The sliding sleeve has been widely used in upper completions as a useful flow management device to enable selective communications between the production tubing and the annulus. Traditional sliding sleeves are mechanically operated by standard wireline method, which not only results in non-productive time and potential operational risks but also restricts sliding sleeve applicable in vertical wellbores only.
To overcome the limitations, this paper introduced an innovative Hydraulic Controlled Sliding Sleeve (HCSS), which eliminates interventions with conventional wireline shifting tools. HCSS offers instant open/close operation by surface controlled hydraulic pressure through a single control line. HCSS features unique advantages over mechanical sliding sleeves, by its operational simplicity, independence on wireline units, and applicability in deviated wells and horizontal wells. The application of HCSS could save non-productive time, reduce operational risks and improve operational efficiency and economics.
This paper will give a comprehensive demonstration of HCSS and illustrate the working principle in detail. Unique features and capabilities over traditional sleeves will be discussed explicitly. HCSS will be opened by applying hydraulic pressure from the surface control unit to activate the movement of the inner sleeve, and it will be closed simply by releasing the pressure, which will allow the inner sleeve to return to its original position. In the case of hydraulic control failure, HCSS also equipped with a secondary open/close mechanism by the special shift tools operated by coiled tubing. The authors conducted two representative case studies of HCSS application in offshore upper completion in Bohai bay in China to further highlight the improvement of operational efficiency and well economics.