Presentation: "Keys to exploration: lake-basin type, source potential, and hydrocarbon character within an integrated sequence-stratigraphic-geochemical framework."

Kevin M. Bohacs - ExxonMobil Upstream Research Company

Table 2: Characteristics of Lake-Basin Types: Strata, Source Facies, and Hydrocarbons

Lake Type & Lacustrine Facies Association

Stratigraphy

Source Potential

Hydrocarbon Characteristics

OVERFILLED

Fluvial-Lacustrine Facies Association

Maximum progradation:

  • Parasequences related to lateral progradation (relatively subtle)
  • Maximum fluvial input
  • Low to moderate TOC
  • Mixed Type I-III kerogen
  • Marked organic facies contrasts
  • Distinct lateral changes in organic facies
  • Generate both oil and gas
  • Very waxy, low-sulfur oils
  • Terrigenous biomarker assemblage dominant

BALANCED-FILL

Fluctuating-Profundal Facies Association

Mixed progradation and desiccation:

  • Distinct shoaling cycles common
  • Fluvial input variable
  • Moderate to high TOC
  • Predominantly Type I kerogen, with Type I-III mixtures near flooding surfaces
  • Relatively homogenous and laterally consistent organic facies
  • Mostly oil generative
  • Paraffinic but relatively non-waxy oils; low sulfur
  • Algal biomarker assemblage dominant

UNDERFILLED

Evaporative Facies Association

Maximum desiccation:

  • High-frequency wet-dry cycles
  • Minimum fluvial input
  • Low overall TOC (w/ some high TOC intervals)
  • Type I kerogen
  • Minimum organic facies contrasts
  • Laterally consistent organic facies
  • Mostly oil generative
  • Paraffinic oils; moderate to high sulfur
  • Distinctive "hypersaline" biomarker assemblage


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