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Preview the first 100 rows

What this is

The M-MONTH group of the OLA013K multi-well record: 51,982 rows, fourteen months for each of the 3,713 groups. Each row is the group's daily oil allowable for the month with the codes that say whether it was limited and what kind of group it was assigned to, the casinghead gas allowable beside it, and the two supplemental allowables a proration analyst can issue mid-month.

What you can do with it

Follow a waterflood unit's allowable through the cycle, including the supplements that changed it after the first of the month.

Gotchas

gas_allow is null where the tape carried all nines -- 'no limit', 6,318 of 51,982 rows.

The supplemental columns are all but unused on the current tape: oil_allow_2 and oil_allow_3 are zero in every row, so a supplement is something this tape records the shape of rather than the fact of.

acode and tcode are one two-digit code split in half -- the manual's Appendix D, which is not part of the record layout. The values in use are acode 0, 1 and 2 and tcode 0, 3, 5 and 7.

month_ordinal is a slot on a rolling tape. Filter on cycle_yyyymm.

Record layout

28 columns. Byte positions are 1-based and come from the RRC record layout, so you can check our decoding against the original file yourself.

`oil_ledger_multiwell_month` 28 columns

Record layout for `oil_ledger_multiwell_month` — 28 columns, with byte positions
#	Column	Type	Bytes	RRC name	Meaning	Lookup
1	`district` key join	text	2-4	`MULTI-W-REC-DIST`	RRC district of the multi-well group this month belongs to, in the ledger's spelling. e.g. 08	RRC district (proration ledger spelling)
2	`field_no` key join	integer	5-12	`MULTI-W-REC-FIELD`	Field number of the group.	—
3	`operator_no` key join	integer	13-18	`MULTI-W-REC-OPR`	P-5 number of the lease operator.	—
4	`lease_no` key join	integer	19-23	`MULTI-W-REC-LEASE`	The five-digit oil lease number.	—
5	`m_record` key	text	27-32	`M-RECORD`	The group's identifier within the lease, right-justified in six bytes. e.g. ' 1'	—
6	`month_ordinal` key	smallint	—	—	Which of the fourteen month slots in the multi-well record this row came from, 1 to 14, oldest first. A position on a rolling tape; cycle_yyyymm is the month itself. e.g. 14	—
7	`cycle_yyyymm`	integer	165-170	`M-MONTH-DATE`	The schedule month this row is for, CCYYMM. The August 2026 tape runs 202506 to 202607. e.g. 202607	—
8	`change`	smallint	171	`MM-CHG`	What changed this month: 1 field name, 2 operator name, 3 lease name, 4 well number, 6 a combination, 0 nothing.	—
9	`no_supp`	smallint	172	`MM-NO`	Whether the month's allowable supplement is trustworthy: 0 fine, 1 an asterisk was printed for an analyst to check, 2 it is the new month and no supplement is allowed. Zero throughout the current tape.	—
10	`oil_allow`	integer measured in bbl/d	173-176	`MM-ALLOW`	Daily oil allowable for the group from the first of the month, in barrels, until a supplement or the next month's schedule replaces it. Non-zero on 35,522 of 51,982 rows.	—
11	`acode`	text	177	`MM-ACODE`	Whether that allowable is limited and why: 0 not limited, 1 limited by test or potential (38,986 rows), 2 limited by the group's own previous production. Read together with tcode. e.g. 1	—
12	`tcode`	text	178	`MM-TCODE`	What kind of well group the allowable was assigned to: 0 prorated (40,092 rows), 3 marginal, 5 shut-in (7,409), 7 exempt from the production factor (4,077). If form_lacking is 1 the wells are shut in for a delinquent W-10. e.g. 0	—
13	`gas_allow`	integer measured in MCF/d	179-183	`MM-LIMIT`	Daily casinghead gas allowable for the group this month, in MCF. Null where the tape carried all nines, RRC's 'no limit': 6,318 of 51,982 rows.	—
14	`oil_allow_2`	integer measured in bbl/d	184-187	`MM-ALLOW2`	Daily oil allowable set by the month's first supplement, effective from date_2. Zero in every row of the August 2026 tape.	—
15	`acode_2`	text	188	`MM-ACODE2`	Limit code of the first supplemental allowable, same values as acode.	—
16	`tcode_2`	text	189	`MM-TCODE2`	Type code of the first supplemental allowable, same values as tcode.	—
17	`gas_allow_2`	integer measured in MCF/d	190-194	`MM-LIMIT2`	Daily gas allowable set by the first supplement, in MCF.	—
18	`date_2`	smallint	195-196	`MM-DATE2`	Day of the month the first supplement took effect, 1 to 31.	—
19	`oil_allow_3`	integer measured in bbl/d	197-200	`MM-ALLOW3`	Daily oil allowable set by the month's second supplement, effective from date_3. Zero in every row of the current tape.	—
20	`acode_3`	text	201	`MM-ACODE3`	Limit code of the second supplemental allowable.	—
21	`tcode_3`	text	202	`MM-TCODE3`	Type code of the second supplemental allowable.	—
22	`gas_allow_3`	integer measured in MCF/d	203-207	`MM-LIMIT3`	Daily gas allowable set by the second supplement, in MCF.	—
23	`date_3`	smallint	208-209	`MM-DATE3`	Day of the month the second supplement took effect.	—
24	`form_lacking`	smallint	210	`MM-FORM-LCK`	1 when a W-10 for this group is delinquent, which shuts the wells in. Zero in every row of the August 2026 tape.	—
25	`potential`	integer measured in bbl/d	211-214	`MM-SPACE1`	Combined potential of the wells in the group -- the most they could produce together, in barrels per day. Non-zero on 39,015 rows.	—
26	`kode_2`	smallint	215	`MM-KODE2`	An item the manual records as no longer used. Zero throughout.	—
27	`gor`	integer measured in cf/bbl	216-219	`MM-SPACE2`	Gas-oil ratio of the wells in the group, in cubic feet per barrel. Non-zero on 126 rows of 51,982.	—
28	`change_status_code`	smallint	220	`MM-JOHN`	1 when the group's allowable was changed this month.	—

