石油技術協会誌
Online ISSN : 1881-4131
Print ISSN : 0370-9868
ISSN-L : 0370-9868
80 巻, 5 号
選択された号の論文の13件中1~13を表示しています
講演
  • 長縄 成実
    2015 年 80 巻 5 号 p. 324-329
    発行日: 2015年
    公開日: 2017/05/10
    ジャーナル フリー

    As an introduction of the drilling symposium entitled “Lessons Learned from Cases of Success and Failure of Drilling Operations,” the author review the Risk Matrix and ALARP (as low as reasonably practical) principle which are today's de-facto standard risk assessment and risk management approaches, to effectively apply the lessons learned from cases of success and failure to the next drilling projects. In particular, actual applications of PDCA cycle in drilling project management are first reviewed, then examples of deficiencies of the risk matrix and pitfalls in risk assessment process pointed in some literatures are described. Recommendations for avoiding these failures in risk assessment and management process and for continuous improvements of drilling operations are finally summarized.

  • 小野寺 壮進, 土井 英太郎
    2015 年 80 巻 5 号 p. 330-335
    発行日: 2015年
    公開日: 2017/05/10
    ジャーナル フリー

    Numerous near misses are caused by lack of knowledge and experience and strongly reflected human errors such as misunderstanding, careless and so on. Although a variety of safety management systems, for example Permit to Work, Job Safety Analysis, are implemented in the rig site to prevent incidents, it is most important that the site crew can understand and utilize our safety systems correctly.

  • 宗像 秀紀, 山口 春輔
    2015 年 80 巻 5 号 p. 339-342
    発行日: 2015年
    公開日: 2017/05/10
    ジャーナル フリー

    Idemitsu is an operator for a block, offshore Vietnam (300 km away from shore with approximate water depth of 120 m) and has drilled 4 exploration wells with semi-submersible rigs in this block. In this symposium, challenges and the lessons learned in the last two wells, Well-A of HPHT condition drilled at 2012-2013 and Well-B drilled at 2014 were presented.

  • 浦野 剛, 松井 耕二
    2015 年 80 巻 5 号 p. 347-351
    発行日: 2015年
    公開日: 2017/05/10
    ジャーナル フリー

    In the drilling operations under 600 m water depth by semi-submersible rig, 13-3/8″ casing had been unfortunately stuck at 1,800 mBRT which was 700 m shallower than section TD while running in hole. In our drilling program, 12-1/4″ shale section should be drilled to 3,700 mBRT with heavier mud (minimum 11.5 ppg) to avoid caving.

    However, because total 300 m thickness of weak zone (limestone) had been remained as bare hole below 13-3/8″ casing shoe, we could not weigh up mud for drilling 12-1/4″ shale section.

    After a challenging strengthen the weak zone had been failed, we had gave up drilling shale section while remaining the weak zone. Finally the weak zone had been covered by sacrificed 9-5/8″ liner, then shale section had been drilled by smaller hole (8-1/2″) than plan, and target formation had been drilled, unfortunately, with unplanned 6″ bit.

    This paper describes its failure of operations and remedial action we performed.

  • 日野 智之
    2015 年 80 巻 5 号 p. 355-361
    発行日: 2015年
    公開日: 2017/05/10
    ジャーナル フリー

    Troubles during drilling the well are often occurred although it is supposed to be made proper drilling plan. On the other hand we can get newly gained knowledge from those troubles. Lessons learned from troubles must be sheared and conveyed for future drilling operations. The most important thing in any troubles in some situation is to make our own efforts to phlegmatically decide what to do, making the most of our knowledge or obtainable information about undergrand situation, as well as commanding our experience of troubles. Our own attitude that shows strong intention to solve problems is equally important.

    JAPEX would like to introduce two cases of troubles especially during liner hanger setting operation. First is the liner setting tool assembly stuck after conducting 7″liner cementing job. Second is malfunction in releasing the liner setting tool from liner hanger.

資料
論説
  • 長縄 成実, 佐藤 亮介, 池田 憲治, 正田 伸次
    2015 年 80 巻 5 号 p. 366-374
    発行日: 2015年
    公開日: 2017/05/10
    ジャーナル フリー

    One of the key issues for economically successful development of shale oil and shale gas is how to produce oil or gas from high productivity areas of the shale play by optimizing well arrangement and hydraulic fracturing design and, in addition, how to enhance the productivity even from low productivity areas of the play.

