Method and system for circulating fluid in a well system

A system for circulating drilling fluid through well bores, comprising:

• a substantially vertical well bore extending from a surface to a subterranean zone;
• an articulated well bore extending from the surface to the subterranean zone, the articulated well bore horizontally offset from the substantially vertical well bore at the surface and intersecting the substantially vertical well bore at a junction proximate the subterranean zone;
• a drainage bore extending from the junction into the subterranean zone;
• a drill string disposed within the articulated well bore, the drill string used to drill the drainage bore;
• a drilling fluid provided through the drill string and exiting the drill string proximate a drill bit of the drill string;
• a tubing disposed within the substantially vertical well bore, the tubing having an open end at the junction;
• fluid provided down the substantially vertical well bore, the fluid exiting the tubing at the junction;
• and
• a fluid mixture returning up the substantially vertical well bore outside of the tubing, the fluid mixture comprising the drilling fluid after the drilling fluid exits the drill string.

A method for circulating drilling fluid in a well system, comprising:

• drilling a substantially vertical well bore from a surface to a subterranean zone;
• drilling an articulated well bore from the surface to the subterranean zone using a drill string, the articulated well bore horizontally offset from the substantially vertical well bore at the surface and intersecting the substantially vertical well bore at a junction proximate the subterranean zone;
• drilling a drainage bore from the junction into the subterranean zone;
• pumping a drilling fluid through the drill string when drilling the drainage bore, the drilling fluid exiting the drill string proximate a drill bit of the drill string;
• providing fluid down the substantially vertical well bore outside of a tubing disposed in the substantially vertical well bore, the tubing having an opening at the junction;
• and
• wherein a fluid mixture enters the opening of the tubing at the junction and returns up the substantially vertical well bore through the tubing, the fluid mixture comprising the drilling fluid after the drilling fluid exits the drill string.

A system for circulating drilling fluid through well bores, comprising:

• a substantially vertical well bore extending from a surface to a subterranean zone;
• an articulated well bore extending from the surface to the subterranean zone, the articulated well bore horizontally offset from the substantially vertical well bore at the surface and intersecting the substantially vertical well bore at a junction proximate the subterranean zone;
• a drainage bore extending from the junction into the subterranean zone;
• a drill string disposed within the articulated well bore, the drill string used to drill the drainage bore;
• a drilling fluid provided through the drill string and exiting the drill string proximate a drill bit of the drill string;
• a tubing disposed within the substantially vertical well bore, the tubing having an opening at the junction;
• fluid provided down the substantially vertical well bore outside the tubing;
• and
• a fluid mixture entering the opening of the tubing at the junction and returning up the substantially vertical well bore through the tubing, the fluid mixture comprising the drilling fluid after the drilling fluid exits the drill string.

A method for circulating drilling fluid in a well system, comprising:

• drilling a substantially vertical well bore from a surface to a subterranean zone;
• drilling an articulated well bore from the surface to the subterranean zone using a drill string, the articulated well bore horizontally offset from the substantially vertical well bore at the surface and intersecting the substantially vertical well bore at a junction proximate the subterranean zone;
• drilling a drainage bore from the junction into the subterranean zone;
• pumping a drilling fluid through the drill string when drilling the drainage bore, the drilling fluid exiting the drill string proximate a drill bit of the drill string;
• providing a pump string down the substantially vertical well bore, the pump string comprising a pump inlet proximate the junction;
• and
• pumping a fluid mixture up the substantially vertical well bore through the pump string, the fluid mixture entering the pump string at the pump inlet.

A system for circulating drilling fluid through well bores, comprising:

• a substantially vertical well bore extending from a surface to a subterranean zone;
• an articulated well bore extending from the surface to the subterranean zone, the articulated well bore horizontally offset from the substantially vertical well bore at the surface and intersecting the substantially vertical well bore at a junction proximate the subterranean zone;
• a drainage bore extending from the junction into the subterranean zone;
• a drill string disposed within the articulated well bore, the drill string used to drill the drainage bore;
• a drilling fluid provided through the drill string and exiting the drill string proximate a drill bit of the drill string;
• a pump string disposed within the substantially vertical well bore, the pump string comprising a pump inlet proximate the junction;
• and
• a fluid mixture entering the pump string at the pump inlet and pumped up the substantially vertical well bore through the pump string.

A method for circulating fluid in a well system, comprising:

• pumping a fluid through an articulated well bore, the articulated well bore horizontally offset from a substantially vertical well bore at the surface and intersecting the substantially vertical well bore at a junction proximate a subterranean zone;
• providing a pump string down the substantially vertical well bore, the pump string comprising a pump inlet proximate the junction;
• and
• pumping a fluid mixture up the substantially vertical well bore through the pump string, the fluid mixture entering the pump string at the pump inlet.

A method for circulating drilling fluid in a well system, comprising:

• drilling a substantially vertical well bore from a surface to a subterranean zone;
• drilling an articulated well bore from the surface to the subterranean zone using a drill string, the articulated well bore horizontally offset from the substantially vertical well bore at the surface and intersecting the substantially vertical well bore at a junction proximate the subterranean zone;
• drilling a drainage bore from the junction into the subterranean zone;
• pumping a drilling fluid through the drill string when drilling the drainage bore, the drilling fluid exiting the drill string proximate a drill bit of the drill string;
• and
• providing fluid to at least one of the well bores to vary a bottom hole pressure of the system.