Over the last 10 years new technology has been developed and successfully tested for optimizing production for oil fields with high gas to oil ratio (GOR). Both theory and practice have demonstrated good matching. The monograph consists of 6 parts which contain the following information:description theory and some results of using the TOP technology; several Methods and Technologies developed by Tseytlin Consulting, Inc.for the purpose of prevention of well explosions; mathematical simulation of EM MWD Telemetry System for vertical, horizontal and declining wells; the development of electromagnetic measurement while (EM MWD) drilling; the case Underbalance Drilling by General Electric Comp.(GE) with using EM MWD simulator created by Tseytlin Consulting Inc.