ico
Off the Louisiana Coast





































U.S. Department of the Interior
Minerals Management Service
Gulf of Mexico OCS Regional Office





OCS Report
MMS 2003-068



Investigation of Loss of Control
Grand Isle Block 90, Well C-7ST
OCS-G 4003
November 14, 2002

Gulf of Mexico
Off the Louisiana Coast








Jack Williams Chair
Lynard Carter
Randy Josey

























U.S. Department of the Interior
Minerals Management Service
New Orleans
Gulf of Mexico OCS Regional Office
October 2003
ii
Conte nts











Investigation and Report

Authority








1

Procedures








2
Introduction

Background








3

Brief Description, Loss of Well Control




3
Findings

Preliminary Activities - Preparation of the Well Plan


5

Drilling Activities - Events Through Loss of Control


6

Drilling Activities - Events to Regain Control



8
Findings Details and Context of Specific Events



10

Shut in of Well Using Diverter System



10

Ability of Diverter to Sustain Pressure



12
Conclusions

Cause of Loss of Control Subsurface




15

Cause of Loss of Control Surface




15

Cause of Rig Evacuation






15


The Cause and Effect Series of Events and Decisions Leading


to the Evacuation





16


Lack of Knowledge of System




17


Lack of Pre-event Planning and Procedures



17

Possible Contributing Cause of Loss of Control and Rig Evacuation

17
Recommendations
19
Appendix

Attachment 1 - Location of Lease OCS-G 04003, Grand Isle Block 90/93.

Attachment 2 - Grand Isle Block 90 C-7 ST Well Schematic at Time of LOC.

Attachment 3 - Diverter Piping Arrangement.

Attachment 4 - Schematic of Diverter and Source of Leak.
Attachment 5 - MMS Safety Alert Notice No. 165.
1
Investigation and Report









Authority


In November 2002, the Diamond Offshore Drilling, Inc. (hereinafter referred to as Contractor
or DODI) jack-up rig Ocean King (hereinafter referred to as the Rig) was engaged in drilling
operations for BP Exploration & Production Inc. (hereinafter referred to as Operator) on
Grand Isle (GI) Block 90 Well C-7 sidetrack (ST). The Rig was in place next to the GI 93 C
platform (hereinafter referred to as the Platform). Drilling operations were being conducted
with the Rig cantilevered over the Platform using the re-claimed slot of the C-7 well, which had
been plugged and abandoned (P&Ad).

Surface casing had been set and cemented to surface. After the cement had been in place
approximately three hours, flow was noted coming from the surface/conductor casing annulus.
The diverter was shut and pressure built up to 400 pounds per square inch (psi). Shortly
thereafter, intermittent leaking of gas past the diverter flowline seals was noted. In the attempt to
open the diverter ventline valves from a remote location to relieve pressure, it was found the
valves could not be actuated. The Rig and Platform were subsequently temporarily abandoned
because of the surface leak and subsurface pressure on the conductor casing shoe. The shallow-
gas-pressure was fully contained within 8 days, at which point normal drilling operations
resumed
.

The event occurred 14 November 2002 at approximately 0230 hrs on the surface location in
Operators Lease OCS-G 2628, Grand Isle Block 93, in the Gulf of Mexico, offshore the State of
Louisiana. Pursuant to Section 208, Subsection 22 (d), (e), and (f), of the Outer Continental Shelf
(OCS) Lands Act, as amended in 1978, and Department of the Interior Regulations 30 CFR 250,
Minerals Management Service (MMS) is required to investigate and prepare a public report of
this accident. By memorandum dated 26 November 2002, the following personnel were named to
the investigative panel:

Jack Williams, Chairman Office of Safety Management, GOM OCS Region
Lynard Carter New Orleans District, Field Operations, GOM OCS Region
Randy Josey New Orleans District, Field Operations, GOM OCS Region 2
Procedures

