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Fracture Systems Prediction for Exploratory Prospects Using Multiscale Data Integration - Application in a Mesozoic Carbonate Reservoir in the Southeastern of Mexico

Abstract

The hydrocarbon exploration in the southeastern of Mexico has been intensified specially in fractured carbonates plays. This requires a detailed integral analysis to reduce the risk of exploratory proposals, and also for better design of well trajectories. The limited information of well data and the poor seismic quality are factors that affect the prediction of the main distribution of fracture. This work shows the application of a methodology which we have developed in PEMEX to model fractured systems, integrating multiscale data. This methodology is focused in the characterization of fracture systems from the identification of fractures sets with the same diagenetic and structural origin, the calculation of fracture attributes, establishment of the stratigraphy-mechanical, images logs interpretation, seismic analysis, and 3D modeling. The main objective is to generate a fracture systems model, to reduce the risk of exploratory prospects. In addition, this study will be the base of future reservoir development. An example from the Southeastern of Mexico is presented. The main target is a sequence of carbonated Cretaceous rocks deposited in basinal facies, with porosities of matrix that varies from 2-4%. We analyzed data from 8 wells near to the prospective area, 14 cores and 5 images logs interpretation. In addition, we performed triaxial and petrophysic tests from 14 cores. The complementary analyses consisted of petrographic description, measurement and characterization of fractures, calculation of fracture attributes, identification of geologic fracture controllers, establishment of layer-mechanical units and structural model. As a result, the intensities of all conductive fracture sets, with direction NW-SE, NE-SW and non conductive N-S and E-W sets were modeling in the study area. In addition, a 3D visualization of potentially fractured exploratory prospects was done, and the proposals of well trajectories that can intercept open fracture sets. With these results, in addition the trajectory of an exploratory proposal was redesigned. That well is currently drilling, and it had a very good oil indication of hydrocarbons while drilling the carbonated Cretaceous sequence. In addition, the study results offers the possibility of the incorporation of reserves in the study area for this sequence, that already had been perforated by 4 wells which were not successful, due to do not have the correct trajectory with respect to the open fracture sets orientations.