油氣層保護(hù)、損害診斷(精要版)

1、胡大平：聽課人的層次第一層次:“水杯法”，帶了水杯，聽課時(shí)喝得舒服，不記筆記，沒有思考，回去后就沒有水喝。一時(shí)痛快，沒有沉淀第二層次:“水桶法”，提一個(gè)水桶來，當(dāng)場(chǎng)喝得過癮，又記筆記，反思過去，設(shè)立目標(biāo)，準(zhǔn)備行動(dòng)第三層次:“鉆機(jī)法”，有自己的實(shí)踐和理論模式，帶著鉆機(jī)來聽課，不僅當(dāng)場(chǎng)喝飽，還學(xué)習(xí)到了他人的鉆井技術(shù)，豐富自己的理論。外行看熱鬧，內(nèi)行看門道，俗稱“偷藝”第五章 油氣層損害診斷康毅力 油氣藏地質(zhì)及開發(fā)工程國家重點(diǎn)實(shí)驗(yàn)室中國石油天然氣集團(tuán)公司油井完井技術(shù)中心西 南 石 油 大 學(xué) 石 油 工 程 學(xué) 院2009年10月21日提 綱0、損害機(jī)理及診斷概述1、DST測(cè)試2、測(cè)井分析3、井史分

2、析4、相鄰井生產(chǎn)動(dòng)態(tài)對(duì)比5、壓力不穩(wěn)定試井分析6、節(jié)點(diǎn)系統(tǒng)分析7、生產(chǎn)效率剖面8、生產(chǎn)測(cè)井9、巖心分析油氣層損害機(jī)理潤濕性改變水鎖凝析液鎖液相圈閉（水，油）氣錐或水錐毛管壓力的改變?nèi)闋钜憾氯惩僚蛎浳⒘＿\(yùn)移云母解體無機(jī)垢注導(dǎo)致的無機(jī)垢酸化引起的二次沉淀碳酸鹽溶解沉淀酸渣有機(jī)垢石蠟，瀝青沉積外來固相的堵塞油氣層固相物堵塞，出砂細(xì)菌損害應(yīng)力損害四大類型物理損害化學(xué)損害生物損害熱力損害損害描述儲(chǔ)層損害診斷方法Methods for Recognition of Formation Damage8儲(chǔ)層物性條件差飽和度、孔隙度、滲透率、裂縫存在儲(chǔ)層損害作業(yè)因素,如完井作業(yè)中：射孔參數(shù)不合理（孔眼密度低、

3、孔眼太小，深度不夠，打開不完善）水泥環(huán)質(zhì)量差、強(qiáng)度不高等低產(chǎn)原因損害可能存在的標(biāo)志壓力與產(chǎn)量關(guān)系變化波動(dòng)很大產(chǎn)量低于經(jīng)濟(jì)下限產(chǎn)量要比中途測(cè)試、巖心分析、測(cè)井計(jì)算所預(yù)測(cè)值低得多同一油氣藏，儲(chǔ)層物性完全相同，但產(chǎn)量差異很大生產(chǎn)井出砂測(cè)試時(shí)出現(xiàn)表皮效應(yīng)有機(jī)結(jié)垢和無機(jī)垢沉積注入能力急劇下降，措施或處理周期短診斷技術(shù)DST測(cè)試分析測(cè)井分析生產(chǎn)史分析相鄰井產(chǎn)量對(duì)比壓力不穩(wěn)定試井分析生產(chǎn)效率剖面生產(chǎn)測(cè)井巖心實(shí)驗(yàn)分析井下照相井下取樣分析節(jié)點(diǎn)分析提 綱0、損害機(jī)理及診斷概述1、DST測(cè)試2、測(cè)井分析3、井史分析4、相鄰井生產(chǎn)動(dòng)態(tài)對(duì)比5、壓力不穩(wěn)定試井分析6、節(jié)點(diǎn)系統(tǒng)分析7、生產(chǎn)效率剖面8、生產(chǎn)測(cè)井9、巖心分析1

4、、鉆柱測(cè)試（Drill Stem Tests）In the early stages of exploratory drilling into a new formation, Drill Stem Testing is normally used to confirm the production potential of a hydrocarbon show However, if geochemical analysis of drill chips and cuttings establishes the presence of hydrocarbons, but DST shows

5、the tested interval to be non-productive, then formation damage possibly existsAnalysis of the pressure versus time data generated during DST can be used semi-quantitatively to determine the severity of damage by calculating the skin. It is, however, desirable to exercise caution during initial DST,

