Applying Stimulation Technology to Improve Production in Mature Assets Alexandr Mocanu Well Production Services, Schlumberger Visegrád, 19 November 2015 Society of Petroleum Engineers 1
Agenda Formation Complexity Why Apply Stimulation in Mature Fields Other Advantages to Hydraulic Fracturing When to Reconsider Fracture Stimulation Key Stimulation Challenges in Mature Fields Engineered Design Workflow New Role of Stimulation Engineers Conclusion 2
Formation Complexity Pannonian, Carpathian basins Complex and variable geological environment Challenging formations Various reservoir types: basement rock - igneous and metamorphic (granites, fissured mica), sedimentary (conglomerates, sandstones, marl etc.) Limited understanding of the reservoir properties Low average recovery factors 3
Drilling & Completion Stimulation Why Apply Stimulation in Mature Fields Economics 90% 10% Increased Field Maturity Integration of Disciplines Reservoir Engineering Matrix Acidizing Conductive Fracture Long Fracture MS Complex Fractures 40% 60% Holditch, Texas A&M 4
Mature Assets Example from Middle East Ref. G.M. Hegazy et. Al, 2013, SPE 164778 74% of STOOIP in tight rock Current completion and stimulation design do not allow for recovery Likely higher STOOIP in k<<0.1md as exploration methods evolve 5
Understanding Reservoir Properties is Key Understanding the reservoir properties is critical for stimulation technique selection Oil Data Points should move further left Ref. G.M. Hegazy et. Al, 2013, SPE 164778 Holditch, Texas A&M Example from Middle East: Current Approach to maximize production: Long laterals Matrix Acid Stimulation Required Approach: Long Fracture Multi-stage Fracturing 6
Hydraulic Fracture Other Advantages Connecting Lenticular Reservoirs Naturally Fissured Systems Orthogonal Fissures Sub - Parallel Fissures Connecting Laminated Formations Pay stimulated by an acid treatment Pay stimulated by a fracture treatment Pressure Distribution of Wellbore Drawdown Reduction in formation sand production Distance 7
Reasons to Reconsider Fracturing 1. High risk to connect to water bearing zone 2. Limited or low pressure formation w/o artificial lift 3. High k h formations with deep damage 4. Difficult to access damage (gravel-pack, screens) 5. Un-proppable formations (soft rocks) 6. Flowback restrictions (especially true for low pressure gas formations) 7. Weak tubulars (old with questionable integrity or under designed) 8. Bad cement sheath that could lead to well integrity issues 8
Key Stimulation Challenges in Mature Fields Limited Information Often only SP, GR and/or resistivity logs available Poor understanding reservoir quality Poor understanding of geomechanics Complex geological environment Brown oilfields - depleted reservoirs Reduced oil mobility & higher water production Hydrocarbon migration Old wells with aging completions Limited wellhead pressures 9
New Technology can Play a Key Role Evaluation Modeling & Design Chemistry & Materials Measurements 10
Engineered Design with Limited Data Basic well data + temperature logs + offset sonic + Frac Diagnostic + Stimulation Soft = Develop Field Scale Geomechanics 11
Integrated Workflow Integration of Wells Data to Characterize, Evaluate and Design Extrapolation of assumptions and workflows to the field level Well to well correlation Corrections of the field model based on the production data and well pumping data Sat. and Young's Modulus Lithology and Stress Fracture Width Proppant Concentration 2075 0.0 kgpa 2100 200.0 kgpa Well Depth (TVD) (m) 2125 2150 400.0 kgpa 600.0 kgpa 800.0 kgpa 1000.0 kgpa 2175 1200.0 kgpa > 1250.0 kgpa 2200 1.0x102.0x10 6 3.0x10 6 4.0x10 6 5.0x10 6 300 400 500 600-50.0 0 50.0 0 100 200 Young's Mod. (psi) Stress (bar) Width (mm) Length (m) 12
The New Role of the Stimulation Engineer Seismic Interpretation Seismic Volume Rendering Well Correlation Geophysicist Petrophysical Modeling Facies Modeling Economist Geologist Fault Analysis Uncertainty Analysis Reservoir Engineer Upscaling Production Engineer Stimulation & Real-time Completion Analysis History Matching Drilling Engineer Well planning Completion design 13
Conclusion Complex variable geology requires thorough analysis Understanding the reservoir quality is a key to choosing the right completion and stimulation approach Workflow integration of disciplines required for better evaluation of the reservoir Challenges do exist in Stimulation of mature fields Limited data and old completions are a challenge not a deal breaker Key challenges and key risks can be addressed with the aid of technology and good engineering practice Variable geologic environment in CEE is challenging from engineering perspective which creates good conditions for a multilateral development of young specialists 14
Questions and Answers Questions?! 15