Study On Fracturing And Increasing Technology Of Screen

Featured with simplified techniques and cost-effectiveness, polymer flooding has become one of the key techniques for efficient development of offshore oil fields. With the extension and expansion of polymer injection, blocking problems start to emerge, influencing the polymer flooding exploitation adversely. Limited to the operation space and screen completion methods, current de-plugging technology has achieved certain effect, but the period of validity progressively decreased. Therefore, fracturing through the screen (FTS) has been proposed to perforate the screen and frac-packing the target interval, enhancing the treatment effect and extending the period of validity. In this paper, theoretical analysis and numerical simulation methods have been applied to investigate the major and relevant technologies in FTS, and the following are the main achievements and recognitions:(1) Pinpoint perforates the screen with abrasive jetting to provide the tunnel for fracturing fluids has been determined in FTS. The flow field has been simulated with computational fluid dynamics to analysis the effect of jet velocity and jet spacing on the distribution of flow field, and providing a reference for the optimization and reasonable selection of jetting parameters.(2) As for the unconsolidated sandstone reservoirs in the polymer flooding area, the mechanism of sand control and stimulation effect has been demonstrated. Study on the relevant techniques has been conducted from the view of proppant flowback control and sand control to ensure the effectiveness of stimulation.(3) Combined with characteristic of frac pack, the method of unified fracture design has been improved with the accurate prediction of fracture height and embedment of proppant. The improvement is beneficial for the design of optimal fracture dimension.(4) Considering the stress sensitivity of unconsolidated sandstone reservoir and the long-term reduction of fracture conductivity, a three dimensional and two-phase reservoir-fracture model has been developed, the effect of fracture parameters, fracture lengths and conductivity, on stimulation effect has been analyzed. The results indicate that the productivity after treatment is non-sensitive to the variation of fracture lengths, but sensitive to the variation of fracture conductivity. Therefore, treatment measurement such as the combined proppant injection and coated resin is helpful to increase or keep the fracture conductivity, and improve the yield potential.With the above study, the approach of FTS has been formulated to provide the latest technology to achieve damage removal, production enhancement or injection increment for unconsolidated sandstone reservoirs, and also laid the foundation for the later refinement of...