A New Methodology and a Computer Software for Delineating Oil and Gas Reservoirs Using Surface Lineament and Fracture Analysis

Abstract

Abstract An innovative methodology and a comprehensive computer software package are presented for delineating subsurface oil and gas traps using remote sensing data and surface lineament and fracture analysis. The methodology applies geological and mathematical analyses of surface lineament and fracture characteristics as well as of surface circular and arcuate patterns in order to identify priority locations for exploratory drilling and/or for further geophysical and geochemical surveys. It employs five structural indicators in inferring subsurface hydrocarbon traps: surface lineaments, residual surface-fracture density, residual surface-fracture frequency, residual surface-fracture orientation complications, and surface circular and arcuate anomalies. The computer software provides easy-to-use tools to apply the methodology. Consisting of six major modules, the software package graphically displays surface linear and curvilinear features interpreted from remote sensing data, generates various types of rose diagrams of surface linear features for identifying regional structural styles, performs statistical and mathematical analysis of surface-fracture characteristics for identifying anomalous locations of potential subsurface oil and gas traps, and integrates and ranks the anomalous locations as indicated by the five structural indicators. The final outputs from the software are graphical displays of ranked anomalous locations as exploration leads. The methodology and software presented in this paper may be used to delineate additional oil and gas reserves in a mature field by establishing the relationship between the characteristics and patterns of surface features and the locations of already discovered subsurface oil and gas traps, and then extrapolating the trend to adjacent areas. They also may be used in a frontier region to initially screen the priority locations for exploratory drilling and/or seismic surveys. Introduction The use of surface features, particularly surface lineaments and fractures, for inferring subsurface oil and gas traps is based on the following two facts and/or hypotheses:The formation of subsurface oil and gas traps, in many cases, is largely controlled by major basement structural events, such as faulting and folding, in geologic history.The basement structural features, particularly basement faults and/or fractures, propagate all the way to the surface. Therefore, surface lineaments and fractures can be used to infer the locations of subsurface oil and gas traps. It is beyond the scope of this paper to discuss the validity of these concepts. Readers may refer to reference 1 for an extensive literature review and a more detailed discussion. The effectiveness of using surface lineaments and fractures for exploration has long been controversial because most techniques reported in the literature are applicable only in specific areas. Furthermore, they are more often qualitative than quantitative and usually based on an individual characteristic of surface lineaments and/or fractures. In this paper, a new methodology is briefly presented which applies both geological and mathematical analyses of surface lineament and fracture characteristics, as well as of surface circular and arcuate anomalies for inferring subsurface oil and gas traps. A complete discussion on the development and effectiveness of this new methodology can be found in references 1–3. The focus of this paper is to present a new computer software package which is specifically developed to apply this new methodology for oil and gas exploration using surface lineament and fracture analysis. It provides a suite of user-friendly tools for analyzing the characteristics and patterns of surface lineaments, fractures, and circular and arcuate anomalies.