1、Petroleum Sience in English,Instructor: Guo Qing,Chapter Six Petroleum Production Production may be considered as that section of the oil industry concerned with conveying（傳送） hydrocarbons（烴） from the reservoir（油藏） to surface, and the separation（分離） of oil, gas, water, and solids to the extent neces

2、sary to provide a saleable primary product（初級(jí)產(chǎn)品） such as crude oil, NGL(natural gas liquids), and gas.,Producing oil is an intricate（復(fù)雜的） art. Oil can be pumped out of the sponge rock（海綿狀巖體） at a certain maximum（最大的） rate, determined by the viscosity（粘稠度） of the oil and the quality（質(zhì)量） of the reserv

3、oir. Oil production must be managed carefully to avoid clogging（堵塞） or collapsing（跨塌） the pores（孔隙）, which can prevent a well from accessing（獲?。?much of the reservoir. Pumping too fast, pumping too slowly or interrupting（間歇式的）production can all damage an oilfield. And not only one but many wells mus

4、t be drilled to fully exploit（開(kāi)發(fā)） the reservoir, raising the expense（費(fèi)用） of production.,Drilling curved（斜的） and horizontal（水平的） wells into reservoirs is a common technique to increase production. Another technique involves fracturing（壓裂） the reservoir rock by pumping fluids and sand into it under hi

5、gh pressure. The fluids open cracks（裂隙）, and the sand keeps them open to let out the petroleum. This can overcome low permeability（滲透率）. Treating the wellbore（井筒） with various acids（酸） or solvents（溶劑） can also raise permeability. This technique is called acidizing（酸化） .,One of the most commonly uses

6、 methods of fracturing is hydraulic fracturing（水力壓裂）. Hydraulic fracturing may be defined as the process of creating a facture（裂縫） or fracture system（裂縫系統(tǒng)） in a porous medium（孔隙介質(zhì)） by injecting a fluid under pressure through a well bore in order to overcome native stresses（天然壓力）and to cause material

7、 failure（巖石破裂） of the porous medium（孔隙介質(zhì)）. Briefly it is the creation（形成） and preservation（保持） of a fracture in a reservoir rock（儲(chǔ)集巖）. To fracture a reservoir rock, energy must be generated by injecting a fluid down a well and into the formation（地層）.,Reservoir Production Mechanisms（機(jī)理） The productio

8、n mechanisms which owe their existence to these sources of energy are referred to as “water drive”（水驅(qū)）, “solution gas drive” (or “depletion drive”)（溶解氣驅(qū)）, and “gas cap drive”（氣頂驅(qū)） respectively. The natural drainage of the oil through the reservoir rock under its own gravity（重力） provides a further pr

9、oduction mechanism. A combination of drive mechanisms may operate in the same reservoir. Generally, however, one system will dominate（占支配地位） the others and the relative importance of these will change with time during the production of oil and for this reason it is convenient to consider each type o

10、f drive mechanism separately and care must be taken during the development of an oil field to use the reservoir drive pressures to their maximum extent（最大程度）.,Water drive（水驅(qū)）: reservoirs drive their energy from water below the oil. Water sweeps the oil up and into the wells. Water drive (edge-water

11、drive) is considered to be the most effective recovery mechanism of all. In order to enable this mechanism to function at its maximum effectiveness（最大程度上發(fā)揮作用）, it may be necessary to limit（控制） the rate of oil production so that the aquifer water（淡水） can enter the vacated（騰出空隙的） section of the oil-be

12、aring zone as fast as the oil is withdrawn.,If the oil production rate exceeds（超過(guò)） this limit there will be a decline（下降） in the reservoir pressure and a consequent reduction（相應(yīng)地降低） in the energy available to produce the oil.,Solution gas drive（溶解氣驅(qū)） (dissolved gas drive or depletion drive) is cause

13、d by gas dissolved in the oil. In the subsurface（地下）, the oil is under high pressure. The higher the pressure, the more gas that can be dissolved in the oil. When a well is drilled into the oil reservoir, pressure is relieved（緩解） and gas bubbles（氣泡） form in the oil.,Expanding gas bubbles（氣泡膨脹） force

