Method for completing well by cementing top of expandable screen

Abstract

The invention relates to the technical field of oilfield well completion, in particular to a method for completing a well by cementing the top of an expandable screen. The method comprises the following steps of: running a casing string comprising a casing tail pipe, a drilling plug-free system and the expandable screen into the well, performing cementing operation on the top of the expandable screen, and running an expansion diameter variation device to expand the expandable screen to cling to the wall of the well, wherein a packing rubber sleeve, an inner pipe device, a cementing hole and a blind plate are machined on the drilling plug-free system. Compared with the conventional screen, the expandable screen has the advantage that the external diameter of the expandable screen is increased after the expandable screen is expanded to enlarge an open area between formation fluid and a shaft and increase a fluid inlet volume, so that the fluid yield of a single well can be improved; and in addition, the high expandability of the expandable screen is used for forming a sand prevention screen system, gravels are not required to be filled into a horizontal well, and when a perforation tunnel or the well is blocked by formation sand to reduce the yield, the perforation tunnel is not required to be pre-filled, so that the repeated operation of sand prevention and well washing is eliminated.

Description

technical field [0001] The invention relates to the technical field of oilfield well completion, in particular to a well completion method applied to injecting cement at the top of an expansion screen in horizontal wells, deviated wells and sidetracked wells. Background technique [0002] At present, the completion method of cementing on the top of the screen is widely used in the completion of horizontal wells, deviated wells and sidetracked wells. It is a well completion method with quick results and high returns after well construction. But at the same time, the screen top cementing process also has some disadvantages: for example, when this process is applied in a horizontal well, if the formation produces sand, the annulus between the screen and the well wall must be filled with gravel to prevent the premature failure of the screen. blocked. In addition, because there is an annulus between the screen and the well wall, if the well wall collapses or the rock shrinks in ...

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Problems solved by technology

But at the same time, the screen top cementing process also has some disadvantages: for example, when this process is applied in a horizontal well, if the formation produces sand, the annulus between the screen and the well wall must be filled with gravel to prevent the premature failure of the screen. blocked

In addition, because there is an annulus between the screen and the well wall, if the well wall collapses or the rock shrinks in diameter, the screen will be crushed, and due to the existence of the annulus, the formation fluid is likely to form a concentrated scour effect, causing the screen to collapse. partial premature damage

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