Regresar

Hydraulic fracture geometry evolution and pressure during pumping: Chicontepec experiences indicate that natural fractures or fissures are not activated

Abstract:

Natural fractures exist in many oil and gas reservoirs. The activation of these fractures can have a significant influence on the initial production and the EUR of the wells. It is therefore very important to know whether they are interconnected and their impact on oil recovery, thus optimizing the development plans of the reservoirs. The giant Chicontepec field, located in central eastern Mexico, with 140 billion barrels of oil in place (OOIP), with laminated turbidite sequences, limited lateral extent, low porosity and permeability, very low current recovery, there are natural fractures or fissures. These natural fractures have been observed in many cores, as well as image logs and outcrops. It is considered that the natural fracture system must be analyzed in Chicontepec in more depth and more importantly, the degree of interconnection may have and its impact on oil recovery because it is estimated that may not be effectively interconnected. Due to the low permeability of the rock, wells are hydraulically fractured. The analysis of the evolution of the pressure at the bottom of the well and or net pressure during a fracturing job is a valuable tool to infer the geometry of the fracture that was generated by the fracturing job. Furthermore, this analysis of the pressure is a powerful tool that can support the identification or existence of interconnected natural fractures and therefore with a certain level of contribution to the producing wells and the recovery of oil from the reservoir. This report presents the application of the analysis of the evolution of the pressure during fracturing jobs in Chicontepec with examples that allow inferring that the natural fractures in Chicontepec are not interconnected or very little. Copyright 2012, Society of Petroleum Engineers.