FORM-A-BLOK AS Acid-Soluble Lost Circulation Pill | Schlumberger

FORM-A-BLOK AS

Acid-soluble lost circulation pill

The FORM-A-BLOK AS* acid-soluble lost circulation pill is a single-sack proprietary blend designed for wellbore strengthening applications and a wide variety of lost circulation scenarios, including fractures and matrix permeability. This product is applied in the form of a pill which, depending on the application, dewaters or deoils rapidly to form a high-strength plug.

The pill can be used in water-base or nonaqueous drilling fluids and at temperatures up to 350 degF [177 degC]. The recommended concentration of FORM-A-BLOK AS pill is 32-lbm/bbl [91-kg/m3] for all fluid densities in freshwater, seawater, or oil- or synthetic-base systems. Mixing a water-base pill will provide the maximum strength. The slurry is weighted with SAFE-CARB* 40 ground marble bridging agent. M-I SWACO recommends continuously agitating the pill until it is pumped and pulling the pump screens prior to pumping.

Water-base Pill Formulation

Density, lbm/galUS [relative density]Freshwater Volume, bblFORM-A-BLOK AS Pill Concentration, lbm/bblSAFE-CARB 40 Agent Concentration, lbm/bbl
Density, lbm/galUS [relative density] 9 [1.08] Freshwater Volume, bbl 0.95 FORM-A-BLOK AS Pill Concentration, lbm/bbl 32 SAFE-CARB 40 Agent Concentration, lbm/bbl 14
Density, lbm/galUS [relative density] 10 [1.20] Freshwater Volume, bbl 0.88 FORM-A-BLOK AS Pill Concentration, lbm/bbl 32 SAFE-CARB 40 Agent Concentration, lbm/bbl 81
Density, lbm/galUS [relative density] 12 [1.40] Freshwater Volume, bbl 0.75 FORM-A-BLOK AS Pill Concentration, lbm/bbl 32 SAFE-CARB 40 Agent Concentration, lbm/bbl 210
Density, lbm/galUS [relative density] 14 [1.60] Freshwater Volume, bbl 0.62 FORM-A-BLOK AS Pill Concentration, lbm/bbl 32 SAFE-CARB 40 Agent Concentration, lbm/bbl 340

NAF-Base Pill Formulation (Based on 0.81-Relative-Density Oil)

Density, lbm/galUS [relative density]NAF Volume, bblFORM-A-BLOK AS Pill Concentration, lbm/bblSAFE-CARB 40 Agent Concentration, lbm/bbl
Density, lbm/galUS [relative density] 9 [1.08] NAF Volume, bbl 0.86 FORM-A-BLOK AS Pill Concentration, lbm/bbl 30 SAFE-CARB 40 Agent Concentration, lbm/bbl 100
Density, lbm/galUS [relative density] 10 [1.20] NAF Volume, bbl 0.80 FORM-A-BLOK AS Pill Concentration, lbm/bbl 32 SAFE-CARB 40 Agent Concentration, lbm/bbl 160
Density, lbm/galUS [relative density] 12 [1.44] NAF Volume, bbl 0.68 FORM-A-BLOK AS Pill Concentration, lbm/bbl 32 SAFE-CARB 40 Agent Concentration, lbm/bbl 280
Density, lbm/galUS [relative density] 14 [1.68] NAF Volume, bbl 0.56 FORM-A-BLOK AS Pill Concentration, lbm/bbl 32 SAFE-CARB 40 Agent Concentration, lbm/bbl 397


Physical Properties 
Physical Properties Physical appearance   Gray powder
Physical Properties Relative density   2.50–2.60
Physical Properties Solubility in water   Insoluble
Physical Properties Solubility in 15% HCl <212 degF [100 degC]   92%–96%
Physical Properties Solubility in 5% HCl >212 degF [100 degC]   92%–96%

Toxicity and handling

Bioassay information is available upon request. Handle as an industrial chemical, wear protective equipment, and observe the precautions described in the material safety datasheet (SDS).

Packaging and storage

The FORM-A-BLOK AS pill is packaged in 32-lbm [14.5-kg] multiwell paper sacks. Store in a dry, well- ventilated area. Keep container closed when not in use. Store away from incompatibles. Follow safe warehousing practices regarding palletizing, banding, shrink-wrapping, and stacking.

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