張荻萩,李治平,蘇 皓
(1.中國地質(zhì)大學(北京)能源學院,北京100083;2.中國地質(zhì)大學(北京)非常規(guī)天然氣能源地質(zhì)評價與開發(fā)工程北京市重點實驗室,北京100083)
頁巖氣產(chǎn)量遞減規(guī)律研究
張荻萩1,2,李治平1,2,蘇皓1,2
(1.中國地質(zhì)大學(北京)能源學院,北京100083;2.中國地質(zhì)大學(北京)非常規(guī)天然氣能源地質(zhì)評價與開發(fā)工程北京市重點實驗室,北京100083)
頁巖氣藏的滲透率極低,儲層流體流動性較差,氣井產(chǎn)能較低,其產(chǎn)量遞減規(guī)律有別于常規(guī)氣藏。研究頁巖氣產(chǎn)量遞減規(guī)律,對預測氣田未來產(chǎn)量變化與最終開發(fā)指標及指導開發(fā)措施調(diào)整等均有重要意義。以美國德克薩斯州Haynesville與Barnett頁巖氣田單井生產(chǎn)動態(tài)為例,研究了層狀硅質(zhì)-鈣質(zhì)頁巖與層狀硅質(zhì)頁巖兩大類頁巖氣田的產(chǎn)量遞減規(guī)律,分析了復合遞減模型以及廣義雙曲型曲線用于頁巖氣研究時參數(shù)發(fā)生的變化及其影響因素。通過Arps廣義雙曲遞減法與復合遞減模型法應用的對比表明,層狀硅質(zhì)-鈣質(zhì)頁巖與層狀硅質(zhì)頁巖兩大類頁巖氣田產(chǎn)量變化規(guī)律有較大差異。
頁巖氣;遞減規(guī)律;Arps遞減曲線;廣義翁氏模型;復合遞減模型
頁巖氣是指賦存于泥頁巖中,以游離態(tài)、吸附態(tài)甚至溶解態(tài)存在的非常規(guī)天然氣[1-3]。頁巖氣具有儲量大、開發(fā)壽命長和清潔環(huán)保等優(yōu)點,但由于其儲層滲透率極低,流體流動性較差,氣井產(chǎn)能一般較低。
近年來,頁巖氣已在美國實現(xiàn)了商業(yè)化開采[4-7],較大程度地緩解了其能源需求壓力。中國頁巖氣資源量較大,但其勘探開發(fā)理論與技術(shù)研究均處于起步階段[8]。由于頁巖氣藏與常規(guī)氣藏存在多方面的差異,頁巖氣井生產(chǎn)動態(tài)相對復雜多變,頁巖氣產(chǎn)量遞減曲線的建立存在一定的不確定因素[9]。因此,研究與借鑒美國頁巖氣產(chǎn)量遞減規(guī)律,對預測我國頁巖氣田未來產(chǎn)量變化與最終開發(fā)指標及指導開發(fā)措施調(diào)整等均有重要意義。
Haynesville和Barnett等2套頁巖在美國頁巖氣產(chǎn)量增長中占有極重要的地位。上侏羅統(tǒng)Haynesville頁巖是一套發(fā)育于相對半封閉沉積環(huán)境下的層狀黑色富含有機質(zhì)的鈣質(zhì)-硅質(zhì)泥頁巖,而石炭系Barnett頁巖則以層狀硅質(zhì)泥巖為主,發(fā)育于遠離物源區(qū)的較深的靜水缺氧海相環(huán)境[10-12]。Haynesville和Barnett頁巖地質(zhì)條件與儲層特征的差異導致其氣井產(chǎn)量遞減規(guī)律也各不相同。
本文基于美國德克薩斯州Haynesville與Barnett頁巖氣田單井生產(chǎn)動態(tài)數(shù)據(jù),將復合遞減模型[13]用于研究頁巖氣產(chǎn)量遞減規(guī)律。通過復合遞減模型及廣義雙曲型Arps遞減曲線[14]的應用和對比,分析模型中有關(guān)參數(shù)的變化及其影響因素,找出適合于頁巖氣產(chǎn)量遞減規(guī)律的模型并指明其適應范圍,以期對我國頁巖氣產(chǎn)能評價等提供依據(jù)。
針對頁巖氣藏,國內(nèi)外目前主要運用Arps遞減曲線法研究其遞減規(guī)律,形成了多元回歸、迭代求解、曲線位移、最佳擬合和典型曲線擬合等多種成熟方法[15]。除此以外,F(xiàn)etkovich[16],Gentry[17],Slider[18]和Long等[19]對典型曲線法也時有應用。在以Arps遞減曲線法為代表的典型曲線法中,通過給定唯一的遞減指數(shù)n值而建立的遞減曲線,其有效性與準確性難以保證。
