D-Grade Self-Destructive Bridging Agent | Schlumberger

D-Grade

Self-destructive bridging agent

Applications

  • Self-destructive fluid loss control pills for completion or intervention operations
  • Tunable, extralong-delay filtercake breaker for moderate temperatures

How it improves wells

  • Offers various size options for blending
  • Easily mixes into the fluid system

How it works

D-Grade self-destructive bridging agent is a versatile additive that can be used both in self-degradable fluid loss pills and filtercake breakers. With sufficient temperature, D-Grade agent reacts with the aqueous phase and dissolves itself, thereby releasing acid that will destroy nearby filtercake components and eliminate the need for postplacement cleanup.

This agent is used in self-degrading fluid loss control pills to provide primary fluid loss control for a desired period of time. D-Grade agent is ground to specific sizes to act as a bridging agent. With an optimized blend of particles, fluid loss control is minimized.

As a bridging solid, concentrations of D-Grade agent range from 10 to more than 70 lbm/bbl [28.5–200 kg/m3], depending on the application. D-Grade agent is available with various particle size distributions. The optimum blend of D-Grade agent sizes is determined using OPTIBRIDGE bridging agent selection software, and fluid loss is optimized in the laboratory.

D-Grade agent is also used as an internal breaker in the D-Link self-dissolving fluid loss control pill at concentrations between 1 to 10 lbm/bbl [2.9 to 28.5 kg/m3].

As a filtercake breaker, the agent is used at concentrations of 15 to 100 lbm/bbl [42.8 to 285 kg/m3], depending on the breakthrough time required and composition of reservoir drill-in fluid. SAFE-VIS E liquid polymer fluid loss control additive at 0.5 to 2.0 lbm/bbl [1.4 to 5.7 kg/m3] is required to suspend solids for filtercake breaker applications.

Degradation time of D-Grade agent will vary depending on the base fluid, density, and bottomhole temperature.

Limitations

  • Agent degrades rapidly above 220 degF [104 degC] and may not activate below 170 degF [77 degC]
  • Dissolution time is dependent on base fluid and temperature; lab testing required to confirm delay
  • Corrosion inhibitor is recommended when used as a breaker
 
Typical Physical Properties
Physical appearance Solid
Odor Sweetish
Specific gravity 1.20 to 1.25
 
Product Name Median Particle Size (D50), um Recommended Test Procedure
D-Grade 4 agent 2–5 Laser light scattering
D-Grade 10 agent 6–15 Laser light scattering
D-Grade 20 agent 12–25 Laser light scattering
D-Grade 40 agent 31–48
Laser light scattering
D-Grade 100 agent
90–110
Laser light scattering
D-Grade 250 agent
225–275
Dry sieve analysis

Toxicity and handling

Bioassay information is available on request. Handle as an industrial chemical, wearing protective equipment and observing the precautions as described in the SDS.

Packaging and storage

D-Grade agent is packaged in 50-lbm [22.7-kg] paper sacks. Store in a dry, well-ventilated area. Keep container closed. Keep away from heat, sparks, and flames. Store away from incompatibles. Follow safe warehousing practices regarding palletizing, banding, shrink-wrapping, or stacking.

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