Low-fluorescence anti-collapse blocking agent for drilling fluid and preparation method thereof

Abstract

The invention discloses a low-fluorescence anti-collapse blocking agent for drilling fluid. The low-fluorescence anti-collapse blocking agent is composed of the following components by mass (100%): 45-60% of paraffin wax, 4-8% of a surfactant, 5-10% of a stabilizer, 0.5-2% of an oxygen scavenger, 0.5-2%of a defoamer and the balance of a solvent. A preparation method of the low-fluorescence anti-collapse blocking agent comprises the following steps: sequentially adding formula amount of paraffin wax and surfactant to a No.1 reactor, heating to 30-50 DEG C, and stirring for 50-60 min; sequentially adding formula amount of solvent, stabilizer, oxygen scavenger and defoamer into a No.2 reactor, heating to 40-50 DEG C, and stirring for 30-40 min; and slowly adding the mixture obtained in the No.2 reactor into the No.1 reactor, and enabling reaction at 40-50 DEG C for 2-3 hours to obtain paraffin microemulsion of the low-fluorescence anti-collapse blocking agent. The product level low-fluorescence anti-collapse blocking agent is provided with micron-sized deformable particles, can effectively improve particle size distribution in a drilling fluid system, improves blocking anti-collapse ability of the drilling fluid, has low fluorescence, has good compatibility with other treatment agents, resists the temperature of 190 DEG C, has significant blocking anti-collapse effect especially for hard brittle shale as well as crushing and micro-crack development stratum, and can effectively protect walls of wells.

Description

technical field [0001] The invention relates to the field of oil and gas well exploitation, in particular to a low-fluorescence anti-collapse plugging agent for drilling fluid and a preparation method thereof. Background technique [0002] Wellbore instability in shale formations has become a technical problem often encountered in drilling engineering. Water-sensitive active mud shale and soft mud rock are very easy to hydrate and expand, especially when drilling into easily collapsed mud shale layers, deep easily collapsed formations, complex salt-gypsum mud formations, etc., are prone to spalling and block loss, resulting in jamming. The phenomenon of holding back the pump has brought greater risks to the construction and post-completion work. In order to prevent the fluid, solid particles and other additives in the drilling fluid from leaking into the formation, it is necessary to add a plugging agent to effectively seal the voids in the wellbore rock. However, conventi...

AI Technical Summary

Problems solved by technology

However, conventional plugging agents are difficult to achieve truly effective plugging, and have poor compatibility, high fluorescence levels, and single functions

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