Well Trajectory Design And Wellpath Control Plan To A High-Inclined Cluster Well

All the directional wells in XX block are double targets and high angle deviated wells.The horizontal displacement,length of the target and angle of inclination are big.At the same time,the displacement of well slot of the platform is small.Through directional drilling risk analysis,circulation loss,bit freezing and H2 S project risk are considered the most critical accidents in XX gas field.Complex situations and accident-prone formations are Asmari(403m ~ 474m),Jahrum(474m ~ 748m),Sachun(748m ~ 956m),Dashtak(2281m ~ 2296m);Mostly formation lithologies are limestone,dolomite and dolomitic limestone.Considering the upper section of the well collision prevention requirements,complex formation and the well structure design,the well track design plan of all directional well should be optimum.Directional wells of relatively large Horizontal displacement are designed by the principle reducing drilling risk and improving drilling speed.Three track design project are proposed: first--“vertical section-angle building section-micro angle building section1-angle holding section1-micro angle building section2-angle holding section”;second-“Vertical sectionangle building section-angle holding section1-micro angle building section-angle holding section2”;third--“Vertical section-angle building section1-angle holding section1-angle building section2-angle holding section2”.Besides,the overall wellhead slot allocation scheme is optimize by the application of genetic algorithms and the anti-collision scan analysis is also done.Considering the well structure and track design project of this block,the design of drilling tools(including helicoid hydraulic motor)and selection of drilling factors are complicated by different drilling periods and hole sections.Each includes two sets of directional drilling tools design and single-stabilizer drilling tools assemble.