Condensate Gas Reservoirs Recoverable Reserves Calculation Method

With rapid development of natural gas industry in China, condensate gas reservoir, as a more economical gas reservoir, is being given more and more discovery and development. But how to predict and calculate net gas and condensate oil recoverable reserve, there is no practical and convenient method so far in home.The paper, illustrated by Banqiao condensate gas field, studied the condensate gas recoverable reserve calibration methods. Firstly, condensate gas reservoir calibrating methods in home and abroad-volumetric method, material balance method, production decline method, elastic two-phase method , prediction model method and empirical formula method have been summarized and verified by the practical production data of Banqiao condensate gas reservoir and shortcomings of all the methods has been pointed out, suitability of all methods to Banqiao condensate gas reservoir has been evaluated, and applicable conditions, parameters and calculation results have been finely analyzed and assessed for all the methods. Material balance method has been theoretically improved for condensate gas reservoir and decline law has been imported to condensate oil recoverable reserve calculation, the application of two methods to condensate reservoir was realized and development was made in method study.The correlate empirical formula between condensate oil recovery and its affection factors has been regressed, the change of abandonment pressure of condensate gas reservoir with gas reservoir depth in different water drive strength has been summarized and correlate empirical formula of gas reservoir off production and originate condensate oil content was also given based on the dynamic production data of Banqiao condensate gas reservoir.The study result provides matching methods for condensate gas reservoir recoverable reserve calibration, especially the creative achievement of condensate oil recoverable reserve calculation method fills the blank of home, compared with originate method, the improved method is more suitable to thermodynamic property of condensate gas reservoir and proved by Banqiao condensate gas reservoir practical production data, the calculation result becomes more precise. Through application and improvement in the practical work, it can better serve the oil field recoverable reserve management and hydrocarbon reservoir dynamic analysis and has great popularization value.