E&Ps Posting Big Dean Wells at Midland’s Martin-Howard Border

Two tests in the tight-sand Dean Formation in Martin County, Texas, have produced more than 500,000 bbl for Diamondback Energy in their first 10 months online, according to Texas Railroad Commission data.

In adjacent Howard County, Occidental Petroleum and SM Energy are also reporting prolific Dean wells, Hart Energy analysis of RRC data shows.

The three E&Ps’ wells are targeting the Dean along the Martin-Howard border, south of the Dean hotspot in Dawson County that has produced more than 15 MMbbl through January in that new play’s first five years.

The Dawson-Dean volume, from 43 wells, ranges from 59 months old to four. The laterals average 2 miles, with output of more than 90% oil.

John Freeman, securities analyst for Raymond James, found that Diamondback’s overall Midland Basin productivity in 2024 had increased by 9% compared to 2023.

And the “Dean formation was a primary driver of the productivity increase,” he added.

The rock, which sits between Spraberry and Wolfcamp, contributed to Diamondback making the highest-return Midland Basin wells last year, along with ConocoPhillips, he wrote.

He also found that Oxy switched to landing more often in Dean rather than Jo Mill in 2024, contributing to 22% better wells than in 2023.

“More Dean—the most productive zone—and less Jo Mill, the least productive zone, was a nice recipe for better overall [Oxy] well performance,” he reported.

Dean in Martin County

Diamondback’s Dean wells have focused on eastern Martin County just across the Howard border from the SM Energy and Oxy wells.

Diamondback’s 12-well Grantham West 50-48 unit, with three wells in Dean, about 25 miles south of the Dawson hotspot, doesn’t include per-well production data in the RRC files.

But the unit made 1.6 MMbbl and 3.4 Bcf in its first 10 months online through January, the most recent month for which the RRC has published production data.

Each of the three Dean lateral wells is between 10,000 ft and 10,100 ft.

The other nine wells include two each in the Middle Spraberry, Lower Spraberry, Wolfcamp A and Wolfcamp B, along with one in Jo Mill.

Jo Mill sits between the Middle Spraberry and Lower Spraberry, while Dean sits between Lower Spraberry and Wolfcamp A.

Separately, Diamondback put two Dean wells in the seven-well Tomcat 23-24 development in Martin, north of Grantham West and nearer to the Dawson hotspot.

Of the total of 502,720 bbl from the two Dean wells beginning in April 2024, Tomcat C made 276,310 bbl and 331 MMcf of casinghead gas in its first 10 months through January from a 10,167-ft lateral, according to the RRC data.

Tomcat D made 226,410 bbl and 271 MMcf from a 10,134-ft lateral.

Dean in Howard County

SM reported IP’s earlier this month from two new Dean wells in western Howard County about 35 miles south of the Dawson Dean wells in its six-well Guitar North multi-formation development.

The other wells are one each in Jo Mill, Middle Spraberry, Lower Spraberry and Wolfcamp A.

In the Dean, Guitar North #2883DN IP’ed 1,805 bbl from a 10,156-ft lateral, according to the RRC file.

A second Dean well, Guitar North #2885DN IP’ed 1,451 bbl from a 10,352-ft lateral.

Nearby—and also in Howard County—Oxy’s 18-well Santana development near Big Springs (about 40 miles south of the Dean hotspot in Dawson) included four wells in the Dean that IP’ed between 1,162 bbl/d and 1,775 bbl/d each.

Oxy’s other wells included six in the Sprayberry and eight in the Wolfcamp A and B.

The Dean performance has held up in their first five years, beginning in 2000.

Santana #2430D made 325,000 bbl through January in its first 57 months online after IP’ing 1,162 bbl from a 10,876-ft lateral, according to RRC data.

Santana #2436D made 320,000 bbl after IP’ing 1,775 bbl from a 12,011-ft lateral.

The third well, Santana #2432D, made 340,000 bbl after IP’ing 1,727 from a 11,137-ft lateral.

More prolific, Santana #2938D made 760,000 bbl after IP’ing 1,343 bbl from a 12,500-ft lateral.

Through January, the 18-well package made 4.6 MMbbl and 15.1 Bcf, according to RRC data.

RELATED

Bernstein: Wells with IPs of 1,000 boe/d the ‘New Norm’

New core inventory

Raymond James’ Freeman found 32% of Dean acreage in the northern Midland is economic at $50/bbl oil and $2.50/Mcf gas, which is a price point he deems “core,” while 49% is profitable at $70/bbl and $3.50/Mcf.

The new Dean wells’ results are picking up where the heavily drilled Wolfcamp A and B inventory is losing after posting 67% of Midland Basin wells in 2019 but 47% in 2024, Freeman reported.

“As core inventory in the Wolfcamp A and B are increasingly played out, we expect operators to seek new core locations in the Wolfcamp C/D, Dean and Jo Mill, which have more fragmented acreage quality and offer less consistent returns.”

While Jo Mill is within the Sprayberry series, Wolfcamp C and D are deeper, underlying Spraberry, Dean and Wolfcamp A and B.