Overview: Wellbore Integrity, Sand Management, and Frac Pack (September 2007)

Abstract

Reviewing papers for this month's Wellbore Integrity, Sand Management, and Frac Pack feature finds our industry hard at work to improve understanding of the complexities of formation failure in the near-wellbore region. This work involves hole-failure modeling and mitigation in the shale sections through the overburden and in the reservoir, with a strong focus on solids-production risk. On the theoretical side, shale-instability mechanisms from purely mechanical failure to accounting for chemical and thermal effects are being modeled and consequences are being addressed in the well-engineering plan. The complexity of predicting wellbore-stability behavior is daunting when the "wish list" of model-prediction input-data requirements is considered. Even so, these comprehensive theoretical approaches to hole-failure modeling provide critical insight to complex formation-failure processes that then is used to underpin the shortcuts we are often forced to take in hole-instability prediction because of a lack of data. Furthermore, this research provides guidance in determining the measurements operators should invest in (e.g., cores, logs, and well tests) to achieve the desired hole-instability-prediction uncertainty range for a specified well plan. This paper review also finds exploration- and development-prospect environments to be increasingly complex. Deepwater subsalt plays are becoming more common. The trend in technology development and application for these harsh and correspondingly expensive projects finds extensive early-project predrill performance modeling the norm, not the exception. However, even with the most comprehensive predrill model prediction, uncertainty still is present. Often, the gap between predicted hole instability and reservoir-sand production vs. field-performance results is great, leading to heavy R&D on tools and techniques that can preserve hole integrity while ensuring that the hole size needed to install sand-control completions, including frac packs, is achieved. Wellbore Integrity, Sand Management, and Frac Pack additional reading available at the SPE eLibrary: www.spe.org SPE 100202 "Maintaining the Stability of Deviated and Horizontal Wells: Effects of Mechanical, Chemical, and Thermal Phenomena on Well Designs" by Jianguo Zhang, SPE, Baker Atlas and Baker Hughes Drilling Fluids, et al. SPE 102626 "Remediation of Production Loss Due to Proppant Flowback in Existing Wellbores" by Philip D. Nguyen, SPE, Halliburton, et al. SPE 108241 "Sustainable Deployment of Geomechanics Technology to Reducing Well Construction Costs" by Fersheed K. Mody, SPE, Shell, et al.