43 C.F.R. § 3179.71
(c) High-pressure flares requiring measurement must use either orifice plates and orifice meter tubes, or ultrasonic meters. High-pressure flare measurement systems must meet the following requirements:
(2) Ultrasonic metering systems must comply with the following requirements:
(d) The gas sample must be taken from one of the following locations when the high-pressure flare is measuring a single lease, unit PA, or CA:
(e) The gas sample must be taken from one of the following locations for a common high-pressure flare that measures more than one lease, unit PA, or CA;
(f) Appropriate meters must be installed at all high-pressure flares pursuant to paragraph (c) of this section, and gas sampling must be taken from the appropriate location pursuant to paragraphs (d) or (e) of this section according to the following phase-in timeline:
| Flare flow category | Deadline for measurement compliance for high-pressure flares and gas sampling location |
|---|---|
| ≥30,000 Mcf per month | December 10, 2024. |
| <30,000 Mcf per month and ≥6,000 Mcf per month | June 10, 2025. |
| <6,000 Mcf per month and ≥1,050 Mcf per month | December 10, 2026. |
| <1,050 Mcf per month | Not applicable. |
(g) For high-pressure flares with volumes less than 1,050 Mcf per month, the flared volume may be estimated, or measured. Estimated flared gas volumes must be based on production reported on the ONRR OGORs over the previous 6 months and calculated as follows:
Equation 1 to Paragraph (g)

Where: GORr = The gas-to-oil ratio for the previous 6 months of production as reported on the OGOR m = The previous 6 months of flaring Vg = The total volume of gas produced from oil wells in the previous 6 months as reported on the OGOR Vo = The total volume of oil produced from oil wells in the previous 6 months as reported on the OGOR
Equation 2 to Paragraph (g)
Vf = (Vop × GORr)−VLU−Vs
Where: Vf = The estimated gas flared from oil wells to be reported on the OGOR Vop = The total oil produced from oil wells while flaring GORr = The gas-to-oil ratio for the previous 6 months of production as calculated from Equation 1 to Paragraph (g) using volumes reported on the OGOR VLU = The total gas used on lease, unit PA, or CA pursuant to subpart 3178 Vs = The total gas volume produced and sent through a gas FMP from oil wells while flaring
(h) If a flare is combusting gas that is combined across multiple leases, unit PAs, or CAs, the operator may measure the gas at a single point at the flare and allocate flared volumes based on the oil production while flaring from each lease, unit PA, or CA as follows:
Equation 3 to Paragraph (h)

Where: n = The total number of leases, unit PAs, or CAs sending gas to a common flare VFi = The volume flared from the ith lease, unit PA, or CA sent to a common flare VFt = The total volume flared from a common flare Vopi = The total volume of oil produced from oil wells on the ith lease, unit PA, or CA while flaring
[89 FR 92605, Nov. 22, 2024, as amended at 90 FR 57923, Dec. 15, 2025]