Research On Water Damage Mechnisim And Prevention Technology Of Low Permeability Injection Reservoir

According to the current situation of water flooding in low permeability reservoir ,inorder to prevent the water damage of low permeability reservoir, this paper Proposes a newwater injection anti-swelling technology :trapezoid-antiswelling water injectiontechnology ,and synthesizes a new anti-clayswelling agent-PTACore sensitivity experiments of Chunliang Oil plant low permeability reservoir showthat these cores are middle water sensitive and part of highly velocity sensitive and saltsensitive. A series of clay antiswelling experiments indicate trapezoid antiswelling agent canprevent caly swelling during the injection development process, has minor core damage andlong antiswelling period. This paper gets the trapezoid antiswelling injection operatingtechnique which is: high concentration slug at the beginning, to middle concentration ,andat last low concentration big slug. And defines the best opportunity to carry out antiswelling:conversion well, injection well after fracturing, injection well after acidizing and injectionwell with short injection time and low injection pressure. At last, gets the formula ofantiswelling validity.Through optimization experiment of washing oil agent and PTA, comes to a conclusionthat 0.3% PTA antiswelling agent combined with 0.15% XCJ-2 washing oil agent canachieve the best antiswelling effect.Eventually, carry out antiswelling operation to an injection well.Results of laboratoryexperiments and field application demonstrate that trapezoid antiswelling injectiontechnique plays a good function in water damage prevention of low permeability injectedreservoir, and has good economic benefit, and is worth to be popularized and applied.