Prediction of exploration targets based on integrated analyses of source rock and simulated hydrocarbon migration direction: a case study from the gentle slope of Shulu Sag, Bohai Bay Basin, northern China

Changqing Ren,Fugui He,Xianzhi Gao,Dongsheng Wu,Wenli Yao,Jianzhang Tian,Huiping Guo,Yuanxin Huang,Li Wang,Han Feng,Junwei Li 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.6

The Shulu Sag which is a rifted sag with NNE trend is located in the south of Jizhong Depression, Bohai Bay Basin, northern China. The gentle slope and three troughs are situated in the west and east of the sag, respectively. Both of the lower part of Shasan Member (Es3x) and the lower part of Shayi Member (Es1x) act as source rocks in this sag. Researches on the type, quantity, quality and thermal maturity of the respective organic matter have been conducted using Rock-Eval pyrolysis data. Type II is the dominant kerogen in Es1x of all troughs. However, Type II1 and III is the dominant kerogen in Es3x of Middle-Southern and Northern trough, respectively. TOC (total organic carbon) and pyrolysis S2 (hydrocarbon) values suggest that the Es1x source rocks in Middle-Southern and Northern trough are fair to good and poor to fair generative potential of hydrocarbon, separately. The Es3x source rocks in Middle-Southern and Northern trough possess fair to excellent and poor to fair generative potential of hydrocarbon, individually. Tmax (pyrolysis temperature at maximum S2) values indicate that most of Es3x samples are thermally mature, but all Es1x samples are thermally immature. Under large scale condition, the hydrocarbon secondary migration in the upper part of Shasan Member (Es3s), Shaer Member (Es2) and the upper part of Shayi Member (Es1s) have been simulated using fluid potential model with Arcgis 9.3 software. The simulation results reveal the direction of hydrocarbon secondary migration and the distribution of hydrocarbon migration-accumulation units (HMAUS), and also suggest that the hydrocarbon migration direction is obviously controlled by nose-like structure belts where most of hydrocarbons accumulate. That shows high reliability because they are consistent with the hydrocarbon exploration result in this area. On the basis of integrated analyses of source rocks and hydrocarbon migration direction, the following five areas in the gentle slope are identified to be the preferred hydrocarbon accumulation area: Taijiazhuang area, northern and southern Xicaogu area, as well as northern and southern Leijiazhuang area. It is considerably helpful to reduce the risk in hydrocarbon exploration of Shulu Sag.

Experimental investigation and performance analysis of a dual-cylinder opposed linear compressor

Huiming Zou,Liqin Zhang,Guohong Peng,Changqing Tian 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.8

The dual-cylinder opposed linear compressor (DOLC) contains a couple of symmetrical gas loads on the two sides of the movement components. Because the gas loads are symmetrical, the balanced position of movement components will not be offset by gas force during the operating process, and piston displacement can be detected and controlled more easily. Based on the kinetics and thermodynamics theory, the non-linear gas load of the DOLC was linearized by the Fourier method. The relationship between the supply voltage and displacement is presented. Through air compression experiments, the operation features of the DOLC with different syntonic spring groups were analyzed. The performance of the DOLC was considerably affected by work conditions and the stiffness of syntonic spring groups;the closer the work condition was to the sympathetic vibration, the higher the observed efficiency of the DOLC. A jump, hysteresis, and an unstable phenomenon in the process of voltage regulation occurred around sympathetic vibration conditions. In the process of increasing voltage on a certain discharge pressure condition, the displacement jump phenomenon occurred when the intrinsic frequency approacheds power frequency, causing the discharge pressure to drop synchronously. In the process of decreasing voltage on the lower discharge pressure condition, the displacement shrink phenomenon occurred when the intrinsic frequency approached power frequency. Because sympathetic vibration conditions changed with discharge pressures, a hysteresis district existed between the displacement jump point and shrink point. The DOLC worked unstably on the hysteresis district because the discharge pressure fluctuated between the two values. To make the DOLC work stably on higher efficiency, the intrinsic frequency should be configured to a slightly larger value than the power frequency by setting the syntonic spring groups and the mass of movement components to the ratings on the work conditions. Controlling the power frequency after is needed to adhere to the intrinsic frequency of the variable work conditions.