翁文波[20]于1984年提出了翁氏模型,陳元千等[21]于1996年重新推導了翁氏模型,得到了廣義翁氏模型,從而拓寬了翁氏模型的應用范圍。2008年,陳軍等[13]將Arps遞減曲線與廣義翁氏模型聯(lián)立,得到了復合遞減模型。該模型在常規(guī)氣藏中的實驗結(jié)果表明,由于其建立的遞減曲線由3個給定的參數(shù)值(b,c與n)決定,因此較Arps遞減法的適應性更強。
由于頁巖氣藏與常規(guī)氣藏存在很大差異,頁巖儲層滲透率極低,儲層中存在少量裂縫,且天然氣存在吸附氣與游離氣2種狀態(tài),開發(fā)井多為水平井,導致其滲流以非穩(wěn)態(tài)流為主[22]。筆者考慮復合遞減模型法的應用范圍較常規(guī)的Arps遞減法更為廣泛,可以用復合遞減模型法來預測較為復雜氣藏的開發(fā)動態(tài)[23-24],故嘗試將其用于頁巖氣產(chǎn)能分析和產(chǎn)量遞減規(guī)律研究。
1.1Arps遞減曲線法
Arps產(chǎn)量遞減的公式為
式中:n為遞減指數(shù),無量綱;Di為初始遞減率,無量綱;t為遞減時間,d;qi為初始遞減時的產(chǎn)氣量,×103m3/d;qt為t時間的產(chǎn)氣量,×103m3/d。
Arps遞減曲線有雙曲型、調(diào)和型、指數(shù)型及廣義雙曲型等多種形式。對于常規(guī)油氣藏,當遞減指數(shù)n∈(0,1)時為雙曲型遞減,n=1時為調(diào)和遞減,n=0時為指數(shù)遞減[14,25-26]。對于頁巖氣等非常規(guī)油氣藏,n值可能大于1,將n∈R的曲線稱為Arps廣義雙曲型遞減曲線。
針對廣義雙曲型遞減情況,為求解其n值,可將式(1)進行變換[13]為
其中,A=nDi。
1.2廣義翁氏模型及復合遞減模型
翁氏模型采用Poisson分布概率函數(shù)描述油氣藏的產(chǎn)量變化過程[20]。陳元千等[21]利用概率統(tǒng)計學的伽馬分布將其重新推導,推廣為廣義翁氏模型,拓寬了其使用范圍,其表達式為
式中:a,b及c均為模型常數(shù),無量綱。
陳軍等[13]結(jié)合Arps指數(shù)遞減和廣義翁氏模型得到了復合遞減模型,其表達式為
為求解b,c及n的值,將式(4)進行變換
由式(5)可見,B與t成正比關(guān)系,由此可采取線性回歸的方法求取參數(shù)b與n的值。首先確定截距的值為0,需假設(shè)一系列b值與一系列n值,再輸入氣藏產(chǎn)量和時間數(shù)據(jù)到復合遞減模型中進行回歸,由此可得到一系列相關(guān)系數(shù),當相關(guān)系數(shù)接近1時,即可確定最優(yōu)的參數(shù)b與n,而此時的直線斜率即為-c,再將這3個參數(shù)代入式(4)即可得到復合模型表達式。
2.1頁巖儲層類型及特征
本文以美國2套重要的含氣頁巖Haynesville和Barnett為例,研究其產(chǎn)量遞減規(guī)律。該2套頁巖雖然具有相似性,但它們的形成環(huán)境、巖性組合和礦物組成等又有較大的差異,由此導致其頁巖氣藏產(chǎn)量的變化趨勢不同。Haynesville頁巖分布于德克薩斯-路易斯安那盆地,是一套發(fā)育于相對半封閉沉積環(huán)境下的層狀富含有機質(zhì)的鈣質(zhì)-硅質(zhì)泥頁巖。德克薩斯州福特沃斯盆地Barnett頁巖發(fā)育于遠離物源區(qū)的較深的靜水缺氧海相環(huán)境,主力產(chǎn)氣層(上Barnett頁巖和下Barnett頁巖)以層狀硅質(zhì)泥巖為主,缺乏粗粒的陸源碎屑物質(zhì),有利于優(yōu)質(zhì)頁巖發(fā)育和有機質(zhì)的保存[11]。因此,Haynesville和Barnett頁巖分別代表層狀硅質(zhì)-鈣質(zhì)頁巖和層狀硅質(zhì)頁巖兩大類不同的頁巖。
