US 7,401,665 B2 · Apparatus and method for drilling a branch borehole from an oil well

Abstract

A wireline drill train is used to drill an elongated, small diameter, lateral branch borehole from near the base of a main well. The drill train, includes a drill module, a first self-propelled thrust module coupled to the drill module, and a second self-propelled thrust module pivotally coupled to the first self-propelled thrust module. Each thrust module includes at least two extendible thrusters. Each extendible thruster includes a six-bar mechanism and a traction tread. The drill train further includes a first articulated linkage linking the first self-propelled thrust module to the drill module, and a second articulated linkage linking the second thrust module to the first thrust module. The second articulated linkage includes a thrust-transmission bar and three retractable stiffener bars. The method for drilling the curved transition region of the lateral branch borehole includes executing a series of alternating pivotal drilling steps and forward drilling steps to create a step-cut region of branch borehole having very small radius of curvature.

Claims23

Dependent claims

An articulated modular drill train for drilling through the wall of an oil well and into earth formation to make a branch borehole at a selected depth, the drill train comprising:

a drill module;
a first self propelled thrust module coupled to the drill module, the first thrust module including at least two extendible thrusters having an articulated multi-bar mechanism associated therewith;
a second self propelled thrust module pivotally coupled to the first thrust module, the second thrust module including at least two extendible thrusters.

A method for drilling through the wall of an oil well and into earth formation to make a branch borehole, using an axially-aligned articulated modular drilling train, the drilling train having a drill module, a cuttings removal module, a first self-propelled thrust module with at least two extendible thrusters having six-bar mechanisms, and a second self-propelled thrust module with at least two extendible thrusters, the modules coupled by articulated linkages, the method comprising the steps of:

placing a whipstock at a selected depth within the well corresponding to the desired depth of the planned branch borehole;
attaching the drilling train to a wireline above the well;
lowering the drilling train down the well to a position just above the whipstock;
extending the first and second traction treads into contact with the wall of the oil well;
setting tilt in the first thrust module such that the drill module is oriented within the well to execute a first drilling step for cutting through the wall of the well at an acute angle;
executing a first series of drilling steps to open a sharply-curved step-cut region of branch borehole;
and
executing a second series of forward drilling steps to open an extended lateral region of branch borehole.

5 more elements

Dependencies are inferred from the claim text.

Apparatus and method for drilling a branch borehole from an oil well

Life of this patent

Apparatus and method for drilling a branch borehole from an oil well

Life of this patent

Abstract

Claims23