초록 ▼

Well casing assembly for use in oil and gas wells, and especially deviated or horizontal wells, has an inner pipe member with threaded ends which permit a number of casing assemblies to be joined in a string. The inner pipe has a series of perforations along a segment of its length which are covered

Well casing assembly for use in oil and gas wells, and especially deviated or horizontal wells, has an inner pipe member with threaded ends which permit a number of casing assemblies to be joined in a string. The inner pipe has a series of perforations along a segment of its length which are covered by an elongated screen member which prevents the passage of sand particles. A concentric outer protective cover member is devoid of perforations in regions which are radially opposite the inner screen to prevent damage to the screen. One or more perforated segments of the outer member are axially spaced from the screen member so that inward flow from a formation will have its energy and velocity reduced before it reaches the screen, thereby minimizing erosion of the screen surface. If desired, perforated flow control devices such as annular rings can be located between the inner pipe and outer member at the ends of the screen segment to allow a more uniform flow to the screen, and thus further reduce erosion.

대표청구항 ▼

[ The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:] [1.] A casing assembly for a well, the casing assembly comprising:an essentially cylindrical inner pipe extending along a casing axis for the entire length of the casing assembly, the i

[ The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:] [1.] A casing assembly for a well, the casing assembly comprising:an essentially cylindrical inner pipe extending along a casing axis for the entire length of the casing assembly, the inner pipe having a series of perforations formed through its surface along a first length segment of the casing axis;an essentially cylindrical outer member radially spaced from and concentrically located about the inner pipe and also extending along the casing axis, the outer member having a series of perforations formed through its surface along a second length segment of the casing axis;a screen mounted over an outer circumferential surface of the inner pipe and over the series of perforations formed on the inner pipe;wherein the first length segment and the screen mounted over its surface and the second length segment along the casing axis are substantially offset with respect to one another.