Method of well placement modeling and geosteering

A method for geosteering while drilling comprising:

• receiving a first geographical model of the wellbore;
• receiving measured log data and a trajectory of the wellbore;
• simulating a first simulated tool response along the trajectory based on the first geographical model;
• determining a measured tool response based on the measured log data;
• finding a first portion of the first simulated tool response corresponding to a second portion of the measured tool response, the first portion and the second portion having substantially a same interval of length along the trajectory;
• comparing the first portion and the second portion to generate a second geographical model;
• steering a bottom hole assembly based on the second geographical model.

A system for geosteering while drilling comprising:

• a computer having a processor and a memory wherein the memory stores a program having instructions for:
• receiving a first geographical model of the wellbore;
• receiving measured log data and a trajectory of the wellbore;
• simulating a first simulated tool response along the trajectory based on the first geographical model;
• determining a measured tool response based on the measured log data;
• finding a first portion of the first simulated tool response corresponding to a second portion of the measured tool response, the first portion and the second portion having substantially a same interval of length along the trajectory;
• comparing the first portion and the second portion to generate a second geographical model;
• and
• selecting a steering solution for the bottom hole assembly.