Gas Well, A Single Well The Dynamic Calculation Of Reserves

In gas field development, calculation of natural-gas reserves is an important part—not only the significance fruit of natural-gas field comprehensive evaluation, but also the basic of gas field development . As gas well is the foundation unit of gas field development, it is very important to analyse and discuss the single well reservoir for stable gas supply and high efficiency development. There are many methods to calculate natural-gas reserves reservoir, but only to investigate the single well dynamic methods.On the basis of great research of the result of the scholars, the proven calculation of reserves methods' adaptiveness—material balance method, the methods of transient pressure testing(early transient regime method, pseudosteady state method, pressure buildup method, pressure difference curve method, logarithm method), rate cumulative curve method, are analysed one by one .Material balance method is fit for early development and multiple geologic condition gas fields; its calculation process is easy to work; but this method is dependent on formation pressure, also limited in abnormal pressure gas reservoir and low permeability gas reservoir. In the whole process of gas field development, the method of transient pressure testing can calculate reserves; because of the differences between measured pressure curve and ideal pressure curve, it is hard to accurately identify the flow regime. In the late period of gas field development, rate cumulative curve can be used to calculate reserves, but well needs to shut off for a long time.On the basis of fore study, a series of new calculation methods are presented. The method of transient pressure testing with material balance method, avoids the subjective choice of line and dependence of formation pressure; it makes sure the reliability of parameters by means of fitting pressure; in the process of calculation , it can constantly examine accuracy of the dynamic reserves to safeguard the final result. Material balance method with productivity equation, can get the factors of productivity equation and formation pressure; it makes fitting both productivity and pressure to safeguard the final result. As productivities and pressures can not always keep steady, the method of nonresistant with material balance method is based on Duhamel's principle to safeguard the final result.The program of calculation of single gas well dynamic reservoir is compiled by Visual C++, and then is applied in-situ. The results show that the fruit of research is dependable.