Fan Jianchun

Research on Mechanism of Casing Wear in Sliding-Impact Wear Condition

Casing wear already becomes one key technological problem in the west and offshore oilfield in China. The severe casing wear in the deep and ultra-deep well drilling in these area, usually takes place in the deep of well where the lateral pressure on the casing inner surface seems to be lower, sometimes even the dog-leg severity was very small. Many investigators considered that the lateral vibration of the drilling pipe is the main reason which brings serious casing wear in the section of drilling pipe under the neutral point. Indoor impact-sliding tests show that fatigue wear is one of the main wear types of casing on impact-sliding condition. Higher frequency and impact load are, more serious fatigue wear is. Field monitoring shows that chips, adhesive and fatigue wear are main wear mechanism of casing in deep and ultra-deep well drilling process. If wellbore quality is bad, adhesive wear and chips wear caused easily in drilling process. And if the wellbore quality is good, there are rather less stable contact points between casing and tooljoint, vibration energy of drilling pipe abates rather slowly, influence of lateral vibration has become more prominent and fatigue wear become main wear mechanism.

Research on casing wear monitoring technique based on detection of tool joints and its field test

Casing wear monitoring is basis of scientific casing wear prevention work, and now there is no scientific and convenient casing wear monitoring techniques in current drilling engineering. Wear characteristics of the casing — drill pipe system is further analyzed, basic theory and analysis methods of casing wear monitoring based on detection of tool joints are established through reasonable assumptions, and corresponding computer software is developed to form a complete set of casing wear monitoring technique which achieves quantitative calculation of casing wear at any depth of the well. Field tests indicate that this casing wear monitoring technique based on detection of tool joints can calculate the well casing wear volume (or weight) at any depth easily, its monitoring and computation are simple and the process has no impact on drilling, so it is suitable method for field operations.

Design and Application of Buttress Thread Buckle Marine Conductor

At present, offshore drilling operations often use buttress thread casing as surface casing. The design conception of buttress thread casing is comes from the offshore drilling’s demands and this kind of casing is mainly used as surface casing. This paper has taken strength experiment, numerical simulation analysis and field test, the research results show that the various parameters of buttress thread casing fully complies with the drilling design requirements and the offshore oilfield production demands. This product can reduce drilling cost effectively, improve working efficiency and safety, and realize manufacture domestically. Meanwhile, the development of this project will fill the blank of the ERW (Electrical Resistance Weld) casing in CNOOC (China National Offshore Oil Corporation), and have a broad prospect of application.

Wavelet energy entropy based multi-sensor data fusion for residual stress measurement using innovative intense magnetic memory method

In this paper, a novel and effective NDT method named Intense Magnetic Memory (IMM) was introduced to inspect transmission pipeline, which can provide early indications of residual stress status and eventual failure in pipeline. An experimental system was set up and the abnormal signals obtained from pipeline specimens were decomposed by wavelet transform (WT). Wavelet energy entropy was used to extract characteristic from abnormal signals. Multi-sensor data fusion algorithm was applied to get the whole stress concentration distribution. Initial experimental result shows that it is promising for IMM technology being applied to pipeline inspection.