The Modeling On Track Designing And Casing Running In Stepped Horizontal Well

Daqing Zhao Zhou Oil Field locates in outside of Daqing Placanticline. Based on its reserve features of low abundance and slight thickness, this field is exploited universally with stepped horizontal well. Stepped horizontal well is a special kind which originates from conventional horizontal well. Its horizontal part can fluctuate many times on vertical profile and pass through different depth of oil layer, and can also pass through the different directions of oil layer in the identical depth horizontal plane for many times. In order to decline friction resistance as a result of low smoothness, the thought that two-stage track design is proposed. The part of the track above the first target spot is designed with mathematical model based on nonlinear programming (NLP), while connecting part of two tracks separately penetrating two horizontal oil layers, consists of two smooth curves. According to features of deflecting tools and relative position of two oil layers, vertical track model, horizontal circumvention track model and targeting track model are built to obtain a smooth well track. In the view of contact between casing string and sidewall, mechanical problem in the process of casing running is abstracted to contact nonlinear and geometric nonlinear problem. So, a finite element model of holistic casing string is established, and in light of this model, a software is programmed used to evaluate casing throughput capacity and analysis casing centrality. The achievement of this paper makes the design of stepped horizontal well track more scientific and reasonable, and supplies a gap in the design of stepped horizontal well track in Daqing Oil Field.