Pressure losses occur in restriction, especially in the Subsurface Safety Valve (SSSV) might not be major but can be significant in some wells. As we could not always predict the behavior of the dynamic entity such as the reservoir and the flow of fluid, the production system could exceeds the expected performance, which then could affect the SSSV. Therefore, a proper management of SSSV could help overcome this problem. This project attempts to develop a numerical model which could predict the pressure drops in the SSSV in single and two-phase, subcritical flow as a part of the SSSV proper management program. The project also had done several sensitivities analysis on the parameters that could affect the pressure drops in SSSV which are presented in this paper. The knowledge on the parameters affecting the pressure drop can be used in designing an efficient and optimized SSSV. It is also hope that a proper and dynamic control over the SSSV could be achieved by using this model.

Carbon dioxide injection in oil reservoirs is one of the main improved oil recovery methods; in addition, it is a useful method for the reduction of carbon dioxide in the atmosphere. Carbon dioxide generally exists in supercritical state in hydrocarbon reservoirs that are usually explored, but the temperature of some shallow reservoirs and reservoirs underlying permafrost is below the critical temperature of carbon dioxide which provides a unique opportunity for liquid carbon dioxide storage and the application of a novel enhanced oil recovery method. During this work, a compositional simulation study is conducted by a commercial compositional reservoir simulator to evaluate performance of the liquid carbon dioxide injection in a low temperature heterogeneous reservoir. The results show the oil recovery factor after 24 years of production, during liquid carbon dioxide injection is 14.79 %, which is 3.90 and 8.59 % higher than the water flooding strategy and natural depletion respectively. It also finds that the huge amount of CO2 is stored in the reservoir. This study further shows that the oil recovery increases by increasing the injection pressure and the injection of the liquid carbon dioxide in bottom of the reservoir.

The current research is based on modeling approach, where the objective is to develop a series of computer codes with the reference of existing pressure bleed-off time mathematical models. The results generated from the model are based on the three parameters: temperature, type of gases filled in annulus and depth of well. These three parameters can affect pressure bleed-off time in well's annulus, with the fixed size of needle valve. Using this model generated from Wolfram Mathematical 8.0, it is enable to notify engineer to receive an early sign of warning if the well is suspected to leakage. Meanwhile, based on the matching process of field data and modeled data, field engineers will be able to aware and determine whether the occurrence of annular pressure is due to thermal induced annular pressure buildup or it is because of leakage in well components. The SCP well will eventually loss in production, caused severe failure in well's integrity.

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