馬英俊

(中國(guó)石化 江蘇油田分公司 勘探開(kāi)發(fā)研究院，江蘇 揚(yáng)州 225012)

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蘇北盆地金湖凹陷阜二段砂巖物性影響因素分析

馬英俊

(中國(guó)石化 江蘇油田分公司 勘探開(kāi)發(fā)研究院，江蘇 揚(yáng)州 225012)

利用巖石薄片、鑄體薄片、孔滲分析等實(shí)驗(yàn)手段，對(duì)蘇北盆地金湖凹陷阜二段砂巖儲(chǔ)層的礦物巖石特征、儲(chǔ)層物性特征、孔隙結(jié)構(gòu)特征以及儲(chǔ)層物性的主要影響因素進(jìn)行了相關(guān)分析。研究表明，阜二段儲(chǔ)層巖石顆?？傮w偏細(xì)，不同地區(qū)巖石成分成熟度均值差別小、范圍值都較寬；西部斜坡帶儲(chǔ)層物性相對(duì)較好，其他地區(qū)以低孔、低滲—特低滲儲(chǔ)層為主；壓實(shí)和碳酸鹽膠結(jié)是導(dǎo)致儲(chǔ)層物性變差的主要原因；溶蝕作用和油氣充注是抑制物性變差、改善儲(chǔ)集性能的重要因素。西部斜坡帶等地區(qū)是儲(chǔ)層物性相對(duì)較好的有利地區(qū)。

砂巖物性；沉積微相；成巖作用；油氣充注；阜二段；金湖凹陷；蘇北盆地

1 砂巖儲(chǔ)層基本特征

1.1 沉積特征

圖1 蘇北盆地金湖凹陷構(gòu)造區(qū)劃及沉積相Fig.1 Geotectonic division and sedimentary facies of in the Jinhu Sag, Subei Basin

1.2 巖礦特征

根據(jù)大量巖石薄片統(tǒng)計(jì)(表1)，金湖凹陷E1f2碎屑巖儲(chǔ)層以細(xì)粒、極細(xì)粒、粗粉砂級(jí)的長(zhǎng)石巖屑石英砂巖、長(zhǎng)石巖屑砂巖為主，部分含云質(zhì)、含灰質(zhì)長(zhǎng)石巖屑砂巖、巖屑長(zhǎng)石砂巖。碎屑成分以石英為主，次為長(zhǎng)石、巖屑，成分成熟度較高，石英含量平均為60%～65%；結(jié)構(gòu)成熟度中等，以次圓—次棱、次棱—次圓狀為主；碎屑顆粒分選普遍較好；膠結(jié)物總體含量較高，平均20%左右，以灰質(zhì)為主，部分云質(zhì)、泥質(zhì)，少量硅質(zhì)；膠結(jié)類型主要為接觸—孔隙、孔隙—接觸，部分為基底式膠結(jié)。

表1 蘇北盆地金湖凹陷阜二段砂巖巖礦特征統(tǒng)計(jì)

注：表中數(shù)值意義為最小值～最大值/平均值。

表1反映，不同地區(qū)巖礦特征平均值差異很小，說(shuō)明區(qū)域范圍內(nèi)沉積環(huán)境相對(duì)穩(wěn)定，但各主要成分的含量范圍相對(duì)較寬。石英含量45%～89%，長(zhǎng)石含量3%～40%，巖屑含量7%～41%，這種現(xiàn)象表明巖石成分成熟度有一定差異，可能有不同距離的物源影響。膠結(jié)物含量差異明顯，平均20%～30.5%；其中，西斜坡、汊澗地區(qū)平均含量最低，三河次凹含量平均最高，說(shuō)明不同地區(qū)成巖環(huán)境有較大差別。

2 儲(chǔ)層物性及孔隙結(jié)構(gòu)特征

2.1 物性特征

按地區(qū)統(tǒng)計(jì)表明(圖2)，各區(qū)帶都以特低—低孔滲砂體為主；其中，西斜坡、汊澗斜坡砂體物性較好，卞閔楊、龍崗地區(qū)次之，石港、唐港地區(qū)較差，三河次凹最差。

