Schlumberger

Technical Paper: A Comprehensive Approach to Well-Collision Avoidance

Society: AADE
Paper Number: 07-ntce-28
Presentation Date: 2007
 

Abstract

Well-collision avoidance has gained greater importance, as fields become more crowded and well paths increasingly complex. The safety and financial implications of shutting in production wells on platforms or repairing damaged wells have established a need for the industry to evaluate the potential for collision with a producing well.

This paper will cover three main topics related to minimizing the risk of well collisions:

  • Evaluating the risk
  • Managing the risk
  • Demonstrating the results of the new risk-minimization process

The paper will detail the processes of gathering appropriate data such as completion type, offset surveys, well pressures, casing depths, reservoir fluids and mud densities. Each well and field poses different challenges; not all data is available and wells can vary from simple vertical land wells to crowded offshore fishbone designs.

The well position uncertainties are determined by using survey error models from the Industry Steering Committee on Wellbore Survey Accuracy. This method was chosen because it is an industry-recognized standard of defining the magnitude of survey uncertainty.

Recommendations for minimizing risk are based on the status and conditions of the adjacent wells and the nature and severity of the risks associated with a collision. These recommendations are formulated to minimize the risk while ensuring that production is disturbed as little as possible.