New API Practices for Isolating Potential Flow Zones During Drilling and Cementing Operations
Authors: Bybee Karen 
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 97168, "New API Practices for Isolating Potential Flow Zones During Drilling and Cementing Operations," by M. Bannerman, Chevron; J. Calvert, SPE, Consultant; T. Griffin, SPE, Griffin Cement Consulting LLC; J. Levine and J. McCarroll, MMS; D. Postler, SPE, Devon Energy; A. Radford, API; and R. Sweatman, SPE, Halliburton, prepared for the 2005 SPE Annual Technical Conference and Exhibition, Dallas, 9-12 October.
The full-length paper summarizes the progress by government and industry representatives of the American Petroleum Inst. (API) Work Group on Annular Flow Prevention and Remediation in studying the causes and prevention of deepwater shallow water flows (SWFs) and annular-flow incidents in other wells resulting in loss of well control (LWC) linked to the well-cementing process. An overview is provided on two new API recommended practice (RP) publications that describe preventive and controlling measures for SWF in deepwater wells and for any flow zone in almost any type of well.

Work Group
On 16 August 2000, the Minerals Management Service (MMS) presented safety concerns on uncontrolled annular flows to a new API work group. Issues related to sustained casing head pressure (SCP) in more than 8,000 wells in the Gulf of Mexico (GOM) also were discussed. The MMS challenged the participants to prepare "best cementing practices" to improve zonal isolation, reduce the occurrence of SCP, and help prevent annular flows during and after cementing. The MMS then would "consider" the incorporation of these documents into federal regulations as standard practices.
In later Work Group meetings, annular-flow statistics were presented including MMS records on the occurrence of SCP and on 34 LWC incidents that occurred during drilling operations and were reported from 1992 through 2002. Of the 34 LWC incidents, 19 (56%) were caused by annular flows associated with the cementing process.
The first charge to the Work Group was to prepare an API RP on a zone-isolation engineering process for prevention of annular-flow events from deepwater shallow formations during and after primary cementing. In September 2002, this document was published as API RP 65, Cementing Shallow Water Flow Zones in Deep Water Wells, first edition and is now called "Part 1" of a three-part series of RP 65 publications.
The second charge was to prepare a second RP titled Isolating Potential Flow Zones in Well Drilling and Cementing Operations. This will be API RP 65 "Part 2" on a zone-isolation engineering process that helps prevent well-control events caused by annular flows of water and hydrocarbons (primarily gas) from flow zones of any depth in offshore shelf wells and from deeper formations in deepwater wells during and after primary cementing. The first draft of this RP is complete and in review.
The third charge was to prepare a third RP on a zone-isolation engineering process to help prevent SCP from formations at any depth in all types of wells. A section on remediation of SCP will be included in this publication designated as API RP 65 "Part 3." Work on this RP began in mid-2005.