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v3.25.3

Supplementary Information for Exploration and Production Activities - Proved Developed and Undeveloped Oil and Gas Reserve Quantities (Details) Bcf in Thousands | 12 Months Ended |
--- | --- | ---
Sep. 30, 2025 Bcf MBbls MMcf | Sep. 30, 2024 Bcf MBbls MMcf | Sep. 30, 2023 MMcf MBbls Bcf | Sep. 30, 2022 MBbls MMcf
Proved Developed and Undeveloped Reserves [Roll Forward] |  |  |  |  |
Proved undeveloped reserve volume | Bcf |  | 1,316,000,000 | 1,267,000,000 | 985,000,000 |
Marcellus Shale Fields |  |  |  |  |
Proved Developed and Undeveloped Reserves [Roll Forward] |  |  |  |  |
Proved undeveloped reserve volume | Bcf |  | 197,000,000 | 342,000,000 | 112,000,000 |
Marcellus Shale Fields | Gas MMcf |  |  |  |  |
Proved Developed and Undeveloped Reserves [Roll Forward] |  |  |  |  |
Extensions and Discoveries | Bcf |  | 0 | 230 | 163 |
Production |  | (209,379) | (235,955) | (190,290) |
Percentage exceeding total reserve of production in proved developed and undeveloped reserves |  | 15.00% |  |  |
Utica Shale |  |  |  |  |
Proved Developed and Undeveloped Reserves [Roll Forward] |  |  |  |  |
Proved undeveloped reserve volume | Bcf |  | 1,119,000,000 | 925,000,000 | 873,000,000 |
Utica Shale | Gas MMcf |  |  |  |  |
Proved Developed and Undeveloped Reserves [Roll Forward] |  |  |  |  |
Extensions and Discoveries | Bcf |  | 633 | 372 | 507 |
Production |  | (215,681) | (154,701) | (180,750) |
Percentage exceeding total reserve of production in proved developed and undeveloped reserves |  | 15.00% |  |  |
Appalachian Region | Gas MMcf |  |  |  |  |
Proved Developed and Undeveloped Reserves [Roll Forward] |  |  |  |  |
Proved Developed and Undeveloped Reserves, Beginning of Period |  | 4,751,762 | 4,535,084 | 4,170,662 |
Extensions and Discoveries | [1] | 632,536 | 601,679 | 670,438 |
Revisions of Previous Estimates |  | 22,469 | 7,046 | 32,379 |
Production | [2] | (426,357) | (392,047) | (372,271) |
Purchases of Minerals in Place |  |  |  | 33,876 |
Proved Developed and Undeveloped Reserves, End of Period |  | 4,980,410 | 4,751,762 | 4,535,084 |
Proved developed reserves volume |  | 3,664,381 | 3,484,852 | 3,550,034 | 3,312,568
Proved undeveloped reserve volume |  | 1,316,029 | 1,266,910 | 985,050 | 858,094
Appalachian Region | Oil Mbbl |  |  |  |  |
Proved Developed and Undeveloped Reserves [Roll Forward] |  |  |  |  |
Proved Developed and Undeveloped Reserves, Beginning of Period | MBbls |  | 193 | 216 | 250 |
Extensions and Discoveries | MBbls |  | 0 | 0 | 0 |
Revisions of Previous Estimates | MBbls |  | 15 | 8 | (4) |
Production | MBbls |  | (28) | (31) | (30) |
Purchases of Minerals in Place | MBbls |  |  |  | 0 |
Proved Developed and Undeveloped Reserves, End of Period | MBbls |  | 180 | 193 | 216 |
Proved developed reserves volume | MBbls |  | 180 | 193 | 216 | 250
Proved undeveloped reserve volume | MBbls |  | 0 | 0 | 0 | 0
[1] | Extensions and discoveries include 163 Bcf (during 2023), 230 Bcf (during 2024) and 0 Bcf (during 2025), of Marcellus Shale gas (which exceed 15% of total reserves) in the Appalachian region. Extensions and discoveries include 507 Bcf (during 2023), 372 Bcf (during 2024) and 633 Bcf (during 2025), of Utica Shale gas (which exceed 15% of total reserves) in the Appalachian region.
[2] | Production includes 190,290 MMcf (during 2023), 235,955 MMcf (during 2024) and 209,379 MMcf (during 2025), from Marcellus Shale fields. Production includes 180,750 MMcf (during 2023), 154,701 MMcf (during 2024) and 215,681 MMcf (during 2025), from Utica Shale fields.

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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Definition Additions to proved reserves that result from (1) extension of the proved acreage of previously discovered (old) reservoirs through additional drilling in periods after discovery and (2) discovery of new fields with proved reserves or of new reservoirs of proved reserves in old fields. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Form 20-F -Number Part II -Section Item 18 -Subparagraph (Instruction 2) -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 55 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477916/932-235-55-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-8 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-3 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-8 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-5 + Details
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- Definition The net quantity of proved reserves as of the balance sheet date. Proved oil reserves are the estimated quantities of crude oil and natural gas liquids which geological and engineering data demonstrate with reasonable certainty to be recoverable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Form 20-F -Number Part II -Section Item 18 -Subparagraph (Instruction 2) -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 55 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477916/932-235-55-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-8 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-3 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-8 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-4 + Details
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- Definition Production of proved reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Form 20-F -Number Part II -Section Item 18 -Subparagraph (Instruction 2) -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 55 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477916/932-235-55-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-8 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-3 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-8 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-5 + Details
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- Definition Revisions represent changes in previous estimates of proved reserves, either upward or downward, resulting from new information (except for an increase in proved acreage) normally obtained from development drilling and production history or resulting from change in economic factors. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Form 20-F -Number Part II -Section Item 18 -Subparagraph (Instruction 2) -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 55 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477916/932-235-55-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-8 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-3 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-8 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-5 + Details
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- Definition Net quantities of an enterprise's interests in proved developed reserves of either crude oil (including condensate and natural gas liquids), natural gas, synthetic oil and gas, or other nonrenewable natural resource that is intended to be upgraded into synthetic oil and gas as of the beginning and the end of the year. "Net" quantities of reserves include those relating to the enterprise's operating and nonoperating interests in properties. Quantities of reserves relating to royalty interests owned are included in "net" quantities if the necessary information is available to the enterprise. "Net" quantities does not include reserves relating to interests of others in properties owned by the enterprise. The unit of measure for reserve quantities is defined as "barrels" for oil and synthetic oil reserves or "cubic feet" or "cubic meters" for natural gas and synthetic gas reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Form 20-F -Number Part II -Section Item 18 -Subparagraph (Instruction 2) -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 55 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477916/932-235-55-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-8 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-3 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 8 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-8 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 932 -SubTopic 235 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477215/932-235-50-4 + Details
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