Risk assessment of surface conductor jetting installation during deep-water drilling in sloping seabed

Abstract

With the increasing exploration and development area of deep-water oil and gas fields in the South China Sea, well construction operations in the deep-water sloping seabed area become more and more frequent, so it is of great significance to accurately assess the safety of jetting well construction in the sloping seabed. Based on the characteristics of jetting well construction technology, the soil disturbance model was established and the wellhead instability mechanism in sloping seabed was studied. It was found that the jetting flow rate and fluid range were the main factors to determine the disturbance intensity and disturbance range to sloping seabed. The risk of jetting well construction in the sloping seabed was also studied based on the geologic models of various forms of sloping seabed. The finite element strength reduction method was used to analyze the influence of seabed dip angle, soil strength and soil stratification on sloping seabed stability, and the sloping seabed instability evolution law under different jetting disturbance parameters was obtained. Through the assessment of the risk of jetting well construction in the sloping seabed, the selection range of well locations was expanded, which could aid in ensuring the security of deep-water oil and gas field construction.