Fracturing Mechanism of Difficult-to-Fracture Thin Poor Reservoir Layers and Depressurization Modification Analysis in Daqing oil-field

摘要

The thin and poor reservoir layers have been used as target supplementary layers of production, and it considered as difficult-to-fracture layer as high calcium content and compact cementation, the emphasis focus on study and application of fracturing technology in Daqing oilfield in this paper. The rock which is difficult to fracture has the characteristics of high density, high strength and impermeability, so it is difficult for the fracturing fluid to enter the formation. Therefore, it should firstly to overcome the wellbore stress concentration and when the fracture pressure is higher than thirty-seven MPa, The formation is fractured. Modification of the layer can through acidification treatment, which can destroy the cementation among the rocks, thus decrease the tensile stress of the rock and increase the rock Permeability near the well bore, finally decrease the fracture pressure.