Haynesville頁巖主要為層狀硅質(zhì)-鈣質(zhì)頁巖,其有機質(zhì)豐度較高、演化程度高,總孔隙度高,礦物組成中鈣質(zhì)含量較高(體積分數(shù)為30%~50%),硅質(zhì)含量較低(體積分數(shù)為14%~35%),頁巖埋藏深、地層為高壓高溫(表1)[12,27]。
表1 Haynesville頁巖儲層特征Table 1 Reservoir characteristics of Haynesville shale
福特沃斯盆地Barnett頁巖主要為層狀硅質(zhì)頁巖[28-33](表2),有機質(zhì)豐度高,硅質(zhì)體積分數(shù)大(30%~50%),鈣質(zhì)體積分數(shù)較小(<15%),厚度大,埋深較?。?4-35]。
表2 Barnett頁巖儲層特征Table 2 Reservoir characteristics of Barnett shale
本文基于美國Haynesville頁巖氣田與Barnett頁巖氣田共5口水平井的日生產(chǎn)數(shù)據(jù),分別用上述2種模型進行計算與分析,由此確定頁巖氣實際生產(chǎn)數(shù)據(jù)對該2種模型的適用性及適用條件,并討論各模型中的參數(shù)分布規(guī)律,進而了解不同類型頁巖氣生產(chǎn)動態(tài)變化規(guī)律。
2.2Haynesville層狀硅質(zhì)-鈣質(zhì)頁巖氣田遞減規(guī)律
截至2013年,美國德克薩斯州Haynesville頁巖已完鉆井2 508口(包括生產(chǎn)井2 274口),全區(qū)產(chǎn)氣量達1.60億m3/d[11-12,26]。本文選擇Haynesville頁巖氣田3口井(w1,w2和w3井)進行分析,發(fā)現(xiàn)用Arps遞減法計算得到的遞減指數(shù)n∈(0,1),屬于Arps雙曲型遞減形式;用復合遞減模型法計算得到的遞減指數(shù)n∈(0.23,0.50),反映n值在頁巖氣藏中一般較小。
以w1井為例,對其日生產(chǎn)數(shù)據(jù)[28]擬合發(fā)現(xiàn),其與Arps雙曲型遞減形式相符,與指數(shù)遞減形式不符。經(jīng)線性回歸得到:n=0.48,A=0.001。將n與A代入式(2),經(jīng)變換,即可求得該井遞減階段產(chǎn)量表達式為
用復合遞減模型法研究氣井遞減規(guī)律,線性回歸結(jié)果為:b=-64,n=0.31,c=0.001 03(圖1)。將回歸后的b,c與n值代入式(4)即可求得該井遞減階段的產(chǎn)量表達式為
可見該井產(chǎn)量遞減符合Arps雙曲型遞減與b<0復合遞減模型。Arps廣義雙曲型遞減法和復合遞減模型法得到的氣井產(chǎn)量的平均誤差分別為6.63%與1.62%(表3),說明復合遞減模型法擬合效果更好(圖1)。
圖1 w1井Arps遞減法和復合遞減模型法對比Fig.1 Contrast between compound decline model and Arps decline equation of w1 well
表3 w1井Arps遞減法與復合遞減模型法對比與誤差計算Table 3 Contrast and error calculation between compound decline model and Arps decline equation of w1 well
對w2井日生產(chǎn)數(shù)據(jù),用Arps遞減法計算得到:n=0.80,A=0.005 4,用復合遞減模型法線性回歸得到:b=-47.6,n=0.28,c=0.001 5(圖2);對w3井日生產(chǎn)數(shù)據(jù),用Arps遞減法計算得到:n=0.96,A= 0.005 2,用復合遞減模型法線性回歸得到:b=-74.5,n=0.24,c=0.000 89(圖3)。
