Simultaneous Real-Time Top-Of-Cement and Memory Cement Evaluation Delivery in Deepwater Operations, Nigeria

Cement bond logs are traditionally acquired via wireline after the well has been drilled to its total depth. Waiting for wireline-based cement bond logs usually takes time and can cause delays in obtaining timely completion approvals from regulatory bodies. Turnaround times for providing cement bond logs (CBL) have been drastically reduced with the introduction of quantitative cement evaluation based on logging while drilling (LWD) memory data. Further optimization of the delivery time of these cement bond logs has now been achieved with the introduction of simultaneous real-time top-of-cement (TOC) and quantitative cement evaluation services. Real-time TOC ensures the availability of CBL across the casing of the previous hole section, even before drilling the target reservoir section. Top-of-cement behind casing is identified in real-time, facilitating an immediate approach of the regulatory agency for completion approval. The consistency between real-time TOC and quantitative cement evaluation services based on LWD memory data provides a more robust decision on well integrity based on cement bond integrity. Real-time top-of-cement and Cement Evaluation services acquired in recorded mode were simultaneously delivered in two deep water wells to validate their application – a first in Deepwater Operations in Nigeria. This paper presents the outcome of the work and outlines the workflow for providing the required CBL with the fast turnaround needed to obtain timely completion approval.