Successful Deep Openhole Cement Plugs for the Anadarko Basin

A cement plug is placed above a non-retrievable fish when a hole is to be sidetracked. The plug provides support and strength to commence deviation from the original hole. Setting a firm high strength cement plug in order to sidetrack is a difficult task. The volume of wellbore and displacement fluids are quite large compared to the volume of cement in the plug. This situation is compounded in a deep hole. Placement of the cement slurry without contamination from wellbore and displacement fluids becomes an exceedingly difficult task. Several cement plugs may be required before a successful plug is set. The techniques described were developed for sidetracking purposes. However, they can be applied in setting other types of cement plugs. Parameters involved in properly setting an open hole cement plug are defined in detail in this report. The primary objective of this work was to define techniques and materials necessary to optimize success with deep hole cement plugs. Important factors in successfully setting an open hole cement plug are hole condition, mud condition, cement composition, and placement technique. An example is included describing a successful technique used to set deep open hole cement plugs in the Anadarko Basin.