Pinpointing new potential of mature fields in Mexico: An example from Vernet Field

Abstract

In 2002, Compania Mexicana de Geofisica (CMG) conducted an integrated study of Vernet Field. Located in the southern part of Macuspana Basin and discovered in the 1930s, this field has produced oil and gas from 13 intervals in approximately 25 wells. Macuspana, a mature basin in southeast Mexico where hydrocarbon production dates to the early part of the 20th century, is predominantly gas-prone with production of 5.4 trillion ft3 of gas and limited oil from Mio-Pliocene clastics in approximately 35 fields of varying sizes (Figure 1). Figure 1. Map of Macuspana Basin and Vernet Field. Pemex estimates substantial undiscovered hydrocarbons remain in this 160 × 50 km basin. At the end of the study, several recommendations were made for additional exploration opportunities. The first proposed location, drilled by Pemex in December 2002, resulted in a success that will be described in this article. Pemex has subsequently planned additional drilling on this discovery to delineate the reservoir and to produce from other recommended prospects. During the integrated study and after the discovery, a 3D stratigraphic inversion and an AVO analysis were performed. Those results will also be presented. Figure 2 is a line through the field showing our interpreted horizons. It is an extremely complex area consisting of a major growth fault and numerous subsidiary synthetic and antithetic faults that create small traps at various intervals. Production comes from the crestal fault-bounded traps on the downthrown side of the major fault. Most production comes from the Z9-E15 interval on the structure. Production from AS 50 and deeper sands is very limited (40 000 bbls and 1 million ft3) and from only two wells. Initially, it was believed that the sand quality deteriorated with depth; this is no longer the case. The depositional facies varied from nonmarine, channel, near shore to offshore. …