Safety evaluation method and system for tripping in of shale gas long-section horizontal well casing

Abstract

The invention discloses a safety evaluation method and system for tripping in a shale gas long-section horizontal well casing, and the method comprises the steps: carrying out the sensitivity analysisof a hook hanging load and a casing string friction coefficient through a three-dimensional soft rod pipe string model, and determining a predicted well casing tripping-in depth range; performing calculating to obtain the accumulated value of the actual drilling track dog-leg degree along with the well depth, comparing the accumulated value with the accumulated track dog-leg degree of the adjacent well and the actual casing running friction data, and determining the predicted critical accumulated dog-leg degree value of the casing running of the well; calculating a borehole diameter variablecoefficient by utilizing the borehole diameter observed values of the well sections at certain intervals, analyzing the relationship between the borehole diameter variable coefficient of the adjacentwell and the actually measured friction data of casing running, and determining the predicted critical borehole diameter variable coefficient of casing running of the well; determining the tripping-infriction resistance coefficient range of the adjacent well casing according to casing tripping-in measured data; determining a predicted well friction coefficient according to the result; and according to the predicted well friction coefficient, determining the maximum well depths and risk levels of different casing running modes are determined, and generating a safety evaluation result.

Description

technical field [0001] The invention belongs to the technical field of drilling engineering in the petroleum industry, and specifically proposes a safety evaluation method and system for casing running in a long section of shale gas horizontal well. Background technique [0002] In recent years, with the rapid development of shale gas exploration and development, three-dimensional horizontal wells with large offset and long horizontal section are increasing. At present, the length of domestic shale gas horizontal section has reached more than 3000m. , the well lost circulation and diameter shrinkage collapse are serious, the lateral distribution of high-quality reservoirs is uneven, and the trajectory adjustment of the horizontal section is frequent, resulting in complex wellbore trajectory and extremely irregular well diameter, which greatly increases the risk and difficulty of casing running in the horizontal section. Currently, about 80% to 90% of shale gas horizontal wel...

AI Technical Summary

Problems solved by technology

[0002] In recent years, with the rapid development of shale gas exploration and development, three-dimensional horizontal wells with large offset and long horizontal section are increasing. At present, the length of domestic shale gas horizontal section has reached more than 3000m. , the well lost circulation, diameter shrinkage and collapse are serious, the lateral distribution of high-quality reservoirs is uneven, and the trajectory adjustment of the horizontal section is frequent, resulting in complex wellbore trajectory and extremely irregular well diameter, which greatly increases the risk and difficulty of casing running in the horizontal section. Currently, about 80% to 90% of shale gas horizontal wells have difficulty running casing, and even some wells cannot go down to the predetermined depth, resulting in huge economic losses

[0003] In the existing technology, the traditional pipe string friction simulation calculation method is generally used to evaluate the risk of casing running, which has a large error with the on-site construction situation, and cannot accurately guide the on-site construction

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