圖2 蘇北盆地金湖凹陷各區(qū)塊E1f2儲(chǔ)層物性分布頻率Fig.2 Frequency of reservoir physical properties of E1f2in different areas of the Jinhu Sag, Subei Basin

由圖1、圖2看出，金湖凹陷分區(qū)砂體物性的差異充分反映了砂體巖相和成巖作用的重要影響。譬如，西斜坡、汊澗三角洲前緣分支河道砂體最發(fā)育、單層厚、累計(jì)厚度大，埋藏較淺，物性相對(duì)較好；而三河次凹處于砂泥坪和半深湖區(qū)，砂坪?jiǎn)紊绑w薄、累厚小、埋藏深，物性最差。

2.2 孔隙類型及孔隙結(jié)構(gòu)特征

鑄體薄片反映，E1f2砂巖孔隙主要有原生粒間孔、粒間溶孔、粒內(nèi)溶孔、鑄?？椎阮愋汀Ｆ渲?，粒間溶孔是主要類型，其次是原生粒間孔，部分粒內(nèi)溶孔，少量鑄?？?。儲(chǔ)層面孔率普遍偏低，多數(shù)在5%以下；部分面孔率較高，譬如天76井1 864.97 m樣品面孔率達(dá)18.43%，其中，溶蝕粒間孔為9%，原生粒間孔為6.2%，其他類型孔隙占3.23%?？紫督Y(jié)構(gòu)參數(shù)統(tǒng)計(jì)表明，喉道平均寬度一般在4～8 μm之間，配位數(shù)在1～3之間，孔喉比差異較大，最高近10，最低為1.22?？勺償嗝娴氖湛s部分是主要喉道，次為片狀、彎片狀喉道。

3 儲(chǔ)層物性的主要影響因素

沉積相類型、碎屑顆粒大小、礦物的成分成熟度、結(jié)構(gòu)成熟度、含油性，以及成巖壓實(shí)、膠結(jié)、溶蝕等作用都是影響儲(chǔ)層物性的重要因素[7-8,15-18]。分析表明，金湖凹陷E1f2砂巖物性與埋深、碳酸鹽含量、溶蝕等成巖因素和顆粒粗細(xì)、砂體類型等沉積因素密切相關(guān)。

3.1 成巖作用

3.1.1 壓實(shí)作用

壓實(shí)和膠結(jié)是儲(chǔ)層埋藏過(guò)程中主要的成巖要素，對(duì)砂巖物性的影響作用很大。譬如，在埋深較淺，壓實(shí)作用相對(duì)弱的崔4、程6井，鏡下見(jiàn)碎屑顆粒間主要為點(diǎn)和點(diǎn)—線接觸,保留了較多的原生孔

隙；埋深相對(duì)較大的高21、河參1等井在鏡下可見(jiàn)碎屑顆粒主要為線—鑲嵌、鑲嵌接觸，顆粒發(fā)生變形、甚至破裂，見(jiàn)云母受壓彎曲，原生孔隙基本消失(圖3)。砂巖壓實(shí)作用使得其物性由淺層的較好，到中深層、深層迅速變差。

E1f2砂巖物性與深度相關(guān)關(guān)系分析表明，φ、K總體隨埋深增加而減小(圖4)，同一深度孔滲分布有一定寬度范圍，深度越大、分布范圍越窄，越趨近于低孔滲、特低孔滲帶。埋深小于2 000 m，φ多在5%～28%左右，K多在(1～1 000)×10-3μm2；埋深大于2 000 m，φ多在2%～20%左右，K主要在(0.1～100)×10-3μm2間。說(shuō)明壓實(shí)是導(dǎo)致砂巖物性變差的重要因素之一。

