Depleted hydrocarbon reservoirs are known to provide an opportunity for CO2 sequestration. A new 5300 cm(3) stainless steel high pressure chamber (crystallizer), employing horizontal CO2 injection, is used to demonstrate the sequestration of CO2, via hydrate crystallization, in depleted hydrocarbon reservoirs. The crystallizer was employed to carry out laboratory injection trials. A bed of silica sand with a porosity of 0.35 and a water saturation of 0.22 was used in these experiments. CO2 is sequestered into the crystallizer by constant flow rate (1200 cm(3)/h) followed by constant pressure CO2 injection. This method has been shown to increase CO2 hydrate formation compared to only using constant pressure CO2 injection. Experimental pressures (pressure targets) ranging from 2.2 MPa to 3.2 MPa at 277 K are investigated. A total storage density of 126.6 kg.m(-3) is found 24 h after the start of injection at a pressure target of 3.2 MPa. Crown Copyright (C) 2017 Published by Elsevier Ltd.