In order to maintain the excellent stability of various properties of the mud, and to meet the needs of the drilling process, it is necessary to add processing agents (additives) to various types of mud (water base, oil base, and gas), especially in complex formations such as collapsed layers and salt. Paste layer) When performing deep drilling or horizontal drilling, various treatment agents are required. There are as many as 2,520 types of mud treatment agents on the market, and in fact there are approximately 100 to 200 chemical agents contained therein. According to the use of the product is divided into 16 categories, such as tackifiers, fluid loss additives, corrosion inhibitors, dilute dispersants, plugging agents, emulsifiers, shale control agents. In the late 1960s, the application of organic flocculants (polyacrylamides) and selective flocculants (vinyl acetate-maleic anhydride copolymers) developed non-dispersive mud systems and achieved excellent results.
For example, in Western Canada, the use of this flocculant increased the drilling footage by 56%, extended the working time of the drill by 45%, and increased the mechanical footage by 12%; China promoted the non-dispersed mud system since 1974, resulting in an average increase in drilling rate. 20%. In order to drill deep wells and geothermal wells (250°C) with a 7km (bottom well temperature above 200°C), additives such as resin and lignite, styrene maleic anhydride copolymers, and special synthesis can be added to the water-based mud. The high temperature resistant salt-resistant polymer.