6、 since pressure surges and high drawdown can initiate fines movement. Review of prior operational history is then necessary to establish which aspect of the drilling process may have given rise to damage.The following figure shows a typical DST output illustrating a high permeability damaged zone. N

7、otice the following features that are characteristic of damage:Short radius curve along CDE* An almost flat slope along DEA sharp rise after closed-in period as along EFA high differential pressure between a closed-in and final flow pressure (EG)DST Trace Showing Extreme Damage in a High Productivit

8、y Zonept坐封開井關(guān)井開井關(guān)井開封Exercise in Class1。指出下列測(cè)試卡片曲線中，A、B兩口井是否存在損害，并說明理由。2。油田開發(fā)中哪些作業(yè)可以增加滲透率pt曲線A曲線B測(cè)井曲線上的泥漿侵入響應(yīng)Mud Invasion Effects on Well Logs2、測(cè)井分析中子孔隙度降低感應(yīng)電阻率降低The degree and depth of filtrate invasion during drilling can be estimated from deep, medium and shallow resistivity devices (e.g Laterolog

9、) or conductivity devices such as dual induction logs or combinations thereof (e.g Induction-Laterolog). These devices will give semi-quantitative indications of possible damage during production. Analytical models presented by Hassen for describing filtrate invasion can also be used to estimate the

10、 depth of invasion particularly in cases where the depth of investigation of the logging tool is limited.濾液侵入程度和深度可以從深、中、淺電阻率測(cè)井或雙感應(yīng)測(cè)井曲線進(jìn)行半定量評(píng)價(jià)If problems are identified by DST and logs, further investigation is still necessary to pinpoint what aspect of the drilling/completion program is responsible

11、 for the apparent poor formation response作業(yè)史分析 Daily drilling/ cementing/completion reports, mud and completion, workover andwell stimulation fluid programs should be reviewed (Allen). 濾失量、pH值、鉆速隨深度變化Fluid loss, pH and ROP data shouldbe plotted as function of depth to help identify any zones where h

12、igh pH-filtrate loss had occurred. Such zones are good candidates for damage.An individual well analysis then quantifies whether or not the well is producing topotential. If not, why? And the production potential behind pipe.3、井史分析（Well History Review）The production potential of an ideal well in a f

13、ield, pool or lease is evaluated, while recognizing that the well potential will depend on the following factors:Type of drive mechanismStatus of depletionRock and fluid properties (Kh, qh, 1L, Krel, PVT, etc.)The productivity index (PI) is typically computed for unbounded and bounded reservoirs fro

14、mDarcys Law for Steady State Incompressible Flow as follows:Comparison of theoretical to actual production rates can be used to establish whether or not the well is producing at exptected capacity, for the given operating drive mechanism as shown on Figure 5-4A and B.Actual vs Theoretical Specified

15、Productivity IndicesProduction History Showing Well Damage Problem提 綱0、損害機(jī)理及診斷概述1、DST測(cè)試2、測(cè)井分析3、井史分析4、相鄰井生產(chǎn)動(dòng)態(tài)對(duì)比5、壓力不穩(wěn)定試井分析6、節(jié)點(diǎn)系統(tǒng)分析7、生產(chǎn)效率剖面8、生產(chǎn)測(cè)井9、巖心分析When a well experiences an abnormal gradual decline in productivity as compared to other wells penetrating the same formation with similar initial tran

16、smissibility (Kh) values, formation damage can be suspected. Analysis of semilog plots of production rate versus time data forthe candidate well and an offset well can be used to compare their relative productiondecline rates. If the candidate well shows a higher decline rate, then the existence of

17、formation damage is most likely.Figure 5-8 shows a candidate Well B penetrating a similar zone as an offset Well A, but exhibiting a higher decline rate than Well A as shown on Figure 5-9.4、相鄰井生產(chǎn)動(dòng)態(tài)對(duì)比Comparison of ProductionPerformance of Offset WellsComparison of the production performance of Wells

18、A and B can also be accomplished bycomputing their respective theoretical and actual specific productivity indices (SPI) as follows:Problem 5-2 illustrates the use of SPI for comparative evaluation of the productionperformance of two offset wells in a given lease.提 綱0、損害機(jī)理及診斷概述1、DST測(cè)試2、測(cè)井分析3、井史分析4、相

19、鄰井生產(chǎn)動(dòng)態(tài)對(duì)比5、壓力不穩(wěn)定試井分析6、節(jié)點(diǎn)系統(tǒng)分析7、生產(chǎn)效率剖面8、生產(chǎn)測(cè)井9、巖心分析Extensive body of literature exists on the use of well test analysis for diagnosis of damagedformations (Miller et al.; Horner; Hurst; Van Everdingen; Thomas;, Nowak et al.; Matthews et.al.; Mcleod et al.; Earlougher).Pressure transient well test analys

