阅读说明：本技术 一种油基选择性暂堵剂 (Oil-based selective temporary plugging agent ) 是由 王瑞琳 金发扬 于 2020-06-17 设计创作，主要内容包括：本发明公开了一种油基选择性暂堵剂,本发明的暂堵剂由以下原料制成：油溶性树脂主剂、过氧化物交联剂、氢过氧化物破胶剂和柴油,在除氧以及搅拌的条件下,取适量主剂,将其溶解在油性溶剂中,继续加入交联剂和破胶剂,搅拌后配制溶液,本发明的暂堵剂油水选择性强,对油层的暂堵率达到98％以上,突破压力梯度高,暂堵效果明显,解堵率高,能够达到95％以上；同时其溶液配制方法简单,配制时间短。(The invention discloses an oil-based selective temporary plugging agent, which is prepared from the following raw materials: under the conditions of deoxidization and stirring, taking a proper amount of main agent, dissolving the main agent in an oily solvent, continuously adding a crosslinking agent and a gel breaker, and stirring to prepare a solution, wherein the temporary plugging agent has strong oil-water selectivity, has a temporary plugging rate of over 98 percent on an oil layer, has high breakthrough pressure gradient, obvious temporary plugging effect and high plugging removal rate which can reach over 95 percent; meanwhile, the solution preparation method is simple and the preparation time is short.)

1. The oil-based selective temporary plugging agent is characterized by being synthesized from the following raw materials in percentage by weight based on the weight of an oily solvent:

a main agent: 2.3 to 2.8 percent of the total weight of the mixture,

a crosslinking agent: 2.7 to 2.9 percent of the total weight of the mixture,

a gel breaker: 0.5 to 0.7 percent of,

the main agent is oil-soluble resin, preferably at least one of hydrogenated petroleum resin, phenolic resin, styrene butadiene rubber or polyethylene resin, and the cross-linking agent is peroxide, preferably one of dicumyl peroxide or di-tert-butyl peroxide; the gel breaker is hydroperoxide, preferably cumene hydroperoxide; the oily solvent is diesel oil.

2. The temporary plugging agent according to claim 1, wherein dicumyl peroxide is suitable for a formation with a temperature of 100-120 ℃ and di-tert-butyl peroxide is suitable for a formation with a temperature of 120-150 ℃.

3. The method of preparing an oil-based selective temporary plugging agent of claims 1-2, comprising the steps of: dissolving the main agent in an oily solvent under the conditions of introducing nitrogen to remove oxygen and stirring, continuously adding the cross-linking agent and the gel breaker, and stirring at the speed of 400r/min for 15min to obtain the temporary plugging agent.

Technical Field

The invention relates to the technical field of oilfield chemistry, in particular to synthesis of an oil-based selective temporary plugging agent.

Background

As the oil field development enters the middle and later stages, the problem that the injected water flows along a high-permeability layer with high water phase permeability and cannot reach a low-permeability layer with high oil saturation is faced, and the conventional water-based plugging agent has low selectivity, so that the conventional water-based plugging agent can cause serious pollution even if a small amount of water enters an oil layer while plugging a water layer, and even blocks the oil layer, so that domestic scholars propose a matched temporary plugging selective water plugging technology of a temporary plugging agent matched with a high-strength plugging agent, namely, before the high-strength plugging agent for plugging the water layer is injected, the temporary plugging agent for plugging the oil layer is injected at a low speed, the temporary plugging agent selectively enters the oil layer and is gelatinized, so as to ensure that the subsequent high-strength plugging agent smoothly enters the water layer, and the temporary plugging agent can be broken and is extracted along with crude oil.

The temporary plugging agent is a chemical agent with the function of temporarily plugging the stratum, and is developed from a profile control water plugging agent. The temporary plugging technology is also applied to profile control water plugging or acidification and acid fracturing; the fracturing fluid, acid fluid, and other working fluids are diverted, thereby causing the displacement fluid or acid fluid to flow to the target formation. And are therefore also referred to as diverters.

The temporary blocking technology development in China began in the 80 th century, and a plurality of methods continue to use the traditional water blocking technology. With the development of chemical water plugging technology in the 70-80 s, the temporary plugging agent is widely developed and applied, and fine CaCO is used in the early 90 s₃The temporary plugging agent mainly comprising the oil-soluble resin for protecting the oil field type is rapidly developed and applied; later, with the continuous increase of the water content in the well, people began to develop a cellulose temporary plugging agent for forcing the liquid flow to turn, and adjust the water absorption profile at the deep part of the oil reservoir; since the 21 st century, the temporary plugging agent is developed towards the trends of high adaptability, high selectivity, high environmental protection and low cost.

