<?php
    $static_block_id = $this->getConfig('porto_settings/header/static_block');
    $block = $this->getLayout()->createBlock('Magento\Cms\Block\Block');
    if($block) {
        $block->setBlockId($static_block_id);
    }
    if($block){
        echo '<div class="custom-block">'.$block->toHtml().'</div>';
    }
?>