20、is is perhaps the most effective field technique fordetection of formation damage. Buildup and drawdown tests can be used to establish the existence of formation damage particularly in wells with a high productivity index. Analysis of the test data by any appropriate technique (Horner, Gringarten et

21、 al.; Bourdet et al.) canyield a damage skin factor, S defined by Hawkins. The skin factor is a composite of two skins- one due to damage, S1 and another, S2 due to restricted entry into the wellbore caused by mechanical factors.5、壓力不穩(wěn)定試井分析 Pressure Transient Well Test AnalysisThe skin due to mechan

22、ical factors can be computed by the methods of Brons et al. And Odeh. The skin due to damage, S1 is a cumulative effect of damage from the various operations. Thus, pressure transient analysis is still handicapped by not being able to identifyat what stage of well development the damage occurred.Bui

23、ldup and/or fall-off tests are useful for evaluation of the damage and stimulation potentialof any well.理想的油藏模型Pw (th + t)/t 曲線壓恢與壓降測(cè)試分析關(guān)井后理論與實(shí)際的井底壓力動(dòng)態(tài)壓力恢復(fù)壓力降落The skin factor, S can be computed from a build-up or fall-off curve as follows:where:Pw1hr=Pressure on the straight line portion of the buil

24、d-up or fall-off curve at a shut-in time of 1 hourk=bulk formation permeability, md=porosity, fraction=viscosity, cpc=compressibility, psi-1表皮系數(shù)與附加壓降表皮系數(shù)S與損害帶滲透率和深度有關(guān)式中：Kd損害帶滲透率K地層原始滲透率rd損害帶半徑當(dāng) SD0 ，儲(chǔ)層可能被損害，因 Kd K SD KRd 需要通過其它手段確定，如測(cè)井和模擬實(shí)驗(yàn)Kd 可由 K, rd 和 S 通過下式計(jì)算：損害帶半徑和損害帶滲透率的測(cè)定The additional pressur

25、e drop incurred in the near wellbore region due to the presence of a damaged area, rd, is given by:(P)s=141.2 qB/kh SD=141.2 (m/162.6) SD(P)s=0.87 ms(P)s is the change in the following bottomhole pressure if th altered zone permeability, kd, was equal to the bulk formation permeability, kFor a new r

26、eservoir where pressure transient has not reached the true boundary:re = =0.00633 (K/c)th=Horner Time = 提 綱0、損害機(jī)理及診斷概述1、DST測(cè)試2、測(cè)井分析3、井史分析4、相鄰井生產(chǎn)動(dòng)態(tài)對(duì)比5、壓力不穩(wěn)定試井分析6、節(jié)點(diǎn)系統(tǒng)分析7、生產(chǎn)效率剖面8、生產(chǎn)測(cè)井9、巖心分析并不是所有的表皮系數(shù)都是由儲(chǔ)層損害引起的S損害=S總-S擬完井設(shè)計(jì)或井下管柱結(jié)構(gòu)不合理導(dǎo)致擬表皮系數(shù)限制流入：紊流，裂縫與井筒斜交偏心井射孔孔密、孔深、相位不合理機(jī)械節(jié)流舉升系統(tǒng)不匹配：油管徑小，氣舉閥不合理，地面回壓高薄互層

27、油藏井斜6、節(jié)點(diǎn)系統(tǒng)分析Nodal Systems AnalysisNodal analysis has evolved as a powerful tool for detection of formation damage and evaluation of effective stimulation procedures. As defined by Brown et al., nodal analysis is a systems approach to optimization of oil and gas wells by thorough evaluation of thecom

28、plete producing system. Mcleod referred to this method as Well Flow Analysis in that each component of the well system is checked to determine its contributions to any flow restrictions.自噴井系統(tǒng)中的各種壓力損失泄流邊界 井筒（射孔孔眼）井口與油嘴分離器儲(chǔ)罐氣藏油管管線輸送管線壓力PePwfPwhPspPsTrh氣井壓力剖面The procedure for developing the Inflow Perf

29、ormance Relationship, IPR, (sand face pressure versus rate), Tubing Intake Curve (bottom hole tubing pressure versus rate), Differential pressure available for any rate across the completed interval, and the pressure drop across the completion for various rates have been documented by Mcleod. The pr

30、essure drop across the completion varies with the following completion parameters: length of perforated interval, perforation diameter, length of perforation tunnel, and permeability of the tunnel. Figure 5-14 shows a typical nodal analysis curve which permits determination of optimum production rat