圖2 w2井Arps遞減法和復合遞減模型法對比Fig.2 Contrast between compound decline model and Arps decline equation of w2 well
圖3 w3井Arps遞減法和復合遞減模型法對比Fig.3 Contrast between compound decline model and Arps decline equation of w3 well
2.3Barnett層狀硅質(zhì)頁巖遞減規(guī)律分析
研究區(qū)Barnett頁巖氣可采儲量為0.85~1.24萬億m3[26,36],2011年頁巖氣產(chǎn)量超0.18萬億m3[5,37]。
通過對Barnett頁巖氣田w4與w5井的分析發(fā)現(xiàn),它們與Arps廣義雙曲型遞減形式相符;針對復合遞減模型,n∈(0,0.23),比Haynesville頁巖的n值小。
以w4為例,其日生產(chǎn)數(shù)據(jù)[37-38]經(jīng)Arps遞減法與復合遞減模型法2種方法計算發(fā)現(xiàn),其與n>1的Arps廣義雙曲型遞減形式相符,與指數(shù)遞減形式不符。經(jīng)線性回歸得到:n=1.05,A=0.004 6。該井遞減階段產(chǎn)量表達式為
用復合遞減模型法線性回歸得到:b=-73.9,n= 0.21,c=0.000 96(圖4)。該井遞減階段產(chǎn)量表達式為
可見該井產(chǎn)量遞減符合n>1的Arps廣義雙曲型遞減與b<0的復合遞減模型。該井用Arps廣義雙曲型遞減法與復合遞減模型法得到的氣井產(chǎn)量平均誤差分別為2.14%與2.93%(表4),結(jié)果相近。
圖4 w4井Arps遞減法和復合遞減模型法對比Fig.4 Contrast between compound decline model and Arps decline equation of w4 well
圖5 w5井Arps遞減法和復合遞減模型法對比Fig.5 Contrast between compound decline model and Arps decline equation of w5 well
表4 w4井Arps遞減法與復合遞減模型法對比與誤差計算Table 4 Contrast and error calculation between compound decline model and Arps decline equation of w4 well
對w5井日生產(chǎn)數(shù)據(jù),用Arps遞減法計算得到:n=1.38,A=0.022 9;用復合遞減模型法計算得到:b=-72.0,n=0.08,c=0.000 73(圖5)。
2.4頁巖氣產(chǎn)量遞減規(guī)律分析與對比
通過對Haynesville頁巖氣3口井(w1,w2與w3井)和Barnett頁巖氣2口井(w4與w5井)單井日產(chǎn)氣量數(shù)據(jù)的計算與分析(表5),揭示了頁巖氣產(chǎn)量遞減變化規(guī)律。通過對比發(fā)現(xiàn)該2套頁巖氣產(chǎn)量變化規(guī)律不同,并分析了其可能的控制因素。
表5 復合遞減模型法與Arps遞減法參數(shù)分布統(tǒng)計Table 5 Parameter distribution statistics of compound decline model and Arps decline equation
根據(jù)5口井實際生產(chǎn)數(shù)據(jù),運用復合遞減模型法計算與分析,發(fā)現(xiàn)n值較小:n∈(0,0.5),反映了頁巖氣藏n值往往較小的特征。其中,Haynesville頁巖3口井n∈(0.23,0.50),而Barnett頁巖2口井n∈(0,0.23),較Haynesville頁巖更小,可能與Barnett頁巖氣藏儲層基質(zhì)滲透率偏小,從而使氣體流動能力較小有關(guān)。
