Downhole Production Testing, a Cost Effective, Safe and Environmentally Friendly Well Test Method.

Abstract

AbstractWell testing is important for reservoir formation and fluid characterisation. Well testing is, however, omitted in many instances due to the high cost, risks and environmental restrictions associated with a well test. The Downhole Production Testing (DPT) method1 will have a significant impact on safety, environment and cost aspects compared to conventional production testing or drill stem testing (DST).The Downhole Production Test method allows all the produced reservoir test fluid to be re-injected into another zone within the well bore while flow rate, pressure and temperature data are monitored and controlled from surface. In situ fluid samples are taken during the flow period. After penetration of a zone of interest, an injection zone is selected at a depth which allows a sufficient injection rate. The drilling fluid acts as the primary pressure barrier during the test. The production and injection zones are isolated from the drilling fluid by a packer arrangement.No fluid flows to surface during the test, so the entire surface processing equipment normally associated with well testing is no longer required. This significantly reduces the onshore and offshore logistics operation. Even more important is that hydrocarbons will not flow to surface under high pressure during the test. This significantly improves the risk and safety aspects of conducting a well test. High-risk operations in deep water related to discharge during emergency disconnect or hydrate formation during testing are also eliminated.A "zero emission" goal is achieved by no burning and no hydrocarbon flows to surface.This paper describes the method and the environmental implications of this new testing method. Included also is a detailed discussion of the safety and risk elements involved in different operating scenarios. Furthermore, this paper discusses some of the preliminary design parameters and possible implementation of the concept. It describes potential cost benefits for various applications and demonstrates that this new technology reduces cost and improves the environment, safety and risk while allowing test objectives to be met.