Mechanism Of Sand Production In Ultra-Deep And Compact Gas Reservoir Of Kuche And Countermeasure Of Sand Control

Keshen 8 area of Tarim oilfield is located at Kuche depression in which developing fold-thrust tectonics,fracture is very complicated;The maximum horizontal in-situ stress reaches up to 2.6MPa/100 m,The minimum horizontal stress is 2.15MPa/100 m,the vertical stress is 2.35MPa/100 m,so the in-situ stress intensity is very high;the reservoir pressure reaches up to 122 MPa,the reservoir temperature is 175?,so it is a high temperature and high pressure system;the structural fracture density reaches up to 0.37 strip per meter,it is relatively developed,the whole reservoir is poor.If we want to exploit this kind of reservoir and get considerable and economic output,a series of reconstructive measure such as acid fracturing and production pressure increase must be taken.Sand production in the process of well testing and gas generation in this area seriously influences the process of formation testing,pilot production and reservoir evaluation.This article describes the sand production mechanism in the well productivity layer.It is believed that the main reason for formation sand production in compact and stabilized reservoir should be over-loaded differential pressure and fracture development,which can lead to rock shear fractures or tension fractures.In order to deal with sand production,this article mainly use logging data and other in-situ data,basing on the geological mechanics characteristics of Keshen area,later we get rock mechanics parameters and in-situ stress parameters through a series of calculation,finally we draw the visual ribbon diagram and analyses the relevant factors(tectonic stress factors,cemented particle properties factors,attenuation of the gas layer pressure and production pressure factors,acidification fracturing factors and so on),furthermore we use empirical sanding prediction model to forecast if the formation can produce sand,later build critical sand prediction model based on practical production status in Keshen 8 area,then calculate three wells' critical production pressure,the critical production pressure of Keshen 8-X,Keshen 8-Y,Keshen 8-Z is respectively 8.3MPa,8.5MPa,9.9MPa.Finally aiming at the critical elements of influencing sand production,the article formulates the corresponding countermeasure and comes up with reasonable sand control methods.This study is helpful in quantitatively analyzing sand production and determining optimum well completion scheme,and provides foundation for reservoir sand control decision making.