Geochemical logging instrumentCore application scenarios:
Evaluation of Source Rocks and Prediction of Resource Potential
Quantification of organic matter abundance: Calculate the total hydrocarbon content (Pg) using S ₀+S ₁+S ₂, and evaluate hydrocarbon generation potential by combining TOC (total organic carbon).
Maturity grading: Combining Tmax value with HI (hydrogen index), it is divided into immature (Tmax<435 ℃), mature (435-455 ℃), and highly mature (>455 ℃) stages to guide the selection of exploration target layers.
Case: In the evaluation of Cambrian source rocks in the Tarim Basin, geochemical logging instrument identified highly mature dry gas source rocks with Tmax>460 ℃, providing a basis for deep gas exploration.
Reservoir characterization and development optimization
Oil saturation calculation: Combining the S ₁/S ₂ ratio with the core nuclear magnetic resonance T ₂ spectrum, distinguish free oil from adsorbed oil, and optimize the fracturing transformation plan.
Oil quality type discrimination: Based on the ratio of S ₁/S ₂ to Pr/Ph (phytane/basane), light oil, medium oil, and condensate oil reservoirs are classified.
Case: In the exploration of tight oil in the Chang-7 section of the Ordos Basin, the geochemical logging instrument screened high oil saturation areas through S ₁ values, resulting in a 40% increase in horizontal well production.
Engineering safety and risk warning
Surge/Leakage Warning: Real time monitoring of changes in the content of C ₁ - C ₅ light hydrocarbons in drilling fluid, providing 2-3 hours advance warning of formation fluid invasion.
Formation pressure prediction: Combining geochemical parameters with logging data, establish a formation pressure prediction model to reduce the risk of drilling jamming.
Case: During the drilling of a deep water well in the South China Sea, the geochemical logging instrument used a sudden change in the C ₂/C ∝ ratio to warn of gas invasion and avoid blowout accidents.
Remaining oil distribution and re examination of old wells
Production layer identification: Compare drilling coring with geochemical data during the production stage to verify the contribution rate of the main production layer.
Research on remaining oil distribution: By rechecking geochemical parameters of old wells and combining numerical simulation to optimize the secondary oil recovery plan.
Case: A block in Daqing OilfieldGeochemical logging instrumentAnalyzing the core of the old well, it was found that the low-permeability reservoir has not been utilized, and an additional recoverable reserve of 120000 tons has been added.