Question regarding API number

I have a question that I hope one of you can answer. I was on the states web site to review status of active wells On ours, it lists the wells with description and API number My confusion is the site is showing another line item as a well. It has another API number but the same description as the first well- with the exception that it has an X Example: 16-63-6-7-18-1CH The one with an X shows as: 16-63-6-7-18-X1CH Does anyone know what this means?

Sometimes the X means an extended reach horizontal. Look at the end of the API number to see if the last four digits are 0000 or have a 0001 or something slightly different. If the first well has a different API than the second, may be one well is a one section well and the second similar one is a two section well.