Flexural Attenuation and Annulus Velocity for Cement Evaluation Enabled Fast Well Delivery

Abstract Well integrity is a constant concern in the oil and gas industry, as the specifications for all new wellbores must ensure that its original fluids—oil, gas and water—are kept confined to the formation or the oil and gas well system, successfully preventing any leaks from the system to the surface, subsurface bodies, or the surrounding environment. Good cement coverage and accurate cement evaluation are of prime importance for the integrity of oil and gas wells, to prevent crossflow, leaks and sustained casing pressures. Post-cement placement wait time to enable cement hardening and establish compressive strength contribute to additional ideal rig time. On many occasions traditional cement evaluation measurements fail to evaluate complicated cases of cement at early stages or lower density slurries, the flexural ultrasonic attenuation, and velocity measurements achieved detecting cement accurately behind the casing where traditional ultrasonic and cement bond log-variable density log (CBL-VDL) measurements were not able to detect solids. This situation is especially observed in the early stages of the compressive strength build up for any slurry system. During this transition, traditional evaluation methods are very limited, and it requires additional time for significant increase in compressive strength and multiple runs to have an acceptable, realistic hydraulic evaluation. The asset integrity policies and management are crucial to the oil and gas industry to ensure safety, profitability, performance, compliance with local and international regulations, and to protect society and the environment. So it is, to have a very accurate evaluation to ensure optimum balance between strict integrity policies and sustainability. At various phases of a well's life cycle, the integrity of the well barriers and/or well barrier elements are verified. This verification may require pressure measurement and monitoring, barriers identification, confirmation and tagging, pressure testing, leak testing, leak off confirmation and testing, flow rate measurement, temperature monitoring, and well logging evaluation, especially for the hydraulic isolation confirmation and analysis.