<?php
  $client = get_field('client_name');
  $work_args  = array(
    'post_type' => 'work',
    'meta_key' => 'client_name',
    'meta_value' => $client
  );
  $work_query = new WP_Query($work_args);
  if ($work_query->have_posts()):
  while ($work_query->have_posts()): $work_query->the_post();
?>
        /* Do something here */
<?php
  endwhile; endif;
  wp_reset_query();
?>