    Cuttings analysis conducted as a mud logging service is an effective method to obtain the geomechanical properties of formations required for hydraulic fracturing optimization because information about formations can be obtained directly and continuously while drilling. However, cuttings lag time and lag depth calculated by the conventional method are recognized to be different from the actual ones, particularly in highly directional and horizontal wells because of the radial distribution of cuttings velocity and cuttings accumulation in the wellbore annulus.

    In this paper, we theoretically derived a more precise method of cuttings lag time and lag depth calculation to improve the accuracy of depth information in cuttings analysis. We also validated the method from the results of numerical calculation made by the modified cuttings transport simulator and an experiment using large-scale flow loop system.

  • 平松 力, 高橋 利宏, 東 将士, 入月 俊明, 林 広樹
    2015 年 80 巻 5 号 p. 375-384
    発行日: 2015年
    公開日: 2017/05/10
    ジャーナル フリー

    A biostratigraphic study of fossil diatoms revealed that the most of the Kumi Formation in Dogo, Oki Islands, is correlative with the Crucidenticula kanayae Zone to Thalassiosira yabei Zone, and that the Tsuma Formation with the Rouxia californica Zone to lower Neodenticula kamtschatica Zone, respectively. On the other hand, the lowermost of the Kumi Formation yielded a Lower Miocene freshwater planktonic diatom assemblage. The assemblage mainly consists of various forms of the genus Auracoseira associated with lacustrine Actinocyclus species. It is overlain by the marine Kumi Formation correlated to, or lower than, the Lower Miocene Crucidenticula kanayae Zone (16.6-17.0 Ma) which evidences that the geologic section recorded the first marine water invasion related to the Japan Sea opening in the area. This abrupt change of the diatom assemblage from freshwater to marine planktons suggests the rapid transgression in the area where wide continental shelf did not develop. In addition, this study shows the first discovery of the biostratigraphic index diatom fossil N. kamtschatica from the Tsuma Formation which is the westernmost occurrence from the Japan Sea side.

  • 渡邉 則昭, 臼井 祐人, 木崎 彰久, 坂口 清敏
    2015 年 80 巻 5 号 p. 385-396
    発行日: 2015年
    公開日: 2017/05/10
    ジャーナル フリー

    Inversion techniques utilizing changes in elastic wave velocities, and tilt data of the ground surface, associated with migration of CO2, respectively, are promising options for short- and long-term monitoring in geologic sequestration of CO2. Poroelastic parameters of reservoir rocks (e.g., sandstone) should be well understood to increase reliability of these techniques, because these techniques are based on the poroelastic theory. In this context, the present study, that extends our recent study on Terzaghi's effective stress (σeff) dependencies in poroelastic parameters of sandstones, experimentally explores influences of fractional CO2 saturation (Sx(x=CO2)), pore pressure (Pp), and temperature (T) on poroelastic parameters of Berea sandstone containing water and CO2 under undrained condition (i.e., Skempton's coefficient B, Young's modulus, Poisson's ratio, bulk and shear moduli), to finally provide predictive equations for all poroelastic parameters at σeff of ≥2 MPa, Sx(x=CO2) of 0-1, Pp of 10-30 MPa, and T of 40-60 °C. Experimental results, and a theoretical calculation of bulk modulus of water-CO2 two-phase pore fluid show that, for the undrained poroelastic parameters, CO2 saturation, pore pressure, and temperature dependencies are, respectively, an exponential decrease, linear increase, and linear decrease, in response to the similar dependencies of the bulk modulus of the pore fluid, at the above specific conditions. This finding, in combination with the well-known Terzaghi's effective stress dependency, provides the predictive equations, which quantitatively demonstrates variability of poroelastic parameters. Additionally, an application of the predictive equations for CO2 monitoring in a reservoir consisting of a Berea-sandstone-like rock strongly recommends that fractional CO2 saturation should be smaller than approximately 0.2 (i.e., common residual saturation level) by making a clear CO2 injection strategy, and pore pressure should be continuously monitored, to quantitatively monitor migration of CO2 by elastic wave velocity measurements, with maximizing safety by the capillary trapping mechanism.

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