Slidable isolation sleeve with I-shaped seal

A well system, comprising:

• a first wellbore;
• a secondary wellbore extending from the first wellbore;
• wellbore casing located in the first wellbore, the wellbore casing having a casing window connecting an interior of the wellbore casing and an exterior of the wellbore casing, the casing window located proximate a junction between the first wellbore and the secondary wellbore;
• and
• a downhole tool positioned at the junction, the downhole tool including:
• an isolation system, the isolation system including:
• an elongated tubular, the elongated tubular having an opening connecting an interior of the elongated tubular and an exterior of the elongated tubular;
• a slot located in the elongated tubular, the slot spanning the opening and having an uphole no-go profile and a downhole no-go profile;
• an isolation sleeve located within the isolation system, the isolation sleeve configured to slide within the slot between the uphole no-go profile and the downhole no-go profile to either isolate the interior of the elongated tubular from the exterior of the elongated tubular or provide access between the interior of the elongated tubular and the exterior of the elongated tubular, the uphole no-go profile and the downhole no-go profile preventing the isolation sleeve from sliding out of the isolation system;
• and
• an I-shaped seal located in an annulus between the elongated tubular and the isolation sleeve, the I-shaped seal including:
• first and second opposing members;
• and
• a central member separating the first and second opposing members, the central member defining first and second fluid cavities, the central member and the first and second opposing members formed of a continuous piece of material, wherein the isolation sleeve is a permanent fixture within the isolation system.

A method for manufacturing and accessing a well system, comprising:

• forming a first wellbore and a secondary wellbore within a subterranean formation, the secondary wellbore extending from the first wellbore;
• positioning wellbore casing in the first wellbore, the wellbore casing having a casing window connecting an interior of the wellbore casing and an exterior of the wellbore casing, the casing window located proximate a junction between the first wellbore and the secondary wellbore;
• and
• positioning a downhole tool at the junction, the downhole tool including:
• an isolation system, the isolation system including:
• an elongated tubular, the elongated tubular having an opening connecting an interior of the elongated tubular and an exterior of the elongated tubular;
• a slot located in the elongated tubular, the slot spanning the opening and having an uphole no-go profile and a downhole no-go profile;
• an isolation sleeve located within the isolation system;
• and
• an I-shaped seal located in an annulus between the elongated tubular and the isolation sleeve, the I-shaped seal including:
• first and second opposing members;
• and
• a central member separating the first and second opposing members, the central member defining first and second fluid cavities, the central member and the first and second opposing members formed of a continuous piece of material, wherein the isolation sleeve is a permanent fixture within the isolation system;
• and
• sliding the isolation sleeve within the slot between the uphole no-go profile and the downhole no-go profile to either isolate the interior of the elongated tubular from the exterior of the elongated tubular or provide access between the interior of the elongated tubular and the exterior of the elongated tubular, the uphole no-go profile and the downhole no-go profile preventing the isolation sleeve from sliding out of the isolation system.

A downhole tool, comprising:

• an isolation system for placement at a junction between a first wellbore and a secondary wellbore, the isolation system including:
• an elongated tubular, the elongated tubular having an opening connecting an interior of the elongated tubular and an exterior of the elongated tubular;
• a slot located in the elongated tubular, the slot spanning the opening and having an uphole no-go profile and a downhole no-go profile;
• an isolation sleeve located within the isolation system, the isolation sleeve configured to slide within the slot between the uphole no-go profile and the downhole no-go profile to either isolate the interior of the elongated tubular from the exterior of the elongated tubular or provide access between the interior of the elongated tubular and the exterior of the elongated tubular, the uphole no-go profile and the downhole no-go profile preventing the isolation sleeve from sliding out of the isolation system;
• and
• an I-shaped seal located in an annulus between the elongated tubular and the isolation sleeve, the I-shaped seal including:
• first and second opposing members;
• and
• a central member separating the first and second opposing members, the central member defining first and second fluid cavities, the central member and the first and second opposing members formed of a continuous piece of material, wherein the isolation sleeve is configured to abut the uphole no-go profile when the isolation sleeve is isolating the interior of the elongated tubular from the exterior of the elongated tubular, and configured to abut the downhole no-go profile when the isolation sleeve is providing access between the interior of the elongated tubular and the exterior of the elongated tubular.

A downhole tool, comprising:

• an isolation system for placement at a junction between a first wellbore and a secondary wellbore, the isolation system including:
• an elongated tubular, the elongated tubular having an opening connecting an interior of the elongated tubular and an exterior of the elongated tubular;
• a slot located in the elongated tubular, the slot spanning the opening and having an uphole no-go profile and a downhole no-go profile;
• an isolation sleeve located within the isolation system, the isolation sleeve configured to slide within the slot between the uphole no-go profile and the downhole no-go profile to either isolate the interior of the elongated tubular from the exterior of the elongated tubular or provide access between the interior of the elongated tubular and the exterior of the elongated tubular, the uphole no-go profile and the downhole no-go profile preventing the isolation sleeve from sliding out of the isolation system;
• and
• an I-shaped seal located in an annulus between the elongated tubular and the isolation sleeve, the I-shaped seal including:
• first and second opposing members;
• and
• a central member separating the first and second opposing members, the central member defining first and second fluid cavities, the central member and the first and second opposing members formed of a continuous piece of material, wherein the isolation sleeve is configured to abut the downhole no-go profile when the isolation sleeve is isolating the interior of the elongated tubular from the exterior of the elongated tubular, and configured to abut the uphole no-go profile when the isolation sleeve is providing access between the interior of the elongated tubular and the exterior of the elongated tubular.

A downhole tool, comprising:

• an isolation system for placement at a junction between a first wellbore and a secondary wellbore, the isolation system including:
• an elongated tubular, the elongated tubular having an opening connecting an interior of the elongated tubular and an exterior of the elongated tubular;
• a slot located in the elongated tubular, the slot spanning the opening and having an uphole no-go profile and a downhole no-go profile;
• an isolation sleeve located within the isolation system, the isolation sleeve configured to slide within the slot between the uphole no-go profile and the downhole no-go profile to either isolate the interior of the elongated tubular from the exterior of the elongated tubular or provide access between the interior of the elongated tubular and the exterior of the elongated tubular, the uphole no-go profile and the downhole no-go profile preventing the isolation sleeve from sliding out of the isolation system;
• and
• an I-shaped seal located in an annulus between the elongated tubular and the isolation sleeve, the I-shaped seal including:
• first and second opposing members;
• and
• a central member separating the first and second opposing members, the central member defining first and second fluid cavities, the central member and the first and second opposing members formed of a continuous piece of material, wherein the elongated tubular includes one or more profiles configured to engage with a collet in the isolation sleeve.