3.1.2 膠結(jié)作用

E1f2砂巖膠結(jié)物主要為碳酸鹽，黏土礦物、硅質(zhì)次之(圖5a，b)。碳酸鹽膠結(jié)物以方解石為主，次有白云石。黏土礦物以伊—蒙混層、伊利石、綠泥石為主，它們分布于顆粒及孔喉表面，影響了砂巖儲(chǔ)集性能。硅質(zhì)膠結(jié)主要表現(xiàn)為石英的次生加大，石英生長(zhǎng)于孔隙之中，縮小了儲(chǔ)集空間。

3.1.3 溶蝕作用

從鏡下薄片、電鏡觀察，溶蝕作用主要表現(xiàn)為膠結(jié)物和碎屑顆粒溶蝕。成巖早期的溶蝕作用常在粒間和顆粒中發(fā)生，形成粒間溶孔、粒內(nèi)溶孔、鑄?？?，增大φ、K；成巖晚期的溶蝕作用常形成一些不規(guī)則的非組構(gòu)控制的溶孔，在一定條件下有利于孔隙條件的改善[8]。

圖3 蘇北盆地金湖凹陷E1f2砂巖壓實(shí)現(xiàn)象Fig.3 Sandstone compaction phenomenon in E1f2 in the Jinhu Sag, Subei Basin

圖4 蘇北盆地金湖凹陷E1f2砂巖埋深與物性關(guān)系Fig.4 Relationship between burial depth and physical properties of sandstones of E1f2 in the Jinhu Sag, Subei Basin

圖5 蘇北盆地金湖凹陷E1f2砂巖膠結(jié)和溶蝕現(xiàn)象Fig.5 Cementation and dissolution of sandstones in E1f2 in the Jinhu Sag, Subei Basin

圖6 蘇北盆地金湖凹陷E1f2砂巖碳酸鹽含量與物性關(guān)系Fig.6 Relationship between carbonate content and physical properties of sandstones in 2 in the Jinhu Sag, Subei Basin

根據(jù)鑄體薄片分析，E1f2碎屑巖儲(chǔ)層的孔隙類型主要為溶蝕孔隙，鏡下所見(jiàn)主要為巖屑、長(zhǎng)石和方解石溶蝕(圖5c，d)，形成粒內(nèi)溶蝕孔、粒間溶蝕孔、港灣狀溶蝕孔等各種現(xiàn)象。

3.2 油氣充注

利用墩2-1井單井資料反映砂巖含油性與孔滲之間關(guān)系更加明顯(圖7c，d)，其中油浸砂巖儲(chǔ)層物性最好；油斑、油跡砂巖次之；非含油砂巖最差，非含油砂巖大多φ<10%，全部K<1×10-3μm2。

3.3 砂體微相類型

圖7 蘇北盆地金湖凹陷阜二段砂巖含油性與物性關(guān)系Fig.7 Relationship between oil-bearing and physical properties of sandstones in E1f2+3 2 in the Jinhu Sag, Subei Basin

圖8 蘇北盆地金湖凹陷阜二段砂巖微相與物性關(guān)系Fig.8 Relationship between depositional facies and physical properties of sandstones in E1f2 in the Jinhu Sag, Subei Basin

對(duì)西斜坡、汊澗地區(qū)三角洲前緣分支河道、河口砂壩、砂質(zhì)灘壩及卞閔楊、石港地區(qū)淺湖灘壩的不同沉積類型砂體與物性相關(guān)關(guān)系分析(圖8)，結(jié)果顯示：分支河道砂體儲(chǔ)層φ和K相對(duì)較好，河口壩和淺湖灘壩砂體儲(chǔ)層物性相對(duì)較差，說(shuō)明沉積時(shí)水動(dòng)能條件越強(qiáng)，砂巖顆粒越粗，儲(chǔ)層物性越好。

4 結(jié)論

(1)蘇北盆地金湖凹陷阜二段砂巖儲(chǔ)層以細(xì)粒、極細(xì)粒、粗粉砂長(zhǎng)石巖屑石英砂巖和長(zhǎng)石巖屑砂巖為主，不同地區(qū)巖石成分成熟度均值差異小、范圍變化較寬，結(jié)構(gòu)成熟度基本相當(dāng)。

