Permeability Gas Tibet Fracturing Effect Evaluation Method

The low-permeability gas reservoir spread widely in our country. According to incomplete statistic data, its reserves take about eighty percent of the whole reserves of natural gas. Obviously, it has great realistic significance to exploit this kind gas reservoir. But due to the reasons that the low-permeability gas reservoir is different from general gas reservoir and it has a lot of particularity, the natural deliverability of producing well is very low. If we want to exploit this kind gas reservoir preferably, we must bring the formation hydraulic fracturing into effect. On the one hand, the formation hydraulic fracturing is the most important stimulation treatment reconstructs the low-permeability gas reservoir. On the other hand, it is also a necessary measure that we economically exploit the low-permeability gas reservoir. On account of consuming huge capital to operate the massive scale hydraulic fracturing of this kind gas reservoir, well than, it is very important how to appraise and analysis its fracturing effect exactly. But we have no effective method to appraise the fracturing effect in the low-permeability gas reservoir at present. Therefore, on the theory base of the reservoir fluid mechanics and oil reservoir engineering, the methods of transient well test and deliverability test to appraise the fracturing effect have been studied in the low-permeability gas reservoir. At the same time, applied analysis theory and computational method for the low-permeability gas reservoir that can be used to obtain the fracture parameters and gas well deliverability have been established. This theory supplies exact parameters for accurate fracturing effect evaluation. What's more, on the basis of the studies, in the light of the technical economics principles, a new concept, economic limit stimulation ratio has been put forward. And economic analysis method to appraise the fracturing effect is investigated in the low-permeability fractured gas reservoir. At last, owing to the fact that fracturing effect is influenced by many factors, so we establish a suit of the method of fuzzy mathematics comprehensive evaluationto appraise its effect. In the way, the method shows that the evaluation results are much more reliable than ever. A case study-the 117 well of Shanganning Basin is conducted to verify the correctness and effectiveness of theory and method presented. In a word, according to the studies in the thesis, we gain the satisfied interpretation results.