Texas oil lease · RRC district 04 · Lease 13743
ProducingVANCO
Vanco is an oil lease in Duval County, Texas, operated by Rattlesnake Operating Co, LLC in the Lopez, North (Lopez) field. The Railroad Commission shows 450 bbl of oil in the 12 months through Jul 2026.
Oil lease dossier · 9 wells
- Operator
- Rattlesnake Operating Co, LLC
- County
- Duval County
- Field
- Lopez, North (Lopez)
- RRC lease
- 04-13743
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Where it sits
This county
- Oil in Jul 2026
- 13 bbl
- Reporting to the state
- since Jan 2020
- Wells
- 9
- Data through
- Jul 2026
Production
Month by month, from the state record
Oil output fell 59% over the last 12 months
450 bbl in the 12 months through Jul 2026, against 1,092 bbl in the 12 months before.
- Oil (bars, left axis)
- Last 12 months
SourceTexas Railroad Commission Production Data Query, oil lease 13743, district 04. Reported through Jul 2026. The state revises recent months.
Gas disposition
Where the gas went
No gas disposition reported for this lease
Operator history
Who has run this lease
The operator changed 2 times, most recently in Oct 2025
If your statements skip or shrink around a change, ask the new operator's owner relations department whether the month is in suspense.
- Rattlesnake Operating Co, LLC Oct 2025 to now
- Jalapeno Operating Company, LLC Jun 2023 to Sep 2025
- Dallas Petroleum Group, LLC Jan 2020 to May 2023
SourceTexas Railroad Commission Production Data Query, operator by month. Reported through Jul 2026.
Wells
9 wells on this lease
| API number | Well no. | Status | Total depthft |
|---|---|---|---|
| 42-131-39284 | 1 | Shut-in | – |
| 42-131-39292 | 3 | Shut-in | – |
| 42-131-39295 | 6 | Shut-in | – |
| 42-131-39297 | 8 | Active | – |
| 42-131-39298 | 9 | Shut-in | – |
| 42-131-39378 | 14 | Active | – |
| 42-131-39416 | 15 | Shut-in | – |
| 42-131-39417 | 16 | Shut-in | – |
| 42-131-39419 | 18 | Shut-in | – |
SourceTexas Railroad Commission Wellbore Query, district 04, lease 13743.
Who buys and gathers
Who moves and buys this lease's production
Oil
Gulfmark Energy, Inc. gathers it.
100% of it, on the list since Oct 13, 2025
Companies that used to be listed: Genesis Crude Oil, L.p. (gathers it, until Oct 13, 2025); Gulfmark Energy, Inc. (gathers it, until Oct 13, 2025); Genesis Crude Oil, L.p. (gathers it, until Jun 1, 2023).
SourceRailroad Commission of Texas, Form P-4 file, dated Sep 24, 2026 (source). A listed company is authorised to move or buy the production; the state does not say what it paid.
Unit and wells
1,210 acres on the newest permit
- Wells on the permits
- 98 not plugged
- Horizontal
- 0
- First completion
- Aug 6, 2012
- Latest permit
- Aug 6, 2013
9 wells are listed on this lease
Each well can have its own unit. The decimal for one well does not have to equal the decimal for another.
| API number | Well no. | Permit issued | Completed | Acreson the permit |
|---|---|---|---|---|
| 42-131-39419 | 18 | Aug 6, 2013 | Oct 10, 2013 | 1,210 |
| 42-131-39416 | 15 | Jul 29, 2013 | Oct 12, 2013 | 1,210 |
| 42-131-39417 | 16 | Jul 29, 2013 | Oct 7, 2013 | 1,210 |
| 42-131-39378 | 14 | May 3, 2013 | Jun 20, 2013 | 1,210 |
| 42-131-39292 | 3 | Jun 11, 2012 | Jun 5, 2013 | 1,210 |
| 42-131-39295 | 6 | Jun 11, 2012 | Aug 14, 2012 | 1,210 |
| 42-131-39297 | 8 | Jun 11, 2012 | Aug 6, 2012 | 1,210 |
| 42-131-39298 | 9 | Jun 11, 2012 | Oct 17, 2012 | 1,210 |
| 42-131-39284 | 1 | May 29, 2012 | Aug 9, 2012 | 1,210 |
Estimator
Estimate your royalty for this lease
Estimator
What could your check be?
