Optimized Reservoir Development Using High Angle Wells, El Furrial Field, Venezuela

Abstract

The El Furrial field is one of the major field assets of Venezuela and isoperated by PDVSA (Petroleos de Venezuela, S.A.), the national oil company. Itscurrent production of over 450,000 BOPD makes it a giant oil field. Developmentof the field, which has an average reservoir depth of approximately 15000 feet, is in its mature stages due to implementation of high-pressure gas injection. PDVSA has consistently followed a forward planning approach related toreservoir management. Using high angle deviation drilling techniques allowsdevelopment wells to be strategically located by penetrating the reservoir athigh angles to optimize production rate, extend well life, increase reservesper well, reduce operating expenses, and reduce total field developmentcosts. A reservoir model was constructed and simulated using detailed reservoirstratigraphy to determine realistic potential of high angle wells. Five wellshave been drilled as of June 2000 and the first four wells have proven theeffectiveness of the design. The philosophy, the modeling technique, the welldesign considerations, the problems encountered, well results, and economiccriteria provide a clear understanding of the risk of this technology notpreviously used at this depth in Venezuela. The result was the first high anglewell in the deep, challenging environment of eastern Venezuela, followed byfour others. Results show that optimization objectives can be attained using high anglewells (HAW), mainly increasing per-well production rate, maximizing per-wellrecovery and extending the break-through time of gas or water from pressuremaintenance and enhanced oil recovery projects. Well results indicate thegeological and simulation modeling technique is reliable and accurate. A pilotprogram shows HAW technology provides major advantages to increase productionrate and to reduce the overall number of wells needed to reach productionobjectives. However, the project also has experienced a number of unexpecteddrilling problems.1 The costs associated with the total project are significant but moreimportantly, this program becomes very attractive due to:Long-term benefits of decreased water-cut related to current waterinjection.Decreased gas breakthrough due to high-pressure gas injection.Fewer wells are required to meet production goals. The technical contributions include:The modeling technique of applying detailed stratigraphy to a full-scalereservoir model is accurate if performed with the appropriate objectives inmind.The application of state-of-the-art drilling techniques to attain highangles at deep drilling depth is possible. However, drilling problems caused byformation instability require more study and experience.This method can be applied to other fields in the eastern Venezuelan basincurrently under, or planned to be under, enhanced recovery programs anddevelopment programs.