Saudi Arabian Computerized Log Analysis System

Abstract

Saudi Arabian Well Log Analysis System (SARLOG) is a computerized open hole well log interpretation system developed locally for the Ministry of Petroleum and Minerals. This system consists of a total of forty subprograms. These subprograms will digitize and prepare data, perform chartbook environmental corrections and do perform chartbook environmental corrections and do level by level main calculations. Cross plotting subprograms are included for verification of log calibration, identification of lithology, differentiation of gas and oil and determination of all formation parameters. As the equations and methods used in well logging depend on lithology type, shaliness and available log combination, optional methods have been included in SARA to allow the log analysts to put his own judgement when it becomes required. Six shale indicators are used to approach a mere precise shale value, and seven water saturation methods are optional for shaly sandstones and complex carbonate lithologies. Introduction In the past few years, computers have become one of the most powerful tools for log analysts. Many oil companies and institutions have developed their own software and are still developing new methods in computer and well logging technology. Computers are capable of doing the most complex log analyses in a reasonable amount of time. The interactive communication and graphics capability of the computer, facilitates its utilization by a log analyst who has not had any previous computer experience. The SARIS (Saudi Arabian Log Analysis System) is a computerized well log analysis software system which is developed for the Ministry of Petroleum and Minerals by the University of Petroleum and Minerals Research Institute (UPMRI). This software is designed for open hole well log analysis and consists of various subprograms for performing comprehensive computations and elegant displays. The task of the system has been distributed into five main stages with each of the subprograms functioning as an element in one of the following stages:digitization and data preparation,chartbook environmental corrections,cross-plotting,main interpretation, andpresentation. The SABLOG has been developed to be applied to the interpretation of various log combinations, geologic settings and probable situations related to well logs which might be encountered in Saudi Arabia. The software was developed and applied on both the complex carbonate and shaly sandstone reservoirs. SABLOG is broken into sub-programs to provide more flexibility and the ability to apply to various data combinations. The system has been developed in RP basic language to run on the HP 9845C computer and was later translated to Fortran language to run on the IBM 370/158 system. The specifications and utilization of each version are explained in separate user's manuals. The SARLOG system has been developed by following the essentials of Schlumberger logs and the Schlumberger Log Interpretation Chartbook. HARDWARE The HP BASIC version of the SARLOG system was developed for use on the HP 9845C desktop computer system (with associated peripherals) presently at the UPM Research Institute (Fig. 1). presently at the UPM Research Institute (Fig. 1).