Degradable high-strength temporary blocking agent and preparation method thereof

Abstract

The invention discloses a degradable high-strength temporary blocking agent which is prepared from a viscosity change promoting agent, an adhesive, acrylamide, a potassium ferricyanide solution, a cross-linking agent, ammonium persulfate, sodium hydroxide and water. A preparation method of the temporary blocking agent comprises the following steps: firstly adding the viscosity change promoting agent, the adhesive and the acrylamide into water, and uniformly mixing the viscosity change promoting agent, the adhesive and acrylamide with the water; then adding the potassium ferricyanide, the cross-linking agent and the ammonium persulfate, uniformly stirring the potassium ferricyanide, the cross-linking agent and the ammonium persulfate with the solution, then dropwise adding the sodium hydroxide, and fully stirring sodium hydroxide with the solution; finally performing a temperature-increasing reaction, so as to obtain a finished product. The degradable high-strength temporary blocking agent and the preparation method have the obvious effects that a non-newtonian fluid characteristic of shear thinning is achieved; after stilling is finished, the system viscosity is rapidly improved, i.e., a characteristic of rapidly enhancing the structure is achieved, and assistance is provided for improving the system strength by virtue of the cross-linking agent; a temporary blocking agent material distributed in the degradable high-strength temporary blocking agent achieves a gelatination effect at a reservoir temperature, so that the system strength is improved, and a high-strength gel slug is formed; an effect of a chemical packer is achieved, and a water layer is blocked or injection of a plugging agent for a subsequent stratum is assisted; furthermore, after blockage is finished, automatic gel breaking can be achieved, so that the permeability of the stratum is restored.

Description

technical field [0001] The invention belongs to the field of oil recovery technology, and in particular relates to a degradable high-strength temporary plugging agent suitable for water control and water plugging in horizontal wells and a preparation method thereof. Background technique [0002] Compared with vertical wells, horizontal wells have the advantages of high oil production index, low production pressure difference, and long water-free oil production period. However, with the extension of development time, the water cut of horizontal wells rises rapidly after water breakthrough, and the oil production drops sharply. , Some horizontal wells even see water just after they are put into production, which seriously affects the development effect of horizontal wells. As long as horizontal wells are used for oil production in Xinjiang Oilfield, Jidong Oilfield, Dagang Oilfield, etc., water production problems will inevitably occur to varying degrees. There are three main ...

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Problems solved by technology

There is a literature (Du Zhonglei. Development and performance evaluation of water plugging formula for horizontal wells in Luliang Oilfield [D]. Southwest Petroleum University: Du Zhonglei, 2014.) has examined the strength of the gel formed by the temporary plugging agent before and after shearing, but there is no Check the shear thinning property of temporary plugging agent

[0005] 2. The strength of the temporary plugging agent is not high enough to seal the formation well

Some literature (Wu Lezhong. Research on horizontal well plugging agent and water plugging technology [D]. China University of Petroleum (East China): Wu Lezhong, 2009.) proposed to use HPAM / organic chromium, HPAM / phenolic aldehyde to improve the strength, but the strength still cannot meet the demand

[0006] 3. After the plugging is completed, the gel breaking ability needs to be improved

However, this technology did not achieve the breaking of the temporary plugging agent

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