(2)阜二段砂巖儲(chǔ)層物性總體較差，以中低孔、特低孔，低滲、特低滲儲(chǔ)層為主，粒間溶孔是主要的孔隙類型，物性相對(duì)較好的碎屑巖儲(chǔ)層主要分布在西部斜坡帶。

(3)儲(chǔ)層物性與成巖作用、油氣充注、砂體類型密切相關(guān)。壓實(shí)和碳酸鹽膠結(jié)是砂巖儲(chǔ)層物性變差的主要原因；溶蝕作用和油氣充注是抑制砂巖物性變差、改善儲(chǔ)集性能的重要因素；顆粒相對(duì)粗的、單砂體相對(duì)較厚、埋深相對(duì)較淺、碳酸鹽含量較低、溶蝕強(qiáng)烈的西斜坡和汊澗等地區(qū)是尋找相對(duì)優(yōu)質(zhì)砂巖儲(chǔ)層的有利地區(qū)。

[1] 劉玉瑞,王建.蘇北盆地復(fù)雜斷塊油氣藏勘探及技術(shù)[J].江蘇地質(zhì),2003,27(4):193-198.

Liu Yurui,Wang Jian.Exploration and technology of complex fault block reservoir[J].Jiangsu Geology,2003,27(4):193-198.

[2] 劉敬壽，杜全偉，戴俊生.金湖凹陷阜二段斷裂信息特征與油氣藏分布[J].特種油氣藏,2015,22(3):42-45.

Liu Jingshou,Du Quanwei,Dai Junsheng.Information dimension features of faults and reservoir distribution in Fu 2 Member in Jinhu Sag[J].Special Oil & Gas Reservoirs,2015,22(3)：42-45.

[3] 蘇娟,劉辰生,于汪.金湖凹陷西斜坡阜寧組灰?guī)r段成因機(jī)理[J].石油實(shí)驗(yàn)地質(zhì),2015,37(2):172-178.

Su Juan,Liu Chensheng,Yu Wang.Depositional features and forming mechanism of the limestone member of Funing Formation in Jinhu Sag[J].Petroleum Geology & Experiment,2015,37(2):172-178.

[4] 冀國(guó)盛,戴俊生,馬欣本,等.蘇北盆地閔北地區(qū)阜寧組一、二段火山巖的儲(chǔ)集特征[J].石油與天然氣地質(zhì),2002,23(3):289-292.

Ji Guosheng,Dai Junsheng,Ma Xinben,et al.Reservoir characteristics for volcanic rocks from member Ⅰ, Ⅱ of Funing Formation in northern Minbei region in Subei Basin[J].Oil & Gas Geology,2002,23(3):289-292.

[5] 王偉鋒,楊少春,金強(qiáng),等.金湖凹陷西園地區(qū)阜寧組二段儲(chǔ)層的微觀特征[J].石油大學(xué)學(xué)報(bào)(自然科學(xué)版),1996,20(5):12-16.

Wang Weifeng,Yang Shaochun,Jin Qiang,et al.Reservoir microcharacteristics of member Ⅱ in Funing Formation at Xiyuan area of Jinhu Sag[J].Journal of the University of Petroleum,China,1996,20(5):12-16.

[6] 劉金華,唐建東,鐘思瑛,等.金湖凹陷西斜坡阜二段物源方向再認(rèn)識(shí)[J].復(fù)雜油氣藏,2011,4(3):16-20.

Liu Jinhua,Tang Jiandong,Zhong Siying,et al.Reinterpretation of the source direction of the second member of Funing Formation in the west slope of Jinhu Sag[J].Complex Hydrocarbon Reservoirs,2011,4(3):16-20.

[7] 張妮,林春明,俞昊,等.蘇北盆地金湖凹陷腰灘地區(qū)古近系阜寧組儲(chǔ)層物性特征及其影響因素[J].高校地質(zhì)學(xué)報(bào),2011,17(2):260-270.

