Differential Valves are used in multistage cementing tools to ensure having adequate cement placement and enhanced wellbore isolation. Multistage tools are recommended to use if the formation is unable to support the hydrostatic pressure of the cement column. In cases of lose circulation, multistage tools are used at designated depth to help placing cement all the way to surface.

There are two types of multistage tools: conventional ones that can withstand low-pressure rating and more recently developed high-pressure rating tools. The low-pressure rating tool is used to support cement placement and is not considered as mechanical barrier against high-pressure formations. The high-pressure tools were developed based on additional requirements to improve wellbore isolation in high-pressure gas wells.

The objective of this paper is to:

  • Highlight the importance of multistage cementing tools and to de-risk their use

  • Provide best practices to overcome common multistage tool issues

Potential malfunctions can be due to either mechanical components malfunction or improper operational practices. These can be further divided into 4 categories, which are: packer issues, opening/closing DV ports, and drilling practices such as encountering losses while cementing and finally improper running operational procedures. This paper includes intensive review of actual runs including frequency of multistage tool issues based on casing size.

Different mitigation plans are recommended for each potential issue and optimum drilling practices to overcome them. In addition, high-pressure multiage tools performance will be highlighted in improving wellbore isolation since their initial deployment 3 years ago.

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