TOM OCONNOR (4400), District 02, Texas

A field is the Railroad Commission's unit of geology and of regulation. Its spacing rule is what decides how many wells an acreage can hold.

Leases
33
with a page here
Operators
3
Value, all time
$275.1 M
46% of the register's 71
Discovered
1955-12-27
Oil and gas

Our estimate: volumes the operator filed with the Commission, valued at the EIA first-purchase price for that month. It is not a payment anyone received, and it is not a royalty. It sums the 33 leases in this field that have a page here — 46% of the register's 71 — so it understates the field.

Production, 2025

The Railroad Commission's Oil and Gas Annual Report for 2025, its most recent. These are the state's figures for the whole field, not ours.

WellsIn the fieldProducingProduced in 2025Also producedCumulative
Oil6225107,686 bbl6,215 mcfcasinghead18,998,106 bblsince discovery
Gas000 mcf0 bblcondensate52,052,256 mcfsince 1970

The discovery well's oil measured 23.0° API gravity, perforated at 4,400 ft.

Spacing rule

What the Commission requires of a well on this field.

WellsRuleEffectiveFrom the lease lineBetween wellsAcres per unitMax diagonal
GasB2005-05-10150 ft300 ft100 ft
OilB2005-05-10150 ft300 ft100 ft

Commission remarks: AND FIELD CLASSIFIED AS SALVAGE.

County

Leases in this field

Every lease here files this field's number with the Commission and has a page on this site.

LeaseOperatorValue
LAMBERT, M. F.HILCORP ENERGY COMPANY$92.7 M
HEARD, CLAUDE E. ET ALHILCORP ENERGY COMPANY$46.8 M
MELLON OIL UNITT-C OIL COMPANY, LLC$33.7 M
LAMBERT, M. F.HILCORP ENERGY COMPANY$28.3 M
TOM OCONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$10.3 M
TOM OCONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$8.1 M
TOM OCONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$6.5 M
TOM OCONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$6.2 M
TOM O'CONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$5.9 M
TOM OCONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$5.8 M
TOM OCONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$4.6 M
TOM O'CONNOR 440 SAND GAS UNITHILCORP ENERGY COMPANY$4.2 M
TOM O'CONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$4.0 M
TOM O'CONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$2.9 M
LAMBERT E, M.F.HILCORP ENERGY COMPANY$2.6 M
TOM O'CONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$2.4 M
HEARD, IRA "B"HILCORP ENERGY COMPANY$2.1 M
TOM O'CONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$1.7 M
TOM O'CONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$1.7 M
TOM O'CONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$1.3 M
TOM OCONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$1.0 M
TOM O'CONNOR 4400 SAND GAS UNITHILCORP ENERGY COMPANY$773 k
HEARD, CLEMENTHILCORP ENERGY COMPANY$511 k
THOMAS O'CONNOR 'C'HILCORP ENERGY COMPANY$392 k
IRA HEARD 'A'HILCORP ENERGY COMPANY$228 k
HEARD, FANNIE V. W. MRS.HILCORP ENERGY COMPANY$119 k
OCONNOR, THOMAS, -A-HILCORP ENERGY COMPANY$93 k
CLEMENT HEARDHILCORP ENERGY COMPANY$69 k
WILLIAMS, MAUDE, ETAL -B-HILCORP ENERGY COMPANY$47 k
WILSON HEARD "A"HILCORP ENERGY COMPANY$47 k
TOM OCONNOR 4400 SAND GAS UNITQUINTANA PET. CORP.$34 k
O'CONNOR, TOM 4400 SAND GAS UNITHILCORP ENERGY COMPANY$14 k
TOM OCONNOR 4400 SAND GAS UNITQUINTANA PET. CORP.

Field number 90534325, from the Railroad Commission's field register. The register's own index resolves 71 leases and 224 wells to this field by name, over every lease in Texas rather than only those with a page here. It resolves a lease by NAME and refuses an ambiguous one, so it counts nothing for a field that shares its name with another — which is why the lease count above comes from the field number instead.