石油開采外文翻譯---北?？颂m盆地石油地質(zhì)

1、<p>　　Oil, including oil exploration, is the next big subject for the Falkland Islands. We have pleasure in publishing this very full and detailed study of the oil prospects in the North Falkland Basin. Dr Ian Dunca

2、n is CEO of Desire Petroleum plc, which is a leading operator in this field, and his article is an authoritative account of the current situation.</p><p>　　Petroleum Geology of the North Falkland Basin</p

3、><p>　　by Dr Ian Duncan, CEO of Desire Petroleum plc</p><p>　　Within the Falkland Islands designated area there are three major basins: North Falkland Basin, Falkland Plateau Basin and South Falkla

4、nd Basin. The subject of this article is the North Falkland Basin, where Desire Petroleum has been exploring for hydrocarbons since 1997.</p><p>　　The North Falkland Basin is a failed rift, which formed duri

5、ng the break-up of the ancient landmass of Gondwana. Plate tectonic reconstruction suggests that the entire Falklands area prior to the break-up was originally located to the South-east of South Africa and moved to its p

6、resent position during the opening of the South Atlantic during the Jurassic to the Cretaceous. The North Falkland Basin can be further subdivided into a northern, or main, basin in which Tranches A to Fare located and a

7、</p><p>　　Exploration History</p><p>　　The first phase of exploration was in the early 1990's when Spectrum acquired the first detailed 2D seismic across the area. These data defined the out

8、lines of the N-S trending North Falkland Basin, approximately 180 kms long by 30 kms wide and formed the basis for the evaluation which led to the first round of licensing in 1996. Seven licences were awarded in 1997 to

9、Shell, Amerada, Lasmo, International Petroleum Corporation (IPC) and Desire. These companies acquired more 2D seismic over their </p><p>　　Shell, Amerada, Lasmo and IPC formed FOSA (Falklands Offshore Sharin

10、g Agreement) jointly to conduct a drilling campaign in 1998. The semi-submersible drilling rig the Borgny Dolphin was contracted and drilling began in April 1998. Amerada drilled two wells: 14/9-1 and 14/9-2; Shell drill

11、ed two wells: 14/5-1 and 14/10-1; Lasmo and IPC drilled one well each: 14/13-1 and 14/24-l.Drilling ended in November 1998.</p><p>　　Of the six wells, five recorded good oil and or gas shows but the presence

12、 of hydrocarbons in commercial quantities was not established. Over the next few years Amerada, Shell and Lasmo withdrew from the Falklands and as a result Desire Petroleum became the operator of Tranches C and D and Arg

13、os Evergreen became the operator of Tranche A. Following the acquisition of further seismic in 2000, IPC were acquired by Talisman who became the operator of Tranche F.</p><p>　　Continuing low oil prices sti

14、fled all activity in the area until 2004 when Desire acquired 800km2 of 3D seismic over Tranches C and D. In the same year Rockhopper Exploration was awarded new licences in the area.</p><p>　　At the beginni

15、ng of 2005, Desire raised sufficient money to fund further drilling in the North Falkland Basin and Rockhopper farmed-in to Tranches C and D. At the time of writing (December 2005) Desire is seeking a rig to commence dri

16、lling as soon as one becomes available. During 2005 Desire assumed a 100% interest in Tranche F and Rockhopper acquired further licences in the area. The latest licence position is shown in fig.l.</p><p><

17、;b>　　Geology</b></p><p>　　The North Falkland Basin has a predominantly nonmarine Jurassic to Lower Cretaceous fill overlying Devonian basement. These non-marine sediments are overlain by a marine se

18、quence of Upper Cretaceous to Recent age. In the deepest part of the Basin in Tranche D the total section is over 5 kms in thickness.</p><p>　　The non-marine rocks were deposited in a large lake, into which

19、flowed several large rivers which formed sandstone deltas and fans as shown schematically in fig 2. This lake was of a size similar to the present day lakes of East Africa. The lake filled slowly with fine- grained clays

20、tones, which at times were deposited in oxygen-free conditions resulting in rocks with very high organic carbon content. These rocks are the source of the oil generated in the Basin. Eventually in the Upper Cretaceou<

