ANALYSIS OF GEOLOGICAL STRUCTURE AND GEOMECHANIC AND ITS IMPLICATIONS TO NATURAL FRACTURE PREDICTION OF WFH FIELD RESERVOIR, BANGGAI BASIS, INDONESIA

• Main Author: Armanda, Reza
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/69804
• Institution: Institut Teknologi Bandung

The WFH field is a petroleum field that has been produced since 2005 with reserves of 120 million barrels and has reached peak production at a rate of 4000 barrels of oil per day. The reservoir rock from this field is limestone of Tomori formation which is Early Miocene age with an average matrix porosity of 8% (below the cut off productive zone). Based on the results of core rock studies, interpretation of log images and analysis of well production tests, the reservoir in the WFH field is associated with natural fractures that control the quality of the reservoir. Based on these indications, a natural fracture reservoir modeling is necessary to optimize production from this field. The Elastic Dislocation Method is a method used in this study to predict the orientation, slope and fracture intensity of a deformation process. After obtaining the orientation and slope of a fracture, a fracture modeling that has the potential to open due to current stress conditions (critically stressed fracture) is carried out. This modeling done by determining the value distribution of slip tendency, dilation tendency and slip stability on the reservoir in the WFH field. Collectively, these three parameters provide a physical value regarding the tendency for a fracture to be open (permeable zone) which will potentially become a productive zone. The results of the fracture orientation modeling in the WFH field using the elastic dislocation method show a relatively northeast-southwest direction with a slope of 34-65 degrees. High intensity fractures are concentrated in the maximum curvature of the structures in the WFH field and are associated with fault planes with high displacement values. The slip tendency modeling indicates that several fracture zones have entered a critical zone (critically stressed fracture). Based on the dilation tendency modeling carried out there are several fracture zones with high values which indicate the tendency for the fractures to be more open and have the ability to transmit hydrocarbons. The integration of the productive zone with the production speed provides a positive correlation where wells that penetrate the productive zone with trajectories that are relatively parallel to the direction of the critical fracture will provide a greater production rate in this field.