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Volume 67 (2002)
- Issue 6 Pages 529-
- Issue 5 Pages 431-
- Issue 4 Pages 343-
- Issue 3 Pages 277-
- Issue 2 Pages 143-
- Issue 1 Pages 1-
Volume 67, Issue 5
Displaying 1-9 of 9 articles from this issue
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Takeshi Ohguchi2002 Volume 67 Issue 5 Pages 431-439
Published: 2002
Released on J-STAGE: March 27, 2008
JOURNAL FREE ACCESSThe outline of Tertiary volcanostratigraphy in the Akita Basin is summarized. In particular, the volcanic facies in the Sunakobuchi Formation and the Manaitayama Volcanic Rock-Fukuyama Andesite which form oil and gas reservoirs is reviewed from a view of occurrence, depositional environment and eruption style.
The Sunakobuchi Formation is composed of basaltic volcanic rocks and its volcaniclastics. Those eruption styles change from magmatic eruption in terrestrial to shore environments at lower part, to submarine magmatic eruption mainly composed of pillow lava at upper part, through phreatomagmatic/phreatic explosion and subaqueous fountain eruption at middle part.
The Manaitayama Volcanic Rock comprised of subaqueous volcanic rocks and volcaniclastics is divided into M1 (olivine pyroxene basalt), M2 (pyroxene andesite), M3 (hornblende pyroxene andesite) and M4 (pyroxene hornblende dacite).
The Fukuyama Andesite consists of pyroxene andesite (FKV-1) correlated to M2 and hornblende pyroxene andesite (FKV-2) correlated to M3. The volcanic facies indicate that the andesites erupted under submarine environment and some of the subaqueous lava flows intruded into surrounding unconsolidated sediments.
The Manaitayama Volcanic Rock and the Fukuyama Andesite construct volcanic mounds on sea floor. Part of them is eroded at subaerial condition and reworked-volcaniclastic sediments develop around the mounds.View full abstractDownload PDF (1363K) -
Seiji Saito, Sumio Sakuma2002 Volume 67 Issue 5 Pages 442-449
Published: 2002
Released on J-STAGE: March 27, 2008
JOURNAL FREE ACCESSDrilling problems that occurred during the last 15 years within JMC-Geothermal group while drilling geothermal wells, are reviewed. BHA parting, stuck BHA, and down-time caused by poorly maintained equipment, are three major problems to be avoided. Three processes that occurred during drilling a high temperature geothermal well in Kakkonda, are also discussed. They are mud deterioration caused by high temperature borehole conditions, unsuccessful sidetracking operations, and casing wear.View full abstractDownload PDF (1370K) -
Naoto Goto, Hiroyasu Ishiguro2002 Volume 67 Issue 5 Pages 450-459
Published: 2002
Released on J-STAGE: March 27, 2008
JOURNAL FREE ACCESSRisks of Offshore Operations are more various and complicated than onshore drilling operation due to underwater well bore, meteorological environment and distant location from shoreside. Therefore, when considering the risk management the industrial total safety management system is required. It is important for all companies to extract the element of the risk and take remedial actions to reduce the risks and/or prospect the result. Hereinafter several cases are presented, which were caused by particular offshore operations and rather could not be prospected, and element of those risks are studied.View full abstractDownload PDF (2587K) -
Hiroyasu Ishiguro, Norihiro Inada2002 Volume 67 Issue 5 Pages 460-464
Published: 2002
Released on J-STAGE: March 27, 2008
JOURNAL FREE ACCESSAs to date, and despite investigations into previous accidents, we have not been able to prevent similar accidents from occurring. Reasons why similar accidents continue to occur and an example for preventing such similar accidents in future are given here.
Generally speaking, the conventional accident investigation does not differ substantially from the way it is presently conducted, and conclusions of the report fail to be appropriately conveyed to management. The point at issued is feedback.
In this report an example is given to illustrate the feedback component of Japan Drilling Company's HSE Management System (HSE-MS). The recent incident rate record of the Company is used as the example. Specific identifiable weaknesses of the HSE-MS are considered here.View full abstractDownload PDF (263K) -
Hiroyuki Hashimoto2002 Volume 67 Issue 5 Pages 465-474
Published: 2002
Released on J-STAGE: March 27, 2008
JOURNAL FREE ACCESSInsufficient borehole pressure integrity (BHPI) is a major drilling challenge in deep, high-temperature, high-pressure (HTHP) wells in California and other areas. Shale and sandstone formations with low BHPI may be weakened by leaking faults/fractures or poor rock properties, causing lost returns with mud weights close to pore pressures. Drilling through depleted or low pore pressure formations with some probability of drilling into higher pressured zones in the same hole section compounds the severity of this challenge in the Temblor formation in Kern County, California.
This challenge was solved by an innovative treatment applied in the Berkley East Lost Hills No. 1 well. Compared to conventional methods, it increased leakoff test (LOT) and formation integrity test (FIT) pressures to incremental values higher than those typically seen in the industry. Increasing BHPI allowed an additional 293m to be drilled before a 7-in, liner was set, and the well was drilled to 6, 012m. This depth met the objective of the well (to obtain full penetration through the objective sands) and allowed the subsequent discovery of a pay zone. If the new treatment to increase the LOT had not been used, the 7-in, liner would have been set early, and it is unlikely that the discovery zone would have been penetrated. Preventing skin and formation damage in potential zones of interest while treating weak points was another major concern heightened by a wide range of pore pressures. This paper discusses a theoretical mechanism to help explain how the treatment rapidly and substantially increases pressure integrity across both sand and shale formations. Minor penetrations in high and low permeability sandstone core tests help explain why the treatment system minimizes or prevents skin damage. Skin damage in the zones of interest may be prevented or minimized by BHPI treatments that only enter leaking fractures or faults. Further development and deployment of BHPI treatment technology promises a step change in industry practice to optimize well plans with lower cost programs for drilling fluids, casing design, cementing, and completion equipment. Optimized well designs should reduce both drilling days and flat time by allowing operators to drill smaller-diameter holes while using fewer casing strings to achieve the same production string dimensions.View full abstractDownload PDF (684K) -
Yoshiyuki Matsuura2002 Volume 67 Issue 5 Pages 475-481
Published: 2002
Released on J-STAGE: March 27, 2008
JOURNAL FREE ACCESSIn making a drilling program, many drilling engineers try to find the best way to prevent drilling problems by analyzing another well data and consideration of technical calculations. However, once the drilling operation is started, people often come up against unexpected drilling troubles and can't move forward, taking much time and cost. Borehole stability problem is one of the most difficult trouble, because prompt measures should be taken to improve the well condition. And as each well has each characteristic, even if countermeasures which had an effect on another well, may have no effect on well that is drilled now. So it is very important to investigate the data of wells in detail which had met with borehole problems, and know the many method to deal with it, and hold these knowledge in common. I report a few cases about borehole stability problem, those wells were operated by Teikoku oil company and, would like to make good use of these knowledge to future wells.
Well A Bore hole stability problem was caused by caving of the formation which consists of tuff and dolerite. By increasing mud weight and viscosity, and doing short trip at regular intervals, flush high viscosity mud properly, well condition became stable, had no trouble after taking these way.
Well B Bore hole stability problem was caused by pushing plastic mineral from well bore. By checking and adjusting the MBC value, concentration of potassium ion, and doing short trip at regular intervals, well condition became stable, had no trouble after taking these way.
