Expandable sand screen for use in a wellbore

#1. Field of the Invention

#The present invention relates to expandable sand screen. More particularly the present invention relates to an expandable sand screen that permits fracturing of a hydrocarbon bearing formation after the well screen is expanded in a wellbore.

#2. Description of Related Art

#So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.

#It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

#FIG. 1 is a section view showing an open, horizontal wellbore with an expandable sand screen disposed therein.

#FIG. 1 is a section view of a wellbore 200 with an expandable sand screen 210 according to the present invention disposed therein. The wellbore includes a central wellbore which is lined with casing 215. The annular area between the casing and the earth is filled with cement 220 as is typical in well completion. Extending from the central wellbore is an open, horizontal wellbore 225. A formation 226 is shown adjacent the wellbore 225. Disposed in the open wellbore is an expandable sand screen (ESS) 210. As illustrated in FIG. 1, the ESS 210 is run into the wellbore on a tubular run-in string 230. Disposed at the end of the run-in string is an expander tool 100. In the embodiment shown, the expander tool 100 is initially fixed to the expandable sand screen 210 with a temporary connection 235 like a shearable connection or some other temporary mechanical means. Typically, the ESS 210 is located at the lower end of a liner 218 which is run into the well and hung from the lower portion of the casing 215 by some conventional slip means. Below the liner top, the outer diameter of the liner 218 is reduced to a diameter essentially equal to the diameter of the ESS.

#FIG. 2 is an exploded view of an exemplary expansion tool 100. The expansion tool 100 has a body 102 which is hollow and generally tubular with connectors 104 and 106 for connection to other components (not shown) of a downhole assembly. The connectors 104 and 106 are of a reduced diameter compared to the outside diameter of the longitudinally central body part of the tool 100. The central body part has three recesses 114 to hold a respective roller 116. Each of the recesses 114 has parallel sides and extends radially from a radially perforated tubular core (not shown) of the tool 100. Each of the mutually identical rollers 116 is somewhat cylindrical and barreled. Each of the rollers 116 is mounted by means of an axle 118 at each end of the respective roller and the axles are mounted in slidable pistons 120. The rollers are arranged for rotation about a respective rotational axis which is parallel to the longitudinal axis of the tool 100 and radially offset therefrom at 120-degree mutual circumferential separations around the central body. The axles 118 are formed as integral end members of the rollers and the pistons 120 are radially slidable, one piston 120 being slidably sealed within each radially extended recess 114. The inner end of each piston 120 is exposed to the pressure of fluid within the hollow core of the tool 100 by way of the radial perforations in the tubular core. In this manner, pressurized fluid provided from the surface of the well, via a tubular, can actuate the pistons 120 and cause them to extend outward whereby the rollers contact the inner wall of a tubular to be expanded.

#FIG. 3 is a section view of the expandable sand screen 210 of the present invention in a wellbore 200 prior to expansion. The ESS includes a base pipe 240 having perforation 242 formed therein, woven filter material 245 and an outer shroud 250 having perforations 255 formed therein and also having outwardly formed longitudinal channels 260 formed thereupon. The channels 260 are formed by bending the surface of the outer shroud 250 between perforations 255 to create two sides 265, 270 and a bottom portion 275. In the preferred embodiment illustrated in FIG. 3, the bottom portion of each channel is welded or otherwise attached to the base pipe in at least one location 280. The woven filter material 245 is held between the bottom 275 of the channel 260 and the base pipe 240. The outer shroud 250 may be formed by any well-known metal working means including pressing and bending. A longitudinal seam (not shown) is formed by the cylindrical shroud after it is wrapped around the base pipe and filter material and its free ends are connected.