21、/p><p>　　The North Falkland Basin contains all the ingredients necessary for the discovery of hydrocarbons, namely source rocks, reservoir rocks, seals and traps.</p><p>　　Source Rocks</p>&

22、lt;p>　　The 1998 drilling campaign established the presence of a thick (over 1,000 metres) non-marine, oil source rock, believed to be one of the richest in the world. These source rocks were immature in five of the si

23、x wells drilled but attained maturity in one of them; live oil of 27 degree API was recorded at the surface from well 14/ 10-1.</p><p>　　The source rocks are mature in the deeper parts of the Basin where the

24、 temperatures and pressures are sufficiently high to generate and expel oil. The location of this area of mature source rocks "the kitchen" is shown in fig.3. Only the basal part of the source rock is mature wi

25、th the majority of the source rock being immature.</p><p>　　Richards (British Geological Survey) and Hillier (Shell) in 2000 in which they estimated that up to 60 billion barrels of oil had been generated an

26、d expelled from this source rock. There is also a deeper separate source rock, mature for the generation of gas, as demonstrated by the good gas shows at this deeper level in well 14/5-1.</p><p><b>　　S

27、eals</b></p><p>　　The abundant claystones throughout the section including the immature upper part of the source itself provide good sealing potential.</p><p>　　Reservoirs</p><p

28、>　　Desire believes that finding effective reservoir rocks is the largest risk associated with the discovery of hydrocarbons in commercial quantities in this area; i.e. sandstones of sufficient quality to produce oil a

29、t rates high enough to be commercial. However the seismic character of prospects such as the Liz Prospect provide good indications that good quality reservoir rocks may be present.</p><p><b>　　Traps<

30、;/b></p><p>　　The 2D and, in particular, the 3D seismic data show a number of structural and stratigraphic trapping mechanisms.</p><p>　　Play Concept</p><p>　　The 1,000 metres th

31、ick source rock is mature only at the base in the deeper parts of the Basin. The overlying, immature, source rock is a very effective regional seal, see fig 4, and it is believed this has prevented the upward migration o

32、f oil into the overlying horizons. These shallower horizons were the main target in the first drilling campaign and the failure to find commercial hydrocarbons may be the result of the difficulty in charging these horizo

33、ns.</p><p>　　Desire now believes that the major potential of the Basin may be in the untested flanks of the Basin at the level of the mature oil source rock as shown in fig 4. At this level the oil would hav

34、e only a short distance to migrate from the mature oil source rock to the predicted reservoir rocks. In addition the best reservoir development may be on the flanks of the Basin. The 3D seismic data acquired in 2005 was

35、designed specifically to test this new model.</p><p><b>　　Prospects</b></p><p>　　Nine prospects have been identified (see fig.1), most of which have multiple targets. Only two of the

36、se will be described in detail to illustrate the variety of prospect types found in the Basin.</p><p>　　Liz Prospect</p><p>　　This is the largest prospect and is likely to be the first one drill

37、ed in the next campaign. It is a stratigraphic trap and based on seismic amplitude mapping has geometry suggestive of a fan-delta deposited by a large river flowing into the lake see fig 5. This fan-delta is detached by

38、faulting from the up dip feeder channel and lateral sealing is provided by the rich oil source rock, which is mature at the distal end of the fan. The feeder channel shows drape on the seismic data and this is po</p&g

39、t;<p>　　Ninky Prospect</p><p>　　This is an example of a structural trap. At a number of levels immediately above the mature oil source rock the structural contours are closed against a fault. Unlike t

40、he Liz prospect vertical migration up a fault is required to fill the traps but on the seismic a fault is clearly defined reaching from the mature source rock to the overlying traps.</p><p>　　As this prospec

41、t is near the centre of the Basin, thinner poorer quality reservoirs might be expected but again seismic amplitude geometrics suggest that thicker distal fan sandstones might be present. This prospect is located in a wat

42、er depth around 400 metres with a planned total depth of circa 3,100 metres.</p><p>　　Environment</p><p>　　Desire recognises the international importance of the environment of the Falkland Islan

43、ds and is committed to doing everything possible to minimise any impact on the environment its operations may have. All of the operations will be carried out in accordance with UK North Sea standards and only water-based

