2. Polyvinyl alcohol system 

brief introduction 

(1) It is made of polyvinyl alcohol (PVA) fluid loss reducer as main agent, including pre crosslinking type, anti pollution type and anti freezing type.

(2) When there is a certain pressure difference between cement and formation, a dense and tough filter membrane is formed at the interface to reduce water loss and prevent gas channeling. 

Formula: 

Oil well cement: grade G 

Fluid loss additives: ZOC-G70L, ZOC-G71L, ZOC-G72L, dosage 5-9% 

Dispersant: ZOC-F41L, ZOC-F42L, ZOC-F44L, dosage 0.3-2.5% 

Defoamer: ZOC-X60L, ZOC-X61L, dosage 0.2-0.5%

Optional materials: 

Retarder: ZOC-H21L

Accelerator: ZOC-A90L

Expansion agent: ZOC-B10

Gas channeling inhibitor: ZOC-GR5

characteristic; 

(1) The slurry system is suitable for well conditions from room temperature to 110 ℃ 

(2) The water loss of API can be controlled within 50ml

(3) It has a certain ability of salt resistance, and can be prepared with sea water 

(4) Adjustable thickening time, high compressive strength and good settlement stability 

(5) The transition time can be less than 10 minutes by combining with special coagulant 

(6) It has good leak proof, gas channeling proof and impermeability.

(7) The price is cheap and the performance is stable 

It is suitable for cementing operation of adjustment well in low and medium temperature well section, easy channeling and loss formation.

Formula performance:

Key points of system use and maintenance: 

(1) The service temperature shall not exceed 110 ℃ 

(2) In order to control the water loss well, the threshold dosage must be more than 5% (BWOC). 

(3) It has slight thixotropy and can increase the dosage of dispersant appropriately. 

(4) The expansion agent can prevent the shrinkage of cement paste. 

(5) The ability of anti pollution is poor. Good flushing fluid and isolation fluid are used in cementing to prevent pollution.

Formula: