Modeling and Analysis of Salt Creep Deformations in Drilling Applications

Drilling through salt has created increasing challenges for the oil and gas industry. In many cases, deepwater exploration around the world requires drilling through salt layers above oil and/or gas reservoirs. Borehole closure and instability due to salt creep are two major concerns in designing completions for production wells drilled through salt layers. Similar issues also occur where gas storage caverns are built in salt formations. Pressure changes that occur in the salt cavern during operation can cause cavern closure and instability. As such, predicting salt creep deformations is essential for designing completions for wells drilled through salt and for storage caverns built in salt formations. This paper presents a literature review of material models describing the behavior of salt creep. Using an established material creep model, a finite element analysis (FEA) methodology using Abaqus is then presented for analyzing salt creep deformations. Application examples are included to demonstrate the use of this methodology.