BROWNLEE-COOK 127

Oil · District 10 · Lease #8428

Operator: HIGHMARK ENERGY OPERATING, LLC

Cum Oil

301k BBL

Cum Gas

1.7M MCF

casinghead

Wells

4

Production

2010-09 — 2026-04

Peak Month

2011-03

Production History

Cum Oil: 300,998 BBL Cum Gas: 1,678,302 MCF

RRC production reported through Apr 2026 · recent months incomplete

Decline Curve Analysis

qi

26,104 BBL/mo

Di (annual)

458.8%

b-factor

0.8

EUR

249,588 BBL

R-squared

0.902

type

hyperbolic

Operator History (from monthly production reports)

2022-02 — 2026-07 HIGHMARK ENERGY OPERATING, LLC 54 mo
2010-09 — 2022-01 EOG RESOURCES, INC. 137 mo

Wells (4)

WELL#APIOPERATORPERMITSDEPTHLAST_ISSUED
5HHIGHMARK ENERGY OPERATING, LLC19,0002010-06-18
3HHIGHMARK ENERGY OPERATING, LLC19,0002010-06-17
4HHIGHMARK ENERGY OPERATING, LLC19,0002010-06-17
2HHIGHMARK ENERGY OPERATING, LLC19,0002010-03-04