Title : Bridging the gap between cement quality and bond integrity: Good Cement Quality Parameter (CQP) fails to deliver a reliable Cement Evaluation Log (CEL)
Abstract:
Objectives/Scope:
While Cement Quality Parameters (CQP) are the foundation of cement evaluation, field evidence indicates it cannot standalone guarantee zonal isolation. This paper challenges industry’s over-reliance on CQP by demonstrating how optimal field results frequently fail to translate into successful Cement Evaluation Log (CEL) outcome, exposing wells to integrity risks.
Methods, Procedures, Process:
To assess the disconnect between good Cement Quality Parameters (CQP) and poor Cement Evaluation Log (CEL) results, a study will be conducted to analyze field cases while drilling. Beginning by collecting cementing data from wells where CQP met industry standards. Data will be collected including both successful and failed cementing operations. Then compare these cases with CEL results to identify discrepancies. After that, identify common failure trends and classify them based on operational challenges, well conditions, formation response and cement placement issues.
Results, Observations, Conclusions:
An analysis has been conducted to compare field measured Cement Quality Parameters (CQP) with downhole Cement Evaluation Log (CEL) results. It has been confirmed that although high-quality cement is a crucial factor for achieving zonal isolation, a good CQP alone does not confirm a strong cement bond with the casing and the formation. Therefore, CQP is only a starting point, not a guarantee. Study resulted that the cancellation of cement logs risked compromising well integrity and operational safety by eliminating critical quality assurance measures. Without CEL, operators cannot verify the external barrier envelope, validate cement quality improvements, or comply with international standards. This leads to insufficient risk assessment, increased risk of underground blowouts, and fewer wells deemed safe to operate due to missing data. Additionally, the lack of cement logs hinders diagnostic investigations and remediation efforts, increasing long-term risks and costs.
Novel/Additive Information:
The Cement Evaluation Log (CEL) is essential to ensure well integrity, safety, and regulatory compliance. It verifies zonal isolation, prevents sustained casing pressure, and mitigates risks such as gas migration, crossflow, underground blowouts and LOPC. Early detection of cementing issues through CBL avoids costly future workovers and ensures operational continuity. Compliance with API, NORSOK, and ISO standards mandates its use, and cancelling a CEL without thorough risk assessment and regulatory approval compromises safety, environmental protection, and reservoir management.
