The Bermudez geological complex includes mature oil-producing fields in the Tabasco State, Southern Mexico. These fields typically produce from underpressured, fractured Cretaceous reservoirs. Similarly, the mature Jujo-Tecominoacán fields are producing from fractured Jurassic carbonate reservoirs.
Drilling the pay zone in these fields with conventional drilling fluids results in lost circulation and associated problems such as differential sticking and poor hole cleaning. Local field experience also has found that drilling with conventional lost circulation materials (LCM) impairs production and causes handling problems when received at production facilities.
Managed-pressure-drilling (MPD) techniques using low-density fluid systems had been capable of successfully addressing the challenges in these fields since 1996. Recently, however, new drilling challenges in highly depleted fractured reservoirs have occurred. These required new advances in MPD techniques, and these innovations have included:
High-temperature recyclable foamed drilling fluid
Hybrid foam/2-phase fluid systems for tapered tubular geometries
Foam bullheading to re-establish circulation
Methods to address hole-cleaning challenges in geo-mechanically unstable areas.
This paper will discuss the innovative solutions to the challenges later experienced and the resulting extension of managed-pressure-drilling solutions to meet the specific needs of an integrated services drilling project. Examples will demonstrate how these solutions are improving drilling success for the service company that drilled the wells as well as provided added value to the operator developing the fields.