| This dissertation consists of seven chapters which mainly focus on the identification and classification of condensate gas reservoirs, evaluation of the productivity of gas wells, methods for calculating recoverable reserves, research on several important issues concerning condensate gas reservoirs and speculation about the development practice of condensate gas reservoirs in Qianmiqiao buried hill. In this dissertation, three-phase composition and phase map identification technologies are proposed to identify and classify condensate gas reservoirs. Based on this, the condensate gas reservoirs are classified and studied in detail according to reservoir types, flooding factors, condensate content and saturation types. The evaluation methods for the productivity of condensate gas reservoirs include steady well test, pseudo single-phase flow and two-phase pseudo pressure. For determining the rational production of condensate gas wells, nodal analysis method and ultimate flowing rate method are usually adopted. And for calculating recoverable reserves of condensate gas reservoirs, both static and dynamic methods are proposed according to theoretical research and practical experiences.There are some important achievements in this paper in terms of the following aspects: I. Composition variation has impact on calculation of reserves when using pressure drawdown technology. Through theoretical derivation, an improved material balance method for calculating reserves has been proposed in this paper, of which the calculating results fit the actual reservoir situation better. II. Production decline method is an important technology to estimate the recoverable reserves of oil, gas and condensate reservoirs. We have found that they all belong to one decline type and almost have the same decline rate after a great deal of theoretical research and lots of practical application. According to this decline rule, the recoverable reserves of dry gas, condensate oil and total borehole fluid can be simultaneously calculated. What's more, the results fit the reality quite well. III. The recovery factor of condensate is a problem to be solved in calculating recoverable reserves of condensate gas reservoirs. It is obvious that by now research on it is not enough. In this dissertation, factors affecting condensate recovery ratio have been verified through research on the actual data of 47 condensate gas reservoirs exploited through depletion-drive in Banqiao area, Dagang Oilfield, and relevant empirical formula have been set up, which have improved the methods for calculating recoverable reserves of condensate gas reservoirs. IV. Due to the existence of retrograde condensation and condensate, it's quite difficult to forecast the pressure when flowing stops in a water-flooding condensate gas reservoirs. In this paper, formula of calculating pressure when flowing stops that are suitable for wells of constant volume, weak water-flooding and strong water-flooding wells have been proposed through research on actual data of Banqiao condensate gas reservoirs. V. In this thesis, the condensate gas reservoir in Qianmiqiao buried hill is a stress for research, for it is the largest condensate gas reservoir found in East China in 20th century. Qianmiqiao buried hill belongs to fracture system, and it has complicated reservoirs, water-gas relations and fluid distribution. We re-estimated the reserves of the key blocks based on the original 305×108m3 reported reserves and found there were big contraction in reserves. By calculating the dunamic reserves of three wells with pressure drop method and elastic two-phase method, it has been proved in this paper that the range of connecting reservoirs controlled by producing wells in Qianmiqiao buried hill is quite small and produced reserves can be further increased by deploying new wells. Meanwhile, specific suggestions have been proposed as for how to carry out further study on the condensate gas reservoirs of Qianmiqiao buried hill.
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