为了探讨吐哈盆地沙尔湖凹陷侏罗系煤层气的勘探潜力,应用大量最新分析化验数据和钻井资料,分析了煤层发育特征、煤岩热演化规律和显微组分、煤储层物性、煤层气成因类型、煤岩吸附特征、含气性、构造运动、水动力条件、煤岩直接顶板的岩性等保存条件及前期煤层气井勘探失利原因等.结果表明,沙尔湖凹陷煤岩热演化程度低,具典型的煤层原生生物气特征,均质性差;但煤层厚度大,煤层裂隙及大孔发育,原煤含气量高,煤层气保存条件较好,煤层气总资源量较大.总之,沙尔湖凹陷侏罗系煤层气成藏条件优越,资源丰庹高,采用合适的钻井、完井、储层改造措施及排采制度,将会取得一定的勘探成效.

The corrosion rate and characteristics of several kinds materials are studied under the in situ conditions of high pressure and high temperature in the stirring aqueous solution in a nickel-based alloy autoclave.The test results show that the corrosion rate and characteristics under different well conditions are different,the highest corrosion rate is 5 times greater than the lowest one.And in the same well,the corrosion rates of different materials and sections of a well are also different under the simulating test conditions.The differences come from the joint effects of multi-factors in different degrees.In different sections of a well,different corrosion characteristics of the same material are observed.As can be seen from the topography of the corrosion scales,the binding force of the corrosion scales with the base metal and the corrosion rate itself,the most serious corrosive section is at a depth from 1500m to 3500m,with the top 1500m part slightly corroded.At the bottom of the well,the corrosion is also gentle according to the formation of corrosion scales and the excellent binding force which would obstruct the corrosion process.Therefore,many factors should be considered when studying the CO2 corrosion characteristics of tubing materials in deep or super deep wells,such as the tendency of the corrosion rate,and the conditions of the well.The temperature,the pressure and the flow rate of each well in different sections should also be tested and calculated to find out the most serious section under the corrosion,conditions and the effects of different factors are not the same on the corrosion rate.Therefore,the joint effects of all factors should be considered when studying the CO2 corrosion of tubing.

Based on the studies of favorable geological conditions and key control factors of tight sandstone gas reservoirs in the piedmont in northern Tuha basin,it is suggested that these reservoirs are characterized by the same source rocks,self generation and self reservoir.The coal measure strata of Shuixigou group of Middle-Lower Jurassic are a set of quality source rocks and the dominant contributors to natural gas enrichment in the studied area.In the sedimentary period of Shuixigou group,the source materials supplied from the piedmont zone was abundant in the north,so underwater channel sand bodies developed at front of braided river delta,becoming the main site of the tight sandstone gas accumulation.In structural highs,fractures and fissures commonly occurred under the strong folded process,raising the percolation capability of the sand bodies;while in the flat slope area,the following tectonic movement was faint and favorable to large-scale original tight sandstone gas accumulation.And the source rocks of Shuixigou group entered into great amount of gas-generating stages in Neogene and Quaternary period,characterized by late gas accumulation,being favorable to preservation of the tight sandstone gas reservoirs.