Method and tool for perforating a wellbore casing in a formation using a sand jet, and using such tool to further frac the formation

A downhole tool for creating perforations in a wellbore casing and further injecting a fluid in the created perforations using such tool, comprising:

• an elongate substantially cylindrical member, having a hollow bore and an outer periphery, adapted for insertion in a wellbore, comprising:
• (i) an uphole cylindrical, hollow slidable sleeve within said bore;
• (ii) a jet port, situated in said outer periphery, configured to direct a stream of pressurized abrasive fluid radially outwardly from said tool, fluid communication of said jet port with said bore allowed and prevented by slidable movement of said slidable sleeve;
• (iii) an uphole packer member, situated on a portion of said periphery downhole of said jet port;
• (iv) an expandable chamber and associated piston member, said chamber adapted to receive fluid under pressure from said bore and cause said associated piston member, when pressurized fluid is supplied to said bore, to compress and outwardly expand said uphole packer member;
• (v) a downhole packer member, situated on a portion of said periphery downhole of said uphole packer member;
• slidably moveable on said cylindrical member;
• (vi) a frac port in said periphery of said cylindrical member, intermediate said uphole and said downhole packer members;
• (vii) a slidably moveable guide member, having radially protruding slip members thereon configured to frictionally engage said wellbore casing when said tool is inserted therein, said guide member situated on said tool downhole of said downhole packer member, said guide member further having radially expandable jaw members on an uphole side thereof;
• and
• (viii) a ‘j’ slot subassembly within said tool, situated downhole of said downhole packer member, and having an associated cylindrical hollow mandrel with a slotted profile therein;
• wherein said ‘j’ slot subassembly, when downward force is applied to said tool and said guide member frictionally engages said wellbore casing , said ‘j’ slot subassembly does not allow further relative downward movement of a lower portion of said downhole packer member relative to said guide member and thus does not allow said jaw members to become actuated;
• and
• wherein said ‘j’ slot sub-assembly, when an upward pulling force is applied to said tool and thereafter a downward force is re-applied to said tool, is then in a ‘set’ position where:
• (i) said lower portion of said downhole packer member is allowed further downward downhole movement to allow said lower portion of said downhole packer member to be forced against said jaw members so as to expand them radially outwardly to engage said wellbore casing.