Ishidi likathayela elipendwe kusengaphambili yikhoyili yensimbi ependwe kusengaphambili esebenzisa insimbi eyisithako noma insimbi ye-aluzinc njengesisekelo.Ngemuva kokwelashwa kwangaphambili (ukususwa kwamakhemikhali kanye nokwelashwa kokuguqulwa kwamakhemikhali), indawo engaphezulu embozwe ngongqimba noma izendlalelo ezimbalwa zokumboza, ngokubhaka nokuphulukiswa, bese iba umkhiqizo oqediwe.
Ishidi lokuphahla elipendwe kusengaphambili linezinzuzo zeyunithi yesisindo sokukhanya, amandla aphezulu, ukusebenza kahle kwe-seismic, ukufakwa okusheshayo, ukubukeka okuhle, njll. Kuyinto enhle yokwakha kanye nengxenye.Isetshenziselwa ikakhulukazi izakhiwo zemvilophu, ama-slabs aphansi, amathayili ophahleni, futhi ingasetshenziselwa ezinye izakhiwo.