致密高压裂缝性气藏超深水平井钻井技术难点与对策

Challenges and Solutions of Ultra-Deep Horizontal Well Drilling in Tight High Pressure Fractured Gas Reservoir

川西深层须2段气藏埋藏深,地层致密、石英含量高,主要靠钻遇裂缝获得工业产能。而直井钻遇裂缝的概率很小,为了尽可能多地钻遇裂缝,宜采用水平井开发。详细分析了川西深层须2段气藏由于埋藏深、岩石致密、地层高温、高压、研磨性高和可钻性差给水平井钻井带来的技术难点,并针对技术难点提出了对策,即要在高精度地质预测的基础上以可靠的抗高温、高压的随钻测量仪器、长寿命螺杆和钻头做保障,并兼顾优化井身结构、井下动力钻具的水力参数和钻井液流变性能。

The gas reservoir of Chuanxi Xuerduan, is ultra-deep ancl ultra-tlglat with hign quartz, The industrial in this area are mainly dependent on drilling cracks. The horizontal well should be used for the purpose of penetrating more cracks due to low possibility of passing cracks using vertical well. Technical challenges of drilling due to deep- bury, tight rock, high temperature, high pressure, high grinding and poor rock drillability, were analyzed in detail. The corresponding measures were also proposed, including using reliable high temperature high pressure measurement tool while drilling based on the reliable geological prediction, employing long longevity mud motor and bits, along with optimizing casing schematics and hydraulics and rheology of drilling fluids.