A PRINCIPLE TO ESTIMATE A FEW SETS OF SUBSURFACE SYSTEMATIC JOINT SPACINGS AND ITS APPLICATION

In this paper,an optimum method is suggested to estimate a few sets of subsurface systematic joint spacings.Instead of fractured rock orientation,core data are used to estimate a few sets of joint spacings.In order to confirm the efficiency of this method,an ideal fracture model is set up.It is discovered that the product of joint spacings is estimated more accurately than joint spacings alone under the same times of observations.Finally,the method is applied in estimating a few sets of joint spacings of reservoir in the 6th member of Triassic Yanchang Formation at the southern 2nd region of Jingan oil field in the Ordos Platform.