Trajectory optimization method of horizontal well build-up section based on variation of formation thickness

Abstract

The invention discloses a method for optimizing the well trajectory of the deflection section of a horizontal well based on the change of the formation thickness, comprising the following steps: 1. Finely comparing the logging data of multiple wells, analyzing the characteristic parameters of lithofacies and formation thickness changes; 2. Calibrating according to the well logging , finely process the seismic data, and find out the stratum thickness and structure change law of the target stratum; 3. Combine the logging and seismic data results to find out the abnormal thickness layer in the deflection section, and determine the stratum thickness variation and buried depth of the abnormal thickness layer. 4. Carry out subdivision of sublayers in the abnormal thickness layer and the upper and lower layers in the build-up section according to the electrical identification marks, and set the electrical identification marks; 5. Design the trajectory of the risky well and propose an optimized drilling plan. The method for optimizing the trajectory of the well under the condition of the stratum thickness variation in the kickoff section of the horizontal well disclosed by the invention provides a design idea and an operation method, and provides a practical and advantageous tool for high-quality landing of the horizontal well.

Description

technical field [0001] The invention belongs to the technical field of geosteering while drilling in well drilling engineering, and in particular relates to a trajectory optimization method for a deflection section of a horizontal well based on formation thickness changes. Background technique [0002] Oil and gas exploration and development rely more and more on horizontal wells to increase oil and gas production. Practice has proved that horizontal wells can greatly increase single well oil and gas production, while high-yield horizontal wells rely heavily on reservoir drilling ratio and drilling engineering quality. During the implementation of horizontal well drilling, due to the complexity and variability of downhole formations, abnormalities such as lithofacies changes, formation thickness changes or buried depth changes are often encountered, and formation thickness changes are the most common phenomenon. When this happens, It is easy to lead to difficulties in stratu...

AI Technical Summary

Problems solved by technology

During the implementation of horizontal well drilling, due to the complexity and variability of downhole formations, abnormalities such as lithofacies changes, formation thickness changes or buried depth changes are often encountered, and formation thickness changes are the most common phenomenon. When this happens, It is easy to lead to difficulties in stratum landing (advance or delay) and complex trajectory of the build-up section. If not handled properly, it will cause chain engineering complexity or even engineering accidents, which poses a challenge to the effective implementation of horizontal well drilling, and is also an urgent problem in horizontal well drilling engineering. one of the problems

[0003] Since this problem involves two fields of geology and drilling engineering, it is difficult to solve it. The current method mainly proposes a method to improve the accuracy of seismic processing to accurately predict the thickness of the formation. However, due to the limited seismic resolution and the influence of various factors Constraints often make it difficult to provide accurate data

The technical method of stabilizing the top of the slope is also proposed. This method assumes how to control the well trajectory under the assumption that the formation is thickened. However, if the formation change cannot be predicted, the trajectory is still difficult to control, so it lacks operability.

Some researchers also proposed to strengthen the identification and judgment of small layers to track and analyze, which has certain auxiliary value for early prediction during the actual drilling process, but how to establish a relationship with trajectory control needs to be explored. If the identification of small layers is difficult, it will be difficult to play a role

Therefore, the above method still has great limitations in guiding the steering of the horizontal well and realizing the smooth landing of the deflection section of the horizontal well, and it is even more difficult to realize the optimization of the well trajectory

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