14、 the oil into the well. Dissolved gas drive is very inefficient, producing only from 10% to 30% of the oil in place（地質(zhì)儲(chǔ)量）, leaving the rest in the reservoir.,Gas cap drive（氣頂驅(qū)） (free gas drive) derives（獲?。?its energy from the pressure of the gas in the free gas cap. The expanding free gas cap sweeps

15、（掃） the oil into the well. Gas cap drive is relatively efficient, producing 355 to 50% of the oil in place.,This type of reservoir is best developed with wells producing only from the oil portion of the reservoir, leaving the gas in the free gas cap to supply the energy.,gravity（重力） is also a drive

16、mechanism. It is present in all reservoirs, as the weight of the oil column creates pressure causing oil to flow into the well. This is usually insignificant（不太重要）compared to original pressures（原始?jí)毫Γ?created by the other drive mechanisms. In the later stages（階段） of oil production in a dissolved gas

17、drive reservoir, however, gravity drainage（重力驅(qū)） becomes significant（重要）. This is called a gravity drainage pool（重力驅(qū)動(dòng)油藏）.,（Hydrocarbon Recovery Ratio）,（Total Produced Hydrocarbon ）,（Reserves in Place）,100%,=,Recovery ratio（采收率）,Production of Oil and Gas,Primary recovery（一次采收率） In primary recovery-the

18、 initial approach to produce oil-natural reservoir pressure（油藏的天然壓力）or simple mechanical pumps（簡(jiǎn)單的機(jī)械泵） are used to raise oil to the surface. Until about 20 years ago recovery factors of over 20% during the primary production phase（一次生產(chǎn)階段） were most exceptional（不常見(jiàn)的）. However modern techniques of fie

19、ld development and production have improved these figures considerably and now the average primary recovery（平均一次采收率） is between 20% and 30%. A number of methods can improve primary recovery.,The most common is infill drilling ,which involves drilling more wells into the same pool so the oil does not

20、 have to travel as far through the rock to reach a wellbore. More than one directional well（定向井） can be drilled from a common platform（共同的鉆井平臺(tái)）. Horizontal drilling（水平鉆井）, which extends（使延伸） the wellbore into a much large portion of the oil-bearing formation, has been employed since the late 1980s t

21、o improve production and enhance recovery.,Secondary recovery（二次采收率）: Further oil production can be obtained by injecting（注入） water (waterflooding)（水驅(qū)） or natural gas to maintain（保持） reservoir pressure and push（推） oil out of the rock, therefore achieve more efficient displacement（驅(qū)替） of oil. the dev

22、elopment of secondary recovery schemes（方案） to be an almost standard practice in new fields has almost doubled（使翻倍） the overall recovery percentage.,Tertiary recovery（三次采收率）: The third major phase of crude oil recovery which uses more advanced（先進(jìn)的） methods aiming to（旨在） increase oil recovery ratio. T

23、he most common tertiary recovery method for light and medium crude oil（輕質(zhì)油和中質(zhì)油） is miscible flooding（混相驅(qū)）. In this procedure, natural gas liquids (ethane, propane and butane) are injected into special injections wells（專門的注入井）. When dissolved, these liquids reduce（降低） surface tension（表面張力） and viscos

24、ity（粘稠度） to help release（釋放） the oil from the reservoir rock. Carbon dioxide（二氧化碳） has also been used for miscible floods. This phase is applied before the well can be abandoned（廢棄）. More Researches are conducted continuing to improve the recovery ratio.,Some factors that will limit producing rate.

25、1. Low reservoir permeability（油藏滲透率低） 2. Low reservoir pressure for depth （井深油藏壓力低） 3. Formation damage（地層破壞） 4. Wellbore or tubing plugging（井筒或油管堵塞） 5. High viscosity oil （高粘稠度油） 6. Excessive back pressure on formation （地層回壓過(guò)高） 7. Inadequate artificial lift （人工舉升不足） 8. Other situation （其他情況）,Enhanc

26、ed Oil Recovery（提高采收率） Enhanced oil recovery (EOR) processes have their objective（目標(biāo)） to increase of oil recovery for reservoirs depleted（衰竭） by secondary recovery with water flooding or gas injection. The EOR processes can be divided into three categories; chemical（化學(xué)驅(qū)）, thermal（熱力驅(qū)） and miscible（混

