Geophysical characterization of complex geopressure systems in unconventional reservoirs: A case study of the Jurassic reservoir in the Fuxing area
-
摘要:
异常地层压力预测是油气开发中面临的难点问题之一, 随着页岩油气和致密砂岩气等非常规储层开发的不断深入, 地层压力系统的复杂程度不断增大, 同一地区超压和负压并存的现象时有发生, 对复杂压力系统进行准确刻画具有重要的应用价值。针对复兴地区侏罗系页岩气储层和致密砂岩储层所形成的2套超压系统和1套负压系统, 分析了超压和负压的地球物理响应特征和敏感弹性参数, 发现泥岩地层的体变模量在负压-超压区间与地层压力具有良好的相关性, 据此提出一种基于泥岩体变模量的超压和负压一体化预测方法, 并利用测井数据和地震数据计算了单井压力曲线和三维地层压力数据体。该方法的关键在于利用超压和负压地层的泥岩进行一体化压力预测, 降低岩性变化因素的影响; 其次, 选取与异常压力物理机制具有直接关联的体变模量作为预测参数, 提高预测模型的精度。根据测井和地震压力预测结果, 研究区东岳庙段强超压系统的压力保存条件较好, 压力结构特征稳定, 压力系数最大约为2.0;凉高山组超压系统的压力保存条件相对较差, 压力结构特征横向差异较大, 压力系数最大约为1.65;凉高山组负压系统压力系数约为0.5~1.0, 且与下伏超压系统存在一定的耦合作用。对比超压和负压钻井实测数据, 研究区单井压力曲线与三维地层超压和负压预测结果均达到较高的吻合度。
Abstract:Objective The prediction of abnormal formation pressure is a challenging issue in oil and gas development. With the continuous development of unconventional reservoirs such as shale gas and tight sandstone gas, the complexity of geopressure systems has increased. The coexistence of overpressure and underpressure in the same area often occurs, making it important to accurately characterize complex pressure systems.
Methods In this work, two sets of overpressure systems and one set of underpressure systems formed in the Jurassic shale gas reservoir and tight sandstone reservoir in the Fuxing area were analysed. The geophysical responses and sensitive elastic parameters of overpressure and underpressure were analysed. The bulk modulus of the mudstone formation was strongly correlated with the formation pressure over the underpressure-overpressure interval. Based on this, an integrated prediction method for overpressure and underpressure based on the bulk modulus of mudstone was proposed and applied in this area by using well log and seismic data. The key of this method is to use the mudstone of overpressure and underpressure formations for integrated pressure prediction, reducing the influence of lithological changes. Second, the bulk modulus, which is directly related to the physical mechanism of abnormal pressure, was selected as the input parameter to improve the accuracy.
Results According to the results of pressure prediction in the study area, the preservation conditions of the strong overpressure system in the Dongyuemiao Member are good, the pressure structure is stable, and the maximum pressure coefficient is approximately 2.0. The preservation conditions of the overpressure system in the Lianggaoshan Formation are relatively poor, with large lateral differences in pressure structure characteristics, and the maximum pressure coefficient is approximately 1.65; the pressure coefficient of the underpressure system in the Lianggaoshan Formation is approximately 0.5 to 1.0, and it has a certain coupling effect with the underlying overpressure system.
Conclusion The predictions of overpressure and underpressure using well logs and seismic data in the study area both achieved high agreement with the measured data.
