Seawater cationic polymer drilling fluid

1. Application scope:

It is used for well operations in the middle and lower wellbore sections and formations with strong water sensitivity.

2. Basic formula (kg/m3):

Pre-hydration general soil 20~30

Caustic soda 3~5

Lime 1~2

PAC-HV 3~5

PF-FLO 5~10

PF-CPS (small) 2~3

PF-CPB (large) 1~2

3. Common performance:

FV: 45 ~ 60 s

MW: 1.10~1.50 g/cm3

YP: 15~30 lb/100ft2

Gel: 5~10/8~15

pH: 9~10

FL: <5 ml

MBT: <50 g/l

4. Maintenance treatment:

a. Use caustic soda and lime to control the Pf and Pm of the system;

b. Pre-hydrated general soil is used to control fluid loss and improve mud cake quality. It can be added when preparing new slurry or can be directly added to well slurry. It is best to use diluents such as PF-THIN to treat rubber before adding. ;

c. When preparing new pulp, first add other treatment agents to protect the finely dispersed earthen glue, and finally add cationic polymer;

d. Dilute with thin glue liquid or treat with PF-THIN to control the stickiness of the mud;

e. Use biopolymer XC to improve the yield value and shear force of the mud;

f. PAC-HV and PF-FLO are used to control the fluid loss of mud. When the well temperature increases with the depth of the well, the temperature-resistant starch PF-FLO HT can be used instead of PF-FLO, and PAC-LV can be used instead of PAC-HV. Use SMP and SPNH to control filtration loss;

g. Due to the absorption and consumption of drill cuttings, cationic polymers should be frequently added to the well mud to maintain sufficient concentration to maintain the strong inhibition of the system;

h. Add WFT-666 or PF-GLA to increase the suppression performance of the system;

i. Add PF-LUBE or PF-BLA (plastic microbeads) to improve the lubricity of the system.