Study On The Development Mechanism And Development Potential Of Shale Gas Res-Ervoirs In YW Area

Shale gas is a kind of unconventional natural gas which exists in mud shale with the states of adsorbed gas and free gas.At present,a domestic oil and gas company has drilled an exploratory well named P well which has obtained industrial gas flow,and so the YW area has showed a good prospect of the exploration and development.The area contains gas area is 143.771km2,and the estimate the amount of resources is 1175.27×108m3,so it shows the good prospect of exploration and development in this area.But because the area is still in the early stages of development,the research degree of shale gas microadsorption characteristics and gas reservoir development is low.In order to understand the shale gas development mechanism in YW area,develop a rea-sonable development technical policy,and guide the rational and efficient development of shale gas in this area.This thesis is funded by the research on the potential analysis and coun-termeasure of shale gas development in YW area,a domestic oil and gas company,based on the previous research results obtained,carring out the experiment of high temperature and high pressure adsorption of shale gas,adsorption molecular simulation,adsorption density functional theory study,and using reservoir engineering and numerical simulation technology,the parameters of fracturing horizontal Wells are optimized,and reasonable development technical policies are formulated,and the development concept design is developed and the potential of development is clearly defined.The main results of this paper are as follows:(1)A new device for experimentally simulating the mud pollution of full-diameter core under high temperature and pressure situation is developed,and the device was patented by the state in 2015.The evaluation method of total diameter core mud pollution under real res-ervoir conditions is established,and experiments were carried out on three small seam cores,four middle seam cores and one large seam core,and the pollution degree of the mud to the core was determined under the conditions of different pressure difference and fracture size(2)High temperature and high pressure(75 MPa,200?),gas adsorption test equipment,simulation of shale gas in real formation adsorption characteristics.Measured under different temperature,CH4 and CO2 adsorption isotherm of single component,then water and water for the core respectively,CO2 and CH4 competition adsorption experiment,clear competitive ad-sorption law under the high temperature and high pressure.(3)Using grand canonical ensemble Monte Carlo method,respectively,in view of illite and quartz,kerogen and mixed mineral model,pure component are calculated respectively according to the different proportions of CO2,CH4 and both mixed gas under the condition of water cut and water adsorption isotherm,analysis of pure components,CH4 and CO2 gas mixture in a dry and water under the condition of adsorption.(4)Based on adsorption mechanism research,by using numerical simulation software,the dual medium single-well numerical model is set up,develop fracturing horizontal well pa-rameter optimization research,the article in view of the horizontal well length,fracturing fracture number,fracture half length and spacing parameters optimization,clear for YW area of shale gas horizontal well parameters;On this basis,the numerical simulation method of constant pressure gas well and open mode of production,as well as gas injection and index comparison optimization of depletion development way,to make reasonable development technology policy,at the same time for three types of shale gas in common use at home and abroad and well spacing model for comprehensive evaluation of technical economy,optimiz-ing model of well spacing,combination of mud pollution research results about pollution im-pact on gas well productivity analysis,finally making development concept plan,YW area clearly shale gas development potential.The research and the results obtained in this paper can provide theoretical and technical guidance to efficient and scale development of shale gas reservoir in YW area,and related research achievements in this paper has reference significance to shale gas reservoirs in other areas.