Shielding diverting agent for drilling fluids

Abstract

The invention discloses a shield diverting agent for drilling fluid. The shield diverting agent is composed of 30-70wt% of middle molecular binding material and 30-70wt% of filtration quality reducing material; wherein the middle molecular binding material is nanmu derivative, and the filtration quality reducing material is the condensation compound formed by the reaction of 40-60wt% of lignite, 5-20wt% of anhydrous sodium sulphite, 5-20wt% of sodium metabisulfite, 5-20wt% of sodium hydroxide, 2-8wt% of formaldehyde, 2-8wt% of sodium carbonate and 5-20wt% of chloroacetic acid. The invention is nontoxic and harmless, has fluorescence anti-interference and lubricity without foaming, strong anti-pressure capability of membrane chained by dense phase and good diaphragm transitivity, has deformability, plasticity and pressure buffer action, and can effectively block stratums of different penetrability as well as relatively large crack, cranny and medium and small cavern during drilling, thus preventing lost circulation and reducing formation damage; furthermore, the use cost is lower, the material is saved, and the confecting process is simplified, thus improving the drilling efficiency, being suitable for drilling of deep wells and large-diameter wells and being applied to drilling in seawater and salt water.

Description

technical field

[0001] The invention relates to a plugging temporary plugging agent for drilling fluid used in petroleum and natural gas drilling and development projects. Background technique

[0002] In recent years, with the expansion of oil and gas exploration and development areas, the strata to be exploited are getting deeper and deeper, and the stratum conditions are becoming more and more complex, making mining more and more difficult. Therefore, effective measures must be taken in the drilling and development process to ensure the smooth progress of drilling operations, especially for the complex problem of oil and gas production - lost circulation, which is a technical problem that cannot wait to be solved today. Because in the drilling, killing, cementing and testing operations, once lost circulation occurs, not only the drilling time will be delayed, but also accidents such as well collapse, pipe sticking and blowout may occur, and even lead to major accidents su...