Oil production from two adjacent offshore fields, KK field and AN field, started in 2006 in conjunction with sour gas injection, followed by the oil production from AS field started in 2011. These marginal sour oil fields, offshore Qatar near the border of UAE, in the Arabian Gulf have been developed incorporated with the challenges to realize the oil production with the minimum cost facilities and designs that would require low operating and maintenance costs for the production, control and monitoring of these offshore fields. Especially the implementation of sour gas injection in minimal offshore platform was most essential achievement. The challenges for the minimum cost facilities and designs to achieve the development of these high sour oil fields will be discussed in this paper.
Abu Dhabi Oil Co., Ltd. (Japan), ADOC, is currently operating three oil fields offshore Abu Dhabi; Mubarraz Field, Umm Al-Anbar (AR) Field and Neewat Al-Ghalan (GA) Field. In 2013, ADOC drilled, completed, tested and abandoned a well to appraise multiple sour reservoirs in a structure nearby to the existing three fields. The appraisal well was located in an environmentally sensitive area, so special measures were put in place to ensure the protection of the area during well testing operations. These measures included the re-injection of the produced hydrocarbon fluid and utilization of special burner booms to perform fallout-free combustion of liquid hydrocarbon. A tool designed by ADOC called the “Surface Testing Tool” was also utilized for safe operations of high H2S fluids and to save rig time. This paper will summarize the various challenges, measures taken and lessons learnt during the well test in complex conditions and under stringent HSE regulations.
JX日鉱日石開発株式会社 (以下JX) は, 米国子会社を通じて, 2007年からメキシコ湾の大水深域にあるK2油田の開発にノンオペレーターとして参加している。K2油田はニューオリンズから南に約180マイルのメキシコ湾グリーンキャニオンエリアに位置する。油田は1999年に発見され, 2005年に生産を開始しており, JXは2007年にファームインしている。生産開始以来, 自然減退で生産を継続しているが, これまでの生産挙動から, 水層からの圧力サポートもそれほど大きくないと見込まれており, このまま生産を続けていても, 回収率は低いレベルにとどまると懸念されている。
このような状況下で, オペレーターならびにプロジェクトに参加している各社は, 回収率向上策として, 追加生産井の掘削, ガス圧入, 水圧入, ポンプなどの採用を検討した。また, JXは独自にフルフィールドの油層シミュレーションモデルを構築しており, このモデルによる計算で, JXは油田内の2つの主力油層に水圧入を適用することで, どちらも自然減退に比べて大きく生産量を増やせると評価し, その結果をパートナー各社にも提示している。現在, K2プロジェクトでは水圧入の実施に向け, 必要な設備の検討などのスタディが, 各社共同で進んでいる。
大水深油田では, 高額な開発コストが最大の制約条件となる。大規模な投資となるため, 特に昨今の経済状況では, パートナー間で合意を形成するのに, より多くの議論が必要となっている。また, 2010年に発生したMacondo Prospectにおける原油流出事故により, 同油田の開発もよりシビアな保安対策とそのアセスメントが求められ, 作業日数増加と掘削コスト上昇という形で影響を受けた。加えて, フローラインが低温環境にある大水深油田では, アスファルテンスケールやハイドレート生成による生産障害が発生しやすくなり, それを解消するための作業も大水深故にコストがかかるので, こういった問題を生産障害につなげないような生産管理が重要となる。
一方, アメリカのプロジェクトは, 操業はオペレーターのリードで行われるが, マイナーシェアのノンオペレーターであっても, 意思決定は自社での評価に基づいて行う。したがって, 当社も独自の地質モデル, 油層シミュレーションモデルを構築し, これまでも個々の開発作業の可否を検討すると共に, 自社の評価結果を, パートナー各社にセカンドオピニオンとして提示も行っている。
メキシコ湾の大水深域という, 高いポテンシャルを持ち, 世界でも最先端の技術が使われるエリアでの油田開発に参加することで, その技術やノウハウを吸収しながら, JXは, 今後ともK2油田の開発に貢献して行く所存である。
One of the flow assurance challenges for offshore oil and gas production systems is the formation of hydrate. The optimal design and operation need to be fully understood, as hydrate formation causes cost and time for the remediation while suppressing oil and gas production. Various hydrate management systems have been ever applied to offshore fields and they are categorized into three different solution types such as thermal management, chemical injection and operation. The purpose of this paper is to introduce a case study of hydrate management system for an offshore oil field development. The case study investigated low pressure operation strategy for the field in Australia with a floating production, storage and offloading facility (FPSO). Dynamic simulation model was developed using a dynamic flow simulator, OLGA to confirm feasibility of the operation.
In the department of resources and environmental engineering of Waseda University, we are performing several classes and research work dealing with oil/gas exploration and development. Although it is difficult to conduct research work targeting the offshore oil/gas development in the university because of its giant scale, we are striving to give lectures on the fundamentals of the technologies applied to offshore oil/gas development taking environmental protection into consideration. This paper introduces the classes and research work for offshore oil/gas development and environmental issues conducted mainly in Waseda University.
