摘要
塔里木盆地北缘已发现11个大中型气田(藏),均以白垩系为最主要的产层,其它天然气储量占该区探明储量60%以上.其中白垩系巴什基奇克组和巴西盖组为主要产层.对巴什基奇克组和巴西盖组岩石物性资料统计分析并对主要控制因素进行了详细的研究,认为其储层物性主要受控于沉积相、压实作用、胶结作用和溶蚀作用,其中沉积相是最主要的控制因素.根据对该区白垩系岩相古地理的研究和各气田物性统计分析,将该区储层划分为Ⅰ、Ⅱ、Ⅲ 3类,其中Ⅰ类和Ⅱ类储层区是油气田(藏)发育区,也是进一步勘探的首选区域.
Eleven intermediate-large gas pools (fields) have been found at northern margin of Tarim Basin. Principal gas producing formations are the Neogene, Eogene, Cretaceous, Jurassic, Triassic and Carboniferous ones. The most important reservoirs are Cretaceous Bashijiqike and Baxigai Formations, with the former as the most important pay formation in this area. The Cretaceous occupies > 60 percent over the proved reserve of the area, and thus is one of the key exploration targets. The sandstone of Bashijiqike Formation is dominantly feldspathic litharenite, with fine well-sorted and sub-rounded grains. Its average porosity is about 10~15 percent, and average permeability is about 1×10-3~100×10-3μm2. The sandstone formed in a fan-delta or braided-delta or shallow-lake environment. The sandstone of Baxigai Formation is mainly composed of fine-grained to silty grains. Its average porosity is about 10 percent, and average permeability about 2.4×10-3μm2. This sandstone formed in a lake-delta environment. The pore structure of Baxigai formation is not as good as that of Bashijiqike Formation. This could explain why Baxigai Formation does not produce oil and gas. The petrophysical property of core sandstones shows that the controlling factors include sedimentary facies, compaction, cementation and corrosion, with the former as the most important one. Three types of reservoir -Ⅰ、Ⅱ、Ⅲ are defined based on controlling factors, petrography-palaeogeography and petrophysical property of core sandstones. The reservoirs of typeⅠand type II produce oil and gas pools (fields), and are proved to be the favorable areas for future exploration.
出处
《新疆地质》
CAS
CSCD
2002年第3期252-255,共4页
Xinjiang Geology
