Reservoir Description Of Chang6~1-Chang6~2in Renshan District, Yongning Oil Production Plant

To reveal the geological characters and reservoir characters of Chang61and Chang62oil-bearing formations in Renshan district, based on gyration and combination of lithology and electricity, Chang-6oil-bearing formation in the studying district is divided into4sub-formations from top to bottom which are Chang61, Chang62, Chang63and Chang64. Chang61and Chang62are the main oil-bearing formations in this study. Based on the comprehensive analysis of testing and analytic data, sedimentary structure, gyration, and combination of lithology and electricity, Chang61and Chang62oil-bearing formations in Renshan district have been defined as lake delta frontal subfacies, including4types of microfacies which are mainly underwater distributary channel, subaquatic inter-distributary embayment, channel mouth bar and subsea natural barrier. Underwater distributary channel sands have relatively coarse grain-size and better reservoir property, thus, their reservoir capacity are better than channel mouth bar sands. The tectonic setting of Chang6reservoirs is a regional monocline which inclines to the west side. Under this tectonic setting, some low-amplitude nosing structures develop caused by differential compaction. Chang6reservoirs are mainly lithologic oil pools and structure-lithology reservoirs drived by solution gas. The proven OOIP (original oil in place) of Chang-61and Chang-62are157.7×104t and133.0×104t respectively. The solution gas in place totted up to1.49×108m3.