Zhang Ni,Lin Chunming,Yu Hao,et al.Quality of reservoir sandstones of Funing Formation in Yaotan area from Jinhu Depression,Subei Basin,and its influencing factors[J].Geological Journal of China Universities,2011,17(2):260-270.

[8] 于雯泉,劉喜歡,徐煥友.金湖凹陷阜二段碎屑巖儲(chǔ)層成巖演化定量分析[J].復(fù)雜油氣藏,2013,6(3):1-5.

Yu Wenquan,Liu Xihuan,Xu Huanyou.Quantitative analysis for diagenetic evolution of clastic reservoirs in the second member of Funing Formation in Jinhu Sag[J].Complex Hydrocarbon Reservoirs,2013,6(3):1-5.

[9] 王新新,戴俊生,馬洪坤.金湖凹陷石港斷裂帶構(gòu)造特征及控油作用[J].斷塊油氣田,2015,22(6):686-691.

Wang Xinxin,Dai Junsheng,Ma Hongkun.Structural characteristics and its control on oil and gas of Shigang fault zone in Jinhu Sag[J].Fault-Block Oil and Gas Field,2015,22(6):686-691.

[10] 劉玉瑞.蘇北后生—同生斷陷盆地油氣成藏規(guī)律研究[J].石油實(shí)驗(yàn)地質(zhì),2016,38(6):721-731.

Liu Yurui.Petroleum accumulation rules in hysterogenetic reconstructive-syngenetic rift basins,North Jiangsu Basin[J].Petroleum Geology & Experiment,2016,38(6):721-731.

[11] 劉玉瑞.蘇北盆地高郵凹陷戴南組物源—坡折控扇研究[J].石油實(shí)驗(yàn)地質(zhì),2016,38(1):23-31.

Liu Yurui.Sediment sources and slope belt controlling fan systems in the Dainan Formation in Gaoyou Sag,North Jiangsu Basin[J].Petroleum Geology & Experiment,2016,38(1):23-31.

[12] 劉玉瑞.蘇北后生斷陷層序地層格架與沉積體系[J].復(fù)雜油氣藏,2010,3(1):10-14.

Liu Yurui.Sequence-stratigraphic framework and depositional system in Subei epigenetic-faulted basin[J].Complex Hydrocarbon Reservoirs,2010,3(1):10-14.

[13] 曾小明,鄒明生,張輝,等.北部灣盆地烏石凹陷東區(qū)流沙港組三段儲(chǔ)層物性主控因素及分布規(guī)律[J].石油實(shí)驗(yàn)地質(zhì),2016,38(6):757-764.

Zeng Xiaoming,Zou Mingsheng,Zhang Hui,et al.Main controls on the distribution of the 3rd member of Liushagang Formation in eastern Wushi Sag,Beibu Gulf Basin[J].Petroleum Geology & Experiment,2016,38(6):757-764.

[14] 王偉鋒,胡瑜,于正軍,等.東營(yíng)三角洲前緣坡移扇儲(chǔ)集體特征及成因研究[J].石油實(shí)驗(yàn)地質(zhì),2016,38(5):600-608.

Wang Weifeng,Hu Yu,Yu Zhengjun,et al.Reservoir characte-ristics and genesis of slope fans in Dongying delta front[J].Petroleum Geology & Experiment,2016,38(5):600-608.

[15] 張琴,朱筱敏,鐘大康,等.山東東營(yíng)凹陷古近系碎屑巖儲(chǔ)層特征及控制因素[J].古地理學(xué)報(bào),2004,6(4):493-502.

Zhang Qin,Zhu Xiaomin,Zhong Dakang,et al.Clastic reservoir properties and their controlling factors of the Paleogene in Dongying Sag,Shandong Province[J].Journal of Palaeogeography,2004,6(4):493-502.

[16] 唐海發(fā),彭仕宓,趙彥超,等.致密砂巖儲(chǔ)層物性的主控因素分析[J].西安石油大學(xué)學(xué)報(bào)(自然科學(xué)版),2007,22(1):59-63.

