%0 Dataset
%T Collection of Research Papers on Key Technologies of Drilling Processes and Wellbore Working Fluids (2016-2021)
%J National Cryosphere Desert Data Center
%I National Cryosphere Desert Data Center(www.ncdc.ac.cn)
%U http://www.ncdc.ac.cn/portal/metadata/5446c4cf-8eb0-4403-b6b2-38a42cb9759a
%W NCDC
%R 10.12072/ncdc.SRIPE.db1711.2022
%A Gao deli
%K Frozen soil layer;Low-Temperature Cement Slurry for Cementing;Low-Temperature Drilling Fluid;Extended Reach Well
%X Collection of Research Papers on Key Technologies of Drilling Processes and Wellbore Working FluidsPublished between July 2016 and May 2021, Beijing. Gas diffusion and intrusion are more prone to occur in oil-based drilling fluids. With the increasing use of oil-based drilling fluids, it is necessary to study the mechanism of gas diffusion and intrusion and establish a quantitative calculation model for the same. The gas diffusion and intrusion pathways are divided into five parts: the gas-filtrate interface, the filtrate retention zone, the inner filter cake zone, the outer filter cake zone, and the interface between the inner wall of the outer filter cake zone and the drilling fluid. Based on the analysis of the mechanism of gas diffusion and intrusion, the control equations and analytical solutions for gas diffusion and intrusion within the wellbore are derived. Based on the analytical solutions, quantitative calculation formulas for gas diffusion and intrusion parameters (such as gas intrusion rate under circulating conditions, total gas volume in the wellbore under circulating conditions, maximum gas concentration under static conditions, and total gas volume in the wellbore under static conditions) are provided. Combined with case study analysis, the influence laws of reservoir length, reservoir porosity, and drilling fluid filtration loss on gas diffusion and intrusion are obtained. Except for the maximum gas concentration under static conditions, the gas diffusion and intrusion parameters have a linear relationship with the reservoir length.