The Lead Reservoir Engineer will carry out reservoir design, fracture modeling, diagnostics design and reservoir parameter testing with a focus on delivering required reservoir characteristics for Enhanced Geothermal Systems (EGS) development. This role is responsible for working within the Resource & Operations team to transform analytical reservoir models into field-executable reservoir design concepts. This role will evaluate reservoir modeling and lead efforts to test the uncertainties in those models.

This role will work closely with drilling, completions, power plant design, and exploration geology.

Essential functions (Reasonable accommodations may be made to enable individuals with disabilities to perform these essential functions.)

Reservoir Engineering Ownership

• Lead reservoir simulations to evaluate design scenarios, completions hardware and power plant design criteria.
• Advise Resource & Operations teams on the design and objectives of diagnostic programs, including pressure transient tests, interference tests, DFITs, step-rate tests, and completion step-down tests.
• Independently review and interpret pressure, rate, and temperature data to assess reservoir properties, fracture behavior, and well performance.
• Evaluate crossflow behavior, injector-producer connectivity, and reservoir compartmentalization to inform development strategy.
• Provide guidance on lateral rate distribution and zonal performance diagnostics (e.g., PLT/DTS/DAS, tracer programs).
• Review completion step-down tests, injection/falloff programs, and stimulation diagnostics to assess near-wellbore and fracture performance.
• Support resource assessment work teams in prospect screening, reservoir characterization, and early-stage risk assessment.
• Provide input on location selection and wellbore targeting based on structural, thermal, and permeability models.
• Define minimum viable data acquisition strategies to evaluate new prospects efficiently and reduce uncertainty.
• Deliver clear technical recommendations to asset teams to guide optimization, stimulation strategy, and injection management.
• Promote consistent diagnostic standards and interpretation methodologies across projects.
• Partner with D&C to refine stage design, cluster efficiency, and stimulation strategy based on observed performance.
• Integrate diagnostic findings into reservoir models and development plans.

Cross-Functional Reservoir Development Support

• Support technical evaluation of geothermal leases from initial screening through completions readiness.
• Incorporate risk assessment, uncertainty analysis, contingency planning, and stage-gate decision logic into development program design.
• Work closely with earth science, drilling, completions, reservoir engineering, land, permitting, environmental, development, and HSE teams during exploration campaign.
• Utilize geomechanics and permeability indicators relevant to geothermal reservoir performance and EGS stimulation design.
• Provide technical recommendations related to logging programs, casing points, coring, well trajectories, and other geologic decisions during drilling operations.
• Partner with geologists, geophysicists, and data scientists to support geothermal reservoir conceptual models and pre-development reservoir evaluations.
• Support resource assessment, reserve estimation, asset management, investment analysis, and technical diligence activities for geothermal opportunities.

Technical Leadership and Team Development

• Provide technical leadership, mentorship, and quality oversight for consultants, contractors, and field personnel.
• Establish exploration workflows, data standards, reporting practices, prospect review processes, and technical assurance procedures supporting geothermal development activities.
• Serve as a visible field safety leader by supporting HSE initiatives, participating in site safety reviews, and reinforcing safe operational practices.
• Promote a culture of safety, accountability, scientific rigor, collaboration, and continuous improvement.
• Perform other related duties as assigned.

Competencies

• Reservoir engineering, simulation, forecasting, and performance optimization.
• EGS development, stimulation design, fracture mechanics, and geomechanics.
• Reservoir testing, diagnostics, surveillance, and data interpretation.
• Integration of geologic, geophysical, well-log, pressure, temperature, and flow data.
• Technical software, modeling platforms, and data-analysis tools.
• Cross-functional collaboration with geoscience, drilling, completions, facilities, and power-generation teams.
• Clear technical communication, leadership briefings, and defensible recommendations.
• Independent ownership, sound judgment, and comfort operating in a high-growth environment.

Supervisory Responsibilities

• Provide technical mentorship and guidance to engineers, contractors, consultants, and field personnel.
• May assist with recruiting, onboarding, and training technical staff.
• May oversee the work of external consultants and service providers supporting exploration and drilling activities.
• This role does not currently include formal direct people-management responsibilities but may evolve over time with organizational growth.

Education and Experience

• Bachelor's degree in petroleum engineering, mechanical engineering, chemical engineering or a related discipline required.
• Advanced degree in engineering, or related field preferred.
• 5+ years of relevant reservoir engineering, oil and gas, subsurface development, or related technical experience required.
• 10+ years of relevant geoscience experience in geothermal, EGS, oil and gas, mining, or other subsurface resource industries preferred.
• Demonstrated experience leading exploration or subsurface evaluation programs from concept through drilling or appraisal.
• Experience supporting completions operations, well planning, reservoir development, or subsurface operational activities preferred.
• Experience interpreting pressure transient tests, interference tests, DFITs, step-rate tests, and DFITs associated with completion step-down testing preferred.

Physical requirements

• Ability to travel periodically to field locations, lease areas, drilling sites, and contractor or partner offices.
• Ability to work outdoors in remote environments, including hiking over rough or uneven terrain while wearing required PPE.
• Ability to safely work around drilling operations, field equipment, and industrial environments while adhering to established safety procedures.
• Ability to operate or ride in 4WD vehicles in variable terrain and weather conditions.
• The employee is regularly required to stand, sit, walk, stoop, kneel, crouch or crawl, as well as use hands to feel, reach, grasp, handle, or operate objects, tools and/or controls.
• The employee may occasionally lift, move, push, pull, or carry items up to 20 pounds for operational or field support needs.
• Ability to adjust work hours and travel schedules as needed to support field operations and project activities.
• The vision requirement includes reviewing written and electronic materials in digital and physical format.

Other duties

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities required of the employee for this job. Management reserves the right to change, rescind, add, or delete the duties and responsibilities of positions within this job classification at any time.