用于砂岩地层的稠化土酸解堵技术

Thickened Mud Acid DXGY-1 for Blockage Removal in Heterogeneous Sandstone Reservoirs

胜利东辛砂岩油藏地质状态复杂多样,非均质性严重,为此研发了稠化土酸DXGY-1并用于油水井解堵。为该酸液选择的稠化剂ZS-03是一种阳离子聚丙烯酰胺,加入5%ZS-03的12%/3%土酸液90℃时表观黏度保留率(相对于30℃值)为82%,70℃老化5小时后黏度为3.4 mPa.s,在30℃、170 1/s剪切3.5小时黏度保留率为82%。在添加剂和总酸量不变,改变盐酸、氢氟酸相对含量及稠化剂用量的情况下得到的优化稠化土酸,90℃、常压下对大理石的4小时溶蚀率为8.76%,对玻片的2小时、6小时溶蚀率分别为8.31%和13.98%,相对于土酸的缓速率(玻片)为55.25%,与胜利油田使用于砂岩地层的含醇、酯、酸的缓速酸HS相比,残酸中H+浓度均较高。所筛选的缓蚀剂为ZY-F1(加量1%)、铁离子稳定剂为DDS-1(1%),防膨剂为KC-1(3%)。2006、2007年在东辛油田19口注水井、5口采油井、4口新投产侧钻或斜油井使用该稠化土酸解堵,均获得成功。

A thichened, or gelled, mud acid, DXGY-1, is developed for removing reservoir blockages in water injection and oil production wells in sandstone oil reservoirs of geological complexity and multiplicity and serious heterogeneity in Dongxin, shengli, with a thickener, ZS-03, specially chosen and added at dosage 5 %, the standard mud acid, 12 % HC1 ＋ 3 % HF, keeps at 90℃ 82 % its apparent viscosity at 30℃, has viscosity of 3.4 mPa·s after 5 hr ageing at 70℃ and maintains 82% its viscosity after shearing at 30℃ and 170 1/s in 3.5 hr. In experiments at 90℃ and atmospheric pressure with varying relative concentration of HC1 and HF and thickener content and with dosages of additives and total acid concentration kept unchanged, an optimal thickened mud acid is eventually formulated and demonstrates 4 hr etching rate of 8.76% for marble, 2 hr and 6 hr etching rate of 8.31% and 13.98%, respectively, for glass platelets and an etching retardation of 55.25 % for glass platelets in comparison with plain mud acid meanwhile higher H^＋ concentrations are observed in the spent thickened mud acid in all cases as compared with retarded acid HS, which comprises alcohol（s）, ester（s）, and acid（s） and used in some sandstone reservoirs in Shengli. The corrosion inhibitor chosen for the thickened mud acid is ZY-F1 at dosage 1%, the ferroferric ions stabilizer-DDS-1, 1%, and the clay stabilizer-KC-1, 3%. In 2006 and 2007, thickened mud acid DXGY-1 was used successfully for reservoir blockage removal in 19 injection wells, 5 production wells, and 4 newly drilled production wells with sidetracked or slant holes.