川西坳陷须家河组气藏产层域探讨

Discussion on the Gas Production Area of Xujiahe Formation in West Sichuan Depression

须家河组二、四段的油气产层在川西坳陷的埋深是有一定规律可寻的,生产研究从钻井部署、钻进、测井、试井、成井全程跟踪,发现:北段浅,中段深、南段又变浅。从产出层位考量,北段老,南段新,中段介于两者之间;为了提高钻井命中率,通过各井产层含气带与气水界面对比分析;目的在较准确的把握油气产层的埋深,知道气水界面的位置,在当前5000~6000米,钻井成本1万元/米的条件下,将在布井、钻井设计、井深结构、油气层预测、钻头选型、钻井液配伍、事故预报等多方面具有一定的地质意义和带来巨大的经济效益;研究认为主要控制因素为盆地结构与构造类型,孔隙演化与地温场。

The layers of Xujiahe's segment 2 and 4 hydrocarbon pay formations in Western Sichuan De-pression shows that there are some regulations on the buried depth of hydrocarbon reservoirs. Discovering from production research such as arrangement of wells, drilling, well logging, well testing, well completion tracing, the buried depth of Xujiahe formation is shallow in the northern, deep in the middle and shallow in the southern. The age of pay formations shows older in the northern, younger in the southern, and the middle is situated between the two. In order to improve the success rate of drilling, according to the comparative analysis of gas zone and air-water interface in these pay formations, we can accurately grasp the buried depth of pay formations and confirm the depth of air-water interface. That will bring the certain geological significance and the enormous economic benefits in the aspects of well spacing, well drilling design, well depth structure, oil-gas layer prediction, drill bit lectotype, drilling fluid compatibility, accident forecasting under the condition of drilling cost price follows ten thousands per meter in the depth range of 5000 - 6000 m. The research suggests that the main controlling factors are basin construction, structural type, pore evolution and formation tem-perature filed.