Study On Optimization Design And Software Development In Complex Structure Wells Trajectory

With the progress of drilling technology of Complicated Structure Well, using complexstructure well to develop low permeability oil fields and Marine oil and gas resources hasbecome the consensus of petroleum engineers. Wellbore trajectory design is the primaryproblem in the process of complex structure drilling, regular trajectory design based on the testalgorithm, namely first assume that part of the design parameters are known, then theunknown design parameters are calculated. This method depends on the designer’s experienceand intuition, the designed trajectory is often not the feasible optimized trajectory. As a result,under the premise of precision to meet the target, the engineering and geological requirements,how to choose reasonable design variables, design a minimum length trajectory has greatsignificance for saving drilling cost and enhancing drilling efficiency.This paper discusses the2D and3D trajectory design model particularly, according to theknown design parameters, the solution expression of all kinds of unknown design parameterscombination is given. It emphatically discusses the design method of multi-objective welltarget area and parameters calculation, the borehole trajectory design model and solvingproblems.Secondly, based on optimization theory, the new model regards the length of trajectory asits objective function, in which main factors affecting trajectory design are considered, in orderto KOP, build up rate, inclination and azimuth angle as the design variables, with the targetaccuracy, formation conditions, the design variables boundary as constraint conditions, such aborehole trajectory optimization design model is established. The genetic algorithm is used tosolve the optimization design model and borehole trajectory design model, and it is verified tobe rational and accurate by example calculate, which avoid the deficiency of easy to fall intolocal convergence and depending on initial value in iterative method.Finally, the borehole trajectory optimization design software is compiled combined withcomputer technology, all parameters of the directional well trajectory can be calculated by thesoftware, when drilling constraint conditions of design parameters are inputted, a feasibleoptimum wellbore trajectory will be designed out automatically. The software can be used asauxiliary tool for wellbore trajectory design.