Modeling the Behavior of Smart Oil Well Cements and Offshore Pipe-Soil Interaction in Very Soft Soil

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It is critical to ensure the durability of the oil and gas production infrastructures from borehole to pipelines. Rheology properties and hardening characteristics are some of the important parameters for cementing slurry during installation. Also over the last decade, health monitoring of the plugging material during service life became more important and vital. In this study, smart cement with enhanced sensing properties was modified with fly ash class C up to 50% to investigate the effect on sensing and strength properties. By adding high volume fly ash class C (50%) to the modified oil well cement, fractional change in resistance during compression was doubled compare to specimens without fly ash and also water loss during curing was reduced greatly. Offshore pipelines play an important role in transporting crude oil and natural gas from wellbore to the controlling platforms. Hence it is critical to understand the supporting mechanism of pipeline on the deep-water sea beds. In this study pipe-soil interaction was investigated by varying the soft soil strength from 0.3 kPa to 1 kPa and embedment depth. Also, this study investigated on using current modified oil well cement for health monitoring of offshore pipeline. Two new models have been developed to predict the vertical soil resistance on plastic pipe. Also by adding 0.5% carbon fiber to the modified oil well cement, soil resistance load during penetration on pipeline was captured. Fractional change in resistivity increased during penetration and for normalized penetration (H/D) of 55%, fractional change was 25%.

Smart cement, Oil well cement, Offshore pipeline, Pipe soil interaction
Portions of this document appear in: Kheiri, P., and C. Vipulanandan. "Models to Predict the Rate of Penetration of Insulator-Coated Pipe into Very Soft Clays Simulating Deepwater Subsea Conditions." In Pipelines 2014: From Underground to the Forefront of Innovation and Sustainability, pp. 549-560. 2014.