There exist different response characteristics in the resistivity measurements of dual laterolog （DLL） and logging while drilling （LWD） electromagnetic wave propagation logging in highly deviated and horizontal we...There exist different response characteristics in the resistivity measurements of dual laterolog （DLL） and logging while drilling （LWD） electromagnetic wave propagation logging in highly deviated and horizontal wells due to the difference in their measuring principles. In this study, we first use the integral equation method simulated the response characteristics of LWD resistivity and use the three dimensional finite element method （3D-FEM） simulated the response characteristics of DLL resistivity in horizontal wells, and then analyzed the response differences between the DLL and LWD resistivity. The comparative analysis indicated that the response differences may be caused by different factors such as differences in the angle of instrument inclination, anisotropy, formation interface, and mud intrusion. In the interface, the curves of the LWD resistivity become sharp with increases in the deviation while those of the DLL resistivity gradually become smooth. Both curves are affected by the anisotropy although the effect on DLL resistivity is lower than the LWD resistivity. These differences aid in providing a reasonable explanation in the horizontal well. However, this can also simultaneously lead to false results. At the end of the study, we explain the effects of the differences in the interpretation of the horizontal well based on the results and actual data analysis.展开更多
This paper addresses the need for systematic evaluation of the station keeping systems of deepwater drilling semi-submersibles.Based on the selected drilling semi-submersible configuration, the mooring systems were an...This paper addresses the need for systematic evaluation of the station keeping systems of deepwater drilling semi-submersibles.Based on the selected drilling semi-submersible configuration, the mooring systems were analyzed and designed for a range of water depths using different mooring line materials.These were steel wire rope, polyester rope and HMPE (high modulus poly ethylene).The mooring analysis was carried out using the advanced fully coupled time domain analysis method in the computer software package HARP.Diffraction analysis was first applied to solve the hydrodynamic properties of the vessel and then the motion equations of the complete dynamic system including the drilling rig, the mooring lines and risers were developed and solved in the time domain.Applying the advanced analysis method, a matrix of mooring systems was developed for operating in water depths of 1000 m, 1500 m, and 2 000 m using various mooring materials.The development of mooring systems was conducted in accordance with the commonly adopted mooring design code, API RP 2SK and API RP 2SM.Fresh attempts were then made to comparatively evaluate the mooring system's characteristics and global performance.Useful results have been obtained in terms of mooring materials, water depths, and key parameters of mooring configurations.The results provide in-depth insight for the design and operation of deepwater mooring systems in the South China Sea environment.展开更多
Mooring systems play an important role for semi-submersible rigs that drill in deepwater.A detailed analysis was carried out on the mooring of a semi-submersible rig that conducted a trial well drilling at a deepwater...Mooring systems play an important role for semi-submersible rigs that drill in deepwater.A detailed analysis was carried out on the mooring of a semi-submersible rig that conducted a trial well drilling at a deepwater location in the South China Sea in 2009.The rig was 30 years old and had a shallow platform with a designed maximum operating water depth of 457 m.Following the mooring analysis,a mooring design was given that requires upgrading of the rig’s original mooring system.The upgrade included several innovations,such as installing eight larger anchors,i.e.replacing the original anchors and inserting an additional 600 m of steel wires with the existing chains.All this was done to enhance the mooring capability of the rig in order for the rig to be held in position to conduct drilling at a water depth of 476 m.The overall duration of the drilling was 50 days and the upgraded mooring system proved to be efficient in achieving the goal of keeping the rig stationary while it was drilling the trial well in the South China Sea.This successful campaign demonstrates that an older semi-submersible rig can take on drilling in deep water after careful design and proper upgrading and modification to the original mooring system.展开更多
基金supported by the National Science and Technology Major Project of China(Nos.2016ZX05014-002-001,2016ZX05002-005-001,and 2017ZX05005-005-005)
文摘There exist different response characteristics in the resistivity measurements of dual laterolog （DLL） and logging while drilling （LWD） electromagnetic wave propagation logging in highly deviated and horizontal wells due to the difference in their measuring principles. In this study, we first use the integral equation method simulated the response characteristics of LWD resistivity and use the three dimensional finite element method （3D-FEM） simulated the response characteristics of DLL resistivity in horizontal wells, and then analyzed the response differences between the DLL and LWD resistivity. The comparative analysis indicated that the response differences may be caused by different factors such as differences in the angle of instrument inclination, anisotropy, formation interface, and mud intrusion. In the interface, the curves of the LWD resistivity become sharp with increases in the deviation while those of the DLL resistivity gradually become smooth. Both curves are affected by the anisotropy although the effect on DLL resistivity is lower than the LWD resistivity. These differences aid in providing a reasonable explanation in the horizontal well. However, this can also simultaneously lead to false results. At the end of the study, we explain the effects of the differences in the interpretation of the horizontal well based on the results and actual data analysis.
基金Supported by China National 111 Project under Grant No.B07019
文摘This paper addresses the need for systematic evaluation of the station keeping systems of deepwater drilling semi-submersibles.Based on the selected drilling semi-submersible configuration, the mooring systems were analyzed and designed for a range of water depths using different mooring line materials.These were steel wire rope, polyester rope and HMPE (high modulus poly ethylene).The mooring analysis was carried out using the advanced fully coupled time domain analysis method in the computer software package HARP.Diffraction analysis was first applied to solve the hydrodynamic properties of the vessel and then the motion equations of the complete dynamic system including the drilling rig, the mooring lines and risers were developed and solved in the time domain.Applying the advanced analysis method, a matrix of mooring systems was developed for operating in water depths of 1000 m, 1500 m, and 2 000 m using various mooring materials.The development of mooring systems was conducted in accordance with the commonly adopted mooring design code, API RP 2SK and API RP 2SM.Fresh attempts were then made to comparatively evaluate the mooring system's characteristics and global performance.Useful results have been obtained in terms of mooring materials, water depths, and key parameters of mooring configurations.The results provide in-depth insight for the design and operation of deepwater mooring systems in the South China Sea environment.
文摘Mooring systems play an important role for semi-submersible rigs that drill in deepwater.A detailed analysis was carried out on the mooring of a semi-submersible rig that conducted a trial well drilling at a deepwater location in the South China Sea in 2009.The rig was 30 years old and had a shallow platform with a designed maximum operating water depth of 457 m.Following the mooring analysis,a mooring design was given that requires upgrading of the rig’s original mooring system.The upgrade included several innovations,such as installing eight larger anchors,i.e.replacing the original anchors and inserting an additional 600 m of steel wires with the existing chains.All this was done to enhance the mooring capability of the rig in order for the rig to be held in position to conduct drilling at a water depth of 476 m.The overall duration of the drilling was 50 days and the upgraded mooring system proved to be efficient in achieving the goal of keeping the rig stationary while it was drilling the trial well in the South China Sea.This successful campaign demonstrates that an older semi-submersible rig can take on drilling in deep water after careful design and proper upgrading and modification to the original mooring system.