用復合遞減模型法分析Haynesville與Barnett頁巖氣田時還揭示,參數(shù)b在頁巖氣藏中一般為負值,不同于常規(guī)氣藏中其常為正值。這種情況可能與頁巖中氣體滲透率極低、氣體滲流狀態(tài)以非穩(wěn)態(tài)流為主,而不同于常規(guī)氣藏中的擬穩(wěn)態(tài)流狀態(tài)有關(guān)。
用Arps遞減法分析Haynesville和Barnett頁巖氣井時發(fā)現(xiàn)該2套頁巖產(chǎn)量遞減規(guī)律有較大差異。Haynesville頁巖3口頁巖氣井在用Arps遞減法計算時的遞減指數(shù)n∈(0,1),屬于Arps雙曲型遞減形式,產(chǎn)量變化具有初始產(chǎn)量高、產(chǎn)量快速遞減的特征;Barnett頁巖2口頁巖氣井的Arps遞減法計算結(jié)果n>1,其屬于Arps廣義雙曲型遞減形式,產(chǎn)量變化具有初始產(chǎn)量不高、產(chǎn)量緩慢遞減特征。
分析認為,Haynesville和Barnett頁巖氣藏產(chǎn)量變化趨勢不同與其儲層等地質(zhì)特征差異有關(guān)。Haynesville頁巖為鈣質(zhì)-硅質(zhì)頁巖,具有較低的硅質(zhì)含量,較高的鈣質(zhì)含量,導致巖石楊氏模量較低,脆性較差;總孔隙度較高,基質(zhì)滲透率較大[27];具超高壓特征。當壓力下降時,高應力可能影響已開啟的水力壓裂裂縫網(wǎng)絡,導致裂縫系統(tǒng)整體導流能力下降。Barnett頁巖總孔隙度較低,基質(zhì)滲透率也較小,其滲流方式以非穩(wěn)態(tài)流為主[10,29,32-33];具有較高的硅質(zhì)含量和楊氏模量,有利于水力壓裂隨時間的傳導;存在大量開啟和閉合裂縫,有利于減少天然氣產(chǎn)量下降。
(1)與常規(guī)氣藏Arps遞減曲線中n∈[0,1]、復合遞減模型中b≥0不同,頁巖氣藏中Arps廣義雙曲型遞減曲線n∈R,復合遞減模型b<0。這些參數(shù)變化與頁巖滲透率極低、井中滲流狀態(tài)以非穩(wěn)態(tài)流為主,不同于常規(guī)氣藏中的擬穩(wěn)態(tài)流有關(guān)。
(2)層狀硅質(zhì)-鈣質(zhì)頁巖氣藏(Haynesville頁巖)遞減指數(shù)n∈(0,1),與Arps雙曲型遞減形式相符,表現(xiàn)為氣井初始產(chǎn)量高、產(chǎn)量快速遞減的特征;層狀硅質(zhì)頁巖(Barnett頁巖)遞減指數(shù)n>1,與Arps廣義雙曲型遞減形式相符,氣井具有初始產(chǎn)量不高、產(chǎn)量緩慢遞減的特征。
(3)Arps廣義雙曲遞減法與復合遞減模型法均適用于預測頁巖氣遞減期產(chǎn)量變化,但二者各有特點。Arps廣義雙曲遞減法只需取1個參數(shù)(n)值即可進行預測,計算過程相對便捷,適用于快速預測頁巖氣產(chǎn)量遞減,但針對不同頁巖氣藏其準確性較差;復合遞減模型法需確定3個參數(shù)(b,c與n),計算過程較Arps廣義雙曲遞減法復雜,但針對不同類型頁巖氣藏,其計算結(jié)果相對更準確,適合精度要求較高時頁巖氣產(chǎn)量遞減規(guī)律預測。
(References):
[1]張金川,徐波,聶海寬,等.中國頁巖氣資源勘探潛力[J].天然氣工業(yè),2008,28(6):136-140. Zhang Jinchuan,Xu Bo,Nie Haikuan,et al.Exploration potential of shale gas resources in China[J].Natural Gas Industry,2008,28(6):136-140.