Your decimal interest is the small number on your division order that says what share of the whole lease (8/8ths) is yours. Type it in and we apply it to what the state says VANCO sold each month.
For example 0.00097656, or a fraction like 1/1024.
Dollars per barrel. Your statements show the gap your operator uses. Leave 0 to price oil at WTI.
Your estimate appears here
An estimate, not your check
Ledger
36 months, newest first
| Month | Oil producedbbl | Oil soldbbl | WTI$ per bbl | Henry Hub$ per MMBtu |
|---|---|---|---|---|
| Jul 2026Rattlesnake Operating | 13 | 0 | $80.46 | $2.89 |
| Jun 2026Rattlesnake Operating | 11 | 0 | $84.81 | $3.15 |
| May 2026Rattlesnake Operating | 11 | 0 | $102.13 | $2.94 |
| Apr 2026Rattlesnake Operating | 12 | 0 | $100.32 | $2.77 |
| Mar 2026Rattlesnake Operating | 15 | 0 | $91.38 | $3.04 |
| Feb 2026Rattlesnake Operating | 15 | 0 | $64.51 | $3.62 |
| Jan 2026Rattlesnake Operating | 51 | 87 | $60.04 | $7.72 |
| Dec 2025Rattlesnake Operating | 137 | 154 | $57.97 | $4.26 |
| Nov 2025Rattlesnake Operating | 150 | 156 | $60.06 | $3.79 |
| Oct 2025Rattlesnake Operating | 18 | 0 | $60.89 | $3.19 |
| Sep 2025Jalapeno Operating | 0 | 0 | $63.96 | $2.97 |
| Aug 2025Jalapeno Operating | 17 | 0 | $64.86 | $2.91 |
| Jul 2025Jalapeno Operating | 80 | 156 | $68.39 | $3.20 |
| Jun 2025Jalapeno Operating | 0 | 0 | $68.17 | $3.02 |
| May 2025Jalapeno Operating | 0 | 0 | $62.17 | $3.12 |
| Apr 2025Jalapeno Operating | 0 | 0 | $63.54 | $3.42 |
| Mar 2025Jalapeno Operating | 95 | 122 | $68.24 | $4.12 |
| Feb 2025Jalapeno Operating | 129 | 0 | $71.53 | $4.19 |
| Jan 2025Jalapeno Operating | 115 | 137 | $75.74 | $4.13 |
| Dec 2024Jalapeno Operating | 157 | 132 | $70.12 | $3.01 |
| Nov 2024Jalapeno Operating | 127 | 302 | $69.95 | $2.12 |
| Oct 2024Jalapeno Operating | 135 | 0 | $71.99 | $2.20 |
| Sep 2024Jalapeno Operating | 124 | 171 | $70.24 | $2.28 |
| Aug 2024Jalapeno Operating | 130 | 154 | $76.68 | $1.99 |
| Jul 2024Jalapeno Operating | 110 | 0 | $81.80 | $2.07 |
| Jun 2024Jalapeno Operating | 60 | 150 | $79.77 | $2.54 |
| May 2024Jalapeno Operating | 117 | 164 | $80.02 | $2.12 |
| Apr 2024Jalapeno Operating | 245 | 159 | $85.35 | $1.60 |
| Mar 2024Jalapeno Operating | 135 | 169 | $81.28 | $1.49 |
| Feb 2024Jalapeno Operating | 84 | 0 | $77.25 | $1.72 |
| Jan 2024Jalapeno Operating | 151 | 156 | $74.15 | $3.18 |
| Dec 2023Jalapeno Operating | 80 | 147 | $71.90 | $2.52 |
| Nov 2023Jalapeno Operating | 117 | 46 | $77.69 | $2.71 |
| Oct 2023Jalapeno Operating | 107 | 138 | $85.64 | $2.98 |
| Sep 2023Jalapeno Operating | 127 | 155 | $89.43 | $2.64 |
| Aug 2023Jalapeno Operating | 50 | 52 | $81.39 | $2.58 |
No report filed More than 3% of gas flared
SourceVolumes: Texas Railroad Commission Production Data Query, reported through Jul 2026. Prices: EIA WTI Cushing spot and Henry Hub spot, monthly, through Aug 2026. “Gas sold” is gas sent to a transmission line (code 2) or a plant (code 3).
