Test of PSHA Map of China – A Case Study of Sichuan Region

The PSHA map must be tested, since hypothesis testing is the heart of a scientific method, and it is inappropriate to adopt the map as the basis of seismic fortification in whole country without any test. Two paths of testing are suggested in this paper. The test result by counting up positive intensity difference shows that up to 2015 the percentages of total underestimation areas on 1990 and 2001 maps of China are equivalences of 5.6% and 6.0% in 50 years, both less than the exceeding probability 10% adopted in the map compiling procedure. The result of a case study of the common buildings with brick-concrete structure and frame structure in Sichuan region by evaluating the benefit of seismic fortification according to the two maps shows that the PSHA maps contribute benefits as economic loss reduction 67.9 and 79.7 billion RMB, death reduction 19439 and 17504 persons, and serious injury reduction 42632 and 37700 persons respectively during 2008 great Wenchuan Earthquake.

8070 Miles from the Field to the Lab and Back: A Pragmatic Sequencing of Laboratory and Field-Based Fluid Testing and QAQC, A Case History from Sichuan Region, China

The application of high viscosity friction reducers (HVFRs) in unconventional plays has steadily increased over the past years, not only as alternatives to conventional friction reducers (FRs) but also as a direct replacement for the use of guar-based fluids. HVFRs demonstrate more efficient proppant transport, due to their unique rheological properties, concurrently with a high friction reduction effect allowing higher pumping rates. However, all these benefits come with few critical limitations related to frac water quality, compatibility with other additives, and static proppant suspension, which makes them very similar to conventional crosslinked gels regarding their Quality Assurance and Quality Control (QAQC) requirements at a well location during the field implementation. This paper illustrates the comprehensive laboratory efforts undertaken to evaluate different HVFR and crosslinked gel products, their successful field application supported by a robust and effective field QAQC process, and the critical importance of maintaining effective field-laboratory-field interaction/cycle to optimize the fluid design and maximize the results. Experimental studies on different products were conducted to measure the effect of frac water quality, HVFR loading, breaker loading, and compatibility with other additives used in the fluid recipe such as surfactants, scale inhibitors, and biocides. The ability of HVFR to suspend and transport proppant is not only a function of polymer loading but also highly influenced by fluid velocity as static and semi-dynamic proppant suspension tests demonstrate. Additionally, a full dynamic proppant transport test was also conducted using a multi-branched slot apparatus to simulate the flow inside a complex fracture network. Field execution followed a strict QAQC protocol including water analysis, field laboratory tests, water filtration, mixing procedure, product storage, and transport allowing direct onsite replication of the results that had been previously obtained in the laboratory. Constant communication between the field and the laboratory allowed a successful execution of several treatments in a challenging shale play in the Sichuan Region, China. These treatments achieved record proppant placements and, just as importantly, they demonstrated repeatability and consistency over time; which had not previously been attained. Laboratory testing proved critical in confirming that product segregation was occurring, even if there was no visual observation of this phenomenon, which had resulted in initial difficulties in fluid quality and reliability. The presence of constant QAQC engineering support on location was instrumental in rapidly identifying the potential root cause(s) and efficiently and correctly applying the necessary corrective actions. This paper will highlight the importance of laboratory testing, in order to design and optimize the fluid system. The paper will also demonstrate how critical the onsite QAQC is through actual examples of fluid optimization and field implementation. These two activities, although requiring a substantial resource commitment and effort, are both required to achieve successful execution.

Measurement of indoor air quality under different heating modes in western Sichuan

Western Sichuan region has a variety of traditional heating methods and excellent outdoor air quality, and the difference with the city is clear. The indoor air quality of the western Sichuan region is worth studying. The diffusion law of indoor and outdoor PM2.5 concentration under different heating methods can be explored to provide effective data support for environmental governance. In this context, the indoor air quality under different heating methods in Songpan County was measured with PM2.5 concentration assessment of indoor air quality (IAQ). By analyzing the indoor air quality under different heating modes, the following conclusions can be drawn: the influence degree of indoor activity on indoor particle concentration level depends on the source and characteristics of the house. Air leakage is one of the main reasons for the rise of indoor PM2.5. Heating methods disturb the indoor air, which significantly affects the migration of PM2.5.

A statistical analysis of TIR anomalies extracted by RSTs in relation to an earthquake in the Sichuan area using MODIS LST data

Research in the field of earthquake prediction has a long history, but the inadequacies of traditional approaches to the study of seismic threats have become increasingly evident. Remote sensing and Earth observation technology, an emerging method that can rapidly capture information concerning anomalies associated with seismic activity across a wide geographic area, has for some time been believed to be the key to overcoming the bottleneck in earthquake prediction studies. However, a multi-parametric method appears to be the most promising approach for increasing the reliability and precision of short-term seismic hazard forecasting, and thermal infrared (TIR) anomalies are important earthquake precursors. While several studies have investigated the correlation among TIR anomalies identified by the robust satellite techniques (RSTs) methodology and single earthquakes, few studies have extracted TIR anomalies over a long period within a large study area. Moreover, statistical analyses are required to determine whether TIR anomalies are precursors to earthquakes. In this paper, RST data analysis and the Robust Estimator of TIR Anomalies (RETIRA) index were used to extract the TIR anomalies from 2002 to 2018 in the Sichuan region using Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) data, while the earthquake catalog was used to ascertain the correlation between TIR anomalies and earthquake occurrences. Most TIR anomalies corresponded to earthquakes, and statistical methods were used to verify the correlation between the extracted TIR anomalies and earthquakes. This is the first time that the ability to predict earthquakes has been evaluated based on the positive predictive value (PPV), false discovery rate (FDR), true-positive rate (TPR), and false-negative rate (FNR). The statistical results indicate that the prediction potential of RSTs with use of MODIS is limited with regard to the Sichuan region.