Abstract: For horizontal wells, in order to reduce the impact of bottom water coning and toe end effect, coning controlling technology with preset multi-stage bottoms in horizontal well annulus was proposed. Simulate development equipment in 3D large-scale bottom water reservoirs. And the experiment on water cresting shape and oil displacement effect was carried out in conventional horizontal wells, horizontal wells with central tube and horizontal wells with multiple bottoms, respectively. Through the experiment, the effectiveness of coning controlling technology with multiple bottoms in annulus was verified. The results show that horizontal wells with multiple bottoms have obvious advantages over conventional horizontal wells and horizontal wells with central tube. The multi-bottom system makes the pressure profile along borehole more balanced, weakens the toe end effect, delays the bottom water breakthrough time, and increases swept volume, whose development effect is 9.98 and 5.95 percentage points higher than that of conventional horizontal wells and horizontal wells with central tube, respectively. The field application of coning controlling and oil stabilizing technology with multiple man-made bottoms in horizontal well annulus shows that the structure of preset multi-stage man-made bottoms in annulus is complicated, while the operation is simple, which has application potential on field. This research can provide technical reference and support for the efficient water controlling development in bottom water reservoirs.

Key words: bottom water reservoir, horizontal well, multi-stage well bottoms, toe end effect, coning control of bottom water