Method for self-adaptive survey calculation of wellbore trajectory

A method for self-adaptive survey calculation of a wellbore trajectory, wherein the method for self-adaptive survey calculation of the wellbore trajectory comprises:

• receiving survey data and processing the survey data, and numbering survey stations and survey intervals according to the survey data;
• calculating, by using a conventional survey calculation method, a coordinate increment of a lower survey station relative to an upper survey station of a 1st survey interval;
• calculating a coordinate increment of a lower survey station relative to an upper survey station of a 2nd survey interval according to the 1st survey interval, the 2nd survey interval and a 3rd survey interval, and calculating a coordinate increment of a lower survey station relative to an upper survey station of other survey interval by analogy, until a coordinate increment of a lower survey station relative to an upper survey station of a penultimate survey interval is calculated;
• calculating, by using the conventional survey calculation method, a coordinate increment of a lower survey station relative to an upper survey station of a last survey interval;
• calculating vertical depths, N coordinates, E coordinates, horizontal projection lengths, closure distances, closure azimuth angles and vertical sections in wellbore trajectory parameters of respective ones of the survey stations, according to coordinate increments of lower survey stations relative to upper survey stations of all the survey intervals;
• wherein the calculating a coordinate increment of a lower survey station relative to an upper survey station of a 2nd survey interval according to the 1st survey interval, the 2nd survey interval and a 3rd survey interval, comprises:
• calculating estimated values of wellbore curvature, torsion and a tool face angle of the upper survey station of the 2nd survey interval according to well depths, well inclination angles and azimuth angles of three survey stations corresponding to the 1st survey interval and the 2nd survey interval;
• calculating estimated values of wellbore curvature, torsion and a tool face angle of the lower survey station of the 2nd survey interval according to well depths, well inclination angles and azimuth angles of three survey stations corresponding to the 2nd survey interval and the 3rd survey interval;
• calculating an estimated average change rate of wellbore curvature, an estimated average change rate of torsion and an estimated tool face angle increment, between the upper survey station and the lower survey station of the 2nd survey interval;
• determining a value range of wellbore curvature, a value range of torsion and a value range of tool face angle of the 2nd survey interval by taking the estimated values of the wellbore curvature, the torsion and the tool face angle of the upper survey station as reference values and taking ±10% of a wellbore curvature increment, ±10% of a torsion increment and ±10% of a tool face angle increment between the upper survey station and the lower survey station of the 2nd survey interval as fluctuation ranges;
• determining a value range of a change rate of the wellbore curvature and a value range of a change rate of the torsion of the 2nd survey interval, by taking the estimated average change rate of the wellbore curvature and the estimated average change rate of the torsion between the upper survey station and the lower survey station of the 2nd survey interval as reference values and fluctuating around the reference values up and down by 5%;
• calculating the well inclination angle, the azimuth angle, the wellbore curvature and the torsion of the lower survey station of the 2nd survey interval, from the wellbore curvature, the torsion and the tool face angle of the upper survey station of the 2nd survey interval and the change rate of the wellbore curvature and the change rate of the torsion of the 2nd survey interval and within the determined value range of the change rate of the wellbore curvature and the determined value range of the change rate of the torsion of the 2nd survey interval;
• calculating a comprehensive angular deviation between the calculated values and measured values of the well inclination angle and the azimuth angle at the lower survey station of the 2nd survey interval and a comprehensive deviation between the calculated values and estimated values of the curvature and the torsion at the upper survey station and lower survey station of the 2nd survey interval;
• determining optimal values of the wellbore curvature, the torsion and the tool face angle of the upper survey station of the 2nd survey interval and the change rate of the wellbore curvature and the change rate of the torsion of the 2nd survey interval, according to a principle of minimum comprehensive deviation of the curvature and the torsion of the upper survey station and the lower survey station of the 2nd survey interval on a premise that an angular deviation at the lower survey station of the 2nd survey interval is less than a specified value of 0.0002;
• calculating the coordinate increment of the lower survey station relative to the upper survey station of the 2nd survey interval, according to the optimal values of the wellbore curvature, the torsion and the tool face angle of the upper survey station of the 2nd and the change rate of the wellbore curvature and the change rate of the torsion of the 2nd survey interval.