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Who We Are

INEOS Energy

INEOS was founded in 1998 by Sir Jim Ratcliffe with a single site and has grown into one of the world's largest privately owned manufacturing groups. We have grown by buying good assets and running them better with small, empowered teams, minimal bureaucracy and a relentless focus on performance.

INEOS Energy is building a global energy business, and our US Onshore team in Denver currently operates approximately 2,000 wells in the Eagle Ford shale play of South Texas. We are a small team with a big mandate: grow the business through disciplined development and acquisitions.

About the job

Job Title: Subsurface Manager

Department: Development

Summary of Position

We are seeking a skilled and motivated Subsurface Manager to play a pivotal role in shaping and scaling our US onshore development program. This is a hands-on role for a strong reservoir engineer who wants real ownership. This high-impact position will lead and develop a small team while owning critical development tracking, capital budgeting, and reserves processes. You will drive accountability across active development pads, lead the capital forecast and capital budget submission process, oversee corporate reserves, and provide essential insight for lender, capital markets, and executive reporting. With significant visibility across the business and direct influence on investment decisions, you will help translate subsurface expertise into disciplined, value-creating development plans.

What We Look For

• Uncompromising on safety.

• An owner's mindset. You treat company capital like it's your own money.

• A bias for action. You make sound decisions quickly with imperfect information, and you don't wait for permission.

• Commercial instinct. You connect subsurface work to value: dollars, barrels and returns.

• Hands-on and unpretentious. You're happy to build the model yourself and to be in the field when it matters.

• Drive and resilience. You thrive in a lean team where everyone carries real responsibility.

Primary Job Responsibilities

• Manage, coach, and develop a Reservoir Engineer and Senior Development Geoscientist, setting clear priorities and ensuring high-quality technical analysis across development planning, capital allocation, and reserves.

• Own development tracking and project accountability across active development pads, including permitting status, land clearance, and engineering milestones. Maintain the Pad Readiness tracking process, proactively identify risks and dependencies, and partner across functions to support on-time execution.

• Lead the monthly capital forecasting process, tracking actual spend against budget, identifying opportunities to reallocate or repurpose capital, and preparing and refining capital budget submissions for Finance.

• Lead and perform economic evaluations and reservoir analyses, including decline curve analysis and type-curve development, to inform development decisions, capital budgeting, and reserves.

• Lead the corporate reserves process, including database management, Lease Operating Statement models, economic model runs, and documentation sufficient to support internal and external audits.

• Support reserve-based lending redeterminations and other capital markets activities by responding to lender and bank-engineering inquiries, preparing Lease Operating Statement updates, and coordinating with third-party reserve auditors and legal counsel to ensure reserve values and technical disclosures are accurate and well-supported.

• Develop clear, decision-ready technical materials for ExCo approval packages, post-investment pad lookbacks, and other internal and external stakeholder updates.

• Champion compliance with safety and environmental requirements while promoting a strong culture of safety across all activities.

Education & Experience:

• Bachelor’s or master’s degree in Petroleum Engineering, Chemical Engineering, or a related technical field.

• Minimum of eight years of upstream oil and gas experience with an operator, including at least three years in reservoir engineering, asset development engineering, or a closely related discipline.

• Strong technical expertise in reservoir analysis, development planning, economic evaluation, capital forecasting, and reserves processes.

• Strong proficiency with ComboCurve, ARIES, reservoir modeling platforms, Spotfire, Power BI, and Microsoft Office. Familiarity with SQL, Python, or other data analytics tools is considered an asset.

• Exceptional communication and interpersonal skills, with the ability to build credibility across disciplines, translate complex technical analysis into clear recommendations, and influence decisions at all levels of the organization.

• Demonstrated leadership capability through mentoring, collaboration, project leadership, or influencing multidisciplinary teams. Prior people-management experience is welcomed but not required; we are equally open to a highly capable technical professional who is ready to step into their first formal leadership role.

• Strong analytical and problem-solving skills, with the ability to work confidently with complex datasets, exercise sound judgment, and adapt to new challenges and technologies.

• Demonstrated commitment to maintaining high standards of safety and environmental responsibility.

Travel & Additional Requirements:

• Work Location: Work is performed at both field and office locations.

• Schedule: 9/80

• Travel required to INEOS field locations.

• INEOS is a drug free workplace. All offers to successful candidates will be subject to successful background check and drug screen.

Relocation:

This role is based in our Denver office; relocation assistance may be available.

Work Authorization:

INEOS USA Oil & Gas LLC is not currently sponsoring employment visas for this position.

Compensation & Benefits

Please note that the compensation information that follows is a good faith estimate for this position only and is provided pursuant to the Colorado Equal Pay for Equal Work Act (EPEWA) and Equal Pay Transparency Rules. It is estimated based on what a successful Colorado applicant might be paid. It assumes that the successful candidate will be in Colorado or perform the position from Colorado. Similar positions located outside of Colorado will not necessarily receive the same compensation.

Compensation:

The annual rate for this position generally ranges between $185,000 - $235,000 with an opportunity for a company-wide annual discretionary bonus, of up to 50% of eligible pay. This role, depending on skill level and experience, may also participate in the Long-Term Incentive Plan with annual awards, vesting over three years. These ranges are estimates, based on potential employee qualifications, operational needs, business performance to metrics, and other considerations permitted by law. The range may vary above and below the stated amounts, as permitted by Colorado Equal Pay Transparency Rule 4.1.2.

Benefits:

Benefits package includes healthcare, dental, and vision insurance for employees and eligible dependents. INEOS also offers several other wellness, financial, and work/lifestyle-specific benefits. 401(k) retirement has both an automatic 6% company contribution and a match of up to an additional 6% of eligible compensation. We offer generous paid time off that includes both sick and vacation which is based on and increases, with industry experience.

Application Deadline:

Application Deadline: October 31, 2026.

Notice To Third Party Agencies:

INEOS does not accept unsolicited resumes from recruiters, employment agencies, or other staffing services. Unsolicited resumes include any resume or hiring document sent to INEOS in the absence of a signed Service Agreement where INEOS has expressly requested recruitment/staffing services specific to the position at hand. Any unsolicited resumes, including those submitted to hiring managers or other business leaders, will become the property of INEOS and INEOS will have the right to hire that candidate without reservation – no fee or other compensation will be owed or paid to the recruiter, employment agency, or other staffing service.