Self-crosslinking soap-free nano latex blocking agent, preparation method thereof, water-based drilling fluid and application

The invention relates to the technical field of oil and gas drilling oil field chemicals, and discloses a self-crosslinking soap-free nano latex blocking agent, a preparation method thereof, a water-based drilling fluid and application. The plugging agent comprises an inner core and a shell covering the outer surface of the inner core, the inner core is of a structure shown in the formula (1), and the molar ratio of a to b to c is 1: (0.5-1): (0.03-0.04); the shell has a structure shown in a formula (2); the molar ratio of a1 to b1 to c1 to d is 1 to (0.11 to 0.16) to (0.015 to 0.017) to (0.013 to 0.13); r1 and R3 are respectively H or CH3, R2 is (CH2) nCH3, and n is 0 or 1 or 2 or 4; r < 4 > is H or CH3, and R < 5 > is CH2OH or CH2OCH2CH (CH3) 2; the plugging agent has good dispersibility in the water-based drilling fluid, and effectively keeps the well wall stable; 本发明涉及油气钻探油田化学品技术领域，公开了一种自交联无皂纳米胶乳封堵剂及其制备方法和水基钻井液以及应用。封堵剂包括内核以及包覆在内核外表面的外壳，内核具有式(1)结构，a、b和c摩尔比为1：(0.5-1)：(0.03-0.04)；外壳具有式(2)结构；a1、b1、c1和d摩尔比为1：(