27、相驅(qū)）, which can be further subdivided into various categories. Thermal processes have been used extensively for the displacement of heavy oil（重油驅(qū)替）, where as chemical and miscible displacement processes have been employed for the recovery of light oil（輕質(zhì)油開(kāi)采）.,Light oil: thinner, freely flowing crude

28、oil of light specific gravity（特殊比重）. Heavy oil: dense, viscous oil, with a high proportion（比例） of bitumen, that is difficult to extract（開(kāi)采） with conventional （傳統(tǒng)的）techniques and is more costly to refine.,API degrees: the American Petroleum Institute（美國(guó)石油協(xié)會(huì)） defines the density（比重） of oil in gravity

29、units called API degrees（API度）. The API degrees are expressed in the following formula（公式）:,API degrees,=,141.5,-,Special gravity 60/60 F,-,131.5,Where specific gravity 60/60 F (15.5 C) is the gravity of the oil at 60 F compared with that of water at 60 F . Note that API degrees are inversely propor

30、tional（成反比） to density. Thus light oil have API gravities of over 40 (0.83 specific gravity), whereas heavy oils have API gravities of less than 10 (1.0 specific gravity). Heavy oils are thus defined as those oils that are denser than water.,Microbial enhanced oil recovery （微生物提高采收率法） The use of mic

31、ro-organisms（微生物） and their metabolic products（代謝產(chǎn)物） to stimulate oil production is receiving interest worldwide. The technique involves the injection of selected（經(jīng)過(guò)挑選的） micro-organisms into the reservoir.,EOR（提高采收率）,Chemical flooding（化學(xué)驅(qū)）,Thermal recovery（熱力驅(qū)）,Miscible flooding（混相驅(qū)）,Surfactant floo

32、ding（表面活性劑驅(qū)）,Polymer flooding（聚合物驅(qū)）,Caustic flooding （堿法驅(qū)）,In-situ combustion（火燒油層）,Steam injection（蒸汽驅(qū)）,Wet combustion（濕式燃燒）,Miscible slug process（混相段塞法）,Enriched gas process （富氣注入法）,High pressure lean gas process（高壓貧氣注入法）,Mutual solvent process（中性溶劑注入法）,CO2 process （二氧化碳注入法）,Illustration of Steam

33、Flood Process,There are three main types of conventional natural gas wells. Since oil is commonly associated with natural gas deposits（天然氣藏）, a certain amount of natural gas may be obtained from wells that were drilled primarily for oil production. These are known as oil wells（油井）. In some cases, th

34、is “associated” natural gas is used to help in the production of oil, by providing pressure in the formation for the oils extraction（石油開(kāi)采）. The associated natural gas may also exist in large enough quantities to allow its extraction along with the oil. Natural gas wells（天然氣井） are wells drilled speci

35、fically for natural gas, and contain little or no oil.,Condensate wells（凝析油井）are wells that contain natural gas, as well as a liquid condensate（凝析油）. This condensate is a liquid hydrocarbon mixture that is often separated from the natural gas either at the wellhead, or during the processing of the n

36、atural gas. Depending on the type of well that is being drilled, completion may differ slightly. It is important to remember that natural gas, being lighter than air, will naturally rise to the surface of a well. Because of this, in many natural gas and condensate wells, lifting equipment and well t

37、reatment are not necessary.,Artificial Lift（人工舉升） In most oilfields reservoir pressure decline（下降） and increased volumes（體積） of water produced with the oil give rise to（導(dǎo)致） conditions where the wells will not flow unaided（沒(méi)有幫助）. A number of options, such as gas lift（氣舉）, subsurface pumps（潛泵） and rod

38、 pumps（有桿泵）, are open to assist oil flow to surface.,A Horse Head Pump for mechanic production well,Key words separation（分離） primary product（初級(jí)產(chǎn)品） the sponge（海綿狀巖體） viscosity（粘稠度） clogging（堵塞） collapsing（跨塌） Interrupting production （間歇式的生產(chǎn)） exploit（開(kāi)發(fā)） fracturing（壓裂） cracks（裂隙） acids（酸） solvents（溶劑） acidizing（酸化） .,hydraulic fracturing（水力壓裂） porous med