KEYSTONE CATTLE CO.

Oil · District 08 · Lease #8745

Operator: PENNZOIL PETROLEUM COMPANY

Cum Oil

360k BBL

Cum Gas

1.3M MCF

casinghead

Wells

10

Production

1993-01 — 2026-04

Peak Month

1993-11

Production History

Cum Oil: 360,024 BBL Cum Gas: 1,341,190 MCF

RRC production reported through Apr 2026 · recent months incomplete

Decline Curve Analysis

qi

2,100 BBL/mo

Di (annual)

18.5%

b-factor

1.2

EUR

351,321 BBL

R-squared

0.303

type

hyperbolic

Operator History (from monthly production reports)

2023-03 — 2026-07 HIGHMARK ENERGY OPERATING, LLC 41 mo
2008-05 — 2023-02 LEGACY RESERVES OPERATING LP 178 mo
2000-04 — 2008-04 DEVON ENERGY PRODUCTION CO, L.P. 97 mo
1999-03 — 2000-03 PENNZENERGY EXP. & PROD., L.L.C. 13 mo
1995-02 — 1999-02 PENNZOIL EXPLORATION & PROD. CO. 49 mo
1993-01 — 1995-01 PENNZOIL PETROLEUM COMPANY 25 mo

Wells (10)

WELL#APIOPERATORPERMITSDEPTHLAST_ISSUED
213HIGHMARK ENERGY OPERATING, LLC311,7772017-06-12
192HIGHMARK ENERGY OPERATING, LLC210,5352017-04-10
362HIGHMARK ENERGY OPERATING, LLC510,9002009-07-09
377HIGHMARK ENERGY OPERATING, LLC39,9502009-01-16
378 HHIGHMARK ENERGY OPERATING, LLC210,0001990-08-22
135D42-495-01289HIGHMARK ENERGY OPERATING, LLC------
17442-495-01326HIGHMARK ENERGY OPERATING, LLC------
17542-495-01327HIGHMARK ENERGY OPERATING, LLC------
21742-495-01365HIGHMARK ENERGY OPERATING, LLC------
31342-495-30099HIGHMARK ENERGY OPERATING, LLC------