Water Huff-n-Puff Optimization in High Saturation Tight Oil Reservoirs  

作　　者：Zhengyang Zhang Jing Sun Xin Shi Dehua Liu 

机构地区：[1]School of Petroleum Engineering,Yangtze University,Wuhan,430100,China [2]Cooperative Innovation Center of Unconventional Oil and Gas(Ministry of Education&Hubei Province),Yangtze University,Wuhan,430100,China [3]Engineering Cost Department of PetroChina Changqing Oilfield Company,Xi’an,71000,China

出　　处：《Fluid Dynamics & Materials Processing》2025年第3期509-527,共19页流体力学与材料加工(英文)

基　　金：supported by the Innovation Fund of China National Petroleum Corporation(2020D-5007-0209).

摘　　要：High saturation pressure reservoirs experience rapid pressure decline during exploitation,leading to significant changes in crude oil phase behavior and a continuous increase in viscosity after degassing,which adversely affects oil recovery.This challenge is particularly acute in tight sandstone reservoirs.To optimize the development strategy for such reservoirs,a series of experiments were conducted using core samples from a high saturation tight sandstone reservoir in the JS oilfield.Gas-dissolved crude oil was prepared by mixing wellhead oil and gas samples,enabling the identification of the critical point where viscosity changes as pressure decreases.Oil-water relative permeability experiments under varying viscosities revealed crude oilmobility trends with declining production pressure.Additionally,physical and numerical simulations of water huff-n-puff processeswere performed,while nuclear magnetic resonance methods explored the effects of soaking time on oil-water imbibition.Key findings include the following optimal parameters for water huff-n-puff:(1)initiating the process when formation pressure is 75%of its original level,(2)a soaking time of 48 h,(3)an injection volume of 0.6 pore volumes per cycle,and(4)a 5 MPa pressure reduction per production stage.Numerical simulations further recommend initiating water injection after one year of depletion,with an optimal cumulative injection volume of 18,000 cubic meters,a soaking time of 10 days,and a producing pressure difference of 5 MPa.

关 键 词：High saturation reservoirs tight sandstone huff-n-puff nuclear magnetic resonance numerical simulation 

分 类 号：TE357[石油与天然气工程—油气田开发工程] TE349