# Research on Intelligent Optimization of Wellbore Trajectory in Complex Formation
## 1 Introduction
found that the local layer depth change and reservoir heterogeneity brought great difficulties to drilling engineering in the development process of the reef-bank facies gas reservoir of the Upper Permian Changxing Formation in Yuanba Gas Field, Sichuan Province. In order to solve this problem, their team established the horizontal well trajectory optimization adjustment technology, and then established the reservoir horizontal well trajectory. [PERSON], [PERSON], and [PERSON] et al. [18] (2016) established a new well trajectory optimization model to optimize the target well production in view of the lack of understanding of the formation uncertainty in the reference model based on the fluid simulation model in the actual oilfield development and drilling operation. From the experimental results obtained, the NPV coefficient of each year is greater than 0, indicating that the proposed well trace oil production is high and reasonable. [PERSON] et al. [19] (2016) proposed a two-dimensional wellbore trajectory design method for the drilling difficulties of shale gas horizontal wells. The research results showed that the trajectory design of horizontal wells in two intersecting vertical planes will greatly reduce the difficulty of drilling construction. [PERSON] [20] (2017), on the basis of summarizing the previous research, in order to further improve the scientific nature of wellbore trajectory planning introduced the vertical depth of kickoff point, tool build-up rate, formation conditions, and other formation characteristics into the model as parameters. In view of the requirements and difficulties of platform well deployment, the optimization method of platform well deployment and the optimization design method of well trajectory in the platform are given. [PERSON] and [PERSON] [21] et al. (2022) conducted technical research on directional well trajectory design, the safe drilling cycle of extended reach wells, wellbore structure optimization, friction torque, and drilling fluid performance in view of the complex conditions of shallow extended reach horizontal wells in the Bohai Oilfield in China, such as loose shallow strata, difficult wellbore trajectory control, easy hydration and expansion of mudstone, frequent reverse reaming difficulties, and casing resistance. [PERSON] [22] (2022) also conducted in-depth research on the drilling process in complex geology. Firstly, in order to ensure the stability of the wellbore, she proposed a trajectory optimization model considering formation constraints. Secondly, in view of the fact that the drilling process will destroy the original stress balance of the formation, [PERSON] adjusted the mud density, and took the trajectory length and drill string torque as the optimization objectives to establish the trajectory optimization problem under the constraint of wellbore stability. [PERSON]. [PERSON] and [PERSON]. [23] (2022) et al. studied the case of the southeastern Sulige gas field. Considering that the fluvial sand bodies change rapidly, the spatial distribution is complex, and the contact mode of single sand bodies is mainly formed by lateral deposition, [PERSON] et al. carried out three-dimensional geological modeling to improve the prediction accuracy of interwell sand bodies. [PERSON] et al. [24] (2022) established a geomechanical model for shale gas reservoirs in the Changning area, Sichuan Province. Combined with logging data, the influence of rock mechanical properties, in situ stress distribution, and other factors influencing wellbore stability were analyzed. A wellbore stability analysis method based on modified plate-weak plane failure criterion was proposed, which provided guidance for optimizing drilling fluid density and trajectory.