Details

Autor(en) / Beteiligte

• Huang, Haiping
• Jin, Guangxi
• Lin, Changsong
• Zheng, Yabin

Titel

Origin of an unusual heavy oil from the Baiyinchagan depression, Erlian basin, northern China

Ist Teil von

• Marine and petroleum geology, 2003, Vol.20 (1), p.1-12

Ort / Verlag

Oxford: Elsevier Ltd

Erscheinungsjahr

2003

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• A detailed organic geochemical analysis of six oil samples from the Baiyinchagan depression in the Erlian basin, Northern China, was carried out in order to evaluate their origin. The oils are reservoired at a very shallow depth (223–560 m subsurface) and their chemical and physical properties vary greatly, ranging from normal to extremely heavy oil. The preservation of non-biodegraded oil in such a shallow reservoir is possibly related with palaeo-pasteurization of the reservoir before uplift. Maturity difference is not the primary control on the chemical and physical properties of the oils and there is considerable geochemical evidence to suggest the additional influence of in-reservoir/post-accumulation processes such as biodegradation, water-washing and (possibly) evaporation. Whereas some oils appear to be less affected, others are moderately biodegraded up to level 4 on the Peters and Moldowan (1993) scale, with sterane distributions largely unaffected and 25-norhopanes undetected. Contrary to classical biodegradation, the unusual heavy oil shows little evidence of biodegradation from aliphatic components. Water-washing is suggested to be the primary process leading to its formation since the severe alteration of soluble aromatic hydrocarbons is observed. In addition, since the oils have been uplifted significantly after accumulation, evaporation and/or leakage to modify oil compositions cannot be ruled out.