First-Time Application in Mexico's Burgos Basin of a New Technology Multistage Completion Process: A Successful Case History

摘要

The Burgos Basin, located in Northern Mexico, is considered by PEMEX to be one of Mexico’s major natural gas reserves, and contributes a large portion of the country’s current gas production. The basin’s gas production comes from a series of sandstone intervals, which are primarily characterized as very low permeability. Consequently, the only way to obtain optimum production rates is using hydraulic fracturing techniques. Given that all the wells of the basin offer multiple potential productive zones, PEMEX was driven to look for alternative methods and technologies, focusing their efforts on finding the most cost effective completion processes while maximizing the production and returns in the field development. For years, the conventional completion process used by PEMEX has been PFFP ( perforate-fracturing-flowing- plugging), then moving up hole to the next interval and repeating the process. This process was strongly debated internally for quite some time due to considerable concerns of formation damage caused by fracturing fluids remaining in formation for extended periods of time prior to being recovered. Thus the focus became to modify and optimize each step of PFFP in order to reduce these concerns and their impact on the well’s production. In 2003, a fairly new technology in multi-stage treatment completion process was used. This technique, known as “External Casing Perforating” allowed PEMEX to perforate and isolate individual zones in as little as minutes between stages. As many as 5 zones have been completed within a 30 hour period. The time from completion to production has been reduced from days to hours. This paper will describe the implementation of this technique in the Cuitlahuac Field, Burgos basin. Most importantly, the case history is substantiated by a comparison with offset wells. The analysis includes the completion processes used, early and normalized gas production and an economical analysis made using both the conventional and the multi-stage processes. In conclusion, the Production Company’s perspective about implementing this technology in a massive operation will also be presented.