Improving the recovery factor of heavy oilfields of Marañón Basin by using new completion and EOR technologies (#1370)

Authors

Huerta Quiñones, Victor Alexei

Moran Quiliano, Alfredo Misael

Adriano, Leonardo

Abstract

Mature heavy and light oilfields in the Northern Peruvian Jungle have produced oil for more than 40 years under primary recovery mechanisms (cold production methods). According to production performance and subsurface engineering analysis, reservoirs are exploited by a flank, and eventually bottomhole strong water drive mechanisms assisted with ESPs; cumulative oil production in mature fields has exceeded more than 1 billion barrels of oil with a recovery factor range in between 4% to 60% (with an average of 29%). In addition. The ultimate recovery factor is expected to account for a range in between 9% to 63%, with an average of 33% at an economic limit of approximately 98% water cut. On the other hand, new heavy oilfields with new completion technology, in early development blocks such as 67, 39, 64 and 95 may be expected to arrive at a primary recovery factor in between 7% to 40% with an average of 15% at an economic limit. This study makes a diagnosis of waterdrive mechanism in heavy oilfields of Marañón Basin and explores the technology options to increase production and recovery of heavy oil resources at commercial rates. Technology options assessment include selective completion technologies for new horizontal infill or extended wells, as well as the application of improved oil recovery techniques such as polymer injection and cycling steam stimulation (CCS). A workflow is proposed starting by modelling water encroachment mechanism by using analytical methods such as WOR vs. Np, Chan’s curves, and Ramos’ method; this analysis is well complemented with numerical simulation modelling to determine the influence of either flank or bottomhole waterdrive (or both). Then, a screening process using statistics of worldwide oilfields with some criteria is carried out to select the most appropriate technologies to optimize production performance and increase recovery efficiency; 8-parameters related to petrophysical properties, fluid behavior, drive mechanism and completion system were included in the screening model run by analogy combined with machine learning algorithm, to select the suitable technology for oilfields in Marañón. Typically, primary recovery factors for heavy oilfields range between 9 to 24% with an average of 15%. Horizontal and multilateral drilling with new completion technologies (by using Autonomous Inflow Control Devices and/or selective production) would allow increasing recovery factor by 30% as it is expected in Bretaña oilfield, a green field whose production history started by 2018. On the other hand, polymer flooding, cycling steam stimulation and HASD would at least double production rates and increase recovery factors by 10% to 15%. Pilot tests of thermal recovery methods are strongly recommended for some fields in early development stage such as the Bartra field in Block 192 and the Raya and Paiche fields in Blocks 39 and 67 respectively.