31、es for various wellbore mechanical considerations. When the predicted and actual performance of the oil or gas well are compared, it is easy to establish that the well is not producing at capacity and that formation damage may be present. Nodal Analysis Curve Relates Production Rate to Bottomhole Pr

32、essure (BHP) or Change in Pressure (P). Optimum Production Rates are shown for various perforation densities (SPF)壓力產(chǎn)量曲線lbesn developed a production efficiency pro for evaluation of well performance.This technique is analogous to Nodal Analysis. However, the technique relates the radius of possible

33、damage to what the author calls incremental pore volume, IPV and incremental fluid velocity, IFV. The radius from the wellbore to any zone of the reservoir is plotted asfunction of both IPV and IFV. The point of intersection of the IPV and IFV profiles defines a particular critical radius, Rci for i

34、nitial reservoir production and initial pressure, Pi. If the current production is used to compute a new IFV profile, the new intersection of IFV with IPVwill define Rc2 for current pressure, P2. If the ratio of Rc2/Rci P2/Pi,the well is operatingabove optimum, if Rc1/Rc2 = P2/Pi, the well is operat

35、ing at optimum rates and if Rc2/Rcl P2/P1, then the well is producing below optimum and is possibly damaged.Figure 5-15 shows a schematic of a cylinderical shell around the wellbore which illustratesthe concept of production efficiency profile (PEP).7、生產(chǎn)效率剖面Production Efficiency ProfileThe pore volu

36、me, Vpi, at a radius, RI (inches), from the wellbore is given by:At a radius, R2, where R2 = R1 + 1 inchIncremental pore volume (IPV, Vp within the one inch by one foot shell is given by:提 綱0、損害機(jī)理及診斷概述1、DST測(cè)試2、測(cè)井分析3、井史分析4、相鄰井生產(chǎn)動(dòng)態(tài)對(duì)比5、壓力不穩(wěn)定試井分析6、節(jié)點(diǎn)系統(tǒng)分析7、生產(chǎn)效率剖面8、生產(chǎn)測(cè)井9、巖心分析生產(chǎn)測(cè)井可以作為診斷損害的補(bǔ)充手段生產(chǎn)測(cè)井的基本功能是追蹤套

37、管內(nèi)及套管外 流體運(yùn)動(dòng)，監(jiān)測(cè)流體接觸界面的運(yùn)動(dòng)情況 生產(chǎn)或注入流動(dòng)剖面用于確定各個(gè)射孔層段流量的分布， 以判別某個(gè)層是否存在損害 技術(shù)應(yīng)用轉(zhuǎn)子流量計(jì)（Spinner Flowmeter ）流體密度計(jì)（ Gradiomanometer ）8、生產(chǎn)測(cè)井（Production Logging） The spinner flowmeter is used to measure fluid velocities in the tubing or casing(Figure 5-16). The tool is centrally located within the fluid column and m

38、oved at aconstant speed against the direction of flow. The spinner speed is linearly relatedto the fluid velocity relative to the tool and recorded continuously as function ydepth. A typical spinner tool is the continuous flow meter which is useful for determination of production and injection profi

39、les, analysis of fracture or acidizing jobs for evaluation of productivity index.8.1 轉(zhuǎn)子流量計(jì)（Spinner Surveys）After McKinleyAfter McKinleyThe gradiomanometer tool is designed to determine the changes in pressure gradient. This tool is useful in high flow rate wells and is well-suited for pro in two pha

40、se flow. This tool measures the pressure difference in the well between any two points and if frictional losses are negligible, then the pressure difference is equal to the hydrostatic pressure gradient, due to the average fluid density in the pipe over the investigated interval.8.2 流體密度計(jì)Gradiomanom

41、eter SurveyHold-up Determination from Grandiomanometer Data8.3 其它方法溫度測(cè)井井下電視井壁取樣分析提 綱0、損害機(jī)理及診斷概述1、DST測(cè)試2、測(cè)井分析3、井史分析4、相鄰井生產(chǎn)動(dòng)態(tài)對(duì)比5、壓力不穩(wěn)定試井分析6、節(jié)點(diǎn)系統(tǒng)分析7、生產(chǎn)效率剖面8、生產(chǎn)測(cè)井9、巖心分析All the field techniques discussed so far can identify the probable existence of damage but none can either pinpoint at what operational stage the damage may have occurred and/or quantify the relative contribution to damage from various well operations.However, laboratory testing of the fluids and techniques used in various well operations will help decipher not only the pot