Tohoku Natural Gas(TNG), headquartered in Sendai, as well as Sendai City Gas, a regional gas business leader, are now exposed to vehement competition which has never been seen, by encroachment of new players outside. In general, you may well consider TNG, originated from EPC(Elecric Power Company), to be antagonistic to Sendai City Gas, a leader of the gas trade. However, multiple cooperation has been established between the two in the region while competing each other. Their collaboration in required fields is fully witnessed with their competition fairly made, which may be attributable to the geographic, historical or cultural essence of Tohoku. The clear fact is that Tohoku EPC and Sendai City Gas share a strong spirit for contribution to their homeland. Sendai City Gas, the biggest gas utility viewing Tohoku overall which suffers with decreasing population, aging society, and dwindling number of children, also in political perspective. And Tohoku EPC, who holds the strongest ties with natural gas historically, and has been proceeding with its business aiming at the promotion of widespread gas utilization. There is no doubt that the strong spirit shared by the two leaders for “being for the region” is the very base on the relationship toward mutual cooperation and benefit.
Kenji Miyazawa is one of the most popular literary men in Japan. He was well grounded in geology because he was highly educated for geology. Therefore geological issues underwent a good infl uence on his literary productions. For example, he used colors of minerals to represent atmospheric phenomena such as colors of sky, cloud, mist, sunshine etc. However, the past annotations for technical terms of geology in Kenji's literary works are much doubtful from the viewpoint of geologists. I, a geologist, would like to introduce some examples of the investigation about his intended discrepancy between strict description of geological terms and literary expressions. 1. Kenji ventured to adopt technical terms which were not always ordinary in even his days. For example, he used the term“ gastaldite” , blue-colored minerals to express blue ship beacons. But in general“ glaucophane” is used. Kenji used the former in order to make rhythm“ da-da-da” in his poem. 2. Kenji also adopted wrong technical terms purposely. For example, he used“ dihexagonal pyramid” as a crystal form of quartz. He said it is originated from high quartz in rhyolite or dacite, therefore they must be“ hexagonal bipyramid”. Of course he understood the difference between them, however he adopted the former wrong terms purposely because the former term is more beautiful in Japanese linguistic sense. 3. Special pronunciations of technical terms peculiar to Kenji were used. For example, he read Lepidodendron, a plant fossil as“ Rinboku” in Japanese. Today“ Rinboku” is common pronunciation, however it was named“ Urokogi” originally as Japanese name, therefore the latter was also common in Kenji's days.
I introduce a model for generation of interplate, intraslab and shallow inland earthquakes in the NE Japan subduction zone and for magma genesis and ascent within the mantle wedge beneath the arc. Waveform inversion studies of recurrent earthquakes have revealed that large slip areas(asperities) of successive ruptures are in the same place on the plate boundary. Back slip inversions of GPS data show that asperities once ruptured by past large earthquakes are locked at present. These observations strongly suggest that the asperity model is applicable to the process of seismic and aseismic slip on the plate boundary in this subduction zone. Studies on spatial distribution of intermediate-depth earthquakes and seismic velocity structure within the slab provide the evidence which supports the dehydration embrittlement hypothesis for the generation of intraslab earthquakes beneath this arc. Seismic tomography studies have shown an inclined sheet-like seismic low-velocity zone in the mantle wedge at depths < 150km, which probably corresponds to the upwelling flow of the subduction-induced convection system. This upwelling flow reaches the Moho immediately beneath the volcanic front, suggesting that the volcanic front is formed by this upwelling flow. Aqueous fluids dehydrated from the slab are probably transported upward through this upwelling flow to reach the crust, where the surrounding crustal rocks might be weaken resulting in local contractive deformation under the current compressional stress field of this arc. GPS data have revealed a notable concentration of contraction deformation there. Shallow inland earthquakes are also concentrated in the upper crust of this locally large contraction deformation zone, suggesting that their occurrence is closely related with local weakening of the crust by aqueous fluids originated from the slab dehydration.
Cuttings transport is one of the biggest challenges in extended reach drilling(ERD). However, few simulation tools satisfy the industry requirement for more practical and comprehensive study on cuttings transport in ERD. The problem might lie in the situation that most conventional cuttings transport models or simulators are of steady state calculations obtaining critical flow rate for a single section of the whole well. In this study, our previously developed prototype simulator of transient cuttings transport using two-layer model formulation was modifi ed and improved for more practical use. Modifi cations of the simulator include(1) setup for simulation input of precise well profile based on the directional survey data,(2) consideration of moving bottomhole boundary with increases of drilling depth as time elapsed,(3) a simple model for effects of drillpipe rotation. To evaluate functionality and potential of the modified simulator, some post analyses on cuttings transport were carried out for an extended reach well drilled in the Sarukawa Oil Field. The simulator successfully demonstrated transient behaviours of cuttings bed height and annular pressure over the whole well trajectory.
Drill pipe failure is a very serious problem for Teikoku Oil Company(TOC) to continue deep well drilling. Then TOC has continued to carry out research in order to avoid this trouble and started some innovative methods to cope with the drill pipe failure. This paper introduces the following methods. One is drill pipe coating with zinc plating on surface as corrosion victim. The other is drill pipe management by using drill pipe fatigue database. In this database, the amount of fatigue is calculated from cumulative degree of Von Mises Stress on drill pipe multiplied by its rotational time. Von Mises Stress is calculated from equation and rotational time is referred from past drilling record. It has not been concluded yet whether this database would show correct amount of drill pipe fatigue. However, TOC continuously needs to perform trial and error and achieve a proper drill pipe management method.