44、 drilling muds and low toxicity chemicals will be used.</p><p>　　To identify all the possible impacts of the three well operation, Desire commissioned RPS, one of the leading environmental consultancies in E

45、urope, to undertake an environmental impact assessment (EIA). RPS suggested a number of measures to minimise environmental impact and concluded that the proposed operations can be carried out without a significant impact

46、 on the environment. Full details of the EIA can be found on the Desire website at www.desireplc.co.uk.</p><p><b>　　Drilling</b></p><p>　　Drilling in the North Falkland Basin is rela

47、tively straightforward. The first drilling campaign established that there were no serious drilling hazards and that a 3,000 metre well could be drilled injust over twenty days. In addition the water depths (350-410 metr

48、es) are not considered deep in today's terms and the weather conditions are similar to the Central North Sea.</p><p>　　As a result a heavy duty deep water drilling rig is not required and, as in the prev

49、ious campaign, Desire intends to use a third generation semi-submersible rig as shown in fig 6.</p><p>　　Development</p><p>　　In the event of a commercial oil discovery the most likely developme

50、nt scenario is one now widely employed throughout the world and particularly in the North Sea. It would involve completing the producing wells on the seabed and tying them back to a FPSO (Floating Production, Storage and

51、 Offloading) facility. Oil would be transported to a refmery located anywhere in the world by shuttle tankers. Minimal onshore facilities would be required in the Islands.</p><p><b>　　Economics</b&g

52、t;</p><p>　　Based on the above assumptions, a number of economic models have been run. As a result of the favourable fiscal regime in the Falklands, relatively small oil fields are likely to be commercial. F

53、or example, based on a $30/barrel oil price and a 10% discount factor, oil fields containing 40 million barrels would be commercial. Oil prices have risen considerably during 2005 and, although costs have also risen, it

54、is believed the overall commerciality of a discovery has been considerably enhanced.</p><p>　　Conclusions</p><p>　　1. A working hydrocarbon system in the north Falkland Basin has been establishe

55、d.</p><p>　　2. The area has the potential to become a major hydrocarbon province, but further drilling can only prove this.</p><p>　　3. Desire has identified nine prospects for drilling and prep

56、arations are well underway for resumption in drilling as soon as a suitable rig can be contracted.</p><p>　　4. An Environmental Impact Assessment has determined that a three well exploration-drilling program

57、me will not have a significant impact on the environment.</p><p>　　Further explanatory diagrams can be found on Desire Website at www.desireplc.co.uk.</p><p>　　c. Copyright retained by Desire Pe

58、troleum plc.</p><p>　　References: Richards, P. C. and Hillier, B. V., 2000 Post- Drilling Analysis of the North Falklands Basin - Part 2:Petroleum System and Future Prospects. Journal of Petroleum Geology, V

59、ol23 (3),pp273-292.</p><p>　　Acknowledgements: I would like to thank Dr Colin Phipps for his helpful suggestions in the presentation of this article.</p><p>　　石油,包括石油勘探,是?？颂m群島下一個大的主題。我們很高興地出版這非常

60、充實(shí)詳細(xì)的北方福蘭克群島石油前景研究。伊恩·鄧肯博士是Desire Petroleum plc的首席執(zhí)行官，這個領(lǐng)域的領(lǐng)頭者，在現(xiàn)狀下，他的文章是權(quán)威的。</p><p>　　北?？颂m盆地石油地質(zhì)</p><p>　　伊恩·鄧肯博士，Desire Petroleum plc的首席執(zhí)行官</p><p>　　在福蘭克群島指定區(qū)域有三個主要盆地：北福

61、克蘭盆地，?？颂m高原盆地，南福克蘭盆地。這篇文章以北?？颂m盆地為主，自1997年開始Desire Petroleum已在此勘探烴類物質(zhì)。</p><p>　　北福克蘭盆地是岡瓦納古陸解體時形成的衰退峽谷。板塊構(gòu)造重組學(xué)說指出整個福蘭克地區(qū)在解體之前侏羅紀(jì)與白堊紀(jì)南大西洋板塊開放之時，從南非東南部移動到現(xiàn)在位置。北?？颂m盆地可進(jìn)一步細(xì)分為南北兩部分，北部也就是主要的包括A區(qū)到F區(qū)，南部盆地為I區(qū)和L區(qū)。南部盆地未被

