GB1441131A - - Google Patents

Abstract

1441131 Well driving E LYNES INC 29 May 1973 [14 June 1972] 25588/73 Heading E1F An inflatable packer for incorporation in a drill string and adapted to receive a fluid sampling unit 61 (Fig. 3) when the latter is dropped, pumped or run by wireline through the drill string includes a seating valve sleeve 17 which during normal drilling operations is biased by spring 19 to an upper position in which its groove 57 connects a port 42 in the housing 11 to a passage 59 leading to an annular recess 50 in a control valve sleeve 35. the latter being biased by a spring 36 to the upper position shown in which an inflation passage 60 leading to the space within packer element 14 and a passage 37 by passing the packer element are both connected to a chamber 38 communicating with the well annulus via port 41, the packer element thus remaining deflected. When the sampling unit lands on a shoulder 18 in sleeve 17, it depresses the latter to its alternative operative position. the depression of the sleeve being cushioned by shock absorber arrangement 30. In its depressed position, sleeve 17 disconnects recess 50 from port 42 and instead connects recess 50 via port 47 with the clearance space around the sampling unit and via port 48 via the space below a valve spool 62 whose upper end is also subjected via port 66 to the pressure in the clearance around the sampling unit so that this spool is pressure balanced and accordingly retained by a spring 63 in an upper position disconnecting sample chamber 61' from a passage 65 leading to an entry chamber in the unit which communicates with the passage 16 in housing 11 and which accommodates a pressure sensor. When the packing element is to be set and a sample taken, the pressure in the drill string is increased to a first predetermined level and this pressure acts on differential areas defining the ends of recess 50 and depresses sleeve 35 to a position in which the inflation passage 60 is disconnected from chamber 38 and connected instead to the recess 50 so that the drill string pressure is applied to the packer element 14 to cause inflation thereof. A subsequent increase in the drill-string pressure causes further depression of sleeve 35 to a position in which it disconnects the bypass passage 37 from chamber 38, and yet further pressure increase depresses the sleeve 35 to its lowermost position in which the space below spool 62 is disconnected from recess 50 and connected instead to chamber 38 so that drill string pressure acting on the top of the spool can depress it to allow a sample to flow into chamber 61'. Subsequent lowering of the drill string pressure produces a reverse resetting sequence, although if a malfunction occurs the pressure can be increased to open a shear safety valve 85 which will, then permit deflection of the packer element. A check valve 95 enables the pressure below the packer element to bleed off as the latter is inflated. In modifications, the sleeve 35 may be inverted and move upwards in response to increasing drill-string press, or this sleeve may be replaced by a spool. The exterior of the body may be of non-circular form above and below the packer element to provide a centralizing effect.