Hydrogen sulfide gas drilling site online spectra monitor Feasibility Study

Abstract

Through the hydrogen sulfide and other common small molecular gas near infrared absorption spectrum analysis, propose that analyzing spectral absorption peak at a wavelength of hydrogen sulfide 1.578um neighborhood undisturbed common gases and water vapor from small molecules, which can be used for quantitative analysis; By analyzing suitable NIR light sources and detectors, propose to use laser diodes, infrared photon detectors constituting the hydrogen sulfide-line near infrared detector. Transmission method is based on the difference in absorption peak of hydrogen sulfide and other common small molecular gas in the near infrared spectrum, use this method to achieve spectroscopic detection of hydrogen sulfide line can achieve multi-point line detection. KEYWORD: Hydrogen sulfide, Near Infrared, Drilling, Spectroscopy. 4th International Conference on Mechanical Materials and Manufacturing Engineering (MMME 2016) © 2016. The authors Published by Atlantis Press 546 3 DRILLING FIELD OF HYDROGEN SULFIDE GAS MONITORING 3.1 oilfield rapid chemical analysis commonly used (1) standard iodometric method: on-site detection of hydrogen sulfide in the drilling fluid volume fraction commonly used method is the standard iodometric method. (2) Rapid assay tube method: Determination of the rate-determining field test tube method is atmospheric hydrogen sulfide content commonly used method. (3) lead acetate paper test: lead acetate test paper reacts with hydrogen sulfide brown lead sulfide, and hydrogen sulfide obtained by comparing the standard shade guide volume fraction. 3.2 Comprehensive Judgement Comprehensive evaluation method is mainly for logging work with high volume fraction of hydrogen sulfide formation occurs when one turtle jump drilling, drilling speed or venting, pump pressure drop, drilling fluid tank rises, accompanied by intermittent wells Chung and hydrogen sulfide odor; second, the drilling fluid density and pH valuedecrease ,the viscosity rises, the color changes to gray; the third is well temperature of logging and borehole fluid resistivity values drop by resistance, when the drilling fluid in the wellbore still some time , due to the diffusion of hydrogen sulfide gas expansion heat, so cooling gas cut-segment display as increasing resistance, which can be used the well temperature and fluid resistivity anomaly, the card takes the hydrogen sulfide-containing layer. Since the conventional method susceptible to cross-contamination of other gases, thus lagging response, repeatability and low range of issues, it is difficult to achieve large-scale continuous monitoring. Near-infrared spectral properties of the gas detected gas concentration method can solve these problems, near-infrared spectroscopy combined withfiber-optic communications, which can meet a wide range of hydrogen sulfide gas, long distance and continuous monitoring. 4 HYDROGEN SULFIDE ONLINE NEAR INFRARED DETECTION PRINCIPLE Spectral detection of hydrogen sulfide is based on light absorption Lambert Beer law, the mathematical expression is as follows, kbc = /I) log(Io = A A Absorbance Ioincident light intensity I transmitted light intensity k absorptivity b absorbing optical path c light-absorbing substance concentration From Lambert Beer law shows that the ratio of intensity of incident light and the transmitted light intensity is only related to the concentration of lightabsorbing substance, measure the change in intensity of incident light and the transmitted light intensity through the spectrometer detector, you can get lightabsorbing substance concentration changes. 4.1 Analysis of infrared absorption characteristics of Hydrogen sulfide In the infrared absorption spectrum, the lightabsorbing substance molecule or group absorbs infrared light certain frequency later, when their energy level transitions from the ground state to the first excited state; and the absorption peak of the fundamental frequency peak; from the ground state to the second excited state absorption peak produced an octave peak; peak transition to the third generation of the excited state as a secondary harmonic peaks. Wherein the strongest peak of the fundamental frequency[Yi kan Ke, 1998].Hydrogen sulfide (H2S) molecular structure: molecule is V-shaped molecular structure, bond angle is 92 °, hydrogen sulfide molecule is a polar molecule. According H2S molecular structure has been that they have three different basic vibration frequency [L. R. Brown, 2004]: v1 = 2564.34927cm-1, v2 = 1159.44766cm-1 and v3 = 2565.37647cm-1.Each natural vibration corresponding to a spectral absorption region, the corresponding wavelengths, respectively 3.89962 m  , 8.62480 m  , 3.89806 m  . Its frequency in the near infrared combined in Table 2, Table2 The molecular of hydrogen sulfide’s vibrational absorption line in the near infrared Co-frequency   1 cm      m       1 1 2 / S cm molecule cm     2 3 3   6.077.5947 1.6454 8.32×10-23 1 2 3    6074.5808 1.6462 9.03×10-23 2 5 5797.2380 1.7250 6.93×10-24 1 2 3      6289.1734 1.5900 7.96×10-21 2 3 2    6385.2990 1.5661 4..99×10-23 1 2 2   6288.1462 1.5903 2.23×10-21