| 摘要 |
The present subject matter relates to the drilling fluid field, and discloses a bionic drilling fluid and a method for preparation of the bionic drilling fluid. The bionic drilling fluid comprises a specific bionic wall bracing agent, a bionic shale inhibitor, a filtrate reducer, and an amphiphilic reservoir protectant, wherein, the filtrate reducer comprises microcrystalline cellulose. The bionic drilling fluid provided in the present subject matter can effectively solve the problem of well wall instability, and has great industrial application prospects. |
| 主权项 |
1. A bionic drilling fluid, comprising a bionic wall bracing agent, a bionic shale inhibitor, a filtrate reducer, and an amphiphilic reservoir protectant, wherein the filtrate reducer comprises nanocrystalline cellulose;
wherein the bionic wall bracing agent comprises a backbone moiety of carboxymethyl chitosan with dopamine-derived base groups grafted on the backbone, wherein, the dopamine-derived base groups are represented by formula (1): wherein the bionic shale inhibitor is composed of structural units represented by formula (2) and structural units represented by formula (3): wherein the molar ratio of the structural units represented by formula (2) to the structural units represented by formula (3) is 0.2-6:1, and the weight-average molecular weight of the bionic shale inhibitor is 800-4,000 g/mol; wherein the amphiphilic reservoir protectant is composed of structural units represented by formula (4), formula (5), formula (6), and formula (7): where, R1, R2, R3, R4, and R5 are H, C1-C4 alkyl or C1-C4 alkoxyl respectively and independently; R6 and R6′ are C1-C3 alkyl respectively and independently; R7 is substituted or unsubstituted C1-C6 alkyl; M is H or an alkali metal; R8 and R8′ are C1-C6 alkyl, hydroxyl-substituted C1-C6 alkyl, phenyl or C1-C6 alkyl-substituted phenyl respectively and independently; the molar ratio of the structural units represented by formula (4), the structural units represented by formula (5), the structural units represented by formula (6) and the structural units represented by formula (7) is 1:0.4-2:0.5-1:0.1-0.5; the weight-average molecular weight of the amphiphilic reservoir protectant is 150,000-350,000 g/mol; and wherein based on the total weight of the bionic drilling fluid, the content of the bionic wall bracing agent is 3-7 wt %, the content of the bionic shale inhibitor is 1-2 wt %, the content of the nanocrystalline cellulose is 0.5-1 wt %, and the content of the amphiphilic reservoir protectant is 2-3 wt %. |
