库车坳陷X井致密砂岩储层氮气钻井实践与认识

通过欠平衡钻井技术的理论研究和室内试验,形成了一套较完善的适用于高压高产致密砂岩储层的氮气钻井方案,具有合理的注气设备配套方案、钻具组合、井身结构设计以及整套工艺流程。以库车坳陷东部的X井为例,通过与多口邻近致密砂岩储层的常规钻井液钻井技术相比,X井的机械转速最大提高了24.3倍,钻井周期最多缩短了62 d,单井产量是邻井的4.2倍。致密砂岩储层氮气钻井在X井的成功应用,再次证明了在致密砂岩储层使用氮气钻井技术可以提高机械钻速、缩短钻井周期、提高单井产量的目的。同时验证了氮气钻井技术和装备的安全可行性,为库车地区乃至全国推广高压高产致密砂岩储层氮气钻井技术奠定了基础。

Practice and understanding on nitrogen drilling of tight sandstone reservoir in Kuqa Depression Well X

Through theoretical research and inhouse test on under-balanced (UBD) drilling technology, a set of complete nitrogen drilling programs applicable to high pressure and high production tight sandstone reservoir has been formulated, which includes reasonable gas injection equipment supporting program, bottom hole assembly, well configuration design as well as the whole technological process. Take X-Well in the east of Kuqa Depression as an example, compared with the conventional drilling fluid drilling technology used in drilling of tight sandstone reservoirs in a number of adjacent wells, the penetration rate of X Well was improved by 24.3 times as a maximum, and the drilling cycle was shortened by 62 d to the most extent, and the single well production was 4.2 times that of offset well. The success of nitrogen drilling in tight sandstone reservoir in X Well shows again that the use of nitrogen drilling technology in tight sandstone reservoir can increase the ROP, shorten the drilling cycle and increase the single well productions. It also verifies the safe practicability of nitrogen drilling technology and equipment, laying out a foundation for promoting this nitrogen drilling technology in tight sandstone reservoir of high pressure and high production in Kuqa region and even nationawide.