Method and apparatus for producing fluids from a production zone(s) by drilling and completing multiple laterals from primary wellbore. One or more pre-formed window units are provided in a casing string before it is cemented in the well. Each unit is comprised of a housing having an inlet and two outlets, one of which forms the pre-formed window. The axes of the two outlets forms a relatively small angle (e.g. from 1.degree. to about 10.degree., preferably 3.degree.) whereby a well string will follow a gently curved path as it exits through the window. A re-entry line from the surface can be attached to the housing so that a work-over string can be lowered into a selective lateral without having to shut-in production from the other laterals.
A method of fracking multiple laterals sequentially is described. It allows the drilling rig to be moved off site as the laterals are fracked. Thereafter, they can all be produced simultaneously. The laterals begin from a main lateral that is already oriented in the producing zone and preferably exit in a coplanar manner so as to extend immediately into the producing formation.
A method of casing multilateral wells and associated apparatus provide increased diameter in wellbores drilled below a casing splitter. In a described embodiment, a casing splitter is positioned in a subsea wellbore with a minimum restriction of 18.565", with the casing splitter attached at a lower end of a 133/8" casing string. Two 81/2" bores extend through a lower end of the casing splitter, whereby only one standard casing size is skipped due to the wellbore junction formed by the casing splitter.
A well completion apparatus and method comprises a junction assembly having a template and a lateral branch connector engageable with the template to couple a main bore to a lateral branch bore. To improve inter-engagement characteristics of the template and connector, one arrangement of the junction assembly utilizes a continuous rail and groove inter-engagement mechanism. In another arrangement, a portion of the rail and groove inter-engagement mechanism is segmented instead of continuous. A method and apparatus is also provided in some arrangements to enable placement of intelligent completion devices in a lateral branch. Additionally, some junction assemblies comprise flow control mechanisms to control commingling, or not, of fluids from different regions in the well bore.
A subterranean well completion system and associated methods of servicing wells provide convenient access to selected ones of multiple tubing strings installed in wells. In a described embodiment, a completion system includes a wye block device which has an access control assembly separately conveyed into a housing assembly installed in a well. The access control assembly is conveyed into the housing assembly when it is desired to access a selected one of multiple tubing strings attached to the housing assembly.
An improved method for drilling a lateral well from an existing wellbore is disclosed whereby a section of said existing wellbore is preferably enlarged such as by under-reaming. The enlarged section is filled with a material such as, for example, epoxy which hardens to form an impermeable body. The hardened material is drilled out laterally and also longitudinally, such that a sealed junction is formed within the impermeable body between the lateral well and existing well. The longitudinal drilling follows an arcuate path. In one embodiment of the present invention, a packer positioned within the enlarged section may be filled with the pumped material to thereby avoid any contamination of the material with other downhole elements such as mud and oil whereby the composition of the pumped material is consistent and known. In one embodiment, an arcuate drillable guide may be positioned in the enlarged section prior to filling the enlarged section with material. The arcuate drillable guide thereby subsequently guides a drill bit through the hardened material along an arcuate path for reconnecting the existing wellbore through the enlarged section.
