| Tight sandstone gas reservoir takes a considerable part reserves in our country and in theworld. Long-term development practice has proved that fracturing technology is an effectivemeans to develop such gas reservoir economically. In the process of exploration tightsandstone gas reservoir fracturing well usually appears as output and pressure decline rapidlyand shut-in pressure can’t return to the original pressure etc. Thus establishing the relationshipbetween fracturing scale and production capacity after fracturing, analyzing the productioninfluence factors, understanding the production decline law is of great significance in gasreservoir fracturing design and technique optimization. However, the special pore structureand complex porous flow rule makes it difficult to evaluate the productivity ability offracturing well in tight sandstone gas reservoir, which of course seriously restricted thepromotion and large-scale application of fracturing technology in such kind of gas reservoir.Considering the actual characteristics of Changling gas field Denglouku formationreservoir, the thesis started its research with thoroughly study on special pore structure andcomplex porous flow rule of tight sandstone gas reservoir. Based on porous flowexperiments taking start-up pressure gradient and long-time fracture conductivity effectinto account, a three dimensional mathematical model of reservoir-fracture, gas-water twophase system and its numerical solution equation were established. Applying IMPES methodto solute this model and corresponding computer program was composed with Visual Basicand Visual C++programming language. The production fitting analysis shows that thedeveloped software productivity prediction of tight sandstone gas reservoir fracturing wellhas the very good adaptability. The production influence factor of fracturing well in tightsandstone gas reservoir was analyzed with this software. The results shows that the formationpermeability, heterogeneity, fracture length, fracture conductivity, production pressuredifference is the main influencing factors on gas well productivity and drainage radius,formation porosity, start-up pressure gradient and fracture conductivity failure coefficient isless affected. Finally using Arps conventional decline analysis and Fetkovich standard curvedecline method, completed the Denglouku formation production decline research. The resultsof the study can be used to guide tight sandstone gas reservoir fracturing construction, toimprove the technological adaptability and economic effect. The result has great significancein comprehensive adjustment and production improvement of tight sandstone gas reservoir. |
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