苏里格气田水平井井身结构优化及钻井配套技术

苏里格气田致密气藏埋藏深，钻遇地层塌漏问题突出，机械钻速低，前期水平井采用三开井身结构，难以达到钻井持续提速和降低钻井成本的目的。为此，在开展缩短中完周期、优化封固段和井眼尺寸等方面的理论分析，并进行井身结构优化过渡性方案现场试验的基础上，提出了井身结构优化思路，分析了可行性；然后，进行了封固段优选、井眼尺寸优化，设计了水平井小井眼二开井身结构。基于此井身结构，研究了井眼轨迹控制、个性化钻头和配套提速工具优选、强抑制高效润滑钻井液分段措施优化等关键钻井配套技术。该技术在19口井进行了现场应用，解决了长裸眼段“塌漏同存，上漏下塌”的问题，提高了各井段的机械钻速，大幅度缩短了钻井周期。研究结果表明，小井眼二开井身结构设计合理，钻井配套技术提速效果显著，可在苏里格气田水平井钻井中推广应用。 

Casing Program Optimization and Drilling Matching Technologies for Horizontal Wells in Sulige Gas Field

The tight gas reservoirs in Sulige Gas Field are characterized by deep buried depth, prominent collapse and leakage of drilling strata, low rates of penetration (ROP). Thus, with the three-section casing program of early horizontal wells, it is difficult to continuously increase the ROP and reduce the drilling cost. In response, a theoretical analysis was carried out on reducing the intermediate completion cycles and optimizing the sealing section and the borehole size. And a transitional test of casing program optimization was performed. On these basis, ideas for casing program optimization were proposed and their feasibility was analyzed. The sealing section and the borehole sizes were optimized, and a two-section casing program was designed for slim boreholes in horizontal wells. The key drilling matching technologies were studied, including borehole trajectory control, optimization of customized drill bits and matching speed-up tools, and segmentation measure optimization for drilling fluids with strong inhibition and high-efficiency lubrication. The field application proved that the proposed technologies had a good application effect and they solved the “collapse and leakage coexist, with leakage above and collapse below” problems in long openhole sections. The ROP in each section was improved, and the drilling cycle was greatly shortened. The application suggests that the two-section casing program for slim boreholes is reasonable, and the drilling matching technologies dramatically increase the ROP and therefore can be applied in horizontal well drilling in Sulige Gas Field.