in those cases where the sand control provided by the screens 42 is not necessary or desired fig8 illustrates another aspect of the current invention in which the conduit 16 having check valves 22 therein which happen to be incorporated into sand screens 42 in fig8 is combined with in line flow control valves 47 the in line flow control valves 47 may be used to regulate e g choke the flow to or from the various zones 46 see u s patent application publication no u s 2001 0045290 a1 published nov 28 2001 for some examples of in line valves 47 another problem often associated with injection applications involves channeling uncontrolled injectivity can create channeling which prevents sweep uniformity and can lead to early water production in the production well 10 as illustrated in fig9 the present invention provides for variation in the density and concentration of valves 22 according to the well 10 using data relating to the well s or reservoir spacing between conduit apertures 20 is set to provide a uniform sweep of injected fluid by varying the spacing between apertures 20 and associated valves 22 in the conduit 16 the sweep of injected fluid into the well 10 and target reservoir 46 is controlled to alleviate the risk of channeling in fig9 the conduit 16 has one section 48 with a relatively lower concentration of openings and associated valves 22 and another section 50 with a relatively higher concentration of openings and associated valves 22 the relative concentration may vary depending upon the particular requirements and characteristics of the well 10 the varying of the concentration of the valves 22 also.