COMPATIBILITY EVALUATION OF BZ25-1 CRUDE OILS IN BOHAI BAY, CHINA

ABSTRACT BZ25-1 oilfield is located in the southeast of Bohai bay which geographically lies between 119 o 00′to 119 o 15′east longitude and 38 o 10′to 38 o 20′north latitude. It has two oil blocks, including Shahejie (SHJ) waxy oil and Minghuazhen (MHZ) heavy oil, with six wellhead platforms WHPA~WHPF and six submarine pipelines. Therein, the WHPC-WHPB and WHPB-SPM (Single Point Mooring) pipelines transport the mixture of the two produced crude oils. However, the mixing of the two oils will certainly bring out a change in their components and properties, which directly affects the safe operation of the submarine pipelines and offshore production facilities. Therefore, this paper compounds three kinds of MHZ/SHJ mixed oils with blending ratios of 1:1, 3:1 and 9:1, mainly studies how the components, rheological and thermophysical properties of the oil mixtures change with the blending ratio. The major objective of this study is to evaluate the compatibility of the two crude oils and provide a theoretical basis for the production optimization and risk elusion of the oilfield. The results of the study show that the components and properties of SHJ crude oil are quite different from those of MHZ oil, the flow behavior of SHJ oil is more sensitive to temperature. As MHZ oil in the compounds increases, the contents of asphaltene, resin, sulfur and carbon residue will increase except wax contents, their viscosities, densities and flash points will also increase, but their pour points, yield stresses, calorific values and other major thermophysical parameters will decrease. A blending ratio of 2~7:1 for MHZ to SHJ crude oil can be concluded to make the properties of the compounds meet the safe and economic requirements of the subsea pipeline and offshore facility operations and ensure the compatibility of the mixed oils. In actuality, the field operations have confirmed that the recommended blending ratio is reasonable and practicable

Magnetic structures and interplay between rare-earth Ce and Fe magnetism in single-crystal CeFeAsO

Neutron and synchrotron resonant x-ray magnetic scattering (RXMS) complemented by heat capacity and resistivity measurements reveal the evolution of the magnetic structures of Fe and Ce sublattices in a CeFeAsO single crystal. The RXMS of magnetic reflections at the Ce L-II edge shows a magnetic transition that is specific to the Ce antiferromagnetic long-range ordering at T-Ce approximate to 4 K with short-range Ce ordering above T-Ce, whereas neutron diffraction measurements of a few magnetic reflections indicate a transition at T* approximate to 12 K with an unusual order parameter. Detailed order-parameter measurements on several magnetic reflections by neutrons show a weak anomaly at 4 K that we associate with the Ce ordering. The successive transitions at T-Ce and T* can also be clearly identified by two anomalies in heat capacity and resistivity measurements. The higher transition temperature at T* approximate to 12 K is mainly ascribed to Fe spin reorientation transition, below which Fe spins rotate uniformly and gradually in the ab plane. The Fe spin reorientation transition and short-range Ce ordering above T-Ce reflect the strong Fe-Ce couplings prior to long-range ordering of the Ce. The evolution of the intricate magnetic structures in CeFeAsO going through T* and T-Ce is proposed

Hydra: A Massively-Multiplayer Peer-to-Peer Architecture for the Game Developer

We present the design and implementation of Hydra, a peer-to-peer architecture for massively-multiplayer online games. By supporting a novel augmented server-client programming model with a protocol that guarantees consistency in the messages committed when nodes fail, existing game developers can realize the benefits of a peer-to-peer architecture without the burden of handling the complexities associated with network churn. Our key contribution is the development of a programming interface that is intuitive and easy to use, and that can be supported transparently at the network layer. We have implemented a prototype of Hydra and we demonstrate that our proposed architecture is practical by developing two games under the Hydra framework: a simple “capture the flag” tank game and a squad-based real-time strategy (RTS) game. Our experience in developing these games suggests that our proposed programming model is suitable for game development. Our preliminary experiments also show that Hydra imposes only a small message overhead and is thus scalable

