Wherein the rigid inert material comprises at least one of mica, nut shells, vermiculite, nano silica, nano cellulose and superfine calcium carbonate.
2. 2. The degradable temperature-controlled delayed water absorption expansion plugging agent according to claim 1, wherein the rigid inert material is a modified rigid inert material and is obtained by modifying the surface of an aluminate coupling agent accounting for 0.5-2% by mass.
3. 3. The degradable temperature-controlled delayed water-swelling plugging agent according to claim 2, wherein the rigid inert material is particles with the mesh number less than or equal to 60 mesh.
4. 4. The degradable temperature-controlled delayed water-swelling plugging agent according to claim 3, wherein the cross-linking agent is N, N-methylenebisacrylamide or a mixture of N, N-methylenebisacrylamide and triallylamine in a mass ratio of 4-6:1.
5. 5. The degradable temperature-controlled delayed water absorption expansion plugging agent according to claim 4, wherein the redox system initiator comprises persulfate and sodium bisulphite in a mass ratio of 1:1-2.
6. 6. The degradable temperature-controlled plugging agent for delaying water absorption expansion according to any one of claims 2-5, wherein the raw materials further comprise 30-60 parts of water.
7. 7. A method for preparing a degradable temperature-controlled plugging agent with delayed water absorption expansion according to claim 6, which is characterized by comprising the following steps: the raw materials are weighed according to the parts by weight, evenly mixed, added with an initiator under the condition that the reaction temperature is 55-70 ℃, evenly mixed, subjected to crosslinking reaction to obtain elastic gel, and dried to obtain the degradable temperature-control type water-absorption-expansion-delaying plugging agent.
8. 8. The method for preparing the degradable temperature-controlled plugging agent with delayed water absorption expansion according to claim 7, wherein the reaction time of the crosslinking reaction is 120-240 min; the degradable temperature-control type water-swelling-delay plugging agent is crushed into particles.
9. 9. The application of the degradable temperature-controlled water-swelling-delaying plugging agent is characterized in that the degradable temperature-controlled water-swelling-delaying plugging agent is added into drilling base slurry according to the mass fraction of 2% -8% to plug.

Description

Degradable temperature-control type water-absorption-expansion-delaying plugging agent and preparation method and application thereof Technical Field The invention belongs to the technical field of well drilling plugging in petroleum industry, relates to a temperature-control type delayed water-absorbing expansion plugging agent, and in particular relates to a degradable temperature-control type delayed water-absorbing expansion plugging agent, and a preparation method and application thereof. Background Drilling fluid plays a vital role in geological drilling and petroleum drilling construction, but for abnormal stratum with permeability, cracking property and other characteristics, if the drilling fluid leaks into the stratum under the action of pressure difference, huge safety risks and economic losses are brought to drilling construction. Therefore, the plugging agent is used as a material for effectively plugging a stratum leakage channel, and becomes one of key factors influencing the plugging construction effect. At present, a quick water-absorbing expansion material is generally adopted as a plugging agent, for example, chinese patent publication No. CN104726078A is adopted, sodium polyacrylate, cotton yarn and polyacrylamide are adopted as main components, the material absorbs water instantly and rapidly, the expansion speed is extremely high, the material can expand tens of times within 1 hour, the maximum expansion speed is hundreds of times, however, the excessively high expansion speed also causes inconvenience to construction operation, in the on-site plugging construction operation, a certain time is required for preparing plugging slurry and pumping the plugging agent into a stratum, if the plugging agent does not enter a target leakage layer, the plugging cannot be accurately performed at the target position, and thus the plugging failure is caused. In addition, the excessively high expansion speed can not only cause pipeline blockage and bring difficulty to pumping operation, but also the compressive strength of the water-absorbing expansion material is obviously reduced along with the expansion of the volume, thereby causing hidden trouble of re-leakage to later operation of drilling engineering, and the construction safety cannot be ensured. In the aspect of the plugging principle, the prior art mostly adopts a bridging plugging process of multilevel granular materials, wherein large particles play a role in bridging in a leakage channel, and small particles are refilled to form a plugging layer. However, in the actual construction process, the underground leakage channel condition is various and complex, the stratum leakage channel condition cannot be accurately mastered, and the selection of the particle size of the plugging material, the selection of the particle size of each stage of particles and the comprehensive consideration of concentration ratio are complex. If the particle size is too large, the plugging material cannot smoothly enter the plugging layer, a gate sealing effect is formed, and if the particle size is too small, the plugging material is directly leaked, so that the plugging method adopting the principle cannot form effective plugging due to improper concentration ratio of particles at all levels. Besides the above materials, part of gel materials can be used as plugging agents, but are difficult to be degraded by microorganisms, so that the problems of long-time incapability of decomposition exist, and soil pollution and water pollution can be caused. Disclosure of Invention In order to solve the problems of the prior art that the water absorption expansion speed is too high without delay, the compressive strength is low and the water absorption expansion is not degradable, the invention aims to provide the degradable temperature-control type water absorption expansion delay plugging agent, the plugging agent which has proper expansion speed, does not generate expansion or has extremely low expansion rate under the water environment of normal temperature, and only absorbs water to expand under the action of the stratum temperature to form the degradable plugging material with high strength, strong temperature resistance and capability of being obtained through modification and grafting crosslinking reaction of the rigid inert material. The invention also aims to provide a preparation method and application of the degradable temperature-control type water-swelling-delaying plugging agent. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The degradable temperature-control type water-swelling-delaying plugging agent comprises, by weight, 8-18 parts of hydroxyethyl acrylate, 2-12 parts of acrylamide, 0.5-8 parts of starch, 1-9 parts of bentonite, 0.01-0.4 part of a crosslinking agent, 0.01-0.2 part of an initiator and 0-8 parts of a rigid inert material; Wherein the rigid inert material comprises at least one of mica,