A Calibration Method for the Logging Instrument Used in Harsh Environments

2013 ◽  
Vol 365-366 ◽  
pp. 708-715
Author(s):  
Zhen Huang ◽  
Li Kong ◽  
Pu Zhang ◽  
Xiao Nan Liu ◽  
Cheng Zhang
Keyword(s):  
Measurement Error ◽  
Calibration Method ◽  
Harsh Environments ◽  
Formation Water ◽  
Gain Error ◽  
Water Logging ◽  
Large Measurement ◽  
The Impact ◽  
Large Measurement Error

Due to the impact of harsh environments with temperatures higher than 150 °C, the characteristics of the amplifying circuits of logging instrument can be changed, to cause the large measurement error. Therefore, a new calibration method is proposed to obtain the gain value and offset for pre-amplifier system. This method use multiple calibration signals and based on the last square theory to complete the calibration work. At the experiment of calibration for the multi-parameter formation water logging instrument, the gain error for the pre-amplifier system by this calibration be improve to no exceed 0.15% to compare with over 1% by tradition method.

INFLUENCES OF AGGREGATION ON THE TWO-PHOTON FLUORESCENCE PROCESS

2013 ◽  
Vol 22 (01) ◽  
pp. 1350011 ◽  
Author(s):  
ZHIQIANG ZHOU ◽  
CHANGGUI LU ◽  
YIPING CUI
Keyword(s):  
Measurement Error ◽  
Cross Section ◽  
Correction Method ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Large Measurement ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence ◽  
Large Measurement Error

Rhodamine B (RhB) is most often used as the reference in the two-photon induced fluorescence (TPIF) method to measure the two-photon absorption (TPA) cross-section. In this work, we investigate the influences of dimer formation, energy transfer and self-absorption on the two-photon fluorescence process. Those three effects will result in a large measurement error of the TPA cross-section. We thus provide a concentration gradient correction method by considering the above three processes to eliminate the measurement error.

scholarly journals Perhetaustan yhteys oppimistuloksiin Suomessa PISA- ja rekisteriaineistojen valossa

2020 ◽  
Author(s):  
Hannu Lehti ◽  
Markus Laaninen
Keyword(s):  
Measurement Error ◽  
Learning Outcomes ◽  
Negative Selection ◽  
Parental Education ◽  
Family Background ◽  
Occupational Status ◽  
Large Measurement ◽  
Pisa Data ◽  
School Surveys ◽  
Large Measurement Error

Aikaisempien tutkimusten mukaan oppimistulosten eriarvoisuus vanhemman taustan mukaan on kasvanut Suomessa viime vuosina. Tutkimusnäyttö perustuu vahvasti koulukyselyaineistoihin kuten PISA-aineistoon, jossa vanhempien koulutuksen ja ammattiasema on kysytty lapsilta. Tällaiset kyselyaineistot ovat alttiita vastausharhan aiheuttamalle mittausvirheelle. Tässä tutkimuksessa osoitamme, että PISA-aineistot sisältävät suurta mittausvirhettä vanhempien koulutuksen osalta. Siksi vanhemman ammattiasema on luotettavampi mittari, kun halutaan tutkia kotitaustan yhteyttä oppimistuloksiin PISA-aineistolla. Kun mittausvirhe ja negatiivinen valikoituminen vuosien välillä huomioidaan, oppimistulosten eriarvoisuus ei ole kasvanut Suomessa viime vuosina. / According to previous studies, the inequality of learning outcomes according to family background has increased in Finland in recent years. The evidence is strongly based on school surveys such as PISA data, where children are asked about their parental educational and occupation status. However, such surveys are prone to measurement error due to reporting bias. We show that the PISA data contain a large measurement error in terms of parental education. Therefore, parental occupational status is a more reliable indicator of family background when association between family background and learning outcomes are studied with PISA data. When the measurement error and the negative selection are taken into account, the results show that the inequality of learning outcomes has not increased in Finland in recent years.

