초록 ▼

A subsea well assembly has ability to receive an internal tieback connector when providing full bore access. The subsea well assembly has an inner wellhead housing which has a counterbore at its upper end. A tieback profile is formed in the counterbore. A protective sleeve releasably secures the cou

A subsea well assembly has ability to receive an internal tieback connector when providing full bore access. The subsea well assembly has an inner wellhead housing which has a counterbore at its upper end. A tieback profile is formed in the counterbore. A protective sleeve releasably secures the counterbore, covering the tieback profile. After drilling is completed and tieback installation begins, the protective sleeve is removed. An internal tieback sleeve carried by a tieback funnel engages the tieback profile in the counterbore to secure the tieback funnel to the inner wellhead housing.

대표청구항 ▼

In a subsea well assembly having a tubular wellhead housing having a bore, the improvement comprising in combination: a counterbore in the bore of the wellhead housing, the counterbore having a greater diameter than a diameter of the bore immediately below the counterbore; a tieback profile in the c

In a subsea well assembly having a tubular wellhead housing having a bore, the improvement comprising in combination: a counterbore in the bore of the wellhead housing, the counterbore having a greater diameter than a diameter of the bore immediately below the counterbore; a tieback profile in the counterbore; a protective sleeve releasably secured in the counterbore and covering the tieback profile, the protective sleeve being movable to expose the tieback profile when it is desired to tieback the subsea well assembly; a tieback funnel which is configured to land on the rim of the wellhead housing when it is desired to tieback the subsea well assembly; and a tieback sleeve carried by the tieback funnel, having a profile on its exterior which is configured to engage the tieback profile in the counterbore after the protective sleeve has been moved to secure the tieback funnel to the wellhead housing, the tieback sleeve having a bore that has a diameter at least equal to the diameter of the bore immediately below the counterbore. In a method of drilling and tying back a subsea well which includes the steps of installing an outer wellhead housing with conductor pipe extending into the well, then drilling the well to a greater depth, the improvement comprising: providing an inner wellhead housing with a bore, a rim, a counterbore extending downward from the rim, a tieback profile in the counterbore, and a sealing area located below the counterbore and being of a smaller diameter than the diameter of the counterbore; releasably installing a protective sleeve in the counterbore so as to cover the tieback profile; securing a string of casing to the inner wellhead housing and landing the inner wellhead housing in the outer wellhead housing; drilling the well to a greater depth with the protective sleeve located in the counterbore; securing another string of casing to a casing hanger, landing the casing hanger in the inner wellhead housing, cementing the second string of casing in the well, and sealing the casing hanger to the sealing area of the bore of the inner wellhead housing; then, when it is desired to tieback the well, retrieving the protective sleeve; then providing a tieback funnel with a tieback sleeve which has a bore at least equal to the diameter of the sealing area of the bore of the inner wellhead housing, and landing the tieback funnel on the rim of the wellhead housing; and engaging the tieback sleeve with the tieback profile in the counterbore to secure the tieback funnel to the wellhead housing.