Quebrache field: Evaluations to date of this natural CO2 reservoir

In the search for oil and gas during the past century, other gases have been encountered. These gases had little or no economic value and areas known to contain them were avoided during drilling.

Deposits of CO2 rich gas (>50 %) are present worldwide but in limited areas – USA, mainly. Few studies of natural CO2 reservoirs are currently available to determine and analyze its accurate exploitation. CO2 concentrations ranging between 71 and 98 % have been discovered in the Northeast of Mexico. Preliminary evaluations (SPE-107445) of the available data for Quebrache field indicated potential gas reserves.

Complementary analyses to date have shown that on balance, the Quebrache field offers a significant opportunity for developing Enhanced Oil Recovery (EOR) projects. This new study divides the field into tree important areas. This paper presents: a) recent reservoirs discovered b) estimated reserves for all tree areas with CO2 sources (Central Area, Northern Area and Southern Area), c) efforts made to evaluate its potential d) opportunities to invest in and operate a world-class CO2 reservoir, etc. The Central Area reveals 2 important reservoirs. These reservoirs are relatively continuous and could produce and drain reserves during long period. Original Gas-In-Place (OGIP) volumes are likely conservative because in its calculation it is assumed a gas-water contact (there is contact apparent in the well logs). The Quebrache field would provide strategic value to CO2 injection programs.

The CO2 accumulations described in this paper could play a major role in recovering additional oil from fields in the North of Mexico. Thus, CO2 accumulations in the right place and at the right time may become production targets in the future.