Temporary plugging agent for drilling fluid

Abstract

The invention discloses a temporary plugging agent for drilling fluid, and belongs to the technical field of petroleum drilling. The temporary plugging agent is prepared from the following raw materials in percentage by weight: 60 to 70 percent of hexadecane, 0.5 to 1 percent of catalyst persulfate, 10 to 20 percent of phenol, 10 to 20 percent of formaldehyde, and 1 to 2 percent of cationic surface active agent. The preparation method comprises the following steps of: 1, adding the hexadecane liquid into a reaction kettle, heating the reaction kettle to 50+ / -5 DEG C, adding the phenol, stirring the mixture, controlling the temperature to be 80+ / -5 DEG C and the pressure to 2+ / -0.5MPa, slowly adding the catalyst, adding the formaldehyde solution after 2 hours, stirring the mixed solution for 2 hours while continuously controlling the temperature to 40+ / -5 DEG C, adding the surface active agent, and stirring the mixed solution for 2 hours; and 2, relieving the pressure in the reaction kettle to normal pressure, extracting the mixture, drying the mixture at the temperature of 100+ / -5 DEG C, and then grinding the dried mixture to obtain the temporary plugging agent. The softening point temperature of the temporary plugging agent is within a wide range from 70 to 140 DEG C, so that the temporary plugging agent can almost meet the needs of all layers of earth.

Description

technical field [0001] The invention discloses a temporary plugging agent for drilling fluid, in particular to an oil-soluble resin temporary plugging agent and belongs to the technical field of petroleum drilling. Background technique [0002] During the drilling operation, when the pressure of the fluid column in the wellbore of the oil layer is higher than the pressure of the oil layer, the drilling fluid will be lost to varying degrees, seriously affecting the normal process of the drilling operation, not only wasting the drilling fluid, but also causing damage to the oil layer. Therefore, it is necessary to temporarily block the formation that needs to be protected during the drilling process, and remove the plugging effect after the drilling operation is completed to restore the original state of the formation. The temporary plugging agent for drilling fluid is a treatment agent used in the drilling process to act as a temporary plugging agent. Drilling temporary plu...

AI Technical Summary

Problems solved by technology

[0005] First, the scope of use is narrow

Due to the different sizes of rock pores (pore diameters) in each formation, the required particle size distribution of temporary plugging agents is different, resulting in poor versatility and limited application range of temporary plugging agents.

[0006] Second, the effective content when used cannot be guaranteed

[0007] Third, there is wear and tear on the drill

The rigid and inert granular materials used in this type of temporary plugging agent will cause grinding loss to the surface of all drilling tools, pipelines and other steel materials through the circulation of drilling fluid during the drilling process.

[0008] Fourth, the effect of protecting the formation is poor

Since this kind of temporary plugging agent uses granular materials, it can only form particle accumulation and bridging in the pores of the formation, and can only prevent some harmful particles from entering the formation, but cannot prevent fluid from entering the formation, failing to achieve the purpose of real formation protection.

[0009] Fifth, the plugging removal process is complicated and the formation is easy to be polluted

[0011] First, the on-site use process is complex

The existing oil-soluble temporary plugging agent is a compound, not a single product. It is composed of various organic substances and a small amount of inorganic bridging particles. It is composed of several materials. It is very complicated to use on site, and special preparation tools are necessary. , technology, low efficiency, increased labor intensity and additional equipment, which is not conducive to the needs of modern drilling operations

[0012] Second, poor temperature and salt resistance and pollution resistance

Many organic materials in this kind of temporary plugging agent have poor temperature resistance. At high temperature (above 110°C), organic materials will degrade and completely change their properties, so they are no longer temporary plugging materials; in the environment with high formation salinity, The molecular chains of organic materials will bend or even break, and their properties will change completely

Therefore, the temperature resistance, salt resistance and pollution resistance are poor.

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