Research And Application On Adsorption And Release Of Calcium On Zeolite

Control the gel time of silicate sealing materials effectively is the key technology of sealing using silicate sealing materials. If the gelation time is too short, silicate sealing materials gel completely before the materials pump into the leaking layer and lost circulation materials can’t be able to pump, in contrast, too long gelation time will delay the plugging construction. And it should also be noted that sealing materials should begin to form gel when the materials have pumped into the certain formation to avoid washing away and diluting by crossflow in the formation, which need to design a plan to control the gel time of silicate sealing materials within 1~4 hours.At present, it is mainly through delaying the release rate of hydrogen ion or metallic cations which occur the gelling reaction with sodium silicate to control the gelation time of sodium silicate. Zeolite, a typical porous absorbing materials, has excellent adsorption capacity to the hydrogen ion or metallic cations, and hydrogen ion or metallic cations, which are absorbed on the surface of zeolite, can be released slowly in sodium silicate solution and produce gelatinous precipitation which can delay the gelation time of sodium silicate gel.This paper mainly presents a effective method to control the gel time of sodium silicate-calcium chloride solution. The method build models by response surface method which are baesd on the law of zeolite absorption/release calcium to calculate the dosage of zeolite, calcium chloride, sodium silicate.The specific content of this paper is as follows:(1) Establish the absorption model of calcium on zeolite based on the experiments which research the type and particle size of zeolite, concentration and p H of calcium chloride with seaking zeolite and stirring rate affect the absorption ability of calcium on zeolite and the experimental data.(2) Establish the release model of calcium on zeolite based on the the experiments research which the type and particle size of zeolite, original concentration of calcium chloride affect the release on rate of calcium on zeolite and the experimental data.(3) Verify the absorption and release models can control the gelation time of sodium silicate-calcium chloride gel effectively.The result shows the experimental program calculated by the models of zeolite absorption/release calcium can manage the gelation time of sodium silicate-calcium chloride solution in the time of 1.5h, 2h and 4h successfully.