| The natural gas gathering system which is composed of well site, gas gathering and separating station, booster station, gas pipeline networks and gas field water reinjection station is a complex energy system in accordance with certain topological structure of Zero convergence and it is one of the major gas producing energy-using sectors. Existing gathering system energy analysis and evaluation techniques mostly focus on the aspects of single device, partial technological process adjustments and regional integrated energy-saving, there is not a set of system and method to guide the gathering system energy testing, analysis and evaluation from the perspective of process system energy-saving control. In this article, analyze and evaluate system energy situation by establishing energy analysis model of natural gas gathering system and building energy evaluation index system. The main research work is as follows:(1) Make research of process systems energy analysis, oil and gas gathering systems energy consumption evaluation, energy-saving measures and software technology of energy consumption analysis and evaluation at home and abroad. Summarize the problem of the current researches, such as most of studies does not aim at the natural gas gathering system, analytical method is single, the index system is not integrated and other issues, analyze existing difference between natural gas gathering system and crude oil gathering system in transmission medium, gathering process, energy-using equipment and so on.(2) Define the energy sectors to general natural gas gathering systems, apply black box and white box model to furnace, gathering pipelines, gas engines, compressors, pump units, separators, heat exchangers and other energy-using equipment for energy balance analysis and exergy balance analysis, and carry on the key analysis to the internal energy loss of pumps and compressors. The established evaluation index to energy analysis include energy efficiency, exergy efficiency, thermodynamic perfect degree and analytical indicators to energy analysis contain energy loss factor, exergy loss coefficient.(3) Combine technological process and actual characteristics of energy consumption of the natural gas field gathering system, improve the traditional "three links" process system energy analysis, the gathering system is divided into four segments containing energy conversion, energy transmission, energy utilization and energy recovery. Put forward the "Combined module multi-link analytical method" for a general energy consumption process, and established physical, mathematical models and assessment indicators of each energy sector.(4) Construct the secondary index system and evaluation criteria of including the well site, gas gathering and separating station, booster station, gas gathering pipelines and water reinjection station, determine the index weight levels using the Improved APH, and establish Fuzzy Comprehensive Evaluation Model of a gathering system.(5) Establish energy consumption test database on gathering systems, develop the "energy analysis and evaluation software for the natural gas gathering system" using the C# programming language. The software achieved the function of energy test data sheet management, equipment energy analysis, gathering system energy analysis, adjusting reconstructive decisions, forecasting energy utilization, index weight calculation, gathering system energy fuzzy evaluation. The software has some universality and openness, and it can be conducted modules portfolio analysis and evaluation according to the difference of the actual energy sectors for the specific gathering system.(6) Take the gathering system of A gas field, conduct energy analysis on the equipment and systems and put forward some energy-saving measures aim at the weak link. Determine the energy conversion, transmission, utilization and recycling link efficiency of the gathering system, analysis energy structure and energy flow of the equipment and gathering systems and carry out fuzzy evaluation for energy level of the existing system. |
