Research into a productivity prediction model of radial-borehole fracturing in a shale oil reservoir

The shale reservoir is well stratified, and the conventional horizontal well volume fracturing has insufficient longitudinal penetration ability, leading to a limited degree of reconstruction. In this paper, based on a new idea of radial well fracturing, the fracture network model of the radial well fracturing is built, and the 3-D matrix-cracks-wellbore flow coupling model is established.The shale oil productivity under horizontal well fracturing and radial well fracturing is compared and analyzed, and the influence of natural fractures on shale oil productivity is studied. The results show that radial well fracturing can surpass the conventional limit of fracture height and improve the reservoir reconstruction performance. More radial wells and main wells lead to higher productivity,which can be exemplified by the Gulong shale reservoir in the Songliao Basin. With the presence of natural fractures, the hydraulic fractures directly intersecting the fracture network of 3-well, 3-layer radial wells with 4 branches have 1.35 times overall productivity and more than 2.2 times the oil production rate and total oil production in the third year, compared to the ones created by horizontal well fracturing. The research results can provide a theoretical basis for the efficient development of shale oil by radial well fracturing.