Straddle packer tool and method for well treating having valving and fluid bypass system

A straddle packer tool for treatment of a well having a wellbore, comprising:

• an elongate tool mechanism defining a treatment fluid passage and at least one bypass passage and having an upper end defining a connection for connection of said elongate tool mechanism to tubing for running and retrieval thereof and for conducting treatment fluid to said treatment fluid passage;
• sealing members supported by said elongate tool mechanism and spaced from one another for engaging the wellbore to define a sealed annulus zone between said sealing members;
• said elongate tool mechanism defining at least one treatment port communicating said treatment fluid passage with said the sealed annulus zone, defining at least one bypass passage permitting flow of fluid past said at least one treatment port, and defining at least one bypass port communicating said fluid bypass passage with the wellbore below said sealed annulus zone;
• a check valve located within said bypass passage permitting downward flow of fluid from said bypass passage into the wellbore below said well treatment tool and preventing upward flow of fluid into said bypass passage;
• fluid bypass ports defined by said elongate tool mechanism for conducting fluid flow to and from said bypass passage and the wellbore above and below said sealed annulus zone;
• and
• a fluid bypass valve positionable at an open position permitting flow of well fluid within said bypass passage and a closed position preventing the flow of well fluid within said bypass passage.

A straddle packer well treatment tool comprising:

• a tool body having upper and lower spaced external sealing elements for engaging a wellbore and establishing a sealed annulus zone therebetween, said tool body having a treatment fluid passage opening to said sealed annulus zone and a fluid bypass passage opening to the wellbore above and below said sealed annulus zone and being isolated from said treatment fluid passage, said lower sealing element being movable relative to said tool body by differential pressure;
• a check valve located within said bypass passage oriented for blocking upward flow of well fluid from the wellbore below said sealed annulus zone and for permitting downward flow of well fluid from the wellbore above the tool body through said check valve to the wellbore below the tool body;
• at least one bypass port defined in said tool body and located above said check valve;
• and
• a bypass valve movable relative to said tool body and having an open position relative to said bypass port to permit flow of well fluid from said bypass passage to the wellbore below said tool body and a closed position relative to said bypass port to block the flow of well fluid through said bypass port and to thus permit the flow of well fluid from said bypass passage into the wellbore below said tool body only through said check valve.