Code lookups used here

Every coded column in this dataset resolves to a real lookup table, so a well code of G can be read as what it actually means.

RRC district (proration ledger spelling) 14 values

Read by district

The district as the oil and gas proration ledger tapes write it, which is NOT how the rest of the corpus writes it. The ledger pads the lettered districts to three bytes -- 06E, 07B, 07C, 08A -- where the W-10, the G-10 and PDQ's district_name write 6E, 7B, 7C and 8A. That difference is worth a code set of its own because it is invisible in a join: a query matching ledger.district against w10.district returns rows for the ten numeric districts and silently drops the four lettered ones, which are 24% of the oil ledger's wells. Strip the leading zero before joining, or add it coming the other way. `canonical_value` is the internal district number, the same convention rrc.district uses, so a ledger district resolves to the same district in either numbering.

RRC district (proration ledger spelling) — 14 codes and their meanings
Code	Means
`01`	District 01 — San Antonio Written 01 here and 01 elsewhere.
`02`	District 02 — San Antonio Written 02 here and 02 elsewhere.
`03`	District 03 — Houston Written 03 here and 03 elsewhere.
`04`	District 04 — Corpus Christi Written 04 here and 04 elsewhere.
`05`	District 05 — Kilgore Written 05 here and 05 elsewhere.
`06`	District 06 — Kilgore Written 06 here and 06 elsewhere.
`06E`	District 6E — Kilgore The ledger writes 06E; the W-10 and PDQ write 6E.
`07B`	District 7B — Abilene The ledger writes 07B; the W-10 and PDQ write 7B.
`07C`	District 7C — San Angelo The ledger writes 07C; the W-10 and PDQ write 7C.
`08`	District 08 — Midland Written 08 here and 08 elsewhere.
`08A`	District 8A — Midland The ledger writes 08A; the W-10 and PDQ write 8A.
`08B`	District 8B — reserved The manuals list 08B as reserved for future use. No record of any ledger tape has ever carried it.
`09`	District 09 — Wichita Falls Written 09 here and 09 elsewhere.
`10`	District 10 — Pampa Written 10 here and 10 elsewhere.

Source: RRC manuals OLA013K, GSA020K and OLA028K (DIST/DIST-NO items); the thirteen spellings in use confirmed as the complete distinct set in texas.oil_ledger_field, texas.oil_ledger_well and texas.oil_detail_well on 2026-08-21

What this joins to

The Railroad Commission never states these keys anywhere in the files. They are the reason the data is hard to use, so here they are with the exact columns on both sides.

Oil Ledger — Multi-Well Group Months joins to Oil Ledger — Multi-Well Groups on District and Field number and Operator number and Lease number and M record — many rows here share a single row there.

has fourteen months of allowable

The M-MONTH group of the multi-well record. All 3,000 sampled groups match. Both sides carry m_record right-justified in six bytes, which is why this one joins on it and the join to the detail-well tape does not.

oil-ledger-multiwell-groups.district = oil-ledger-multiwell-months.district AND oil-ledger-multiwell-groups.field_no = oil-ledger-multiwell-months.field_no AND oil-ledger-multiwell-groups.operator_no = oil-ledger-multiwell-months.operator_no AND oil-ledger-multiwell-groups.lease_no = oil-ledger-multiwell-months.lease_no AND oil-ledger-multiwell-groups.m_record = oil-ledger-multiwell-months.m_record

Where this comes from

Published by

Texas Railroad Commission — the original page

Original format

EBCDIC IBM mainframe encoding (cp037). Opening it as text gives you nonsense; it has to be transcoded first.

RRC publishes

Updated once a month (Monthly, with the oil ledger.)

RRC download link

GoAnywhere MFT

Record layout manual

OLA013K — Oil Ledger — Record Layout

Our table

texas.oil_ledger_multiwell_month

EZRRC is an independent mirror of public-domain data published by the Texas Railroad Commission. It is not affiliated with or endorsed by the RRC. For any legal or regulatory purpose, verify against the official RRC release.