Como guardar uma busca com $_SESSION?

<?php

if(isset($_POST['busca-implacavel'])) {

    if( isset( $_POST['tipo'] ) ) $_SESSION['tipo'] = $_POST['tipo'];
    if( isset( $_POST['civil'] ) ) $_SESSION['civil'] = $_POST['civil'];
    if( isset( $_POST['cidade'] ) ) $_SESSION['cidade'] = $_POST['cidade'];
    if( isset( $_POST['valorminimo'] ) ) $_SESSION['valorminimo'] = $_POST['valorminimo'];
    if( isset( $_POST['valormaximo'] ) ) $_SESSION['valormaximo'] = $_POST['valormaximo'];

}

$tipo = isset( $_SESSION['tipo'] ) ? $_SESSION['tipo'] : '';
$civil = isset( $_SESSION['civil'] ) ? $_SESSION['civil'] : array();
$cidade = isset( $_SESSION['cidade'] ) ? $_SESSION['cidade'] : '';
$valorminimo = isset( $_SESSION['valorminimo'] ) ? $_SESSION['valorminimo'] : '';
$valormaximo = isset( $_SESSION['valormaximo'] ) ? $_SESSION['valormaximo'] : '';

##########################################################################################
##########################################################################################
##########################################################################################

    <form id="busca-implacavel" method="POST" enctype="application/x-www-form-urlencoded">
        <div class="full bgazul-fonce search-imovel">
            <div class="container">
                <div id="buscas-imovel" class="row">
                    <div class="col-md-12 padd0">
                        <div class="row row-interno" style="margin: 40px 0 30px 0!important; color:#fff">
                            <div class="col-md-2 first-field-search">
                                <input type="checkbox" name="civil[]" value="solteiro" <?php echo in_array("solteiro", $civil) ? " checked='checked'" : ""; ?>>Solteiro<br>
                                <input type="checkbox" name="civil[]" value="casado"  <?php echo in_array("casado", $civil) ? " checked='checked'" : ""; ?>>Casado<br>
                                <input type="checkbox" name="civil[]" value="viuvo"  <?php echo in_array("viuvo", $civil) ? " checked='checked'" : ""; ?>>Viúvo<br>
                                <input type="checkbox" name="civil[]" value="divorciado"  <?php echo in_array("divorciado", $civil) ? " checked='checked'" : ""; ?>>Divorciado<br>
                                <input type="checkbox" name="civil[]" value="uniaoestavel"  <?php echo in_array("uniaoestavel", $civil) ? " checked='checked'" : ""; ?>>União Estável<br>
                                <!-- input type="text" name="nome" class="form-control" -->
                                <select name="tipo" class="form-control" required>
                                    <option value="">Tipo</option>
                                    <option value="apartamento" <?php echo (($tipo == 'apartamento') ? 'selected="selected"' : ""); ?>>Apartamento</option>
                                    <option value="casa" <?php echo (($tipo == 'casa') ? 'selected="selected"' : ""); ?>>Casa</option>
                                    <option value="flat" <?php echo (($tipo == 'flat') ? 'selected="selected"' : ""); ?>>Flat</option>
                                </select>
                                </div>
                                <div class="col-md-2 second-field-search">
                                    <select name="cidade" class="form-control" required>
                                        <option value="">Cidade</option>
                                        <option value="portoalegre" <?php echo (($cidade == 'portoalegre') ? 'selected="selected"' : ""); ?>>Porto Alegre</option>
                                        <option value="novohamburgo" <?php echo (($cidade == 'novohamburgo') ? 'selected="selected"' : ""); ?>>Novo Hamburgo</option>
                                        <option value="florianopolis" <?php echo (($cidade == 'florianopolis') ? 'selected="selected"' : ""); ?>>Florianópolis</option>
                                    </select>
                                </div>
                                <div class="col-md-2 third-field-search">
                                    <input type="text" name="bairro" id="bairro" class="form-control" placeholder="Bairros" data-toggle="modal" data-target="#modalBairros" data-whatever="@getbootstrap">
                                </div>
                                <div class="col-md-2 fourth-field-search">
                                    <select name="valorminimo" class="form-control" required>
                                        <option value="">Valor de</option>
                                        <option value="1mil" <?php echo (($valorminimo == '1mil') ? 'selected="selected"' : ""); ?>>1mil</option>
                                        <option value="2mil" <?php echo (($valorminimo == '2mil') ? 'selected="selected"' : ""); ?>>2mil</option>
                                        <option value="3mil" <?php echo (($valorminimo == '3mil') ? 'selected="selected"' : ""); ?>>3mil</option>
                                    </select>
                                </div>
                                <div class="col-md-2 fifth-field-search">
                                    <select name="valormaximo" class="form-control" required>
                                        <option value="">Valor até</option>
                                        <option value="1mil" <?php echo (($valormaximo == '1mil') ? 'selected="selected"' : ""); ?>>1mil</option>
                                        <option value="2mil" <?php echo (($valormaximo == '2mil') ? 'selected="selected"' : ""); ?>>2mil</option>
                                        <option value="3mil" <?php echo (($valormaximo == '3mil') ? 'selected="selected"' : ""); ?>>3mil</option>
                                    </select>
                                </div>
                                <div class="col-md-2">
                                    <input type="submit" name="busca-implacavel" class="btn btn-success btn-block nobradius montserrat fs-16" value="Buscar" style="height:39px">
                                </div>
                            </div>
                        </div>
                    </div>
                    <div class="row branco">
                        <div class="col-md-12 montserrat branco fs-18">
                            <p style="margin:0 0 20px">
                                <a class="montserrat azul-claro fs-16" href="busca.php">
                                    Busca avançada e por código
                                </a>
                            </p>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    </form>
</div>

<div style="color:#000">
    <?php echo "<pre>"; print_r($_SESSION);  ?>
</div>