On the morning of 14 November 2002, personnel from the MMS visited the site of the incident to
assess the situation. On 17 November 2002, representatives of the Operator met with New
Orleans District personnel to review the incident and discuss ways to deal with the problem in
future operations in the area. On 16 December 2002, members of the panel reviewed the incident
by telephone with personnel of the Operator. On 11 February 2003, members of the Panel
discussed the incident by phone with drilling engineering, geosciences, and supervisory personnel
from the Operator to further clarify previously acquired information concerning the development
of the shallow-gas hazard study. On 18 June the panel team interviewed Operator and Contractor
management and engineering personnel. On 26 August, interviews were conducted with the
principals present on the rig, and additional data were forwarded by the Operator. In addition to
the interviews, other information was gathered at various times from a variety of sources. This
information included the following reports and statements:
Daily Drilling Reports, 13 October 2002 18 December 2002;
Operators Drilling Plan, Well No. C-7 ST;
Operators GI-90 Incident Investigation Report, 18 November 2002;
Operator 3-Dimensional shallow-gas seismic analysis;
Electric Log, Induction/Gamma Ray, Mobil Oil Corp. GI 93 Well No. C-2,
19 April 1975;
Operators measurement while drilling (MWD) log from Well No. C-7 ST;
Operators noise and heat transfer through-casing log on C-7 ST;
Pictures of equipment, layout, and orientation of Rig and Platform;
Diagrams of diverter system and control mechanism, description, operating
service procedure;
Contractors Diverter Operation procedure;
Interviews with Operator drilling management and engineering, geo-science, and
operational personnel, Contractor drilling management, operational supervisors,
and operational personnel;
MMS records for all wells previously drilled from Platform including logs, plans,
etc.;
MMS Panel Report No. MMS 2003-23;
MMS Safety Alert Notice No. 165. 3
Introduction











Background


The surface location for Well C-7 ST, Lease OCS-G 2823, covers approximately 5,000 acres and
is located in Grand Isle (GI) Block 93, Gulf of Mexico, offshore, Louisiana (for lease location,
see Attachment 1). Lease OCS-G 4003, the permitted bottom-hole location of Well C-7 ST,
covers approximately 5,000 acres and is located in Grand Isle Block 90 adjacent to Grand Isle
Block 93. These leases were issued to Mobil Oil Exploration and Producing Southeast, Inc. who
became the operator effective 28 March 1974. Subsequently, Vastar Offshore, Inc. purchased the
right and title in 1998 and assumed the role of Operator on 20 January 1999. Vastar was merged
with BP Exploration and Production Inc. who became the Operator on 25 April 2002. The lease
is owned by the Operator 100 percent.

The C-7 ST well was permitted to be drilled from a surface location in Lease OCS-G 2623 to a
bottom-hole location (BHL) within Lease OCS-G 4003. This loss of control incident occurred
while the well was still being drilled within Lease OCS-G 2823. However, after the loss of
control was contained, drilling operations continued and the well was bottomed within Lease
OCS-G 4003 as permitted. Because the well was completed as permitted and despite the BHL of
the well at the time of the incident, the well is referred to by its permitted designation.

Brief Description, Loss of Well Control

In November 2002, the Rig was conducting directional drilling operations on GI-90 Well C-7 ST
from the wells surface location on the C Platform of GI 93. Sixteen-inch conductor casing had
been set at approximately 1,200 ft and cemented to surface. The well had been kicked off at
approximately 1,200 ft and the angle had been built to approximately 60 degrees. The well had
reached approximately 5,150 ft measured depth (MD). At 2300 hrs, 13 November 2002, surface
casing was run to approximately 5,140 ft and cemented to surface with returns (for well schematic
at time of incident, see Attachment 2).

At approximately 0230 hrs, 14 November 2002, the surface/conductor casing annulus started to
flow gas and some fluid. The diverter sealing packer element (diverter packer) and diverter
ventline valves were shut by placing the diverter system into test. This action allowed holding 4
back pressure to attempt to let the cement cure. Pressure on the annulus then built to 580 psi.
Intermittent leaking of gas past the diverter flowline seals was observed and heard to be
increasing as the pressure mounted. Because of uncertainty of the cause of the leak, confusion
about the integrity of the diverter flowline seals, and the fact that the event occurred at night, the
Rig floor was evacuated. Attempts to open the diverter ventline valves to relieve the rising
pressure, or to con