钻头选型通用方法研究

提出了一种既考虑地层的多种岩石力学特性又考虑钻头经济效益的具有通用性的钻头选型方法。该方法在待钻地层岩石力学性质评价的基础上，首先应用模糊优选理论建立了地层岩石力学性质相似层位的模糊优选模型，用其进行相似层位的优选，然后应用经济效益指数法对相似层位的钻头性能进行评价，最后给出合理的钻头选型结果。该通用钻头选型方法不受区域限制，克服了常规的依据地质分层或钻井经验进行层位相似判断的不足，不仅适用于PDC钻头选型，也适用于牙轮钻头选型。应用该方法对某新探区进行了钻头选型。现场试验结果表明，该方法是合理、有效的。

Study on universal method of bit selection

A universal method of bit selection was presented in consideration of the rock mechanics properties of formation and economic benefits of the bit. Based on the evaluation of rock mechanics properties of undrilling formation, a fuzzy optimization model for selecting the best similar layers with the same rock mechanics properties was established by applying theory of fuzzy optimization. Firstly the best similar layer located the undrilled area was closen by the model. Secondly the performance of the bit used in the selected layer was evaluated by econonmic benefit index. Finally the rational bit type was given. This method overcomes the shortcomings of conventional method, according to which the best similar layer is decided by geologic classification or drilling experience. This method can be applied without region limited, and it is suitable for PDC bit selection and roller bit selection. The fidd test result of a new exploration area indicates that this method is feasible and effective.