INTEGRATED STEADY-STATE AND DYNAMIC SIMULATION OF MULTI-UNIT AIR CONDITIONERS BASED ON TWO-PHASE FLUID NETWORK MODEL

HONGBO XU,SHUANGQUAN SHAO,Huiming Zou,Changqing Tian 대한설비공학회 2012 International Journal Of Air-Conditioning and Refr Vol.20 No.4

An integrated simulation model is developed to investigate the steady-state and dynamic performance of multi-unit air conditioners (MUACs). It is built as two-phase fluid network which is able to describe different systems by incidence matrixes. And the submodels are embedded in the system framework, where the submodels can be either steady-state or dynamic model, distributed parameter or lumped parameter model. For this case, the numerical submodels are employed with moving-boundary models of condenser and evaporator, steady-state models of compressor and electronic expansion valve. The comparison with experimental data shows that it cannot only predict the steady-state performance, but also catch dynamic trends with high accuracy, for example, the differences of evaporating pressure < ${\pm}4%$, condensing pressure < ${\pm}3%$, compressor discharge temperature < ${\pm}4^{\circ}C$, superheating degree < ${\pm}2^{\circ}C$ and subcooling degree < ${\pm}1^{\circ}C$. Therefore, the simulation model is confirmed as an effective tool to analyze the steady and transient characteristics and optimize the design and control algorithm of MUACs.

Control Method of Self-Frequency Recovery and Active Power Sharing for an Isolated Microgrid Based on VSGs

Pengxiang Xing,Fan Ma,Chunzheng Tian,Changqing Xu,Lili Wang 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.1

The concept of virtual synchronous generator (VSG) is emerging as an attractive solution for renewable energies to enhance the microgrid inertia and damping property by emulating the essential behaviors of conventional synchronous generators. However, in the isolated microgrid based on VSGs, there will be a frequency deviation when the power demand varies because of the droop characteristic of the VSG in active power–frequency regulation. In this paper, a control method for VSGs to implement self-frequency recovery and active power sharing in isolated microgrid is proposed. With this method, the VSGs regulate their power baseline values over multiple iterations through local-feedback of the frequency deviation until the microgrid frequency restores to normal value, and simultaneously share the power demand variation according to the ratio of their power baseline values. Compared to the previous studies, the proposed method can eliminate the output power and frequency oscillations in secondary control, and additionally, reduce the dependence of the microgrid on communication system, which is beneficial to enhance the robustness of the microgrid operation. Simulation results proved the proposed method to be effective.

Coupled irradiation-thermal-mechanical analysis of the solid-state core in a heat pipe cooled reactor

Yugao Ma,Jiusong Liu,Hongxing Yu,Changqing Tian,Shanfang Huang,Jian Deng,Xiaoming Chai,Yu Liu,Xiaoqiang He 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.6

The solid-state core of a heat pipe cooled reactor operates at high temperatures over 1000 K withthermal and irradiation-induced expansion during burnup. The expansion changes the gap thicknessbetween the solid components and the material properties, and may even cause the gap closure, whichthen significantly influences the thermal and mechanical characteristics of the reactor core. This studydeveloped an irradiation behavior model for HPRTRAN, a heat pipe reactor system analysis code, tointroduce the irradiation effects such as swelling and creep. The megawatt heat pipe reactor MegaPowerwas chosen as an application case. The coupled irradiation-thermal-mechanical model was developed tosimulate the irradiation effects on the heat transfer and stresses of the whole reactor core. The resultsshow that the irradiation deformation effect is significant, with the irradiation-induced strains up to2.82% for fuel and 0.30% for monolith at the end of the reactor lifetime. The peak temperatures during thelifetime are 1027:3 K for the fuel and 956:2 K for monolith. The gap closure enhances the heat transferbut caused high stresses exceeding the yield strength in the monolith

Performance characteristics around the TDC of linear compressor based on whole-process simulation

Huiming Zou,Mingsheng Tang,HONGBO XU,SHUANGQUAN SHAO,Changqing Tian 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.10

A whole-process simulation platform is established for linear compressor to analyze the performance characteristics on different pistondisplacement conditions from small oscillation without pumping till to rushing out of the top dead center (TDC). The measuring methodsof the related parameters in the model are presented and the values of these parameters are obtained from an actual test. The simulatedresults agreed well with the experimental results under the same working conditions. The errors of the effective voltage, the effectivecurrent, the compression efficiency and the phase angle between the current and the displacement were within ±6.9%,±8.5%,±6.2%and±13.4%, respectively. Based on this simulation platform, the performance characteristic around the TDC of the linear compressor ondifferent working conditions is analyzed. The performance comparison on 60 Hz shows that the compression efficiency near to the TDCon 0.7 MPa is higher than that on 0.5 MPa because the phase angle α under that condition is around 90°, but the operation reliability on0.7 MPa is worse than that on 0.5 MPa because the jump phenomenon happens when the piston displacement goes near to the TDC. Thejump phenomenon results in unstable operation as the piston displacement jumps from the position before the TDC to the position afterthe TDC. According to the simulation on different power frequency, two important performance characteristics are inferred. One is thatthere is an inflection point in the curve of the phase angle α versus the displacement at the TDC. This characteristic is a good choice forthe TDC detection. The other is that the jump phenomenon is prone to happening when there exist different displacement responses onthe same voltage value, becoming inconspicuous when the power frequency is decreased and disappearing when the power frequency isincreased. Based on this characteristic, the jump phenomenon can be avoided through suitable system configuration and frequency adjustment.