Assembly and method for providing a means of support and positioning for drilling multi-lateral wells and for reentry therein through a premilled window

A method for drilling at least one multi-lateral well from a well bore in a well having a tubular wall comprising;

• adding a junction section member having a premilled window and at least one orientation key-way in communication with said premilled window to a well having a tubular wall;
• orientating the tubular wall and said junction section in the well bore with a temporary orientation key;
• setting a whip stock member which has a compressed spring key for opening in said premilled window of the junction section member;
• sliding said opened uncompressed spring key into said at least one orientation key way formed as part of the longitudinally premilled window for locking engagement as said whip stock member is lowered into said orientation key member for precise orientation;
• drilling the at least one multi-lateral well by deflecting said drill bit off said whip stock as said multi-lateral well is drilled.

A method for drilling at least one multi-lateral well from well bore in a well having a tubular wall comprising.

• adding a junction section having at least one premilled window and at least one orientation key-way in communication with said premilled window to said tubular wall in a well bore;
• orientating the tubular wall and said junction section in the well bore with a temporary orientation key;
• setting a whip stock member which has a compressed spring key for opening in said premilled window of the junction section;
• cementing said well casing and said junction section in proper orientation;
• drilling out said cement, and a temporary orientation key, and a temporary mule shoe carried by a temporary cover closing said premilled window from fluid communication.

A method for entry and reentry into and through the longitudinally premilled window in at least one multi-lateral well comprising,

• running a reentry tool member having a spring driven key member down hole into a longitudinally premilled window having at least one orientation key way located uphole in the longitudinally premilled window and in communication therewith;
• pulling up hole after reaching said longitudinally premilled window which is determined by the spring driven key member opening into said longitudinally premilled window,
• seating the spring driven key member located on said reentry tool member by said up hole motion into said at least one orientation key way;
• kicking said reentry tool member out by continued up hole motion;
• and
• lowering said reentry tool member down with said reentry tool member kicked out for entry into said at least one multi-lateral well.