Abstract:

The lithology of Paleogene reservoirs in the west sag of the beach area in Liaohe oilfield is primarily feldspathic lithic sandstone, lithic sandstone and lithic sandstone with low maturity. The reservoirs were deposited with multiple provenances and near these provenances. The reservoir pores are sorted into primary, secondary and hybrid pores, and the porosity and permeability have good correlation to each other. The relevant statistics indicate that there are two abnormally highvalue zones of porosity and permeability in the intervals of 1,500-2,800 m and 2,800-3,500 m. The storage performance of reservoirs was controlled by both primary deposition and later diagenesis reconstruction. These reservoirs had undergone four types of diagenesis, i. e. mechanic compaction, cementation, dissolution and replacement, and the mutual reaction of these diagenesis controlled four phases of pore evolution. The reservoir properties changed in an apparent zonation pattern around the sag. After the comprehensive analysis on reservoir distribution and properties, and hydrocarbon kitchens, the reservoir zonation could be divided into outer, intermediate and inner zones, in correspondence with reservoirs of II, I and III, respectively.

Key words: clastic rock, reservoir property, main controlling factor, the west sag of the beach area, Liaohe oilfield