Optimization Study On Drilling Site Of Horizontal Wells In Xujiahe Formation, Western Sichuan

The Western Sichuan Xujiahe reservoir heterogeneity is strong, shale and sandstone interbeded frequently, resulting in low ROP, long drilling cycle, difficult to trajectory control and complex borehole resistance card, more complex downhole complicated conditions.And these lead to high operating costs of homework, these cases become more prominent in the construction of horizontal wells. In this paper, its needle Xujiahe horizontal drilling tight gas reservoirs that appeared above problems, carryed out the appropriate technology to optimize and tested form suitable to be home in western Sichuan river Hirai drilling optimization supporting technology.Based on the full investigation of deep horizontal wells drilling at home and abroad, combining with other type of trajectory and optimization of casing, then combined with the present situation analysis of horizaontal well of xujiahe formationin west Sichuan construction and further optimize the Xujiahe horizontal well trajectory design and well the body structure design,and to carry out the pilot test. Well structure consists of four open system optimized for three open system, simplifying the well structure, reducing the borehole size, casing reduce technical level, adopted reasonable adjustments under the technical casing depth, while improved drilling efficiency to meet the needs of western Sichuan deep well drilling horizontal wells. Based on the results of the use of the drill bit, PDC drill bits and roller bits optimized after the site test and application, then forms the bit series of ditectional drilling in favor of xujiahe formation. Meanwhile, through the well trajectory optimization design, drilling-parameters optimization of horizontal wells, horizontal wells and landing control method and combined with real time optimization and control, then forming a tight gas reservoirs in xujiahe horizontal well trajectory control method. The typical guide BHA stress analysis and BHA optimization design research were developed, field test was carried out based on the research achievements. Using the Rotary steering technology according to the directional efficiency of horizontal section. And get the supporting technology through the pilot test of horizaontal well drilling in xujiahe in West Sichuan.The technology of comprehensive application in the new 21-XH well and 21-XIH well, the obvious results had been achieved:the average test well drilling cycle than the design period is shortened by 22.27%, compared with the non test well drilling cycle shortened rate increased by 14.92%; the average of downhole complicated conditions and accident rate of 1.15%, lower thanthe 1.24%.