convert custom query to wp_query

You have missed meta_value parameter.
You can use like this :

$today=date('Y-m-d');
$args = array(
               'numberposts' => 10,
                'post_type' => 'events',
                'meta_key' => 'event_date',
                'meta_value >=' => $today
            );

            // get results
$the_query = new WP_Query( $args );