徐深气田气层压裂后压井液密度选取方法

The Selection Method and Application of Gas Reservoir Killing Fluid Density for Xushen Gas Reservoir

随着近年来深层试气测试工作量逐年增多,压井工程的工程量也同步增长。压井液密度如何选取是压井工程的关键环节。压井液密度过高导致了压井液漏失率高及用量大,由此带来高的压井成本。压井液密度过低给井控安全带来隐患,甚至发生井喷失控事故。为了合理地选取压井液密度,进行了深层压裂后压井液漏失率规律及影响因素分析试验,在试验基础上建立了压裂后气层压井液密度选取方法,充分考虑了地层原始压力系数、压力附加系数、压力衰竭程度和目前井口压力等因素。现场应用结果表明深层压裂后气层压井液密度选取方法适合于徐深气田的实际,有效地降低了压井液漏失率,减少了压井液用量,减轻了对气层的污染,可在徐深气田勘探、开发中普遍应用。

In recent years, with the work of deep-seated reservoir gas testing has been increasing year by year, the work of killing well increases quickly as well. How to select killing fluid density is the key point of killing well engineering. High killing fluid density can lead to high loss rate of killing fluid and high dosage, thus results in high cost of killing well. But it would bring hidden dangers for well control safety, even accidents of blowout happen because of the low killing fluid density. The experiments of the law of the loss rate of killing fluid and influence factors for deep-seated reservoir fracturing are made. The selection method of gas reservoir killing fluid density after fracturing was established on the basis of experiments, full consideration of the original formation pressure coefficient and pressure formation coefficient of additional stress, and the degree of pressure-depleted and current wellhead pressure. Field application shows that after fracturing, the selection method of gas reservoir killing fluid density is suitable for Xushen gas reservoir, it effectively reduces loss rate of killing fluid, reduces the dosage of liquid and the pollution of gas layer, thus this method can be widely used in exploration and exploitation.