用主成分投影法评价和优选钻头

在钻井过程中，钻头的合理选型对提高钻进速度、降低钻井综合成本起着非常重要的作用。钻头性能评价是钻头选型工作的重要环节。评价方法的好坏直接影响到钻头选型结果的合理性。为了全面、系统地评价钻头性能的优劣，必须综合考虑钻头的使用效果和使用争件。在合理选取钻头性能评价指标的基础上，提出了一种新的钻头性能评价方法主成分投影法。该方法不仅考虑了评价指标的权重，而且通过正交变换解决了指标间的信息重叠问题。它以各决策向量在理想决策向量上的投影值作为钻头性能的综合评价值，根据该值的大小对各种型号的钻头进行优劣排序。借助于Matlab软件，该方法计算简单、实用，具有良好的推广应用价值。应用结果表明。该方法是合理的。

Evaluation and Selection of Bits Based on the Principal Component Projection Method

The selection of proper bits is of great importance for higher ROP and lower drilling cost. Evaluation of bit performance acts as a key factor for bit selection. In order to determine bit performances, both bit application conditions and results must be taken into consideration. Based on rational evaluation index system, a new bit performance evaluation method (the principal component projection method ) is presented. This method not only considers the index weight but also overcome the data overlapping by using orthogonal change. By use of this method, decision-making vector is projected on ideal decision-making vector and projection value is regarded as comprehensive evaluation value of bit performance, and then all kinds of bit types are sorted. With the help of Matlab software, the calculation of this method is very simple and practicable. This method is superior to other methods and can be applied widely. The application results indicate that this method is feasible.