The present invention relates to a method for producing fluids or gases from a horizontal well 10, the method comprising the steps providing a horizontal well 10 having a horizontal production openhole 20, dividing the horizontal production openhole 20 into at least two separate compartments 30, 32 by means of blockers 40, 42, providing for each separate compartment 30, 32 at least one production string 50, 52, and passing fluid or gas 100, 102 from each compartment 30, 32 to the surface 106 via the corresponding production strings 50, 52. The present invention further relates to a fluid or gas production device 1 for horizontal fluid or gas wells.