aggregate is prevented from passing inward by screens 35 but fluid is allowed to pass therethrough through perforated conduit 50 up through bore 49 sleeve 46 bore 43 and out primary conduit 39 after the desired quantity of aggregate has been packed in the annulus 53 the well may be killed similarly to the operation of fig2 by actuating sleeve valve 46 to expose ports 47 and pumping the killing fluid down the secondary tube 40 into ports 47 and up through the primary tube 39 checkvalve 51 has been provided to allow production fluid from formation 16 to flow upward while preventing fluid flow downward through packer 12 at all times during treatment of formation 31 as was contemplated with respect to formation 16 other treatment operations such as fracturing and acidizing may be achieved in formation 31 prior to or subsequent to the placing of aggregate pack 52 after the placing of the aggregate pack the desired treatment operations on formation 31 and the well killing operation the dual conduit tubing string 38 may be removed from the well taking with it collar 41 tube 44 sealing disc 45 tube 50 and checkvalve 51 it can be seen from the above description of the operation of this apparatus that subsequent formations above packer 33 may also be treated and packed in very similar operation to that of formation 31 all that is required for additional formation treatments is an additional packer packer mandrel ported screen and seal tube extension for each formation thus it can be seen that with the apparatus of this invention any number of high pressure formations may be treated and.