The Blowout Accident had occurred at 20th April, 2010 in the Gulf of Mexico which included the 11 lives were lost. After that, it was caused the extensive oil spill and serious marine pollution in the coast area. The water depth of well M is 4,992ft and the accident has happened during the temporary abandonment operation after the production casing setting at the 13,000ft below the seabed. This paper describes the technical outline of the accident and analyzes by the collected information which includes issues, questions and unique interpretations. From the aspects of the accident summaries, we suggest the considerations for the future deepwater drilling technology.
The tragedy of Deepwater Horizon happened on 20 April 2010 has been deeply heeded in the people around the world because of the shock of losing the rig with 11 fatalities and following environmental impact with nearly 5 million barrels of spilled oil in the Gulf of Mexico. This incident resulted the Moratorium of offshore oil & gas drilling activities and influenced not only to the offshore oil & gas operators and contractors but the enterprises and their employees of the Gulf coast States. Everybody those who tied with oil business might not be able to realize how it could happen to the combination of Oilfield giants, BP and Transocean who supposed to have advanced operational management systems, and concerned to know the detailed sequence and causes of the incident. It seems to be identified through the internal investigations by the concerned party and investigations by Federal Authorities that the underlying/root causes of the incident are at the failures of implementing the management system and defect/flaw of the system. This paper will study the Management failures at the Macondo operations which are considered to be the underlying/root causes of the tragedy by reviewing the released incident investigation reports, improved offshore regulations, legislated new rules in the States and, finally attempt to find the way to eliminate the failure of management to prevent the hazards become incidents.
On 21st August 2009, the crucial blowout was occurred on the Montara wellhead platform in the Timor Sea at the northern coast of Western Australia. It was just eight months before the Macondo blowout. The uncontrollable state continued until 3rd November 2009 and countermeasure operations continued until 3rd December 2009. The immediate cause was considered as the failure of well integrity caused by poor cement job. The mishandling of well barriers is the primary cause of the blowout. Recently, the Macondo is mainly highlighted due to large-scale damages. However, these two blowouts are significant issues for the oil industry to learn lessons because of many similarities between both incidents.
Needless to say, a lot of uncertainties lie in drilling operations because it is impossible for us to see the underground with our own eyes. Additionally, experiences on drilling operations are hard to be evaluated quantitatively. For that reason, to pass down the experiences to the future and to share the experiences are very difficult. Japan Petroleum Exploration Co., Ltd. (JAPEX) attempts to evaluate drilling operations so that everyone who is involved in drilling operations can make efficient use of them, which he or she doesn't experience directly. In this paper, four examples of JAPEX's effort for quantitative evaluation of drilling operations with the probabilistic point of view are discussed.
With the increasing global demand for oil and gas, target fields are being expanded into difficult and hard to reach targets. Accordingly, drilling operation in high pressure and high temperature (HPHT) condition is an increasing trend. Under these conditions, there are still many technological challenges including surface and subsurface equipment for drilling and completion. Macondo exploratory well is not categorized in HPHT, as the downhole temperature is not so high. However there are many fields drilled much deeper than 7,000m in the Gulf of Mexico. So HPHT has strong relation with exploration and development in Gulf of Mexico. Under the circumstance, JOGMEC-TRC has conducted the study entitled as “Trend Survey on HPHT Field Development” to investigate current status of HPHT Field development issues.
Cuttings transport and management of equivalent circulating density (ECD) are the key issues in designing and drilling extended-reach and directional wells. In this paper, a simulation study on cuttings transport and ECD behavior was carried out by use of field data for highly inclined directional well “Numanohata Higashi (T1) SK-1aD” drilled in Hokkaido, Japan. As a result of simulation study, it was demonstrated that ECD was fluctuated in accordance with drilling history that drilling and mud circulation were alternately repeated. The manner ECD fluctuated was as follows. In the well with short low inclined hole section in which cuttings deposit bed was hardly formed, ECD was increased with increase of cuttings concentration in mud during drilling and was decreased with decrease of cuttings concentration during mud circulation. In the well with long highly inclined hole section, ECD was increased with increase of cuttings deposit bed during drilling and was decreased with decrease of cuttings deposit bed during mud circulation. However, even in the well with long highly inclined hole section, ECD fluctuation was small under the condition that cuttings deposit bed was hardly formed. In addition, optimization study on drilling condition was conducted and the following results were obtained. In consideration of cuttings transport, the optimum mud flowrate existed so that ECD was minimized and the optimum flowrate was small for mud with high YP (yield point) or initial gel strength. Mud with high YP or initial gel strength was preferred for good hole cleaning and mud with low YP or initial gel strength was preferred when ECD should be kept lowered even though some amount of cuttings deposit bed were formed.