Papers by Author: Hui Zhang

Abstract: With the increase of drilling depth, the mechanical properties of H-section steel used in drilling platform are more and more demanding. In this paper, the strength, low temperature impact toughness, plasticity, micro-hardness and microstructure of 500MPa hot rolled H-section steel produced by TMCP process were analyzed, and the strengthening mechanism was also studied. The results show that flanges of TMCP hot rolled H-section steel had the best strength and toughness, while the yield strength at web and R Angle was reduced to 91% and 78% of the flange, respectively. The impact toughness at -40°C of web and R Angle was reduced to 86% and 38% of the flange , and the micro-hardness reduced to 91% and 85% of the flange, respectively. The main strengthening mechanism of the TMCP hot rolled H-section steel is fine-grain strengthening, the carbonitride of V precipitation strengthening and surface bainite transformation strengthening.

Abstract: Drilling is one of the major means for oil and gas exploration and development. Extended reach wells (ERWs) are defined as directional wells or horizontal wells with horizontal displacement (HD) to vertical depth (VD) ratio greater than or equal to 2. Extended reach drilling (ERD) confronted many technical difficulties. Risk analysis of ERD before drilling is of great significance for preventing complex accidents during drilling operations, improving the drilling rate and efficiency. Based on gray matter-element theory, this paper established a comprehensive risk assessment model for ERD operations and applied this model to evaluate the drilling risk of Well B6ERW07(HD to VD ratio 5.94, horizontal displacement 7,419.42 m, vertical depth 1,248.50 m, measured depth 8,144.31 m)in the Liuhua oil field, South China Sea. The assessment results show that the predicted success rate of drilling this ERW is 49.9%. This result can be important criteria and thus contributes greatly to decision making.