Volumetric fracturing technology for the tight oil reservoir in Fu 2 formation of the Haian sag

Fu 2 formation of the Haian Sag in the North Jiangsu Basin belongs to typically low porosity and permeability tight oil reservoir. In order to evaluate the reservoir physical property and oiliness of this exploration area and provide the design basis for the well location deployment of horizontal wells, volumetric fracturing was conducted for a vertical wildcat well in this area. On the basis of research on the lithology, brittleness and physical property of the reservoir, slick water and linear gel fracturing fluid were optimized to meet the requirement of increasing sanding concentration as much as possible during volumetric fracturing. For the purpose of recognizing each small layer, the technical measures of bridge plug and separate layer fracturing, separate layer test, fishing the bridge plug and commingled production were adopted. Before the construction, the small scale fracturing testing was carried out to guarantee the success of the main-fracturing. In the construction, the fracture network volume was monitored by using surface micro-seismic technology. The operational discharge capacity reached 4.5-5.0 m³/min, accumulative sand added volume was 140 m³ and the maximum sand ratio was 12%. Fracture monitoring indicates that fracture-making effect is very good in each layer, the fracture geometry is very complicated and the oil testing effect attains the expected geological design.