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The genetic algorithm is a global optimization method and good at flexibility and robustness. It conducts undirected random search, which is not limited by search space. The computational procedure of the algorithm is easy and simple. The genetic algorithm is especially suited to solve multivariate and nonlinear complex problems which are impossible or difficult to be settled by other scientific technologies. The paper introduces the current wide application of genetic algorithm in oil-field development planning, measure optimization, well location deployment, multilateral well design, well testing, steam stimulation, the design of oil production technologies, and so on, which represents the algorithm's advantages in solving problems of oil field development, and reveals the wide ranging application prospect in the field of oilfield development.

The gas producivity is infuluenced by many factors. In the routine calculation of gas productivity, many factors were negelected for convenience such as the non-Darcy flow, the changes of gas PVT parameters and the deformation of rock media. In order to analysis the effect of these factors on gas productivity, the mathematical model of high speed non-Darcy unstable flow in deformed media gas reservoir, which takes the changes of PVT of real gas with pressure into consideration, has been made in this paper. Numerical difference technology is used to find solution to the mathematical model,in which there is a well in the center of the round closed layer and the well bottom hole pressure is kept as constant in the production. And the effect of the factors on the gas productivity is analyzed. The results show that the influences of porosity changes caused by media deformation to productivity can be neglected, the changes of permeability can lead to the decreasing of productivity in the early period. And the productivity under the conditions of the high-speed non-Darcy flow and the changes of gas PVT is higher than the one when the gas flow is linear and PVT of gas is constant. These research results are meaningful to predict the gas productivity accurately.

The grey interconnect analysis method is used in two aspects in this paper. One is to decide the main factor which have great effect on the production decline rate, the other is to select the main wells which have great effect on the main factor. On the first aspect, the affecting factors which are independent and have direct influence on the decline rate are normalized respectively. Then the interconnect sequence of the affecting factors are obtained by using the grey interconnect analysis method. On the second aspect, the water cut is taken as the reference sequence, the water production rate of every wells is taken as the factors sequence, then the main wells which have great effect on the water cut are selected by using the Grey interconnect analysis method. The results shows that the grey interconnect analysis method can adapt to the features of the more influence factors and the larger date size, and can be used in the analysis and trace for affecting factos of production decline.