At present, most of domestic oil fields enter a medium-water-content stage and a high-water-content stage, so that injected water flows along a water flow channel with high water phase permeability to form a 'flow channeling' phenomenon, the injected water cannot spread to a high-low-permeability stratum with oil saturation, the water drive efficiency is low, in order to start a low-permeability layer, a high-permeability layer needs to be blocked, a general injection technology is applied to an inhomogeneous oil deposit with an oil-water layer to inject a blocking agent, even if a small amount of the blocking agent enters the oil layer, the stratum is damaged, even the oil flow channel is completely blocked, a temporary blocking protection technology needs to be used, the temporary blocking agent can temporarily block the oil layer, so that a subsequent blocking agent only blocks a high-permeability area and does not block a low-permeability area, the aim of protecting the reservoir is fulfilled, then, the temporary blocking agent is mixed with crude oil along with the lapse of time, and the temporary blocking agent.

The temporary plugging agent commonly used in China is water-based, namely, the solvent or dispersion medium is water, and the temporary plugging agent has the defect of limited selectivity and can enter a water layer when entering an oil layer, so that the subsequent plugging agent is influenced to enter the water layer. The oil-based temporary plugging agent automatically and preferentially enters an oil layer by utilizing the characteristic of high oil phase permeability, and the oil-based temporary plugging agent intelligently enters a potential oil layer with high oil saturation to realize the purpose of protecting the potential oil layer. And for a high water-bearing stratum, the oil saturation is very low, even the residual oil saturation is reached, the oil-based temporary plugging agent has little entering amount, and even if the oil-based temporary plugging agent enters a small amount, the oil-based temporary plugging agent can be diluted by formation water and does not gel. The subsequent high-strength plugging agent can not enter the pipe.

Disclosure of Invention

In view of the above technical problems, the present invention aims to provide a temporary plugging agent for temporarily plugging an oil layer before water plugging, which has strong oil-water selectivity, in view of the defects of the prior art.

The invention adopts the following technical scheme that:

an oil-based selective temporary plugging agent is synthesized by the following raw materials in percentage by weight based on an oily solvent:

a main agent: 2.3 to 2.8 percent of the total weight of the mixture,

a crosslinking agent: 2.7 to 2.9 percent of the total weight of the mixture,

a gel breaker: 0.5 to 0.7 percent of,

the main agent is oil-soluble resin, preferably at least one of hydrogenated petroleum resin, phenolic resin, styrene butadiene rubber or polyethylene resin, and the cross-linking agent is one of dicumyl peroxide or di-tert-butyl peroxide; the gel breaker is cumene hydroperoxide; the oily solvent is diesel oil.

When the temporary plugging agent is used for the stratum with the temperature of 100-120 ℃, the adopted crosslinking agent is dicumyl peroxide, and when the temporary plugging agent is used for the stratum with the temperature of 120-150 ℃, the adopted crosslinking agent is di-tert-butyl peroxide.

The invention also provides a preparation method of the oil-based selective temporary plugging agent, which comprises the following steps: under the conditions of introducing nitrogen to remove oxygen and stirring, taking a proper amount of main agent, dissolving the main agent in an oily solvent, subsequently adding a cross-linking agent and a gel breaker, and stirring for 15min at the speed of 400r/min to obtain the temporary plugging agent.

The invention has the beneficial effects that:

the temporary plugging agent has strong oil-water selectivity, high breakthrough pressure, obvious temporary plugging effect and high plug removal rate which is more than 90 percent, and the temporary plugging rate of an oil layer is more than 95 percent; the temporary plugging agent is simple in preparation method, can be produced by simple stirring equipment and oxygen removal equipment, does not involve heating or pressurizing equipment, is low in production cost and high in safety, is short in preparation period, can be stirred for only ten minutes after being uniformly mixed, and has wide application prospect, good economic benefit and practical application value.

Drawings

FIG. 1 is a broken line comparison graph of the flow rates of high and low permeability parallel cores injected with the temporary plugging agent of the present invention;

FIG. 2 is a broken-line comparison of the split flow rates of high and low permeability parallel cores without the temporary plugging agent of the present invention.

Detailed Description

The technical solutions of the present invention will be described in detail below in order to clearly understand the technical features, objects, and advantages of the present invention, but the present invention is not limited to the practical scope of the present invention.