1. You can create widget with the static block in Appearance > Widgets > Custom Sidebar. Create a new sidebar and drag “8theme – Static Block” widget into there. Then in Visual Composer you can select the element “Widgetised Sidebar” and choose the sidebar you created. Or you can try using Text element and insert the shortcode for static block: [block id=" "].
2. Static block id can be found in the address bar of your browser: