Ball Drop Reverse Circulation Valve & Method of Downhole Ball Caging
Publication Date: 2015-Jan-02
The IP.com Prior Art Database
The purpose of this concept is to expand existing capabilities of the well services companies to effectively reverse circulate sand by allowing larger area of reverse circulation as needed. When running a jet tool on coiled tubing either for plug setting or running another tool below, reverse circulation capability is quite diminished. The only area that is available for reverse circulation is the location of the jet orifices or, if no check valve is installed below the sleeve tool, the ID of the tool placed below. Reverse circulation of sand through the tools below creates risk of erosion. The general scope of this publication is to present a reverse circulation valve which will save the jetting tool part of the BHA from unnecessary erosion. The key benefit is to provide an arrangement to cage the dropped ball downhole so that not to allow the ball to flow back to surface. The proposed concepts also prevent reverse flow through tools below and channel the reverse circulation through the large ports. This will allow shorter intervention times and customer savings. The sand cleaning stage may be performed by direct circulation using N2 if desired. The concept proposed in this disclosure can be deployed across other processes including horizontal applications.
Version 1-Caged Drop Ball RCV
The operation of this reverse circulation valve is purely mechanical. A flapper is enclosed in sub housing. A sleeve keeps flapper open and protected behind it. The sleeve is held in place with the help of lower rating shear screws attached to sub housing. The sleeve also has ball seat on its ID. The entire subassembly is connected to main housing with the help of another set of larger rating shear screws. Dedicated ports will be opened up by shifting sub housing and shearing large screws. The benefit of the flapper is, act as a cage for the ball and also prevent flow from below.
Please refer to Figure. 1 given below for sequence of operations explained with help of tool cross section. The flapper housing and protective sleeve is connected to each other with lower rating shear screws. When circulated ball seats on its seating at the sleeve ID, the lower rating screws will shear first and releases the flapper. Further, the sleeve shoulders on the sub housing and upon continuing pressurizing the larger screws will shear. Main housing is provided with large ports which are protected initially behind sub housing so that there is no communication between pumping fluid through ID and OD of valve. These large ports will be opened when the large screw shears. The flapper checks flow from tools below. This way not only the ball is caged behind flapper so that it would not flow back to surface but also reverse flow from tool below is stopped. The sub housing is secured at the shifted position with the help of a snap ring so that flow from below would not shift it accidentally.
Figure 1: Sequences of working for Caged Drop Ball Reverse Circulation Valve
Version 2-Collet Caged Drop Ball RCV
The operation of this reverse circulation valve is purely mechanical. This uses a collet finger mechanism for ball caging. The sleeve is designed with collet fingers at its one end. The sleeve held in a place such a way that all collets are in a relaxed position in the groove. This sleeve shifted when circulated ball seats on its seating provided at the internal diameter. Main housing is provided with ports for reverse circulation, these ports are initially protected behind collet sleeve. The collet sleeve is also provided with similar ports which are NOT aligned initially with ports in main housing so that there is no communication between pumping fluid through ID and OD of valve. These ports will be aligned and flow establishes between ID and OD of valve by circulating a ball downhole. This ball will pass though collet section before seats on its seating. Since all collets are in relaxed position they do not stop the ball from flowing through it. Pumping pressure will shift collet sleeve and also force all collets to collapse. Internal diameter of collets will be decreased so it won’t allow the ball to flow through it. Ball will be trapped downhole BUT not flow uphole. With the sleeve shifted the ports are aligned for reverse ci...