Practices of geological and engineering integration of ultra-deep and ultra-long displacement wells in the "Shendi-1" ultra-deep zone of Tarim Basin

The Sinopec "Shendi-1" project in Tarim Basin is characterized by the exploration and development of ultra-deep strike-slip fault-controlled oil and gas reservoirs. Yuejin block, located on the southern margin of Shaya uplift and adjacent to the northern part of the Shuntuoguole low uplift, develops three oil and gas enrichment belts primarily controlled by NE-trending strike-slip faults. This region is distinguished by its ultra-deep target formations (>7 000 m), high reservoir heterogeneity within fault zones, and surface coverage by poplar forest reserves. Despite breakthroughs in exploration since 2012 and more than a decade of production, there are still a large scale of untapped reserves. Great challenges are encountered in the geological engineering practices, and it is required to deepen the understandings of hydrocarbon accumulation and distribution patterns and achieve the efficient production of ultra-deep reservoirs beneath protected areas. Based on analyses of the regional fault-controlled hydrocarbon accumulation conditions and faults, as well as three-dimensional reservoir characterization in the well area, the geological study has identified the distribution of oil and gas reservoirs and untapped reserves, thus optimizing target selection. From an engineering perspective, solutions to the difficulties of ultra-deep layer and ultra-long displacement during well completion mainly include optimization of borehole trajectory design and control, borehole cleaning, stable large-inclination and long-open borehole, as well as the technologies of accelerating drilling operations and safe casing running. These techniques can enable the successful completion of Well Yuejin 3-3XC, which has obtained high-yeld oil and gas flow during testing. The well has set a domestic record with a measured depth of 9 432.55 m(slant)/ 7 212.53 m (vertical)and a horizontal displacement of 3 439.34 m, marking it as a landmark case in geological and engineering practices for complex ultra-deep reservoirs.