Controlling factors for the heterogeneity of the Putaohua oil reservoirs in the Daqing Oil Field

The reservoir heterogeneity tends to exert an important effect on the oil and gas exploration. The quantitative and semi-quantitative analysis of the heterogeneity of the Putaohua oil reservoirs in the Daqing Oil Field indicates that the intrastratal heterogeneity is very poor in the PI2 bed in the Putaohua oil reservoirs, and closely related to sedimentary microfacies. Vertically, the distribution of the permeability displays the variations of positive and compound rhythmicity with local reversed rhythmicity. There are gradations in intrastratal heterogeneity degree from PI2a through PI3 to PI2b, PI1 and finally to PI4. The interstratal heterogeneity is strongest at the boundary between the PI3 and PI4 beds in the Putaohua oil reservoirs. Laterally, the heterogeneity is relatively stronger on the whole in the Putaohua oil reservoirs.