[2]張小龍,張同偉,李艷芳,等.頁巖氣勘探和開發(fā)進展綜述[J].巖性油氣藏,2013,25(2):116-122. Zhang Xiaolong,Zhang Tongwei,Li Yanfang,et al.Research advance in exploration and development of shale gas[J].Lithologic Reservoirs,2013,25(2):116-122.
[3]王拓,朱如凱,白斌,等.非常規(guī)油氣勘探、評價和開發(fā)新方法[J].巖性油氣藏,2013,25(6):35-39. Wang Tuo,Zhu Rukai,Bai Bin,et al.New methods for the exploration,evaluation and development of unconventional reservoirs[J]. Lithologic Reservoirs,2013,25(6):35-39.
[4]黃玉珍,黃金亮,葛春梅,等.技術(shù)進步是推動美國頁巖氣快速發(fā)展的關(guān)鍵[J].天然氣工業(yè),2009,29(5):7-10.Huang Yuzhen,Huang Jinliang,Ge Chunmei,et al.A key factor promoting rapid development of shale gas in America:technical progress[J].Natural Gas Industry,2009,29(5):7-10.
[5]李新景,胡素云,程克明.北美裂縫性頁巖氣勘探開發(fā)的啟示[J].石油勘探與開發(fā),2007,34(4):392-400. Li Xinjing,Hu Suyun,Cheng Keming.Suggestions from the development of fractured shale gas in North America[J].Petroleum Exploration and Development,2007,34(4):392-400.
[6]閆建平,言語,司馬立強,等.泥頁巖儲層裂縫特征及其與“五性”之間的關(guān)系[J].巖性油氣藏,2015,27(3):87-93. Yan Jianping,Yan Yu,Sima Liqiang,et al.Relationship between fracture characteristics and“five-property”of shale reservoir[J]. Lithologic Reservoirs,2015,27(3):87-93.
[7]何建華,丁文龍,付景龍,等.頁巖微觀孔隙成因類型研究[J].巖性油氣藏,2014,26(5):30-35. He Jianhua,Ding Wenlong,F(xiàn)u Jinglong,et al.Study on genetic type of micropore in shale reservoir[J].Lithologic Reservoirs,2014,26(5):30-35.
[8]王冕冕,郭肖,曹鵬,等.影響頁巖氣開發(fā)因素及勘探開發(fā)技術(shù)展望[J].特種油氣藏,2010,17(6):12-16. Wang Mianmian,Guo Xiao,Cao Peng,et al.Influence factors on shale gas development and prospet of its exploration and development technology[J].Special Oil and Gas Reservoirs,2010,17(6):12-16.
[9]白玉湖,楊皓,陳桂華,等.頁巖氣產(chǎn)量遞減典型曲線中關(guān)鍵參數(shù)的確定方法[J].特種油氣藏,2013,20(2):65-68. Bai Yuhu,Yang Hao,Chen Guihua,et al.Methods to determine the key parameters of typical production decline curves of shale gas reservoirs[J].Special Oil and Gas Reservoirs,2013,20(2):65-68.
[10]聶海寬,張金川,張培先,等.福特沃斯盆地Barnett頁巖氣藏特征及啟示[J].地質(zhì)科技情報,2009,28(2):87-93. Nie Haikuan,Zhang Jinchuan,Zhang Peixian,et al.Shale gas reservoir characteristics of Barnett shale gas reservoir in Fort Worth Basin[J].Geological Science and Technology Information,2009,28(2):87-93.
[11]朱彤,曹艷,張快.美國典型頁巖氣藏類型及勘探開發(fā)啟示[J].石油實驗地質(zhì),2014,36(6):718-724. Zhu Tong,Cao Yan,Zhang Kuai.Typical shale gas reservoirs in USA and enlightenment to exploration and development[J].Petroleum Geology&Experiment,2014,36(6):718-724.
[12]房大志,曾輝,王寧,等.從Haynesville頁巖氣開發(fā)數(shù)據(jù)研究高壓頁巖氣高產(chǎn)因素[J].石油鉆采工藝,2015,37(2):58-62. Fang Dazhi,Zeng Hui,Wang Ning,et al.Study on high production factors of high-pressure shale gas from Haynesville shale gas development data[J].Oil Drilling&Production Technology,2015,37(2):58-62.