scholarly journals Measurement error of waist circumference: gaps in knowledge

2012 ◽  
Vol 16 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Lisanne M Verweij ◽  
Caroline B Terwee ◽  
Karin I Proper ◽  
Carel TJ Hulshof ◽  
Willem van Mechelen
Keyword(s):  
Measurement Error ◽  
Waist Circumference ◽  
Repeated Measurements ◽  
Short Term ◽  
Relevant Change ◽  
Measurement Protocol ◽  
Large Measurement ◽  
Art Research ◽  
Definition Of ◽  
Large Measurement Error

AbstractObjectiveIt is not clear whether measuring waist circumference in clinical practice is problematic because the measurement error is unclear, as well as what constitutes a clinically relevant change. The present study aimed to summarize what is known from state-of-the-art research.DesignTo identify the magnitude of the measurement error of waist circumference measurements from the literature, a search was conducted in PubMed from 1975 to February 2011.ResultsThe measurement error may vary between 0·7 cm and 15 cm. Taking a realistic range of measurable waist circumference into account (60–135 cm), we argue that a short-term clinically relevant change in waist circumference of 5 % may lie between 3·0 and 6·8 cm and a maintained clinically relevant change of 3 % between 1·8 and 4·1 cm.ConclusionsBased on these results, we conclude it may be difficult to distinguish clinically relevant change from measurement error in individual subjects, due to the large measurement error and unclear definition of clinically relevant change. More research is needed to address these gaps in knowledge. To minimize measurement error, we recommend using a uniform measurement protocol, training and repeated measurements.

Experimental Study of Natural Ions and Rock Interactions for Seawater Breakthrough Percentage Monitoring during Offshore Seawater Flooding

SPE Journal ◽  
2021 ◽  
pp. 1-21
Author(s):  
Yanqing Wang ◽  
Xiang Li ◽  
Jun Lu
Keyword(s):  
Porous Media ◽  
Fluid Flow ◽  
Barium Sulfate ◽  
Large Deviation ◽  
Exchange Process ◽  
Reaction Model ◽  
Sodium Content ◽  
Flow In Porous Media ◽  
Formation Water ◽  
The Impact

Summary Seawater breakthrough percentage monitoring is critical for offshore oil reservoirs because seawater fraction is an important parameter for estimating the severity of many flow assurance issues caused by seawater injection and further developing effective strategies to mitigate the impact of those issues on production. The validation of using natural ions as a tracer to calculate the seawater fraction was investigated systematically by studying the natural chemical composition evolution in porous media using coreflood tests and static bottle tests. The applicable range of ions was discussed based on the interaction between ion and rock. The barium sulfate reactive model was improved by integrating interaction between ions and rock as well as fluid flow effect. The results indicate that chloride and sodium interact with rock, but the influence of the interaction can be minimized to a negligible level because of the high concentrations of chloride and sodium. Thus, chloride and sodium can be used as conservative tracers during the seawater flooding process. However, adsorption/desorption may have a large influence on chloride and sodium concentrations under the scenario that both injection water and formation water have low chloride and sodium content. Bromide shows negligible interaction with rock even at low concentrations and can be regarded as being conservative. The application of a barium and sulfate reaction model in coreflood tests does not work as well as in bottle tests because fluid flow in porous media and ion interaction with rock is not taken into account. Although sulfate and barium adsorption on clay is small, it should not be neglected. The barium sulfate reaction model was improved based on the simulation of ion transport in porous media. Cations (magnesium, calcium, and potassium) are involved in the complicated cation-exchange process, which causes large deviation. Therefore, magnesium, calcium, and potassium are not recommended to calculate seawater fraction. Boron, which exists as anions in formation water and is used as a conservative tracer, has significant interactions with core matrix, and using boron in an ion tracking method directly can significantly underestimate the seawater fraction. The results give guidelines on selecting suitable ions as tracers to determine seawater breakthrough percentages under different production scenarios.

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