Company lists · Data refreshed September 2026

Top 25 Petroleum engineering firms based in the United States

Name: Petroleum engineering firms based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 17, 2026 1,462 companies tracked

RevenueBase identified 1,462 petroleum engineering firms headquartered in the United States as of September 2026 and tracks 107,706 professional contacts across them, including 31,269 with verified work emails. Houston is the largest hub.

This list covers petroleum engineering firms headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 17, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 17, 2026 86% judged on-target in blind review

1,462Companies

107,706Contacts tracked

31,269Verified emails

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The 25 largest petroleum engineering firms based in the United States

Ranked by team size

Top 25 of 1,462 petroleum engineering firms based in the United States, ranked by team size, largest first. Data refreshed Sep 17, 2026. RevenueBase Smart Search rates how each company's information relates to petroleum engineering firms: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Halliburton	Indirect evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	10001+	53,380 contacts →
	Indirect evidence “We collaborate and engineer solutions to maximize asset value for our customers.” Source: RevenueBase Database · checked Sep 17, 2026
2	Nabors Industries	Indirect evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	10001+	5,865 contacts →
	Indirect evidence “Nabors Industries is a leading provider of advanced technology for the energy industry.” Source: RevenueBase Database · checked Sep 17, 2026
3	NESR	Indirect evidence	Houston, United StatesHQ checked Sep 17, 2026	5,001-10,000	3,683 contacts →
	Indirect evidence “National Energy Services Reunited Corp.(NESR) was founded in 2017 as one of the largest national oilfield services providers in the MENA and Asia Pacific regions and was the first…” Source: RevenueBase Database · checked Sep 17, 2026
4	KEY Energy Services	Indirect evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	1,001-5,000	2,755 contacts →
	Indirect evidence “Headquartered in Houston, Texas, Key Energy Services provides a wide array of leading edge energy production solutions and services.” Source: RevenueBase Database · checked Sep 17, 2026
5	Patterson-Uti	Indirect evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	10001+	2,317 contacts →
	Indirect evidence “Patterson-UTI is a leading provider of drilling and completion services to oil and natural gas exploration and production companies in the United States and other select…” Source: RevenueBase Database · checked Sep 17, 2026
6	Core Laboratories	Indirect evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	1,001-5,000	1,500 contacts →
	Indirect evidence “With over 70 offices in more than 50 countries located in major oil-producing provinces, Core Laboratories provides services to the world's major, national, and independent oil…” Source: RevenueBase Database · checked Sep 17, 2026
7	Partner Engineering & Science, INC	Indirect evidence	Torrance, CA, United StatesHQ checked Sep 17, 2026	1,001-5,000	1,358 contacts →
	Indirect evidence “Partner Assessment Corp.” Source: RevenueBase Database · checked Sep 17, 2026
8	Atwell, LLC	Partial evidence	Southfield, MI, United StatesHQ checked Sep 17, 2026	1,001-5,000	1,290 contacts →
	Partial evidence “Atwell is a full-service consulting, engineering and construction services firm that delivers a broad range of creative solutions to clients in the real estate and land…” Source: RevenueBase Database · checked Sep 17, 2026
9	Cudd Energy Services	Indirect evidence	The Woodlands, TX, United StatesHQ checked Sep 17, 2026	1,001-5,000	1,285 contacts →
	Indirect evidence “Cudd offers a broad range of technical and specialized oilfield services to companies engaged in the exploration and production of oil and natural gas worldwide.” Source: RevenueBase Database · checked Sep 17, 2026
10	Newpark	Indirect evidence	Katy, TX, United StatesHQ checked Sep 17, 2026	1,001-5,000	1,244 contacts →
	Indirect evidence “Newpark Fluids Systems is the world’s leading pure-play oil & gas and geothermal fluid solutions provider.” Source: RevenueBase Database · checked Sep 17, 2026
11	Knight Piesold	Indirect evidence	Denver, CO, United StatesHQ checked Sep 17, 2026	1,001-5,000	1,231 contacts →
	Indirect evidence “Knight Piésold is an employee-owned, global consulting firm providing specialist services to the mining, power, water resources, and infrastructure industries.” Source: RevenueBase Database · checked Sep 17, 2026
12	Barr Engineering CO	Partial evidence	Minneapolis, MN, United StatesHQ checked Sep 17, 2026	1,001-5,000	1,088 contacts →
	Partial evidence “Barr provides engineering and environmental consulting services to clients across the Midwest, throughout the Americas, and around the world.” Source: RevenueBase Database · checked Sep 17, 2026
13	Nine Energy Service	Indirect evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	1,001-5,000	712 contacts →
	Indirect evidence “With a culture built on high performance and flawless execution, Nine Energy Service is a unique kind of oilfield services company, offering industry-shaping completion solutions…” Source: RevenueBase Database · checked Sep 17, 2026
14	EDG	Indirect evidence	Metairie, LA, United StatesHQ checked Sep 17, 2026	501-1,000	700 contacts →
	Indirect evidence “EDG Inc.” Source: RevenueBase Database · checked Sep 17, 2026
15	Fesco, LTD	Indirect evidence	Alice, TX, United StatesHQ checked Sep 17, 2026	1,001-5,000	651 contacts →
	Indirect evidence “FESCO is a diversified energy services company providing quality equipment and experienced personnel since 1949.” Source: RevenueBase Database · checked Sep 17, 2026