62、鉆探，并含有一套比北部盆地老的巖層。這篇文章把重點(diǎn)放在將要開始鉆探的C區(qū)和D區(qū)。</p><p><b>　　勘探歷史</b></p><p>　　第一階段的探索是在90年代初由頻譜獲得整個地區(qū)第一個詳細(xì)的二維地震數(shù)據(jù)。這些數(shù)據(jù)指出了福蘭克北部盆地輪廓,大約有180公里寬長和30公里寬,形成了1996年第一輪評價的基礎(chǔ)。在1997年7個許可證被授予Shell, Ame

63、rada, Lasmo, International Petroleum Corporation(IPC) 和Desire公司。這些公司獲得了超過許可證更多的二維地震數(shù)據(jù)，另外，shell公司獲得了小部三維調(diào)查許可。</p><p>　　1998年，Shell, Amerada, Lasmo 和 IPC組成了FOSA組織（?？颂m群島海岸共享協(xié)議）來共同管理鉆井工程。在1998年4月，Borgny Dolphin半

64、潛式鉆探簽約并開始鉆探。Amerada公司鉆了兩口井：14/9-1 和14/9-2井；Shell公司鉆了兩口井：14/5-1 和 14/10-1井; Lasmo公司和IPC公司各鉆了一口井：14/13-1 和14/24-1井。鉆探于1998年11月結(jié)束。</p><p>　　在這6口井中，5口有良好的油氣顯示，但是烴類物質(zhì)的商業(yè)儲量并不足夠。在以后的幾年里，Amerada, Shell 和Lasmo公司將從?？颂m

65、地區(qū)退出，這導(dǎo)致Desire Petroleum公司成為C區(qū)和D區(qū)經(jīng)營者，Argos Evergreen公司成為A區(qū)經(jīng)營者。通過2000年更深的地震測井，Talisman獲得了IPC成為F區(qū)的經(jīng)營者。</p><p>　　持續(xù)低迷的油價抑制了該地區(qū)的所有活動直到2004年獲得了C區(qū)和D區(qū)800km2的地震數(shù)據(jù)。在這一年，洛克霍普勘探公司獲得了這一地區(qū)的開發(fā)許可。</p><p>　　200

66、5年初，Desire公司斥巨資投資北?？颂m盆地深部鉆井，Rockhopper加入到C區(qū)和D區(qū)。在本文攥寫時（2005年12月）Desire公司正在尋找鉆機(jī)盡快開鉆。在2005年Desire公司承擔(dān)了F區(qū)100%的產(chǎn)權(quán)，Rockhopper獲得了該地區(qū)更多的開發(fā)許可。最近的開發(fā)許可位置如圖1所示。</p><p>　　圖1.北福克蘭盆地目前許可和前景圖</p><p><b>　　

67、地質(zhì)</b></p><p>　　北福克蘭盆地?fù)碛幸惶滓躁懴噘_紀(jì)到下白堊紀(jì)為主下附泥盆紀(jì)的地層。這些陸相沉積物上附晚白堊紀(jì)到新近紀(jì)海相沉積序列。在盆地D區(qū)最深部分總截面厚度要超過5千米。</p><p>　　這些陸相巖層在一個大的湖泊中沉積，幾條大型河流匯入形成砂巖三角洲和扇形沉積，如圖2所示。這個湖和現(xiàn)在東非的湖泊大小相近，湖中慢慢沉積細(xì)粒粘土礦物，這些物質(zhì)在缺氧環(huán)境下沉積

68、導(dǎo)致巖石有機(jī)碳含量很高，這些巖石是石油主要來源。最終在早白堊紀(jì)，海平面上升造成盆地海相條件確立。</p><p>　　北福克蘭群島盆地含有尋找烴類物質(zhì)的所有條件，即烴源巖，儲集層，蓋層和圈閉。</p><p>　　圖2.北?？颂m盆地下白堊紀(jì)地質(zhì)圖</p><p><b>　　烴源巖</b></p><p>　　1998年

