Some experiences in heavy and extra heavy oil exploitation in The Orinoco BELT, Venezuela

Abstract

This work presents an overview of the development strategic followed by Petroleos de Venezuela, S.A. (PDVSA) for the production of the heavy and extra heavy oil in the Orinoco Belt, in Venezuela. Also will be presented the result of a specific integrated study conducted in the larger reservoir (U2-3 MFB 53) located in the Bare Field, in the Ayacucho area. The study consisted in the construction of a geostatistical model 3D, integrating the information of the different disciplines: geophysics, geology, petrophysics and production-reservoir engineering, which allowed the calculation of an OOIP of 5,935 MSTB with greater certainty. It was determined that the paleotopography of the basement controlled the process of sedimentation of the U2-3 basal sands, confirmed by the drilling of vertical wells and by means of the interpretation of the seismic 3D. This concept was applied to relatively undeveloped neighboring areas of the reservoir to identify new development opportunities. A dynamic model of this area was generated to evaluate cold production using horizontal and multilateral wells of long reach. Using the dynamic model, the optimum flowing bottom hole pressure to avoid the early production of gas was determined, in order to maximize the efficiency of the electrosubmersible and progressive cavity pumps. Based on this study, the first horizontal well (MFB-664) of long reach was drilled, which represent a record for PDVSA of 5,070 feet of horizontal section. The initial production for this well was 2,130 bopd. Other record was obtained in the drilling of the multilateral well MFB-667 (two branches) with an overall length of 8,260 feet; the initial production test was 1,820 bopd at minimal draw down. On the other hand, PDVSA also has developed innovative completions that improve recovery of heavy or extra heavy crude oil: Intelligent Completion, Selective Steam Injection Completion and Progressive Cavity/Sucker Rod Pump Optimization Systems