For the implementation of automatically extracting planar geologic features in borehole images, the methods of detecting single cycle sinusoidal curves in images were studied. An improved Hough transform were proposed. The proposed method voted in the two-dimensional accumulator based on three related points in the sinusoidal curve, to determine the phase and baseline depth. Then vote was performed in one-dimensional accumulator, to determine the amplitude. The simulated images and borehole images were processed. The proposed method was compared with the traditional Hough transform and fast Hough transform. The results show that the proposed method not only improves the detection efficiency, but also has high accuracy.

An induction logging inversion algorithm based on the Differential Evolution (DE) was proposed to avoid the dependency of initial model. This inversion algorithm was applied to induction logging inversion on the 2-D axisymmetric models of different thickness layers, and yielded consistent results with the models in the noise-free case. When noises of 5%, 10% and 15% were added, the inversion results of thick reservoir remain fairly good but the results of thin reservoir became slightly inferior. The numerical experimental results demonstrate that the proposed inversion algorithm has the capabilities of global optimization and anti-noise. It is more independent of initial model than the traditional ones.