Determination of Water Saturation and Porosity in a Carbonate Formation Using Mud Logging Data

Abstract

Abstract The economic and operational limitations in formation evaluation based on well logging operations have revealed the exigency of a technique that provides detailed information on the target formations. At the same time, it is more economical and less troublesome in different well designs and operational environments. However, there was always room for uncertainty in the quantitative application of mud logging in formation evaluation. Thus, the mud logging industry has introduced more developed and improved systems of mud gas acquisition and data analysis that can provide high-quality information about the subsurface formations. This paper discussed a new approach to determine real-time porosity and water saturation from mud logging data in a cretaceous carbonate formation. Drilling, mud logging, and wireline logging data, from four wells penetrating the Mishrif reservoir, were used. The results showed a good match between the interpretation resulted from mud logging data and that from wireline logs data. Feasible applications of this technique can be very useful in cost reduction and optimizing the design of logging programs for unstable hazardous formations and horizontal development wells where it is risky and costly to run open hole logs. Furthermore, it can be used as a potential tool for evaluating low-resistivity reservoirs.