40 CFR Appendix 8 to Subpart A of Part 435 - Appendix 8 to Subpart A of Part 435—Reference C16–C18 Internal Olefin Drilling Fluid Formulation
The reference C16–C18 internal olefin drilling fluid used to determine the drilling fluid sediment toxicity ratio and compliance with the BAT sediment toxicity discharge limitation (see § 435.13) and NSPS (see § 435.15) shall be formulated to meet the specifications in Table 1 of this appendix.
Drilling fluid sediment toxicity ratio = 4-day LC5. of C16-C18 internal olefin drilling fluid/4-day LC5. of drilling fluid removed from drill cuttings at the solids control equipment as determined by EPA Method 1644: “Method for Conducting a Sediment Toxicity Test with Leptocheirus plumulosus and Non-Aqueous Drilling Fluids or Synthetic-Based Drilling Muds” after sediment preparation procedures specified in EPA Method 1646, which are published as appendices to Subpart A of this part and in “Analytic Methods for the Oil and Gas Extraction Point Source Category,” EPA–821–R–11–004. See § 435.11(ee) and (uu).
Table 1—Properties for Reference C16–C18 IOs SBF Used in Discharge Sediment Toxicity Testing
| Mud weight of SBF discharged with cuttings (pounds per gallon) | Reference C16–C18 IOs SBF (pounds per gallon) | Reference C16–C18 IOs SBF synthetic to water ratio (%) |
|---|---|---|
| 8.5–11 | 9.0 | 75/25 |
| >11–14 | 11.5 | 80/20 |
| >14 | 14.5 | 85/15 |
| Plastic Viscosity (PV), centipoise (cP) | 12–30 | |
| Yield Point (YP), pounds/100 sq. ft | 10–20 | |
| 10-second gel, pounds/100 sq. ft | 8–15 | |
| 10-minute gel, pounds/100 sq. ft | 12–30 | |
| Electrical stability, V | >300 |