A random copolymer, a preparation method of the random copolymer, a drilling fluid containing the random copolymer. The random copolymer contains structural unit (A) represented by formula (1), structural unit (B) represented by formula (2), structural unit (C) represented by formula (3), and structural unit (D) represented by formula (4) or (5):
wherein X is halogen. When the random copolymer is used as a filter loss reducer in a high-calcium drilling fluid, the filter loss of the high-calcium drilling fluid can be reduced.
一种无规共聚物,一种无规共聚物的制备方法,一种含有无规共聚物的钻井液。无规共聚物包含由式(1)表示的结构单元(A)、由式(2)表示的结构单元(B)、由式(3)表示的结构单元(C)和由式(4)或(5)表示的结构单元(D):
其中 X 为卤素。当无规共聚物用作高
钙钻井液的降滤失剂时,可降低高
钙钻井液的滤失。