Check your statements
Do your checks match this lease?
Upload your statements for VANCO. We compare volumes, prices, deductions and timing with the state record and give you the exact question to ask Rattlesnake Operating Co, LLC.
- A month that was never paid
- Your share of the barrels and mcf
- The price against WTI and Henry Hub
- Fees taken on gas
- Late payment interest
Around this lease
Walk the neighborhood
This lease belongs to
Rattlesnake Operating Co, LLC in Duval County
- SANTERRA
2,200 bbl last 12 months
- WIEDERKEHR 365
10,778 mcf last 12 months
- PETERS A 1721
1,191 mcf last 12 months
- PETERS A 1703
1,184 mcf last 12 months
- PETERS A 1721
1,149 mcf last 12 months
Lopez, North (Lopez) field
- SANTERRA
2,200 bbl last 12 months
- DUVAL CO. RANCH CO. -C-
918 bbl last 12 months
- DCRC SECTION 194
658 bbl last 12 months
- LOPEZ
166 bbl last 12 months
Leases within 10 km
Found by the location of their wells.
- SANTERRA
2,200 bbl last 12 months · 1 km away
- LOPEZ
166 bbl last 12 months · 1.9 km away
- DUVAL CO. RANCH CO. -C-
918 bbl last 12 months · 2.9 km away
- PEAL, J B
37,073 mcf last 12 months · 3 km away
- PETERS A 1703
0 mcf last 12 months · 3.1 km away
Drilling permits within 10 km
KILLAM FREER RANCH '196' #15
new drill · Killam Oil Co., Ltd. · Duval County · 5.7 km away
Permit 0897715 · Mar 4, 2024
DCR 590 #2
new drill · Killam Oil Co., Ltd. · Duval County · 6.8 km away
Permit 0895105 · Nov 14, 2023
DCR 590 #3
new drill · Killam Oil Co., Ltd. · Duval County · 6.5 km away
Permit 0894622 · Oct 24, 2023
How to read this page
Questions owners ask
What is a decimal interest?
It is your share of the whole lease, written as a decimal. A 1/4 royalty on 5 net acres in a 1,280-acre unit is 1/4 × 5 ÷ 1,280 = 0.00097656. Your division order states yours.
How do I use this page to check a royalty check?
Take the “Oil sold” volume for the month the check covers and multiply it by your decimal. The answer should match the barrels on your statement. If it does not, upload the statement and we will show where the two differ.
Why is the newest month Jul 2026?
The Railroad Commission publishes production two to three months after the fact and revises recent months. We re-pull the latest three months on every update.
Does this page show what my check should be?
No. It shows what the state recorded. Prices, fees and taxes depend on your lease and on what your operator gets for the oil and gas. The estimator gives a ceiling to compare against.
Sources and method
Where these numbers come from
- Production and disposition by month: Texas Railroad Commission Production Data Query, oil lease 13743, district 04, reported through Jul 2026.
- Wells: Texas Railroad Commission Wellbore Query.
- Prices: U.S. Energy Information Administration, WTI Cushing spot and Henry Hub spot, monthly.
- Page updated Sep 28, 2026.
We show the state’s numbers as filed. Where the state has no report for a month, we say so instead of guessing.