Determining the value of an oil painting portrait from 1862 by an artist with a name resembling Kesler, Keslen, Keoler, or Keolen would require more specific information about the artist and the artwork itself. If the artist is relatively unknown, the painting's value may be primarily based on its condition, provenance, and aesthetic appeal rather than the artist's name. It's recommended to consult an art appraiser or auction house for a professional evaluation. Additionally, researching auction records or similar works could provide insight into its market value.