[13]陳軍,徐廣鵬,樊懷才,等.一種氣藏產(chǎn)量遞減復合模型研究[J].天然氣勘探與開發(fā),2008,31(3):39-41. Chen Jun,Xu Guangpeng,F(xiàn)an Huaicai,et al.Research on a compound production decline model[J].Natural Gas Exploration& Development,2008,31(3):39-41.
[14]Arps J J.Analysis of decline curves[G].Transaction of American Institute of Mining,Metallurgical,and Petroleum Engineers,1944,160:228-247.
[15]胡建國.產(chǎn)量遞減的典型曲線分析[J].新疆石油地質(zhì),2009,30(6):720-721. Hu Jianguo.An analysis of production-decline type curve[J].Xinjiang Petroleum Geology,2009,30(6):720-721.
[16]Fetkovich M J.Decline curve analysis using type curve[J].Journal of Petroleum Technology,1980,32(6):1065-1077.
[17]Gentry R W.Decline curve analysis[J].Journal of Petroleum Technology,1972,24(1):38-41.
[18]Slider H C.A simplified method for hyperbolic decline curve analysis[J].Journal of Petroleum Technology,1968,20(3):235-236.
[19]Long D R,Davis M J.A new approach to the hyperbolic curve[J]. Journal of Petroleum Technology,1988,40(7):909-912.
[20]翁文波.預測論基礎(chǔ)[M].北京:石油工業(yè)出版社,1984:71-85. Weng Wenbo.Prediction theory basis[M].Beijing:Petroleum Industry Press,1984:71-85.
[21]陳元千,胡建國.對翁氏模型建立的回顧及新的推導[J].中國海上油氣(地質(zhì)),1996,10(5):317-324. Chen Yuanqian,Hu Jianguo.Review and derivation of Weng Model[J].ChinaOffshoreOilandGas(Geology),1996,10(5):317-324.
[22]周登洪,孫雷,嚴文德,等.頁巖氣產(chǎn)能影響因素及動態(tài)分析[J].油氣藏評價與開發(fā),2012,2(1):64-69. Zhou Denghong,Sun Lei,Yan Wende,et al.The influencing factors and dynamic analysis of shale gas deliverability[J].Reservoir Evaluation and Development,2012,2(1):64-69.
[23]劉其先,曲秀娟,朱德燕.化曲為直,借助Excel軟件簡捷準確分析油田產(chǎn)量遞減趨勢[J].海洋石油,2004,24(2):50-53. Liu Qixian,Qu Xiujuan,Zhu Deyan.Analyzing the relationship between time and annual production by transiting the non-linear curve into a linear curve[J].Offshore Oil,2004,24(2):50-53.
[24]何俊,陳小凡,樂平,等.線性回歸方法在油氣產(chǎn)量遞減分析中的應用[J].巖性油氣藏,2009,21(2):103-105. He Jun,Chen Xiaofan,Yue Ping,et al.Application of linear regression method to analysis of oil and gas production rate decline[J].Lithologic Reservoirs,2009,21(2):103-105.
[25]胥元剛,阮敏.氣田產(chǎn)量遞減分析的一種實用方法[J].天然氣工業(yè),2001,21(1):85-87. Xu Yuangang,Ruan Min.A practical method of production decline analysis of gas field[J].Natural Gas Industry,2001,21(1):85-87.
[26]范琳沛,李勇軍,白生寶.美國Haynesville頁巖氣藏地質(zhì)特征分析[J].長江大學學報:自科版,2014,11(2):81-83. Fan Peilin,Li Yongjun,Bai Shengbao.The Haynesville shale gas reservoir geological characteristics analysis[J].Journal of Yangtze University:Natural Science Edition,2014,11(2):81-83.
[27]Parker M,Buller D,Petre E,et al.Haynesville shale-petrophysical evaluation[R].SPE 122937,2009:1-11.
[28]Jin Xiaoze.Gas deliverability using the method of distributed volumetric sources[D].Bryan:the Office of Graduate Studies of Texas A&M University,2008.
