Challenges for Monitoring and Verification of Drill Cuttings Reinjection Performance

Ahmed S. Abou-Sayed; Quanxin Guo; Gary Wang; John D. McLennan; Karim Zaki
Presented at SPE/ISRM Rock Mechanics Conference, Irving, Texas, October 2002.

Abstract

To a certain extent, the success of drill cuttings reinjection (DCRI) has been serendipitous. Aggressive operational parties initially implemented the technique with support from far-seeing researchers. With the favorable economics incentive along with successful and safe implementations, drill cuttings reinjection has been further refined over time with established methodologies for attempting to more precisely predict placement of large solid volumes. There is a need now for verification and accurate monitoring of the process. This paper reviews standard technologies for monitoring cuttings placement; including pressure-time evaluation during and following injection using conventional methodologies, pressure transient evaluation technologies during and between batches. These techniques include interference techniques where appropriate, microseismic monitoring, tiltmeter surveys and logging methods. Future challenges and developments of each relevant technology are suggested in more detail. For example, tiltmeter methodologies have been successfully used in many situations but there remain issues in certain environments, i.e., in some layered scenarios. A good example of this relates to the difficulties that might be encountered in inverting tiltmeter data in arctic regions where DCRI takes place below an extensive permafrost layer. Another example relates to refining concepts for predicting multiple fracture geometries. Most practitioners are familiar with the disposal domain concept where batch-injected fractures are attributed to a simplified and regular three-dimensional domain, with no specific indication of individual fracture morphology. To date, precise prediction of domain geometry from pressure signatures or surface tilts has been weak. Simple methods are presented for identifying from pressure records or surface profiles the three-dimensional extent and near-well azimuths of multiple fractures.