16	Consultec International INC	Indirect evidence	Miami, FL, United StatesHQ checked Sep 17, 2026	501-1,000	580 contacts →
	Indirect evidence “Somos una empresa multinacional líder en servicios de Consultoría de Oil & Gas, IT, Ingeniería, Recursos Humanos, Head Hunter y Proyectos” Source: RevenueBase Database · checked Sep 17, 2026
17	E2 Consulting Engineers, INC	Partial evidence	Emeryville, CA, United StatesHQ checked Sep 17, 2026	501-1,000	526 contacts →
	Partial evidence “Dedicated to “Excellence in Engineering,” E2 Consulting Engineers, Inc.(E2) is a professional services firm established in 1988 specializing in a full spectrum of engineering…” Source: RevenueBase Database · checked Sep 17, 2026
18	Anvil Corporation	Partial evidence	Bellingham, WA, United StatesHQ checked Sep 17, 2026	201-500	460 contacts →
	Partial evidence “Founded in 1971, Anvil Corporation is a 100% employee-owned engineering firm providing multi-discipline engineering, design, project management, procurement, and construction…” Source: RevenueBase Database · checked Sep 17, 2026
19	Cactus Drilling CO	Indirect evidence	Oklahoma City, OK, United StatesHQ checked Sep 17, 2026	1,001-5,000	440 contacts →
	Indirect evidence “As the largest privately-held domestic land drilling contractor in the United States, Cactus provides competent, motivated personnel utilizing premium equipment to meet and exceed…” Source: RevenueBase Database · checked Sep 17, 2026
20	Enervest, LTD	Indirect evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	201-500	424 contacts →
	Indirect evidence “EnerVest is a top-tier, low-cost oil and natural gas operating company.” Source: RevenueBase Database · checked Sep 17, 2026
21	Recon Management Services, INC	Partial evidence	Sulphur, LA, United StatesHQ checked Sep 17, 2026	501-1,000	420 contacts →
	Partial evidence “ReCon was established in 1995 and has matured as a high quality and competitive engineering consulting firm providing engineering design and project management services to the…” Source: RevenueBase Database · checked Sep 17, 2026
22	Express Energy Services	Indirect evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	501-1,000	379 contacts →
	Indirect evidence “Express Energy Services, a leading oilfield services company, is active in every major hydrocarbon basin in the United States and is a premier provider of products and services…” Source: RevenueBase Database · checked Sep 17, 2026
23	Manhard Consulting	Partial evidence	Lincolnshire, IL, United StatesHQ checked Sep 17, 2026	201-500	365 contacts →
	Partial evidence “Manhard Consulting has joined Atwell, a national consulting, engineering, and construction services firm with 2,100 technical professionals across the country.” Source: RevenueBase Database · checked Sep 17, 2026
24	AIR Drilling Associates	Indirect evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	201-500	328 contacts →
	Indirect evidence “ADA is a global energy services company specializing in advanced drilling solutions for oil, gas, and geothermal applications.” Source: RevenueBase Database · checked Sep 17, 2026
25	NCS Multistage	Indirect evidence	Houston, TX, United StatesHQ checked Sep 17, 2026	201-500	301 contacts →
	Indirect evidence “Since our founding in 2006, NCS Multistage has grown to be a leading provider of engineered products and support services for oil and natural gas wells around the world.” Source: RevenueBase Database · checked Sep 17, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: petroleum engineering firms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names petroleum engineering firms.
Partial evidence: Its own public description names part of petroleum engineering firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name petroleum engineering firms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 1,462 petroleum engineering firms based in the United States

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Petroleum engineering firms based in the United States at a glance

As of Sep 17, 2026

29.0%Verified-email coverage

73.7Average contacts per company

11-50Median size (employees)

23.1%Largest-city concentration · Houston

Sep 17, 2026Page data refreshed

Companies by employee count

1-10

685

11-50

465

51-200

203

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 1,462 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among petroleum engineering firms, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies: Companies headquartered in the United States whose own description of what they do matches “petroleum engineering firms”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names petroleum engineering firms), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among petroleum engineering firms, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 31,269 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 17, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Petroleum engineering firms by metro

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names petroleum engineering firms, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many petroleum engineering firms are there based in the United States?

RevenueBase identified 1,462 petroleum engineering firms headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Halliburton, headquartered in Houston, tops this list with the largest team on record.

Which city has the most petroleum engineering firms?

Houston leads with 337 headquartered companies, followed by Denver (45) and Midland (41).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 31,269 verified decision-maker contacts tracked across these 1,462 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 17, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.