Evaluating First Eagle Ford Shale Gas Well—Case History from Northern Mexico

Abstract

Northern Mexico has the first major non-associated gas producer basin in the country. However, unconventional reservoirs (mostly very low-permeability shale gas and oil formations) have not been produced so far in this area. These types of reservoirs are located in sedimentary environments where rocks have a high organic-rich content that, when subjected to pressure and temperature conditions, transform this matter into oil and gas. Stimulating a source rock is relatively a new phenomenon in the oil and gas industry. Because these source rock formations have very low permeability, massive hydraulic fracturing stimulation treatments are required to produce at economical rates. Experience and knowledge in drilling and completing wells in this type of reservoir have increased in the last decade. New technologies to evaluate this type of formation and post-production studies have significantly improved, offering better completion methods and techniques.The Eagle Ford formation in Mexico is located in the northern portion of the country and is considered an extension of the Eagle Ford formation that crosses southern Texas in the United States; during June 2011, production from this US formation was 636 MMscf/D and 97,000 bbl/D.For the completion of this subject well, which was drilled horizontally, the evaluation techniques, completion plan, and stimulation design were performed using local experience acquired in unconventional reservoirs (tight oil and tight gas) along with experience from the US in shale gas and oil shale formations.This work shows how this type of formation was identified through several studies, completion was designed and executed, and the fracture treatments were optimized, as well as production matching and forecasting results. This was all performed in the context of an operation that had never been performed in Mexico.

Successful Extended Injection Test for Obtaining Reservoir Data in a Gas-Oil Shale Formation in Mexico

“…Compared to other methods for the diagnosis of reservoir properties, DFITs are particularly economical and effective, especially in ultralow permeability formations (K Ͻ0.1 md). A previous analysis was performed in a shale reservoir in Mexico through a minifrac injection test pumped in the Eagle Ford extension of the Burgos basin during 2011 (Araujo et al 2012). These results provided valuable information for establishing the final design of the multistage fracturing operation.…”