Gas-Water Distribution and the Countermeasures of Water-Government Based on Reservoir Architecture

Author:Heng Yong

Supervisor:wang hong hui


Degree Year:2018





As an important substitute strategic area for stable production in Sulige gas field,the reservoirs of the 8th memberer of Xiashihezi Formationin in the southern area of Sulige Gas Field are low porosity and low permeability sandstone reservoirs with strong heterogeneity.Since the development of gas field,the wells produce water seriously,which indicated the relationship of gas and water distribution is complex.This phenomenon is not good for the exploration and development of gas field,but at present,the research degree of gas and water distribution is not enough.Based on the previous achievements,guiding with the related theoriesof sedimentology,development geology and gas engineering,by integrated usingof data of logging,coring,testing,gas production and chemical characteristics of formation water,the gas and water distribution was studiedfrom macro and micro aspects.On microscopic aspect,the pore structure,the micro occurrence of formation water and the influence of formation water on gas phase seepage were analyzed by using mercury injection data,gas water displacement and nuclear magnetic resonance(NMR)data.On macroscopical aspect,Combining the reservoir architecture with the distribution of gas and water for the first time,based on the study of the scale,shape and superposition relationship of sand body,the distribution of formation water was made clear.Finally the water sources and production characteristics of wells were analyzed,and the development countermeasures for water producing gas wells are put forward.The main achievements and understanding of the paper are as follows:(1)The types of pore spaces are mainly inter-grain pores and inter-crystal pores,and the reservoirs have the characteristics of small pore,tiny throat,poor sorting,high displacement pressure and low efficiency of mercury withdrawal.Formation water occurs in pores in the form of gaseous water,bound water(membrane water,capillary water)and free water.The mobility of formation water in small pores is weak,and strong in large pores.Bound water saturation has a good logarithmic relationship with permeability.(2)The formation water has a great influence on the relative permeability of gas phase.When the water saturation is higher than bound water saturation,there is gas-water two-phase flow in the reservoirs.The gas relative permeability decreases with the increase of water saturation.The co-permeability range of gas and water is proportional to the permeability,the lower the permeability,the narrower the co-permeability range of gas and water is.(3)According to the idears of vertical staging and lateral delimitation,the scales,shapes and superimposed relationship of architecture units(single braided river belt,single sand body,channel bar)at different hierarachical levels was quantitatively characterized using cycle constraints and hierarchical dissection analysis method.(4)Based on gas testing and well logging,the standard of quantitative identification of gas layer was established and the identification of gas layer was made.The distribution of gas and water was researched by combining the well logging identification results with reservoir architecture,and the volume of macroscopic water body is estimated.Results show that edge water and bottom water do not exist in reservoirs,no unified gas water interface,water scattered distribution in bar and channel sand body.there are several types formation water:the closed formation water within isolated sand body(isolated by mud,isolated by tight dry zone),the residual water with weak dynamic and incomplete gas-water displacement,the stagnant water at lower position of large sand body.(5)The water source of the gas well was analyzed by water salinity,water gas ratio discrimination and production dynamic analysis,and the identification standard of the water source was established.The source of water production and the characteristics of water production in gas wells were analyzed.(6)According the study characteristics of water production,gas production capacity and the bottom hole liquid loading,reasonable production allocation and drainage development measures are proposed,and the drainage is mainly based on its own energy,the foam and velocity string are supplementary.