A packer for wells can include a body having a tubular shape, a sealing element having an upward end and a downward end and disposed around the body. The packer also includes a first prop upward of the sealing element, and a second prop downward of the sealing element. The first prop is configured to wedge under the upward end of the sealing element and the second prop is configured to wedge under the downward end of the sealing element to push the sealing element outward at both the upward end and the downward end.