Abstract: The Shengli oilfield is rich in tight oil reserves, but the reservoirs characterized by deep burial, poor physical properties and complex lithology, leading to unsatisfactory development performance like low yield and fast production decline after conventional fracturing stimulation. Through researches and optimizations, new fracturing techniques, such as commingled fracture network stimulation, were developed for tight oil reservoirs. While increasing the stimulated reservoir volume (SRV), these techniques can greatly improve fracture conductivity and post-fracturing performance. For the reservoirs with multiple layers vertically, two types of treatments were established, i.e. multi-stage fracturing of horizontal wells and multi-stage fracturing of vertical/deviated wells. A fast-dissolving low-concentration guar fracturing system that can be continuously mixed on line and a recyclable emulsion-associating fracturing fluid system that can be mixed with surface water and hot sewage were developed, which can effectively ensure the fracturing fluid preparation and water source for large-scale continuous fracturing operations. Moreover, the well-plant operation mode and fracture monitoring technique were upgraded. The proposed technology has been successfully applied in tight oil blocks such as Y227, Y22 and Y104. By greatly improving the single-well productivity and lifecycle, it helps increase the development benefit. Accordingly, the utilization degree of the tight oil in Shengli oil field has been improved economically and effectively.

Key words: tight oil, staged fracturing, volume fracturing, comingled fracture network