I have a page with some bootstrap wells: http://jsfiddle.net/LmwbkLo6/
<div style="margin:15px;">
<br>
<div class="well">
<div class="col-sm-8">
<h4>Test Title</h4>
<p>Some test text</p>
<p>More text..</p>
</div>
<div class="col-sm-4">
</div>
<p>And Some Text Here
<p>
</div>
</div>
class="col-xs-12"
You need to wrap your class="col-*
divs
in <div class="row"></div>
or it will not apply the negative margin.