Packing means for a wellhead assembly

In a wellhead assembly having a casing head and an inner casing therein rigidly secured adjacent its lower end portion beneath said casing head and having an upper unrestrained free end portion extending above said casing head, said wellhead assembly having a bore therein above the casing head receiving the inner casing defining an annular space between the outer surface of the inner casing and the inner surface defining said bore, guide means within said bore contacting the outer surface of said inner casing to guide said inner casing upon longitudinal movement relative to said casing head upon longitudinal expansion and contraction of said inner casing relative to said casing head resulting from its thermal environment,

• a. a packing assembly mounted within said annular space including a pair of separate packing structures mounted in a spaced relation one above the other secured to said inner casing upper end portion and extending in sealing relation between said inner casing and said inner surface defining the bore, said packing assembly being moveable with said free upper end portion inside said bore as said inner casing moves in said relative longitudinal movement in response to temperature changes of said inner casing,
• b. said packing assembly having a pair of adjacent annular packing members secured to said inner casing by a packing mount means, one of said annular packing members being constructed of a material having suitable high temperature sealing characteristics and the other of said packing members being constructed of a material having suitable lower temperature sealing characteristics,
• c. said guide means having a centralizer rigidly mounted in said casing head and longitudinally slidably engaged with said inner casing, said centralizer having a means to seal same between said inner casing and said casing head and,
• d. said inner casing having means to scrape said bore rigidly mounted on the upper end portion thereof above the uppermost packing assembly, said means to scrape having an annular scraper member in sliding contact with the surface of said bore to scrape the surface of said bore upon said longitudinal sliding motion of said inner casing in said casing head.

In a wellhead assembly having a casing head and an inner casing therein rigidly secured adjacent its lower end portion beneath said casing head and having an upper unrestrained free end portion extending above said casing head, said wellhead assembly having a bore therein above the casing head receiving the inner casing and defining an annular space between the outer surface of the inner casing and the inner surface defining said bore, guide means within said bore contacting the outer surface of said inner casing to guide said inner casing in longitudinal movement relative to said casing head upon longitudinal expansion and contraction of said inner casing relative to said casing head resulting from its thermal environment,

• a. a packing assembly mounted within said annular space and secured to the exterior of said upper end portion of said inner casing for extending in sealing relation between said inner casing and said inner surface defining the bore, said packing assembly being moveable with said free upper end portion inside said bore as said inner casing moves in said relative longitudinal movement in response to temperature changes of said inner casing, and
• b. a means to scrape the inner surface of said wellhead assembly defining said bore rigidly secured on the upper end portion of said inner casing above said packing assembly, said means to scrape including an annular scraping member in contact with said surface defining said bore to scrape said surface upon longitudinal motion of said inner casing in said casing head.

In a wellhead assembly having a casing head and an inner casing therein rigidly secured adjacent its lower end portion beneath said casing head and having an upper restrained free end portion extending above said casing head, said wellhead assembly having a bore therein above the casing head receiving the inner casing and defining an annular space between the outer surface of the inner casing and the inner surface defining said bore, guide means within said bore contacting the outer surface of said inner casing to guide said inner casing upon longitudinal movement relative to said casing head upon longitudinal expansion and contraction of said inner casing relative to said casing head resulting from its thermal environment,

• a. a packing assembly mounted within said annular space and secured to the exterior of said upper end portion of said inner casing for extending in sealing relation between said inner casing and said inner surface defining the bore, said packing assembly being moveable with said free upper end portion inside said bore as said inner casing moves in said relative longitudinal movement in response to temperature changes of said inner casing, and
• b. an auxilliary packing means having a normally closed opening through said wellhead assembly communicably connecting an external point and said annular space, said opening being operable for injecting a sealing compound into said annular space to seal said inner casing and said inner surface defining said bore.

In a wellhead assembly having a casing head and an inner casing therein rigidly secured adjacent its lower end portion beneath said casing head and having an upper unrestrained free end portion extending above said casing head, said wellhead assembly having a bore therein above the casing receiving the inner casing and defining an annular space between the outer surface of the inner casing and the inner surface defining said bore, guide means within said bore contacting the outer surface of said inner casing to guide said inner casing in longitudinal movement relative to said casing head upon longitudinal expansion and contraction of said inner casing relative to said casing head resulting from its thermal environment,

• a. a packing assembly mounted within said annular space and secured to the exterior of said upper end portion of said inner casing for extending in sealing relation between said inner casing and said inner surface defining the bore, said packing assembly being moveable with said free upper end portion inside said bore as said inner casing moves in said relative longitudinal movement in response to temperature changes of said inner casing,
• b. a means to scrape the inner surface of said wellhead assembly defining said bore rigidly secured on the upper end portion of said inner casing above said packing assembly, said means to scrape including an annular scraping member in contact with said surface defining said bore to scrape said surface upon longitudinal motion of said inner casing in said casing head, and
• c. an auxilliary opening through said wellhead assembly communicably connecting a point on the exterior of said wellhead assembly and said annular space, said auxillary opening being normally closed and in use being openable for providing access to said annular space for such purposes as inspection, and placing a sealing compound, lubricating compound, corrosion inhibiting compound in said annular space.