Japex has been developing Katakai Oil & Gas field for more than 50 years and accumulated technique and knowledge about drilling. In 2012 and 2013, two challenging wells, Katakai SK-29D/29D-1 and Katakai SK-30D/30D-1, were drilled with some new technique which was focusing on reducing cost and improving productivity. In Katakai SK-29D/29D-1, 30″ casing was omitted from conventional casing program to reduce cost. And SBM was first adopted to drill mud stone in Katakai field at 12-1/4″ hole section, following knowledge at Yufutsu Oil & Gas field's operation. Consequently SBM maintained good hole condition for 45 days without sloughing and caving of mud stone, therefore drilling period was reduced drastically. At the Green-Tuff reservoir section, multi-branch well was drilled to improving productivity, which is first trial at Katakai field. In Katakai SK-30D/30D-1, Omitting 30″ casing was conducted following Katakai SK-29D/29D-1. SBM was also adopted at Green Tuff reservoir at 8-1/2″ hole section as well as mud stone. Due to controlling to slough clay mineral in reservoir and reducing torque and drag by SBM, high deviation well was drilled with long distance reservoir section. This paper introduces about 1)Omitting 30″ casing, 2)Multi-branch, 3)Adopting SBM, 4)Cementing considering well life, 5)Drilling high deviation deep well in hard formation, 6)Taking action for high temperature condition.
An ICDP workshop proposal “Japan Beyond-Brittle Project (JBBP)” submitted by geothermal researchers mainly in Japanese and other countries was accepted by ICDP (International Continental Scientific Drilling Program) in 2012. The purpose of the scientific drilling project is to demonstrate the feasibility of a new concept of engineered geothermal system (EGS) in ductile formation zone. The target conditions of the JBBP well drilling are 3 to 5 km vertical depth, 350 to 500 °C estimated reservoir temperature, and 30 to 50 MPa estimated reservoir pressure. In this report, the author introduces the project outline, and discusses the technical problems relevant to drilling and completion such as extreme high temperature, hard and abrasive formation, low formation pressure and frequent risks of lost circulation, and HCl-H2S-CO2 coexisting low pH corrosive environment.
Recently, technical requirements to OCTG including Drill Pipe become more complex not only to develop material and connection performance but also to be involved in energy development from the early stage considering of the best practice and operation including HSE. On the other hand, developers are eager to use standardized products like API, ISO and NACE specified. It is a key that a manufacture shall develop a new product in accordance with ISO 9001.
Through recent developments of drilling technology in Oil and Gas business, technical requirements of OCTG increase in multiplicity and variety, especially in HPHT deep wells, critical wells of corrosive environment and economical wells of shale gas. High performance OCTG are developed such as high strength OCTG for high pressure and high temperature, corrosion resistance OCTG and premium connection of OCTG. This article will explain the general selection guidance of OCTG technology for deep well applications or shale gas applications.
Since 2000, backed by with the continuing high price of oil, oil development companies have maintained their active investment stance, and the market for deepwater offshore rigs also remains active. It is one of Japan Drilling Co., Ltd.'s important corporate strategies to enter into the deepwater market. JDC and Japan Marine United Corporation commenced the co-development process of a concept for a state of the art deepwater semisubmersible rig. In 2012 IHI Corporation joined this collaborative design project. The three companies came to an agreement that they would seek a dominant position in Japan with regard to the design development of a deepwater semisubmersible rig that will be globally competitive and highly efficient by combining the strength and expertise of the three companies. JDC is placing great emphasis on a successful project so that it can smoothly enter the deepwater market. This article outlines the project and the specifications of this new state of the art semisubmersible rig.
The marine riser with carbon fiber reinforced plastics (CFRP) is under developing for deepwater drilling, especially for deep sea drilling vessel CHIKYU owned and operated by Japan Agency for Marine-Earth Science and Technology (JAMSTEC). Previous steel riser is so heavy that water depth for drilling with CHIKYU is limited up to 2,500 m, which is far below CHIKYU's final water depth goal for drilling, 4,000 m. Therefore, new marine riser with much lighter material is required and CFRP is the best candidate. Moreover, high stiffness is requreid for riser materials due to prevent large vibration even in case of storm condition. To fulfill this requirement, pitch-based carbon fiber is more desirable because of its higher stiffness coming from higher graphitization. Our early stage of case study shows that water depth over 4,000 m can be achieved with pitch-based CFRP riser. Present assignments and recent developing program is also discussed briefly.
The losses have been general issues and challenges for all wells, which are loss occurs before running casing and cement the liner, uncertainness about the number and depth of the loss zones, a long open hole but no temperature log and no caliper log when getting loss. To meet these challenges, an innovative blend of fibers is designed to cure losses specially caused by the presence of natural fractures (it is not designed for induced fractures). This blend fiber contains two very different types of fibers. One is relatively thick and stiff, and the other is thin and significantly more flexible. In general, the thick and stiff fiber acts as an anchor and also contributes to reinforce the fiber network. The thin and flexible fibers entangle with the stiff fibers also have the tendency to invade the loss zone while remain entangle with the fiber net, thus helps to secure and stabilize the immobilized plugs containing fibers and solids must be suspended properly by the viscous base fluid. To secure losses, the blend fibers are mixed into the pill at the fieled and made the reinforced composite mat. It comprises the optimized solid package and the base viscous fluid besides the engineered two fibers. The fiber plugging mechanism of this pill works on four steps, which are “Disperse”, “Bridge”, “Plug” and “Sustain”. The pill contained blend fibers is designed to enter the well information with the software, then, the pill formation and placement guidelines are generated by the software. The loss has been cured by the pill based on the experimental results of offset wells in the past, on the other hand, this blend fibers with software is trying to propose more engineering solutions for losses. This paper will introduce the innovative blend of fibers.
Significant localized corrosion occurred on injection well 13%Cr stainless steel tubing in the field the natural gas is being dissolved in brine. Maximum corrosion rate of 13%Cr stainless steel was 2.1 mm/y. High concentration of sulfur element was detected on corrosion products by X-ray fluorescence analysis. Main cause of this corrosion was considered CO2 corrosion and microbiologically influenced corrosion. The corrosion was not reproduced by laboratory tests using CO2. Sulfuric acid was considered one of the causes of corrosion added for pH control in iodine extraction process.
Microbiologically Influenced Corrosion (MIC) is considered to play important roles on the corrosion of 13%Cr stainless steel injection tubing in a natural gas dissolved in brine field. The main cause of this MIC was considered to be mainly caused by Sulfate Reducing Bacteria (SRB) from the result of elemental analysis of corrosion products, immersion test and SRB culture in the actual plant. The SRB was activated by the addition of sulfuric acid used for pH control in the iodine extraction process. Changing the pH control agent to hydrochloric acid from sulfuric acid properly alleviated this MIC problem.
We present a new fission track age for a volcanic rock that formed during the opening period of the Japan Sea. A basal rhyolite (partly perlitic) flow of the Fuyube Formation on the Kodomari Peninsula yielded a zircon fission track age of 15.3 ± 0.9 Ma, determined by the external detector method. This result is compatible with published age data for underlying and overlying formations, and can be interpreted to represent the emplacement age of the lava flow. A chronostratigraphic model is given for the Lower to Middle Miocene sequence in the northern part of the Tsugaru district, in which the age of the Fuyube Formation is considered to be about 16 Ma.