The Use of In-Well Flow Control Devices to Address Multiple Challenges of Carbon Dioxide Injection in C.C.S. Projects

Abstract The objective of this paper is to describe several challenges faced by Carbon Capture and Storage projects, how in-well flow control devices can be used to address the challenges, and the benefits and value of designing CO₂ injection wells with these capabilities. Whether a CCS project targets injection in a deep aquifer or a depleted hydrocarbon reservoir, the challenges for CCS injection are: unbalanced injection rates into the leading to uneven growth of the CO₂ plume; back-flow of reservoir fluids into the wellbore or cross-flow between zones during well shut-in causing corrosion and formation of hydrates or scale; flashing of liquid or supercritical phase CO₂ to gas in the injection conduit when injecting into a pressure depleted reservoir causing extreme temperature variations that result in high thermal stress on casing and cement; and, loss of containment in the injection formation or compromise of well integrity. Key to the formulation of solutions is understanding of the expected operating environment. Production scenarios considered are transient start-up, shut-down, and steady state injection, as well as extreme conditions, such as loss of pressure and flow containment at the wellhead. Injection flow and pressure requirements have been gathered, and a CO₂ injection simulator has established the environmental conditions. Operating parameters, functional specifications and qualification testing requirements have been defined for flow control devices for CCS well completions. While depleted oil and gas fields can provide significant storage capacity for CCS, injection of carbon dioxide into pressure depleted hydrocarbon fields can be problematic due to the phase change of CO₂ that can cause flow instability and result in adverse physical phenomena, such as extreme cooling associated with the heat of vaporization. One solution is to use variable, autonomous or surface-controlled, flow control devices strategically placed in the injection tubing string to provide a stepwise pressure reduction and to maintain sufficient back pressure to prevent CO₂ flashing. Distribution of CO₂ injection rates can be controlled with the use of appropriately sized passive ICDs, or by using autonomous outflow control devices. When the passive ICDs or autonomous OCDs are combined with a check-valve element, back-flow or cross-flow of reservoir fluids during injection shut-in can be prevented. This paper continues the work of SPE-209705 and SPE-210651, proposing the use and performance modelling of flow control devices installed in the injection tubing to maintain carbon dioxide in a dense phase (liquid or super-critical) from the wellhead to reservoir interface, and to improve the efficiency of injection wells transporting CO₂ to the storage reservoirs.