Subsurface Geological Study, R&D

Exploration and appraisal work on exploration blocks, reserves estimation and reclassification, geological models and expert review of reserves reports.

This area covers the entire path from primary geological and geophysical data to a reserves report ready for defense. Work is carried out by the geological design and reserves estimation, geological modeling and petrophysics departments.

Scope of work

• Exploration and appraisal work projects for exploration blocks — Justifying the scope and sequence of exploration work on a block: seismic surveys, drilling, coring, well logging. We define the objectives for each target and the expected increase in exploration maturity.
• Reserves estimation, re-estimation and reclassification — Oil, gas, condensate. We justify the estimation parameters, deposit boundaries and reserve categories, and prepare a report with attachments for defense. Re-estimation is carried out when new wells appear, seismic data are reinterpreted, or the understanding of the deposit structure changes.
• Structural modeling — Building a structural framework from seismic and drilling data: correlating reflecting horizons, tying to wells, fault modeling, top and base maps of productive formations.
• Geophysical and petrophysical modeling — Normalizing and interpreting well logs in IP™ Software, justifying reservoir cut-off values, and petrophysical relationships for porosity, permeability and saturation from core and log data.
• Geological model development — A 3D model in Petrel: lithofacies and petrophysical property distribution, volumetric reserves estimation, uncertainty assessment, and preparing the model for handover to reservoir simulation.
• Reserves report review — Checking third-party reports on reserves estimation, re-estimation and reclassification: correctness of estimation parameters, justification of categories, and compliance of the submitted materials with reporting requirements.

How the work proceeds

• Input data and scoping — We collect and check well files, logs, core, seismic data and prior reports for completeness, and formulate the task and the list of estimation targets.
• Interpretation and petrophysics — We normalize the well logs, justify cut-off values and petrophysical relationships, identify reservoirs and determine net pay thicknesses.
• Structural and geological model — We build the structural framework, fault model and 3D property distribution, and tie the model to well data.
• Estimation and reporting — We calculate reserves, justify categories, and prepare the report text along with graphic and tabular attachments.
• Approval and defense — We support the report through review, respond to comments, and make corrections until approval.

What the client receives

• Reserves estimation (re-estimation, reclassification) report with attachments
• Top and base structural maps of productive formations
• 3D geological model in Petrel format
• Petrophysical well-log interpretation report
• Tables of estimation parameters and reserves by category
• Expert opinion on third-party reports

Software

• Petrel
• IP™ Software
• Baspro Optima
• AutoCAD LT
• Excel