Identifier

etd-07022015-181918

Degree

Doctor of Philosophy (PhD)

Department

Petroleum Engineering

Document Type

Dissertation

Abstract

World’s growing energy demand has pushed oil companies to explore and produce hydrocarbons in complex and technologically challenging deepwater environments. These difficult and complex operations involve the risk of major accidents as well, demonstrated by disasters such as the explosion and fire on the UK production platform Piper Alpha and capsizing of the Deepwater Horizon rig in the Gulf of Mexico (GoM). Accidents cause death, suffering, pollution of the environment, disruption of business and bad reputation to oil industry. A quantitative risk analysis technique has been used in this study to identify and categorize risk associated with different life phases of a deepwater well. Volume of oil released to the environment is used as a risk indicator. Five oil spill scenarios related to drilling and production life phases of a deepwater well are modeled. Risks associated with drilling an exploratory well in the deepwaters of GoM are analyzed in Scenario-1. A representative well location and corresponding reservoir properties were used to estimate the worst case discharge rates (WCD). Fault tree analysis (FTA) was performed to identify and categorize different hazards. Unexpected pore pressure and delayed response to an emergency situation were identified as two most important parameters contributing to overall risk of the system. In Scenario-2 an underground blowout was modeled by using representative geological settings from Popeye-Genesis field. A shallower low pressure zone is exposed to a deeper high pressure zone during drilling. The time to recharge the shallower zone to its fracture pressure is estimated. The shallower zone will transmit hydrocarbons to sea floor once its fracture pressure is reached. Risks associated with production life phase of a deepwater well are modeled in scenario-3. A representative well location and corresponding reservoir properties were used to estimate the WCD. FTA showed that sand screen and subsea tree control failures were main elements contributing to risk. In scenario-4 risk associated with floating production and offloading (FPSO) system for GoM are quantitatively and qualitatively presented. Scenario-5 deals with oil spill risk associated with severe weather conditions. An example mudslide calculation for SP-70 block of GoM is presented.

Date

2015

Document Availability at the Time of Submission

Student has submitted appropriate documentation to restrict access to LSU for 365 days after which the document will be released for worldwide access.

Committee Chair

Tyagi, Mayank

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