69、鉆井確定了厚的（超過1000米）被認(rèn)為是世界上最富集的陸相石油烴源巖，6口井中5口烴源巖是不成熟的，只有一口是成熟的。從井14/10-1中開采出來的石油API值為27已標(biāo)記在表面。</p><p>　　烴源巖在盆地更深部分已經(jīng)成熟，那里的溫度和壓力已經(jīng)足夠高到產(chǎn)生和排泄石油。這一地區(qū)的成熟烴源巖“廚房”位置如圖3所示。只有基部烴源巖是有大部成熟源巖組成。</p><p>　　2000年Ri

70、chards（英國地質(zhì)調(diào)查）和Hiller(Shell公司)估計(jì)在這些源巖中曾產(chǎn)生和排泄石油600億桶。還有一個更深的獨(dú)立成熟源巖可生成天然氣，就像在井14/5-1中深部良好的天然氣顯示一樣。</p><p><b>　　蓋層</b></p><p>　　整個地區(qū)豐富的粘土礦物含有未成熟的頂部，這提供了良好的潛在封閉條件。</p><p>&l

71、t;b>　　儲層</b></p><p>　　Desire公司認(rèn)為有效儲集層的發(fā)現(xiàn)是該地區(qū)發(fā)現(xiàn)烴類物質(zhì)商業(yè)儲量的關(guān)鍵。例如，優(yōu)質(zhì)砂巖可產(chǎn)生較高的產(chǎn)油率可以成為商用。然而預(yù)期的地震特性如利茲預(yù)測提供的良好預(yù)測表明良好的優(yōu)質(zhì)儲積巖會顯現(xiàn)出來。</p><p>　　圖3.北?？颂m盆地?zé)N源巖分布圖</p><p><b>　　圈閉</b&g

72、t;</p><p>　　二維，特別是三維地震數(shù)據(jù)顯示了大量的結(jié)構(gòu)和地層圈閉機(jī)制。</p><p>　　Play Concept</p><p>　　1000米厚的烴源巖只有在深部盆地的基底是成熟的。上附未成熟源巖是一種有效的局部圈閉，見圖4，這被認(rèn)為阻擋了石油向上附巖層的運(yùn)移。這些較淺地層是第一次鉆井工程的主要目標(biāo)，把握這些地層的困難可能是導(dǎo)致商業(yè)烴化物發(fā)現(xiàn)失敗的

73、原因。</p><p><b>　　圖4. 未檢測區(qū)域</b></p><p>　　Desire公司認(rèn)為主潛力盆地可能位于與圖4所示烴源巖同一水平位置的未檢測盆地的兩翼部分。從這一位置，石油從成熟烴源巖到預(yù)測儲積巖只有很短一段距離。此外，最好的油氣開發(fā)可能位于盆地的兩翼。2005年三維地震數(shù)據(jù)的獲得就是專門為測試這個新模型而設(shè)計(jì)的。</p><p&

74、gt;<b>　　前景預(yù)測</b></p><p>　　9個前景已經(jīng)被認(rèn)同（圖1），多種擁有多重目標(biāo)。只有他們中的兩個將被詳細(xì)的描述以說明這個盆地所發(fā)現(xiàn)前景類型的多樣性。</p><p><b>　　利茲預(yù)測</b></p><p>　　這將是最大的也是下一輪鉆井工程第一個勘探預(yù)測。這是一個地層圈閉，基于地震振幅映射顯示有

75、一個入湖大型河流沉積形成的扇形三角洲（圖5所示）。這個扇形三角洲從上部傾斜斷層分離，側(cè)圈閉由富含石油的源巖組成，它們在三角洲的末端是成熟的。補(bǔ)給通道顯示了地震數(shù)據(jù)上的褶皺，這可能是形成良好儲層的粗砂巖存在的證據(jù)。除了位于井口位置的三角洲需要利茲檢測外，位于貝絲三角洲的邊緣部分也需要鉆探。水深大概有350米，井的總深大概有3000米。</p><p><b>　　Ninky預(yù)測</b><

