| Fracturing has become a mature and effective technology widely used throughmorethan60 years ofresearch anddevelopment. Sincetwothirds ofthenewly-foundproved reserves in china are low or ultra-low permeabilityreservoirs, fracturingis thenecessary measures and effective means of this kind of reservoirs'exploration anddevelopment. At the same time, fracturing is a high investment and high risktechnology.and the operation cost for a single well is about hundreds of thousands tomillions Yuan. If we have not an full understanding to the reservoir characteristics, ifthewellandlayerselectionisunreasonable,iffracturingliquidandproppantselectionis not appropriate, if construction design is improper, if Construction quality is notreach the standard ,all of these may result construction failure or can not achieve thedesired yield,To make matters worse, it mayresult the well deliverabilityfall or haveno deliverability. To the waterflood development oil field, if the fracturing fracturedirection don't match the flooding well network, it may bring great difficulties to thedevelopment plan adjustment. Making a complete , systematic and deep study to therisks that may be encountered in fracturing and making measures according to theconcrete situation to guide the whole course of fracturing from the reduce risk angle,have an important significance for improveing the succeeding rate and efficiencyrateof construction, decreasing the investment risk and advancing economy benefit.Based on the predecessors' study, this paper comprehensively and systematiclysummarized the risks that fracturing may counter, the cause that brought about therisks, and discussed the method to control risks. at the same time, the paperpreliminary attempt to establish a system of fracturing risk control,and studied themethod of fracturing risk decision-making. In order to study the influence ofhydraulic fracturing on the production dynamic of reservoir, the paper study theinfluence of fracturing length on the production dynamic of five-spot flood system in the situation of the favorable and unfavorable fracturing direction with the method ofreservoir simulation. To realize the science and effectiveness of the hydraulicfracturingriskdecisionmaking,themethodofFuzzycomprehensiveevaluation(FCE)has been used. The paper constructed an evaluation index system of hydraulicfracturing risk , and a compositive method of Specialist Grading and AnalyticalHierarchy Process (AHP) was used to confirm the index weights.Besides, through acomplete example,it has explained how to use Fuzzycomprehensive evaluation(FCE)to make assessment for hydraulic fracturing risks,on the basis of which, a softwarewas programmed. At last, as for the new technology of the proppant-carrying acidfracturing of cross-linking acid fluid which was used in jingbian gas field, the paperanalyses the risks during the process of its implementation and proposed methods todecrease the risk.6 wells have been treated by this technology, with the constructionsuccess ratio 100%, and the construction availability ratio 100%.The maximaldeliverabilityafterhydraulicfracturingis37.0236×104m3/d.andthemaximalproppantvolume is 25.1m3.At the same time, in order to analyze the main influencing factorsand influence degree of all kinds of factors to deliverabilityafter hydraulic fracturing,grey correlation analytical method was applied. The result shows that effectivethickness, operation scale and formation pressure are the main influencing factors,which has certain direction significance to the well and layer selection, fracturingdesign.
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