| The thesis was supported by the projects which are “Research on High Efficient Dewatering Gas Production Technology for CBM Wells on Liu Lin Demonstration Area(No.2011ZX05062-004)” and “Research on the Design of Bottom-Hole Pump Technology for the Drainage of CBM Wells(No.51174224)”.With the analysis of Coal bed gas and tight gas reservoir structure,the characteristics of CBM and tight gas drainage and the laws of the water production and gas production of CBM and tight gas reservoir,According to the Unconventional natural gas resources in China,Features of upper and lower distribution of three gas(or two gas)up and down in the geological distribution,And Generally tight gas has a deep burial,high yield,less water production,Coal bed gas has the characteristics of shallow buried,large reserves,low production water and unstable and desorption gas production.Using the power of rich gas in deepzone to realize drainage coal-bed gas production in shallow layer and commingled exploration and production of several gas in one well bore is an important technical means to increase benefit.This study aiming at the distribution features above mentioned researches on the theories about the flow field in tubes,fluid-carrying capability and the fluid-fixing capability of throat mouth.This study also solves the problem about the interaction on pressure systems in the one well bore development of two gas.We propose a scheme that technology and equipment are developed about commingled production from selected zones in different pressure systems by one well bore and take advantage of the power of rich gas zone to discharge water and drop pressure in coal bed.This study realize commingled production of two gases in different pressure and layer by one well bore meaning coal-bed gas production by drainage and desorption in reservoir and achieve the goal of stable production of tight gas.The accomplishment of this project can establish theoretical system of commingled production in one well bore,complete equipment design and experiment and lay a foundation of technology system of commingled production in one well bore.First,The thesis introduces the basic characteristics of domestic and international oil and gas field of coal-bed methane and tight gas,drainage and mining laws,the process of operation and status of equipment and the storage reservoir characteristics of coal-bed gas and tight gas and the requirements of operation,Analyzed the characteristics of only exploitation coal-bed methane or only exploitation tight gas,drainage and mining laws.Put forward the technology and equipment of the production of coal bed gas and tight gas in one well.This technology can be used in the case of no three pumping equipment,the use of high pressure gas production layer of the production of water to carry out,to achieve the purpose of drainage gas recovery,This technology can be used in the case of no Rod pumping system,using high pressure gas to carry out the production of water in low pressure,to achieve the purpose of water drainage and gas recovery.The Study on feasibility of Pipe String about the Production of CBM and Tight Gas in one Well.Analysis the requirements of the tight gas reservoir,coalbed gas layer,gas production,water production,pressure characteristics and drainage equipment,the plan of Pipe String about the Production of CBM and Tight Gas in one Well is designed and introduced its working principle in detail.The design of Pipe String about the Production of CBM and Tight Gas in one Well is completed.The key point of this process is to use the energy of high pressure gas to carry the water out of the surface and coal-bed gas production by drainage.At the same time,the pressure system and the main channel of the two kinds of gases are constructed.Pipe string system formed by high pressure gas carrying out of water and the production of two layers of gas in one well bore.In order to accomplish the design of the above structure and the production of two gas in one well.Analyzed the theory of pipe flow and gas well with liquid.Design how to select the column,and the nomogram of column selection.To analysis study on the pressure drop of gas production string which is the tube column.Obtained the pressure drop of flow pressure column in different water production,different gas production,different nozzle position,different depth and different bottom.To achieve the purpose of water drainage and gas recovery.The key to ensure the smooth implementation of the technology and the core content of this thesis is the analysis of the theory of water drainage and gas recovery and the change of flow field.Design the work flow chart of pipe column in construction.So that the pipe string can be smoothly down into the underground.In order to ensure the water can be completely ruled out and no lots of water in the bottom of the well,Analysis the liquid carrying capability.At the same time,In order to achieve better effect of the water atomization,Analysis the flow field in the exit of the nozzle.Analysis of the influence of different size of nozzle structure and different water production.on the atomization.Through the nozzle,the liquid column or large droplets become more small droplets.It enhance the liquid carrying capacity and easy to taken out of the liquid out of the ground.Design the selection of one-way valve.Analysis the valve pressure drop,water Flow and the size.In order to ensure the high pressure gas can not enter the coalbed gas reservoir and the water from the coalbed methane layer into a one-way valve,The purpose is towill carry out smoothly.This paper proposed the equipment and crafts of Pipe String about the production of CBM and Tight Gas in one Well,To achieve the purpose of the production of CBM and Tight Gas in one Well.To adapt to the changes of the production of CBM and Tight Gas in the stable production stage,the equipment can simultaneously output of coalbed methane and tight gas.In order to effectively enhance the production and efficiency of the unconventional natural gas and can effectively reduce the number of ground drilling. |
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