Optimization of shut-in time based on saturation rebalancing in volume-fractured tight oil reservoirs  

作　　者：XU Jianguo LIU Rongjun LIU Hongxia 

机构地区：[1]PetroChina Jilin Oilfield Company,Songyuan 138000,China

出　　处：《Petroleum Exploration and Development》2023年第6期1445-1454,共10页石油勘探与开发（英文版）

基　　金：Supported by China National Major Project of Science and Technology(2016ZX05046-004);PetroChina Major Project of Science and Technology(2017B-4905);PetroChina Jilin Oilfield Company Major Project of Science and Technology(JY21A2-12).

摘　　要：Based on imbibition replacement of shut-in well in tight oil reservoirs, this paper expounds the principle of saturation rebalancing during the shut-in process after fracturing, establishes an optimization method for shut-in time after horizontal well volume fracturing with the goal of shortening oil breakthrough time and achieving rapid oil breakthrough, and analyzes the influences of permeability, porosity, fracture half-length and fracturing fluid volume on the shut-in time. The oil and water imbibition displacement in the matrix and fractures occurs during the shut-in process of wells after fracturing. If the shut-in time is too short, the oil-water displacement is not sufficient, and the oil breakthrough time is long after the well is put into production. If the shut-in time is too long, the oil and water displacement is sufficient, but the energy dissipation in the formation near the bottom of the well is severe, and the flowing period is short and the production is low after the well is put into production. A rational shut-in time can help shorten the oil breakthrough time, extend the flowing period and increase the production of the well. The rational shut-in time is influenced by factors such as permeability, porosity, fracture half-length and fracturing fluid volume. The shortest and longest shut-in times are negatively correlated with porosity, permeability, and fracture half-length, and positively correlated with fracturing fluid volume. The pilot test in tight oil horizontal wells in the Songliao Basin, NE China, has confirmed that the proposed optimization method can effectively improve the development effect of horizontal well volume fracturing.

关 键 词：tight oil horizontal well volume fracturing imbibition displacement oil saturation balance shut-in time influence factor development effect 

分 类 号：TE357[石油与天然气工程—油气田开发工程]