About 20 classes deal with the topics related to oil/gas development in the undergraduate and graduate courses. Lectures on offshore oil/gas development are given in three of these classes including one in the international course, where the history of offshore development, offshore production systems including offshore platforms, case studies and environmental protection are explained. On the other hand, about 30 classes are provided for studying environmental issues. In one of these classes, environmentally friendly oil/gas development is introduced from the viewpoints of environmental impact aspects, environmental protection measures and HSE requirements in each project stage.
As for the research related to the environmental protection using petroleum engineering technologies, two programs are now being developed. One is a prototype numerical simulator predicting the bio-remediation of oil contamination in underground water. In this simulator, various reactions induced by microbes such as oil consumption associated with growth/decay of microbes, adsorption of microbes on rock surface and ionization are predicted. The other program is aiming at the optimization of the well locations and CO2 injection rate so that the economics can be maximized in a CCS-EOR project, taking account of oil increment by CO2 injection and CO2 tax credit by storing CO2 in a reservoir.
We are considering the possibility of application of an anaerobic bacterium which degrades long-chain hydrocarbons preferentially and induces oil viscosity reduction to Microbial Enhanced Oil Recovery (MEOR) in an oilfield in North Sea Oil. In this study, we estimated lower grade nitrogen sources which were effective for stimulating the growth of the bacterium and its ability to lower the oil viscosity.
The bacterium was incubated in the culture medium consisting of synthetic sea water, crude oil and lower grade nitrogen sources such as ammonium nitrate, urea, flower fertilizer, and agricultural fertilizer. The flower fertilizer contained 3 % of nitrogen and 16 kinds of amino acids according to the manufacturer. The agricultural fertilizer was made from beer yeast cell wall and contained 3.5 % of nitrogen according to the manufacturer. Retail prices of ammonium nitrate, urea, the flower fertilizer and the agricultural fertilizer are approximately 38 USD/kg, 25 USD/kg, 25 USD/kg and 1 USD/kg respectively while that of yeast extract which is usually used for incubating microorganisms as a rich nitrogen source is about 350 USD/kg.
Growth of the bacterium was clearly found in the culture solution containing the agricultural fertilizer at the concentration ≥ 0.5 g/L. Cell number of the bacterium increased more than 10 times as large as the initial cell number in the culture solution containing the fertilizer at the concentration of 2.0 g/L. This result suggests that the fertilizer can be utilizable as a growth promoter of the bacterium. Although the reduction of oil viscosity was found in all the culture solution containing the agricultural fertilizer, the reduction of oil viscosity in those culture solution was not so much. It can be assumed that the bacterium degrades not only heavier components but also lighter components of the crude oil in the culture medium containing the agricultural fertilizer.
The offshore facilities are in the remote area and the plant area is limited, therefore it is difficult to ensure the safety distance between the processing area and the living quarter area which results in the higher risk in the living quarter due to fire and explosion in the processing area. It is also difficult to ensure the safety distance between the equipment in the processing area which results in more the congested area and the confined area leading to the fire and explosion escalation. In addition, there is frequent ship / helicopter access for the production loading / the operators transfer therefore there is higher risk of the ship collision / the helicopter crash on the offshore facilities.
The risk analyses, such as the fire and explosion risk analysis, the ship collision analysis, the dropped object analysis, the escape, evacuation and rescue analysis, are carried out for the safety in design of the offshore facilities.
The risk analyses need to be completed at the early phase of the projects in order to consider the analysis results in the final designs. While the risk analyses need the design information, such as 3D model which includes process equipment size and layout, therefore it is important to expect the final design properly and carry out the risk analyses at the early phase of the projects.
The appropriate schedule of the risk analyses, and the accurate expectation of the final design information for the risk analyses are the key points for the safety design success.
石油・天然ガスの開発におけるHSEリスクマネジメントは, 安全重視のデザイン, 適切な技術の適用, 多重安全システムの導入などで達成されるが, 中でも操業段階におけるHSEマネジメントは、実際に可燃性の油ガスが生産設備内を流れているという点で, 求められるリスクコントロールのレベルが探鉱・開発段階と比べて一段と高いものとなる。
シンポジウムでは、Pagerungan FieldおよびTSB Fieldという海洋の2つのガス田の開発・生産操業にかかるHSEマネジメントの実際、およびLessons Learnedを紹介した。
Exploration and production of oil and natural gas is synonymous with contributing to realizing an affluent society. In this industry we should strive to create an organization with a corporate culture where securing safety and protecting environment have the highest priority as each of us acts based on highest integrity. We must explore business on a global scale in order to maintain a stable energy supply. In this pursuit, we are expected to comply with international norms and standards while exerting effort to create a globally acceptable corporate culture. Renowned international oil and natural gas companies are proactively involved in HSE (Heath, Safety and Environment) activities with their established HSE Management Systems. INPEX Corporation also established its first HSE Policy in 2006, and subsequently developed a number of standards that we call procedures and guidelines that delineate specific requirements in HSEMS regulations, occupational safety and hygiene, security management and environmental protection. Further, through the establishment of the Corporate HSE Committee and development of the annual HSE Objectives and Programs, we have been vigorously involved in various HSE activities with the PDCA cycle as the basis.
This is to introduce our HSE activities in offshore E&P projects and some of the HSE issues associated with these projects that we believe are important.