Sonic Scanner has been recently introduced to the market. This is the first 3D sonic logging tool developed in Japan. It measures sound slowness(1/velocity) of P and S wave along well axis, around well bore and away from well bore. There are many applications including drilling related applications. One example is “damaged zone” identification. Sonic Scanner is the latest example of logging tool developed in Japan, and there was a history to achieve such advanced tool development. It's been 70 years since the first electrical log was run in Japan, and it's been 50 years since logging service was brought into Japan. Schlumberger opened Engineering and Manufacturing center facility in Sagamihara 20 years ago, and started tool development. The reason Schlumberger opened such center in Japan was to capture Japanese leading technology and manufacturing quality and apply to oil field. One of the examples is color printer for oil field use, which was 20 years ahead of consumer market. The trend to capture leading edge“enabling” technologies to apply them to increase efficiency of oil field development will continue. To do that, we need to work with such technology providers that may be another strong industry in Japan or Academic community.
Drilling operations change along with the improvement in both drilling hardware and software developments in worldwide basis. To cope with the field specific problem or establish effi cient operation, JAPEX continuously keen to adopt new drilling technology as one of the countermeasures. In the course of doing this, JAPEX have accumulated the engineering knowledge and actual operational techniques and refl ected them further in other field operations. This paper outlines JAPEX's drilling operation in two decades and recent engineering subject of the first SBM (synthetic base mud) utilized in the domestic operation.
The drilling technologies are progressing day by day and technical learning is one of the challenges for drilling contractors. This paper outlines some new technologies such as liner drilling, riser cap drilling and solid expandable tubular that JDC experienced, and discusses their advantages and potential operational problems.
The concept of a tapered outside diameter coiled tubing(TODCT) system was first presented in 20041). This paper laid out the basic requirements for a TODCT system and the advantages of the TODCT system in ultra-deep wells( 30,000-ft range). The TODCT system includes: •A modified injector that can handle more than one diameter of tubing and maintain a constant grip on the tubing throughout the length of the TODCT string. •A“ transition tube” that allows sections of tubing with different ODs to be joined together. •Well-pressure control equipment( i.e., blowout preventer and stripper) that has the capability to grip and seal more than one diameter of tubing and can also grip and seal the transition tube. •An operator control house that allows remote control of the stripper elements and injector gripper elements to open or close to different diameters of tubing while still maintaining control of well pressures inside the wellbore and grip on the tubing. This paper continues the work that was started previously. A review of the yard testing completed on the equipment is included along with a subsequent field trial done onshore in south Texas. The end result is that a tested and qualified TODCT system is capable of safely running tubing strings into ultra-deep wells.
The conventional tubular design is based on the API recommendation where collapse tests are conducted under fluid confining pressure. However, the tubular string collapsing process is significantly different when an external load is applied through a solid formation. Laboratory tests showed that tubular strings started yielding significantly earlier if the load was applied through a formation rather than through a confining liquid. However, during additional loading after tubular string yielding, the deformation of the tubular string installed in a formation remained small since most of the external load was supported by the surrounding formation. These laboratory data and field applications of tubulars to deeper fields enlighten field engineers to change the design methods of tubular strings. Since these new design methods are more complex than conventional one, softwares to design tubulars have been also evolved. Analytical or numerical solutions have been developed to calculate the stress state and deformation before yielding and after yielding for gravel packed or cemented tubular strings under directional in-situ stresses. The API tubular string failure criteria have been also modified so that they could be applied to more general stress state around a tubular string. Using the tubular string stress state and the generalized API pipe failure equations, a guideline is given for field design of tubular strings under geotectonic load based on the experimental observations. A software to simplify the tubular string design is also presented.
It follows from the previous papers that we can derive a S-function as long as the complex velocity potential is provided and S-function gives us a good approximation of pressure drops and derivatives. In this paper, S-function analysis will be expanded to free-form curves. For this purpose, we have to derive a complex velocity potential for the given boundary shape. The solution for this kind of problem is found in vulgate textbooks for complex variables, which is known as“ Schwarz-Christoffel conformal mapping”. This theory was discovered soon afterward, independently by Christoffel in 1867 and Schwarz in 1869. In decades, the development of computer enables us to calculate the conformal mapping actually. The typical Schwarz-Christoffel conformal mapping is a formula that will transform the real axis of the w-plane into a polygon in the z-plane; however, here we will mainly discuss about“ strip type transform”. It is rarely mentioned in public, although, this theory can be easily extended to the problem that sinks and /or sources( singular points) exist. Thus, we can obtain the complex velocity potential and equidistance surfaces on physical space of which boundary shapes are complicated. At last we can calculate S-functions for any boundary shapes and it enables us to analyze well testing.
This paper describes that evaluation of soil remediation contaminated with oil on quicklime process and the effect of the treatment for oil degradable bacteria in the soil. In this paper, two different contaminated sites were used. When quicklime method was applied for a contaminated site, the temperature of soil increased over 60 °C by reaction heat and the pH value also rose to about 12. Although the density of bacteria in the contaminated soil decreased from 40 to 5 - 10 x 1010 cells/g-dry soil, they could survive against the increasing of heat and alkalinity caused by the treatment. Some oil degradable bacteria were isolated from original contaminated and treated soil and the abilities of oil degradation were evaluated. These bacteria might contribute the degradation of remained oil in the treated soil. On another site, the oil concentration in soil decreased from 3,555 to 1,430 mg-oil/kg-soil by the treatment. In this case, some light parts of oil, C6 to C10 and C10 to C28, were almost volatized to below 5 and 35% respectively, but the heavy part, C28 to C44 was still remained. However the remained oil decreased gradually after the treatment to 250 mg-oil/kg-soil within 6 month. This shows the high possibility of oil remediation by oil degradable bacteria which survive in contaminated soil against the treatment.