Effective Options Utilized to Wellbore Engineering Data Evaluation and Analysis for Drilling Performance Improvement

Abstract To mitigate drilling risks and enhance the rate of penetration (ROP) in shale gas horizontal wells, wellbore stability analysis and geomechanical studies are essential. However, cluster development of horizontal wells within the same platform alters the original in-situ stress field, rendering the drilling mud weight window calculated based on static mechanical models inaccurate. This frequently leads to wellbore instability during drilling, posing risks to both drilling safety and environmental protection. This paper integrates actual drilling, fracturing, and production data to establish a multidimensional geomechanical model. Building upon a 1D static geomechanical model, it incorporates stress field variations in the target drilling area caused by fracturing and production operations from three previously completed horizontal wells in the northern cluster. Key findings include: 1. Dynamic Stress Field Analysis: After injecting approximately 100,000 m³ of fracturing fluid into three northern horizontal wells and considering cumulative production effects, the "fracturing-production" operations in the northern cluster induced a pore pressure increase of 0.6–1.6 MPa in the southern platform area. This corresponds to a mud weight increment of 0.07–0.1 g/cm³, necessitating adjustments to drilling fluid density for enhanced wellbore stability. 2. Target Formation Mechanical Properties: Poisson's ratio: 0.152–0.22. Young's modulus: 6.1–65.8 GPa. Rock strength: 60.7–117 MPa. The low Poisson's ratio and high Young's modulus indicate medium-hard formations with favorable drillability. 3.Formation Pressure Evolution: The Hanjiadian Formation exhibits gradual pressure buildup, with the Longmaxi source rock reaching a maximum pressure gradient of 1.49 g/cm³.This dynamic geomechanical model demonstrates strong applicability and accuracy in predicting wellbore stability and optimizing mud weight windows. It provides critical insights for drilling design, effectively addressing stress field perturbations caused by multi-well interference in cluster development. For instance, the quantified mud weight adjustment (0.07–0.1 g/cm³) directly translates to safer drilling practices while avoiding excessive mud costs – a balance crucial for both engineering safety and economic efficiency in shale gas operations.