Calculation And 3D Visualization Of Well Trajectory Measurement Error Based On The ISCWSA Model

Well trajectory error analysis is an important factor in determining the position of the wellbore.With the popularization and application of infilled wells and dense cluster wells,the collision probability between adjacent wells increases,well trajectory error analysis has been widely used in directional well path design and control.In recent years,the well trajectory measurement error calculation model has been rapidly developed in foreign countries,but there is little research in this field in China.The Industry Steering Committee on Wellbore Survey Accuracy established the ISCWSA error calculation model for the internationally-recognized directional drilling service company's MWD tools and had been applied in the Landmark software.However,in order to make the ISCWSA error calculation model adapt to China's domestic MWD tools and facilitate the drilling field application,further research works are needed.This paper analyzed the factors that caused wellhole position uncertainty,and introduced the measurement error sources considered in the WdW model and the ISCWSA model,and the calculation of the error ellipsoids respectively,then the wellhole trajectory measurement error calculation and 3D visualization program was developed based on Visual C# and OpenGL.It could be seen intuitively that the measurement errors are continuously accumulated with the well measurement depth and the magnitude of the adjacent well collision risk by the 3D visualization of the measurement errors of the example well trajectory.The well trajectory measurement errors calculated based on the WdW model are much more conservative than calculated based on the ISCWSA model.For the well trajectory measurement using MWD in current directional drilling projects,the analysis of well trajectory measurement error based on the ISCWSA model could more scientifically reflect the actual position uncertainty of the well trajectory.The research achievement can be applied to directional well anti-collision design and control projects.