Calculation of Cement Volume Based on Conventional Logging Data - A Case Study in CFD12-6 Block in Bohai Oilfield, China

Summary Carbonate volume and its occurrence have significant influence on reservoir quality. High cementation volume will result in decrease of porosity and permeability in sand reservoir. However, if the cementation volume or volume is certain, contact cementation is better than non-contact cementation. In this paper, 4 types of cementation, including non-cementation, rim cement (contact cement), scattered cement (non-contact cement), and combination of rim cementation and scattered cementation are identified in CFD12-6 of Bohai bay basin. Generally, cementation volume can be obtained through rock slice identification, but consistent profile of cement volume of the whole well is hardly available as rock silce samples are rare and of the identification process is time-consuming. Thus, obtaining cementation volume based on well-log data is of great importance. In this paper the mathematical relation between contact cementation, scattered cementation and porosity with P&S wave velocity is constructed, and furthermore, the contact cementation, non-contact cementation, and total cement volume based on conventional logging data is calculated.