Well C Bore hole stability problem was caused by caving of the formation of basaltic tuff. By increasing the YV value in drilling mud, improving cutting transport ability and adjusting mud weight, well condition became stable, had no trouble after taking these way.View full abstractDownload PDF (2125K) -
Ryohei Wakishima, Teruaki Kobayashi, Shigeru Mitsuya2002 Volume 67 Issue 5 Pages 482-488
Published: 2002
Released on J-STAGE: March 27, 2008
JOURNAL FREE ACCESSJAPEX has drilled two wildcat wells with a semi-submersible rig in the offshore Browse Basin Permit AC/P 29 of Australian Timor Sea during the year 2000. They were remotely located at 730km from Darwin that is the capital in the State of Northern Territory. The range of water depth was from 300m to 410m. During this drilling campaign, it was happened that Sub-sea Blow Out Preventers (BOP) were dropped unexpectedly to the seafloor from the sea level in the process of the Riser Dump Valve (RDV) function test. Fortunately there were no personnel injuries or near misses during the incident. Then immediately after the incident a special investigation team was organized and the BOP were recovered from seafloor and repaired successfully according to the plan. This paper describes not only this BOP incident itself but also the following key items related to the incident:
1. Flush Mounted Spider (FMS) bottom guide lost in hole
2. Riser-less temporary Plugged and Abandonment (P & A) operationsView full abstractDownload PDF (2150K) -
Yuichi Sugai, Chengxie Hong, Tadashi Chida, Heiji Enomoto, Nintoku Yaz ...2002 Volume 67 Issue 5 Pages 491-500
Published: 2002
Released on J-STAGE: March 27, 2008
JOURNAL FREE ACCESSIn the previous report, we have reported that Clostridium sp. TU-15A is a powerful polymer producing microorganism and has been selected as a candidate for MEOR (Microbial Enhanced Oil Recovery). This microorganism grows easily in the molasses medium and increases the viscosity of the culture solution up to 70 cP (at 38.3s-1) or higher by a 10 day cultivation.
In the present study, two different sets of flooding experiments were conducted for evaluating the effect of TU-15A on displacement efficiency and sweep efficiency. One was for the different pressure gradient experiment and the other was for the anisotropic permeability experiment. The former experimental system consisted of a pair of two independent sand packs with different length (ratio of length is 1 to 1.4) but with the same permeability, connected in parallel for simulating between the highest and the lowest in a five spot water flood pattern. The other consisted of a pair of two independent sand packs of different permeabilities but with the same length, connected in parallel for simulating the anisotropy of reservoir permeability. In these sets of experiments, the high viscous culture solution of TU-15A was injected after water flood experiment, as a tertiary mode and the improved oil recovery were observed.
In the different pressure gradient experiment, the fraction of flow rate into the long sand pack was improved from 22% to 47% by injection of the culture solution of TU-15A, which led to the increase of oil recovery from 69% to 87% in the long sand pack. In the anisotropic peameability experiment, the oil recovery was increased in the low permeability sand pack from 56% to 80%, which was attributed to the modification of flow rate into the low permeability sand pack from 8% to 22% by the injection of the culture solution of TU-15A.
Results obtained in these experiments imply that TU-15A can be utilized for MEOR.View full abstractDownload PDF (622K) -
Itsuki Suto, Yukio Yanagisawa, Masaki Takahashi2002 Volume 67 Issue 5 Pages 501-511
Published: 2002
Released on J-STAGE: March 27, 2008
JOURNAL FREE ACCESSDiatom biostratigraphy was re-examined for the Miocene marine sequence distributed along the Arakawa River in the northern part of the Hiki Hills area, central Japan. Thirteen out of 24 collected samples yielded age diagnostic diatom fossils, which are restricted between diatom biohorizons D41 (15.7Ma) and D41.5 (15.6Ma) in the lower Denticulopsis lauta Zone (NPD 4A). A thin conglomerate layer, which is previously presumed as an unconformably overlying basal conglomerate, is sandwiched between the last occurrence (LO) biohorizon of D. praelauta (D41:15.7Ma) and first occurrence (FO) of D. ichikawae. As the maximal duration between these two biohorizons is estimated as about 20, 000 yr., it is concluded that there is no unconformity along the studied section. Temporal change in the diatom assemblage suggests a transgression in the examined interval.View full abstractDownload PDF (1894K)
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