Study On Well Type Optimization Of Dense Gas Reservoir Development

Suliger gas field in our country at present is the largest proven reserves of natural gas field, geological reserves of whose main sediment group Shi Hezi group and Shan Xi group are600billion cubic. But, as the typical representative of dense sandstone gas reservoir in our country, Suliger gas field has characteristics of "low porosity, low permeability,low abundance,low pressure,difficult to use" and strong heterogeneity, which seriously restrict development activities of natural gas in the area. Horizontal well has been widely used in Suliger gas field for the reason that it constructs a well link between the wellbore and gas reservoir. However,as the development goes by, a single horizontal well type can’t meet the need of higher production and lower cost uder the condition that the porosity and permeability of the remaining reserves are poor as well as the distribution is complex. So it is urging that a research should be done to discuss the possible use of the large distance well,multi-lateral well as well as multi-staged well in the gas field.Therefore, on the basis of the scientific research project "the research on optimization of development well type and well completion method dense gas reservoir", this article began the research of development well type of eastern of Suliger’s gas field. Based on investigating field data and domestic and international documents, firstly, according to the reservoir classification and the logging properties, reservoir was classified. Secondly, based on the rock mechanics experiments and logging data, the profile of properly calculated rock mechanics parameters was bulit;analysing characteristics of many methods of calculating formation pressure, combining with the practice, the paper forecasted the formation pressure; In the context of mechanic parameters and formation pressure, the research set up the longitudinal profile of stress in the area. Next, based on the "Bradley" stress calculation method, the research carried out the mathematical research on the stress distribution of the rock around well, condemned by Mohr-column and Von. Mises rock broken criterion, established the mechanical judgment model of the wall stability, at the same time, analyzed the affecting factors of wall stability; Also, the mechanism of sand production was analyzed, offering a variety of methods for forecasting sand production. Also the evaluation of production and economy was done and the article optimized the well completion method. On the basis of theory research above, the paper programmed a program for the optimization of the well completion method of dense sand gas reservoir in VB6.0language. At the same time, the research of geological suitability of different well types was done. Finally, production and economy evaluation of the horizontal well under different well completion methods was done with the program, giving advice on the selection of development well type of eastern of Suliger gas field.