Well Management Increases Hydrocarbon Production In Mature Fields: PEMEX E&P Case History

Abstract

Abstract This paper presents the applied methodology and results obtained from a new Well Management program to improve oil and gas recovery with minimum investments in certain asset units. In addition to the value of the increased production, the following benefits were obtained from this program: learning and applying the teamwork approach of well productivity improvement, adaptation to a cultural change of working as teams to solve difficult problems, and training and transfer of diverse technologies from the interdisciplinary teams to other technical personnel of PEMEX E&P. Introduction The South Region of PEMEX E&P has hydrocarbon production from five exploitation integrated assets including Bellota-Jujo, Cinco-Presidentes, Macuspana, Muspac and Samaria-Luna. The producer fields and reservoirs of these assets consist of Tertiary sandstones and Cretaceous naturally fractured carbonate rocks, and produce all types of petroleum fluids that include dry gas, wet gas, gas-condensate, volatile oil and black oil, with densities ranging from 10 °API to superior quality oils greater than 45 °API. Production in the South Region started in 1958, reaching a peak in 1979 at 1.213 MMSTB/D (continuous black solid line in Figure 1). Although there were several periods of new field development and workover activity, the oil production rate had declined to 463,995 STB/D by December 2004. The decline was caused by pressure depletion and also water invasion. The peak gas rate of 2,853 MMscf/D was in 1981 (showed as a broken line in Figure 1). The gas production rate decline was similar to oil, reaching 1,434 MMscf/D by December 2004. In the first half of 2005, as a result of this strong production decline and in order to comply with the production agreements of PEMEX E&P, the South Region Management designed and implemented a strategy to increase production and to reverse producction decline. The strategy involves priority management decision lines of action for the short-, medium- and long-terms of fields in development and/or mature fields. Short-term projects with minimum investment and excellent economic returns were given top priority based upon Management's hierarchical decision process guidelines. The investment project guidelines for the medium- and long-term projects include technical justification with economic studies based on the best practices established by Reservoir Management(1, 2), with the intent to optimize the exploitation of fields, i.e., maximize the recovery of hydrocarbons, minimize investments and reduce operating and maintenance costs. Under this scenario, different alternatives are evaluated in order to help optimize the decision-making guidelines necessary for reservoir-well-surface facilities to recover primary, secondary and/or tertiary reserves. On the other hand, in order to increase short-term production, it is necessary to plan and implement different schemes to manage and integrate wells from different fields. This is done with the objective of identifying opportunities that increase production easily, based on detailed static and dynamic studies of the productive zones close to and around producing wells, taking into consideration the production behaviour of the different fields, reservoirs and wells.