Research On Fast And Quantitative Oil &Gas Measurement For In-situ Well Drilling Monitoring

The logging while drilling techniques of oil and gas helps to test and evaluate the conditions of the underground oil and gas during drilling, and to find, to evaluate and interpret the oil and gas zones. The main method of oil and gas testing is the gas chromatography. This method uses the chromatography principle to separate the saturated paraffin (such as methane, ethane, propane, normal butane, iso-butane, pentane, normal pentane, iso-pentane, etc) from the mud and then tests and evaluates them. This thesis is based on the objective of the well site logging while drilling practice. Through the researches of some key techniques concerning mud degassing, gas testing and analyses, oil evaluation and underground logging while drilling, etc , some remarkable progresses have been made in the research of several key factors in the detection of oil and gas. The main innovative achievements involved in this thesis are as follows:A newly developed mud degassing method is proposed. As responding to the low efficiency of existing degassers and their shortcomings of vulnerable to the environment, through analyzing the basic principle of mud degassing, a method of quantitative out flow of mud is put forward and designed to eliminate the leakage of gas in the mud from the well bore, to help realizing the quantification of mud degassing. Based on the analyses of the theory of mud degassing, a new degassing method of air isolation is drew out and a new type degasser is designed and an air equalizer is developed to realize air isolation degassing from the mud. Well site experiments have proved that the new degassing method possesses the advantages of high efficiency, low affection from the environment and quantitative.Through the fast chromatography analysis, a new method of fast gas testing and analyzing is put forward. Through the three basic approaches of optimizing the resolution; maximizing the range of sample selectivity of the chromatography and reducing the amount of time for analyzing the sample at the assurance of a stable resolution, various factors affecting the analysis of oil and gas have been analyzed. Through experiments, a new type of specific use of chromatography column is designed. Based on fast chromatography column and micro current amplifier, a new kind of online gas and oil instrument is designed. The span of detection is from 1×10-6 to 100%, the analysis period is shortened to 30s.By analyzing the uncertain factors which affect the performance of oil & gas test, a conclusion is drawn: mathematics revise can not successfully eliminate the uncertainties to realize the quantitative test of the underground gas & oil. Based on this conclusion, a new method is brought out to test the oil & gas underground quantitatively. In this method, the gas logging on the surface is compared with a certain density gas injected as a reference from the mud inlet and the actual gas density can be got in real time. Experiments show that the method can bypass uncertainties and realize the quantitative detection.Considering the defects of existing surface gas logging techniques, a new concept of underground gas logging while drilling is put forward and a prototype framework is constructed .As the key part , the gas detection methods based on the principals of electrical conductivity, infrared ray gas testing and the interference of sound waves is put forward. The feasibility of the infrared gas detecting mode is discussed. Experiments show that the infrared gas detection method has perfect coherence with the traditional FID gas detection method, and can be used in well site.The feasibility of using gas logging while drilling to monitor the drilling trajectory of horizontal well is discussed by analyzing the relationship between the variation of horizontal well's drilling trajectory and oil & gas logging. A method integrating fast chromatography analysis and real-time oil & gas evaluation is proposed for the drilling trajectory monitoring of horizontal well. This method makes various models of horizontal well's trajectory monitoring using the 3H method. An expert system uses these models and real-time oil & gas information to realize the real-time monitoring of horizontal well's drilling trajectory. A novel mud logging instrument which has the world-leading performance (1ppm logging precision and 30s analysis cycle) is designed in a modularized manner based on the above mentioned techniques.