76、/p><p>　　這是一個典型的構(gòu)造圈閉。在成熟烴源巖上部的大量水平位置，構(gòu)造輪廓在斷層處是閉合的。不像利茲預(yù)測那樣油氣沿?cái)鄬哟瓜蜻\(yùn)移充滿整個圈閉，而是基于地震，斷層從成熟烴源巖到上覆圈閉明確定義。</p><p>　　圖5.上白堊紀(jì)沉積環(huán)境利茲預(yù)測前景圖</p><p>　　由于這次勘探是在盆地中心進(jìn)行，細(xì)薄儲層可能被發(fā)現(xiàn)，但是地層振幅映射顯示，厚的遠(yuǎn)端三角洲砂巖可能

77、會出現(xiàn)。這次鉆探位于水深約400米總計(jì)劃深度約3100米深的地方。</p><p><b>　　環(huán)境</b></p><p>　　Desire公司承認(rèn)?？颂m群島環(huán)境的全球重要性并承諾會做任何可能的事情把開發(fā)帶來的環(huán)境危害最小化。所有的開發(fā)均按照英國北海標(biāo)準(zhǔn)進(jìn)行，只有水基鉆井和低毒化學(xué)物質(zhì)會被使用。</p><p>　　為了確定三口井開發(fā)可能帶來

78、的影響，Desire公司委托RPS公司，歐洲環(huán)境評估的領(lǐng)導(dǎo)者，來進(jìn)行環(huán)境影響評估（EIA）。RPS提出了大量的把環(huán)境影響最小化的措施并得出結(jié)論：被提議的業(yè)務(wù)可以操作并不給環(huán)境帶來大的影響。環(huán)評詳情可見Desire公司網(wǎng)站 www.desireplc.co.uk 。</p><p><b>　　鉆井</b></p><p>　　北?？颂m盆地鉆探是相當(dāng)簡單的。第一輪鉆井工

79、程確定沒有太大的鉆井危害，一個3000米深的井可以20天內(nèi)完成。另外，水深（350-410米）在今天看來也不深，天氣狀況和中央北海類似。</p><p>　　結(jié)果不再需要深水重型鉆機(jī)，在以往工程中，Desire公司需要使用第三代半潛式鉆機(jī)，如圖6所示。</p><p>　　圖6.半潛式鉆井設(shè)備圖</p><p><b>　　發(fā)展</b><

80、/p><p>　　在商業(yè)石油勘探史上，最可能的開發(fā)方案是世界上廣泛應(yīng)用特別是在北海的開發(fā)方案。它包括海底產(chǎn)油井的完成和變成浮動的生產(chǎn)、儲存和卸載設(shè)施。石油將被來回穿梭的油輪運(yùn)輸?shù)饺魏蔚胤降臒捰蛷S。島上可能會需要最小的設(shè)施。</p><p><b>　　經(jīng)濟(jì)</b></p><p>　　基于以上的假設(shè)，大量的數(shù)經(jīng)濟(jì)學(xué)模型已經(jīng)建立。由于福克蘭群島優(yōu)惠的

81、財(cái)政政策，相對較小的油田可能成為商用。例如，基于30美元/桶的石油價格和10%的折現(xiàn)因子，含有40,000，000桶的油田就有商用價值。盡管開發(fā)成本有所增長，但是2005年石油價格也有大幅攀升，商業(yè)勘探從整體上看是平衡的。</p><p><b>　　結(jié)論</b></p><p>　　北福克蘭盆地油氣生成系統(tǒng)已經(jīng)確立。</p><p>　　這一

82、地區(qū)有潛力成為主要的油氣省，但只有進(jìn)一步的鉆井才能證明這一點(diǎn)。</p><p>　　Desire公司已經(jīng)確立了9個勘探前景，鉆井恢復(fù)準(zhǔn)備工作正在逐步進(jìn)行，只要合適的鉆機(jī)已簽訂。</p><p>　　環(huán)境評估最終顯示鉆井開發(fā)工程不會對環(huán)境帶來顯著的影響。</p><p>　　更多的開發(fā)項(xiàng)目可以在Desire公司網(wǎng)站上獲得www.desireplc.co.uk。<

83、/p><p><b>　　參考文獻(xiàn)：</b></p><p>　　Richards, P. C. and Hillier, B. V., 2000 Post-Drilling Analysis of the North Falklands Basin - Part 2:Petroleum System and Future Prospects. Journal of Pe