Tang Haifa,Peng Shimi,Zhao Yanchao,et al.Analysis of main control factors of the physical property of tight sandstone reservoir[J].Journal of Xi’an Shiyou University (Natural Science Edition),2007,22(1):59-63.

[17] 張峰,崔健健,邵先杰,等.高集油田阜寧組湖相碳酸鹽巖儲(chǔ)層特征[J].斷塊油氣田,2015,22(3):296-300.

Zhang Feng,Cui Jianjian,Shao Xianjie,et al.Characteristics of Funing Formation lacustrine carbonate reservoir in Gaoji Oilfield[J].Fault-Block Oil and Gas Field,2015,22(3):296-300.

[18] 范瑞峰,董春梅,吳鵬,等.渤南油田四區(qū)沙三段儲(chǔ)層特征及其控制因素[J].油氣地質(zhì)與采收率,2015,22(4):64-68.

Fan Ruifeng,Dong Chunmei,Wu Peng,et al.Reservoir characteristics and its control factors of Es3member in Area 4,Bonan oilfield[J].Petroleum Geology and Recovery Efficiency,2015,22(4):64-68.

[19] 陳波,尤新才,張銀,等.瑪南地區(qū)烏爾禾組成巖作用對(duì)儲(chǔ)層物性的影響[J].西南石油大學(xué)學(xué)報(bào)(自然科學(xué)版),2016,38(1):10-20.

Chen Bo,You Xincai,Zhang Yin,et al.Effects of Diagenesis and reservoir of the Urho Formation in Manan region[J].Journal of Southwest Petroleum University (Science & Technology Edition),2016,38(1):10-20.

[20] 紀(jì)有亮,高崇龍,劉玉瑞,等.高郵凹陷阜一段油氣充注對(duì)儲(chǔ)層物性演化的影響[J].同濟(jì)大學(xué)學(xué)報(bào)(自然科學(xué)版),2015,43(1):133-139.

Ji Youliang,Gao Chonglong,Liu Yurui,et al.Influence of hydrocarbon charging to the reservoir property in 1stmember of Funning Formation in Gaoyou Depression[J].Journal of Tongji University (Natural Science),2015,43(1):133-139.

(編輯 徐文明)

Influencing factors of sandstone properties of the second member of Funing Formation in the Jinhu Sag, Subei Basin

Ma Yingjun

(SINOPECJiangsuOilfieldBranchCompany,Yangzhou,Jiangsu225012,China)

The lithologic characteristics of minerals, reservoir physical properties and pore structure of sandstones in the second member of Funing Formation in the Jinhu Sag of Subei Basin were studied based on petrographic thin sections, casting thin sections, porosity and permeability, and the influencing factors for reservoir physical properties were discussed. The sandstones in the second member of Funing Formation are generally fine grained. The average maturity of rock composition is similar among different regions, and range widely. The sandstones on the western slope of Jinhu Sag have better physical properties while those in the other areas are featured by low porosity and low to extra low permeability. Compaction and carbonate cementation are the main reasons leading to poor reservoir physical properties. Dissolution and hydrocarbon filling are important factors to restrain diagenesis and improve reservoir characteristics. The western slope has relatively better porosity and permeability and is a favorable target for hydrocarbon pools.

sandstone physical property; sedimentary microfacies; diagenesis; oil and gas filling; second member of Funing Formation; Jinhu Sag; Subei Basin

1001-6112(2017)04-0477-07

10.11781/sysydz201704477

2017-02-10；

2017-06-05。

馬英俊(1964—)，女，工程師，從事油氣地質(zhì)勘探綜合研究。E-mail：mayj.jsyt@sinopen.com。

中石化重大科技項(xiàng)目“蘇北盆地油氣聚集規(guī)律及精細(xì)評(píng)價(jià)關(guān)鍵技術(shù)”(ZDP17010)資助。

TE122.23

A