Abstract
Cement and Casing integrity across the surface aquifers is as imperative as against the reservoir section, to avoid ground water communication. Zonal isolation among aquifers is obligatory as per local regulations. Understanding the expected cement quality in the intermediate casing across aquifers is desirable. It is essential to understand why there are wells with good cement across aquifers while some wells exhibit poor cementing, keeping the procedures and parameters identical.
A study was conducted to understand the aquifer pressures and overburden geologic features in the entire field and understand how they impact cement quality. Aquifer pressures are incorporated with seismic features to anticipate the aquifer behavior. Representative Wells were selected in different field areas encountering either different aquifer pressures or geological features. The cement bond logs (CBL) were interpreted in these wells, along with the information from drilling, and established the link between cement quality and aquifer behavior in the specific area.
It is observed that poor cement is present where either aquifer pressure is low or there are aquifers channels, sinkholes or other geological features derived from seismic interpretation.
To perform better cementation across the aquifers it is essential to understand the aquifer behavior in specific area of the field, address the issues in the well prognosis to the cement team, plan and perform cementing operations accordingly.