Seasonal Variation and Sources of Dissolved Nutrients in the Yellow River, China

The rapid growth of the economy in China has caused dramatic growth in the industrial and agricultural development in the Yellow River (YR) watershed. The hydrology of the YR has changed dramatically due to the climate changes and water management practices, which have resulted in a great variation in the fluxes of riverine nutrients carried by the YR. To study these changes dissolved nutrients in the YR were measured monthly at Lijin station in the downstream region of the YR from 2002 to 2004. This study provides detailed information on the nutrient status for the relevant studies in the lower YR and the Bohai Sea. The YR was enriched in nitrate (average 314 μmol·L−1) with a lower concentration of dissolved silicate (average 131 μmol·L−1) and relatively low dissolved phosphate (average 0.35 μmol·L−1). Nutrient concentrations exhibited substantial seasonal and yearly variations. The annual fluxes of dissolved inorganic nitrogen, phosphate, and silicate in 2004 were 5.3, 2.5, and 4.2 times those in 2002, respectively, primarily due to the increase in river discharge. The relative contributions of nutrient inputs to nitrogen in the YR were: wastewater > fertilizer > atmospheric deposition > soil; while to phosphorus were: wastewater > fertilizer > soil > atmospheric deposition. The ratios of N, P and Si suggest that the YR at Lijin is strongly P-limited with respect to potential phytoplankton growth

Experimental investigation on phase inversion point and flow characteristics of heavy crude oil-water flow

The phase inversion point is of great significance for drag reduction in the flow of heavy crude oil. In this study, we used 25-mm inner diameter (ID) stainless steel pipes to investigate the oil-water flow characteristics of four heavy oils at five temperatures (90, 85, 80, 75 and 70 °C). The effects of temperature, velocity, and oil viscosity on the phase inversion point of heavy oil-water flow were studied. The viscosity of the experimental oil ranges from 358 to 4995 mPa·s. The phase inversion model of Yao and Gong (2006) was modified to fit high-viscosity oils. The proposed model was verified with pipe flow experimental data from various heavy oilfields. This study found that the effect of temperature on the phase inversion point of heavy crude oil is almost negligible. The flow pattern with the largest pressure drop during heavy oil-water flow is Int, and the flow patterns with a smaller pressure drop include semi-Anw, Anw, and DAnw. The water content at the inversion point of heavy oil-water flow is mostly between 45% and 70%. As the viscosity increases, the water fraction at the inversion point decreases. A high velocity helps the water maintain a continuous phase. The occurrence of phase inversion requires the mixture velocity to be maintained above a specific value, which should be high enough for the flow pattern to transition to semi-annular flow

Influence of Thread Pitch, Helix Angle, and Compactness on Micromotion of Immediately Loaded Implants in Three Types of Bone Quality: A Three-Dimensional Finite Element Analysis

This study investigated the influence of thread pitch, helix angle, and compactness on micromotion in immediately loaded implants in bone of varying density (D2, D3, and D4). Five models of the three-dimensional finite element (0.8 mm pitch, 1.6 mm pitch, 2.4 mm pitch, double-threaded, and triple-threaded implants) in three types of bone were created using Pro/E, Hypermesh, and ABAQUS software. The study had three groups: Group 1, different pitches (Pitch Group); Group 2, same compactness but different helix angles (Angle Group); and Group 3, same helix angle but different compactness (Compact Group). Implant micromotion was assessed as the comprehensive relative displacement. We found that vertical relative displacement was affected by thread pitch, helix angle, and compactness. Under vertical loading, displacement was positively correlated with thread pitch and helix angle but negatively with compactness. Under horizontal loading in D2, the influence of pitch, helix angle, and compactness on implant stability was limited; however, in D3 and D4, the influence of pitch, helix angle, and compactness on implant stability is increased. The additional evidence was provided that trabecular bone density has less effect on implant micromotion than cortical bone thickness. Bone type amplifies the influence of thread pattern on displacement