高分子添加剂射流破岩钻孔的试验研究

针对径向水平钻井技术的特点和水射流直接破岩钻孔的需要,试验研究了高分子聚合物添加剂聚丙烯酰胺(分子量大于1000万)对射流破岩钻孔效果的影响。试验是在常压实验架上进行的,由XZ型三柱塞泵提供动力,岩心采用灰砂比1:1.5的自制岩心。为了试验的可比性,聚丙烯酰胺溶液均一次性使用。结果表明:在合适的浓度范围内,高分子添加剂的加入有利于射流破碎岩石;高分子添加剂对旋转射流破岩效果的提高在小喷距条件下尤为突出;高分子添加剂能增大圆射流破岩的最优喷距;在小喷距范围内,添加剂旋转射流的破岩效果仍要优于圆射流。破岩效果表明,对于高分子添加剂射流存在有最优添加剂浓度。

LABORATORY STUDY ON DRILLING BY HIGH MOLECULAR WEIGHT ADDITIVE JETTING

Based on the feature of radially horizontal drilling and the need of drilling through rock breaking hydraulic jetting,a labotatory study was conducted on effect of polyacrylamide(with MW greater than 1000×104) upon rock breaking. Test was done on an atmospheric tester with power provided a XY type triplex plunger pump. A synthetic core with ratio of cement to sand as 1: 1. 5 was used. For comparison,all the polyacrylamide slutions were used only once. The result showed that the addition of this HMW additive with proper concentration facilities rock breaking jetting;particularly its improvement to rock breaking rotory jetting with small jet length is remarkable;it can increase the optimum jet length in rock breaking circular jetting and the rock breaking effect of rototy jet added with the polymer is better than that of circular jet. Rock breaking result indicated that an optimum addition exists for jet added with HMW polymer.