Design, Application, and Implementation of Well Intervention Services within a Deep HPHT Tight Gas Exploration and Appraisal Project
The appraisal of deep tight gas reservoirs can be technically and
economically challenging, with success dependent on applying the most efficient
completion technology. Inevitably, this includes designing well completions
that encompass the deployment of multiple hydraulic fracturing treatments.
There is a tendency in the completion design phase to under-assess the number
and variety of interventions that a well could undergo during its evaluation.
Subsequently, the development and application of the appropriate well
intervention strategy is crucial in maximizing the well potential and reservoir
understanding. The deliverable of any tight gas appraisal program is to
increase the level of confidence in continuing to pursue the resource
opportunity by demonstrating stable and sustainable gas inflow flow rates.
Recent drilling success targeting deep frontier gas reservoirs, such as
the Amin located in the central part of Oman, have resulted in the need to
evolve the well intervention process to include several new (for the region)
technologies. These included the deployment of abrasive perforating to
facilitate the initial formation breakdown operations, milling out the shoe
track for a hydraulic fracturing treatment in an openhole setting, restoring
full wellbore access by milling out multiple frac plugs, and temporary
installation of a velocity string to eliminate liquid loading issues.
Historically, many of these individual processes have been attempted or
deployed with varying levels of success, but this is the first time that they
have been integrated into a well strategy.
This paper summarizes the process of selecting the best options for well
intervention operations in low-permeability gas reservoirs. The integrated work
design consideration and results of these completion techniques will be
presented along with the key learnings derived from the process.