Abstract
In today's world demand for natural gas as a source of energy has been increased. Especially in Iran the main source of home's heat energy is natural gas. In fall and winter demand for natural gas increases that may exceed the amount of total gas production. Underground gas storage is an activity, which allows to efficiently resolve demand seasonality problems. Natural gas injection and storage in depleted gas reservoirs is a common challenge that overcomes this problem. The aim of this study is to use tracer test method as a way to better understand a gas condensate reservoir to use it as a UGS. Case studies showed that gas tracer technology is one of the best methods for improving reservoir characterization and description of gas storage reservoirs. So it is well known in the petroleum industry that tracer data can provide valuable information on reservoir characteristics and fluid flow performance. The reservoir under study in this work is a limestone gas condensate reservoir with high porosity and good permeability, which is located in south of Iran. Therefore, in order to better characterize the reservoir it was decided to implement tracer test in this reservoir. However, a prerequisite for obtaining reliable information is careful planning, design, and experimental investigation. So different reservoir studies such as geological studies, well logging, and well testing was implemented to describe the reservoir truly. By means of these studies, reservoir operation can be predicted and controlled. In order to find the best tracer and its volume, a comprehensive study on the effects of tracer volume, concentration and adsorption on some plugs was also performs. Finally, it was concluded that Helium is the best tracer for this reservoir, because of its low interaction with rock and fluid and also same velocity with the bulk of fluid flow.