The present invention relates to conducting production tests of wells penetrating earth formations, such as oil and gas wells. More particularly, the present invention provides an improved method and apparatus for testing wells without the need to withdraw the drill stem from the borehole.
International patent application number PCT/US98/22379 teaches and discloses methods and apparatuses for testing wells while leaving the drill stem in the borehole. This application is incorporated herein by reference for all purposes.
Significant advances have been made in the present invention to provide a system for shutting in the well so that tests can be made. Such improvements relate to the structural use of the activation mechanism for inflating downhole packers including an improved collet/spline configuration to more positively hold and release the packer mandrel; a simplified hydraulic fluid reservoir and feed system to the packers; the utilization of a plurality of packers having varying pressure capabilities; an improved packer attachment assembly; and an improved hydraulic float valve coordinated with the packer hydraulic system.
The testing drill collar of the present invention may be positioned between the drill bit and the drill collar assembly. The inflatable packer assembly may be dressed to accommodate environments that arise in different geological areas. This may be obtained by selecting a packer design of short element combination, short and long combination, or only one long element. Packer material and designs depend on area, depth, and bottom hole temperature.
The tool is locked in the drill position until deployed by an activating tool via slickline, electric line, or by pumping the activating tool down. Once activated, the lower portion of the drill collar scopes downward. The length of travel is controlled by the amount of pressure applied against the activating tool and consequentially the pressure is delivered to a piston which compresses clean compressible fluid from the reservoir into the packer elements. The packers have separate fluid reservoirs but inflate simultaneously. It should be understood that the fluid utilized in no way limits the present invention. A better packer seat is achieved due to the downward movement while inflating. Once desired pressure is achieved this pressure is locked in and maintained by a locking ratchet design that cannot release until xc2xc round right hand torque is delivered with downward travel of the drill string. This deflates the elements and receives the lower drill collar and latches back in the drill position when very little weight is put on the drill bit. If elected, reverse circulation may be achieved during this procedure.
The drill mode consists of the upper collar receiving the lower collar scoped in. Torque is delivered from the upper collar to the lower collar by a rugged spline section. The spline area is sealed and operates in gear oil, therefore, assuring a clean environment to maximize the life span of the splines and the contact area for weigh transfer. Weight is delivered from the upper collar at the top of the lower collar.
During testing, a multi-flow and multi-shut-in apparatus and method delivers formation pressures, temperatures, and fluid or gas properties to the surface, therefore allowing the test to be engineered efficiently, according to real time data.