针对MX井深层白云岩储层酸液刻蚀裂缝导流能力不足的问题,设计了非均匀酸化压裂工艺,通过不同黏度、不同反应速度酸液的组合注入,在非均匀酸液分布和非均匀酸岩反应强度的双重作用下,可产生极强的不规则刻蚀.运用室内酸蚀裂缝导流能力评价技术,刻画了岩板刻蚀特征,测定了20～ 90 MPa闭合应力条件下的非均匀刻蚀裂缝导流能力.结果表明:交联酸+盐酸和交联酸+胶凝酸的交替刻蚀都在岩板上形成了明显的非均匀沟槽或坑洼,细长的酸蚀沟槽模式在高闭合应力下能提供较好的流动通道,大片的酸蚀坑洼模式在中低闭合应力下导流能力较高.MX井采用交联酸+胶凝酸二级交替刻蚀非均匀酸化压裂工艺,酸液黏度比为6.67,施工排量为5.5～6.0m3/min,压裂后初期日产油达到65 t/d.非均匀酸化压裂技术工艺简单,不额外增加措施成本,对于提高深层白云岩储层改造效果具有重要意义.%The fractures etched by acid in the deep dolomite reservoirs in Well MX don't have sufficient flow conductivity.To solve this problem,non-uniform acid fracturing technology was designed in this paper.By virtue of this technology,the acids with different viscosities and reaction speeds are combined and then injected,so that the etching is strongly irregular under the dual effect of non-uniform acid distribution and non-uniform acid-rock reaction intensity.Then,by means of laboratory etched fracture flow conductivity evaluation technology,the etching characteristics of rock plate were depicted and the flow conductivity of non-uniformly etched fractures under the closure stress of 20-90 MPa was measured.It is indicated that the alternative etching of crosslinked acid+hydrochloric acid and crosslinked acid+gelled acid can generate obvious non-uniform grooves or pits.In the mode of elongated etched groove,good flow paths can be generated under high closure stress,and in the mode of extensive etched pit,the flow conductivity is higher under middle and low closure stress.The non-uniform acid fracturing technology of crosslinked acid+gelled acid two-stage altemative etching is adopted in Well MX.Its acid viscosity ratio is 6.67,the flow rate is 5.5-6.0 m3/min and the daily oil production in the early stage after the fracturing is 65 t/d.To sum up,the non-uniform acid fracturing technology is simple and no extra stimulation cost is needed.It is of great signiflcance to improve the stimulation effect of deep dolomite reservoirs.
展开▼