[29]Baylor B.Marcellus shale decline analysis[D].Marietta:Marietta College,2008.
[30]Ground Water Protection Council.Modern shale gas development in the united states:A primer[M].Oklahoma City:Ground Water Protection Council,2009:16-24.
[31]Bowker K A.Barnett Shale gas production,F(xiàn)ort Worth Basin:Issues and discussion[J].AAPG Bulletin,2007,91(4):523-533.
[32]Jarvie D M,Hill R J,Ruble T E,et al.Unconventional shale-gas systems:The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment[J].AAPG Bulletin,2007,91(4):475-499.
[33]曾祥亮,劉樹根,黃文明,等.四川盆地志留系龍馬溪組頁巖與美國Fort Worth盆地石炭系Barnett組頁巖地質(zhì)特征對比[J].地質(zhì)通報,2011,30(2/3):372-384. Zeng Xiangliang,Liu Shugen,Huang Wenming,et al.Comparison of Silurian Longmaxi Formation shale of Sichuan Basin in China and Carboniferous Barnett Formation shale of Fort Worth Basin in United States[J].Geological Bulletin of China,2011,30(2/3):372-384.
[34]Pollastro R M,Jarvie D M,Hill R J,et al.Geologic framework of the Mississippian Barnett Shale,Barnett-Paleozoic total petroleum system,Bend arch-Fort Worth Basin,Texas[J].AAPG Bulletin,2007,91(4):405-436.
[35]Curtis J B.Fractured shale-gas systems[J].AAPG Bulletin,2002,86(11):1921-1938.
[36]Montgomery S L,Jarvie D M,Bowker K A,et al.Mississippian Barnett Shale,F(xiàn)ort Worth Basin,north central Texas:Gas-shale play with multi-trillion cubic foot potential[J].AAPG Bulletin,2005,89(2):155-175.
[37]許維武.美國福特沃斯盆地Barnett頁巖氣藏特征及開發(fā)技術(shù)特點[J].內(nèi)蒙古石油化工,2014(15):108-110. Xu Weiwu.Fort Worth basin Barnett shale gas reservoir characteristics and development technical characteristics[J].Inner Mongolia Petrochemical Industry,2014(15):108-110.
[38]Cipolla C L,Lolon E P,Erdle J C,et al.Reservoir modeling in shale-gas reservoirs[R].SPE 125530,2010:638-653.
(本文編輯:李在光)
Production decline trend of shale gas
Zhang Diqiu1,2,Li Zhiping1,2,Su Hao1,2
(1.College of Energy Resources,China University of Geosciences,Beijing 100083,China;2.Key Laboratory of Unconventional Natural Gas Energy Geology Evaluation and Development Project in Beijing,China University of Geosciences,Beijing 100083,China)
Shale gas reservoir has low permeability,in which fluid hardly flow and wells have smaller production capacity. The production decline trend of shale gas reservoir is largely different from conventional gas reservoir.The study on shale gas production decline trend is a reference to predict future production changes,development indices and indicators,subsequent adjustment of development measures.Based on Arps decline equation and generalized Weng's model,a new model,compound decline model was proposed.Because the compound decline model has more general applicability rather than Arps decline equation,it was applied to shale gas production decline trend analysis in this paper for the first time.Then the changing parameters and influencing factors of compound decline model and Arps decline equation used on shale gas production were computed and analyzed.Comparing the compound decline model with the Arps decline equation in case of practical application in Haynesville shale and Barnett shale,it was tested and verified that there are great differences between the production decline trends of two categories of shale gas field.
shale gas;production decline trend;Arps decline equation;generalized Weng's model;compound decline model
TE33
A
1673-8926(2015)06-0138-07
2015-06-25;
2015-08-19
國家重大科技專項“煤層氣排采工藝技術(shù)與數(shù)值模擬”(編號:2011ZX05034-001)資助
張荻萩(1991-),女,中國地質(zhì)大學(北京)在讀碩士研究生,研究方向為油藏工程與油藏數(shù)值模擬等。地址:(100083)北京市海淀區(qū)學院路29號中國地質(zhì)大學(北京)能源學院。E-mail:fengydhqss@163.com。