油层酸化按其施工方法可分为哪三类？各自的目的是什么？
参考答案：
①油层酸化按其施工方法可分为：酸洗、基质酸化（常规酸化）、压裂酸化三大类。
②酸洗的目的是清除井内套管壁炮眼的结垢物，疏通炮眼，达到增产的目的。
③基质酸化的目的是扩大地层的孔隙空间，溶解空间内的颗粒堵塞物，提高井筒附近的地层渗透率，达到增产、增注的目的。
④压裂酸化的目的是利用酸对裂缝面的酸蚀作用扩大裂缝的通道，提高压裂效果。
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| Flies (苍蝇) usually live in the dirty places. Let's look at a fly, and see where it 1 . First, it flies out of the window, 2 it stands on 3 dirty things in the street, and then it flies back to the house and walks over your 4 . When a fly walks on the dirty things in the street, its 5 have got some germs 6 them. When the fly walks on your food with its dirty feet, it 7 the germs on your food. What can you 8 this? First, we learn that we mustn't leave dirty things in the street or on the ground near 9 . Second, we learn that all food must be covered so that flies may not 10 it. Third, we learn that flies often carry germs and we must kill them as soon as we see them. | ||||
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