Papers by Author: Yuan Fang Cheng

Abstract: As a kind of emerging energy with massive reserves, natural gas hydrates are becoming the hot spot of global research. The elastic properties of gas hydrate bearing sediments (HBS) are the fundamental parameters for gas hydrates exploration and resource evaluations. As the original coring in HBS is difficult and expensive, experimental method is important to study the problem. An acoustic wave in-situ measuring system for HBS was developed. Using the in-situ method, hydrate bearing rock samples of different hydrate saturation were synthesized, of which the supersonic wave measurement was carried out under different confining pressure. According to the elasticity theory, the dynamic elastic parameters were obtained using the measured ultrasonic wave velocity. The results show that compressional and shear waves increase with the confining pressure and hydrate saturation increasing, and so the dynamic elastic modulus is.

Abstract: The application of well logging data is one of the most common prediction methods of pore pressure. According to acquire the field practical applicability and high accuracy, Eaton’s method proposed a definition of area index which can present the local complex factors resulting in abnormal pressure regardless of overpressure generating mechanisms. However, the computed area index is generally calculated by one layer in the whole formation, thereby generating some prediction errors. This paper presents a new method called “Hierarchical Eaton’s Method” that is considering different computed area indexes from different layers. Therefore, the revised Eaton’s method can have higher accuracy comparing to traditional Eaton’s method. Moreover, the application of this new method in HPHT wells in Yinggehai basin, China has been discussed in this paper and indicates the field feasibility of this approach.