-
Key words:
- unconventional reservoir /
- geopressure prediction /
- Fuxing area /
- shale gas /
- tight sand /
- complex geopressure system /
- geophysics
-
图 2 复兴地区侏罗系地层沉积柱状图和地层压力特征(压力系统划分参考了国内常用分类标准[26])
Figure 2. Characteristics of the lithology, sedimentary facies and geopressure for the Jurassic in the Fuxing area
图 10 复兴地区东岳庙段强超压系统(a)、大安寨段常压-弱超压系统(b)、凉高山组超压系统(c)和凉高山组负压系统压力系数(d)平面图
Figure 10. Maps of pressure coefficients for the strong ovepressure system in Dongyuemiao Member(a), the normal and weak overpressure system in Da′anzhai Member(b), the overpressure system in Liangganshan Formation(c), the underpressure system in Lianggaoshan Formation(d) of the Fuxing area
表 1 单井和地震压力预测精度
Table 1. Predicted accuracy of single well and seismic pressure
井名 类型 地层 岩性 实测压力系数 单井压力系数预测 单井预测精度/% 地震压力系数预测 地震预测精度/% XY1井 超压 凉二段 页岩 1.48 1.43 96.6 1.53 96.6 TY1井 凉二段 页岩 1.25 1.31 95.1 1.19 95.2 FY10井 东一段 页岩 1.93 1.87 96.9 1.95 98.9 Zh1井 负压 凉三段 砂岩 0.60 0.57 95.0 0.58 96.7 FL1井 凉二段 砂岩 0.83 0.87 95.2 0.92 89.1 TL201井 凉三段 砂岩 0.70 — — 0.63 90.0 注:TL201井无横波测井资料,无法采用体变模量法进行单井地层压力预测 -
[1] CHILINGAR G V, SEREBRYAKOV V A, ROBERTSON J O. Origin and prediction of abnormal formation pressures[M]. Amsterdam: Elsevier, 2002. [2] 赵靖舟, 李军, 徐泽阳. 沉积盆地超压成因研究进展[J]. 石油学报, 2017, 38(9): 973-998. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB201709001.htmZHAO J Z, LI J, XU Z Y. Advances in the origin of overpressures in sedimentary basins[J]. Acta Petrolei Sinica, 2017, 38(9): 973-998. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB201709001.htm [3] 邹华耀, 郝芳, 蔡勋育. 沉积盆地异常低压与低压油气藏成藏机理综述[J]. 地质科技情报, 2003, 22(2): 45-50. doi: 10.3969/j.issn.1000-7849.2003.02.010ZOU H Y, HAO F, CAI X Y. Summarization of subnormal pressures and accumulation mechanisms of subnormally pressured petroleum reservoirs[J]. Geological Science and Technology Information, 2003, 22(2): 45-50. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7849.2003.02.010 [4] 许浩, 张君峰, 汤达祯, 等. 低压油气藏形成机制研究现状及发展趋势[J]. 地球科学进展, 2009, 24(5): 506-511. doi: 10.3321/j.issn:1001-8166.2009.05.006XU H, ZHANG J F, TANG D Z, et al. The study status and tendency of low pressure[J]. Advances in Earth Science, 2009, 24(5): 506-511. (in Chinese with English abstract) doi: 10.3321/j.issn:1001-8166.2009.05.006 [5] 李士祥. 鄂尔多斯盆地中生界异常低压成因及对成藏的影响[D]. 成都: 成都理工大学, 2017.LI S X. Effects on petroleum accumulation and genesis of the Mesozoic abnormal low pressure in Ordos Basin[D]. Chengdu: Chengdu University of Technology, 2017. (in Chinese with English abstract) [6] 袁际华, 柳广弟. 鄂尔多斯盆地上古生界异常低压分布特征及形成过程[J]. 石油与天然气地质, 2005, 26(6): 792-799. doi: 10.3321/j.issn:0253-9985.2005.06.015YUAN J H, LIU G D. Distribution characteristics and formation process of Upper Paleozoic abnormally low pressure zones in Ordos Basin[J]. Oil & Gas Geology, 2005, 26(6): 792-799. (in Chinese with English abstract) doi: 10.3321/j.issn:0253-9985.2005.06.015 [7] WANG Q C, CHEN D X, WANG F W, et al. Origin and distribution of an under-pressured tight sandstone reservoir: The Shaximiao Formation, Central Sichuan Basin[J]. Marine and Petroleum Geology, 2021, 132: 105208. doi: 10.1016/j.marpetgeo.2021.105208 [8] DUTTA N C. Geopressure prediction using seismic data: Current status and the road ahead[J]. Geophysics, 2002, 67(6): 2012-2041. doi: 10.1190/1.1527101 [9] 樊洪海. 异常地层压力分析方法与应用[M]. 北京: 科学出版社, 2016.FAN H H. Analysis methods and applications of abnormal formation pressure[M]. Beijing: Science Press, 2016. (in Chinese) [10] EATON B A. The effect of overburden stress on geopressure prediction from well logs[J]. Journal of Petroleum Technology, 1972, 24(8): 929-934. doi: 10.2118/3719-PA [11] 陈亚琳, 郁飞, 罗兵, 等. 四川盆地涪陵地区页岩储层压力预测及高压形成机制分析[J]. 石油实验地质, 2018, 40(1): 110-117. https://www.cnki.com.cn/Article/CJFDTOTAL-SYSD201801017.htmCHEN Y L, YU F, LUO B, et al. Formation pressure prediction and high pressure formation mechanisms of shale reservoirs in Fuling area, Sichuan Basin[J]. Petroleum Geology & Experiment, 2018, 40(1): 110-117. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-SYSD201801017.htm [12] FILLIPPONE W R. Estimation of formation parameters and the prediction of overpressures from seismic data[C]//Anon. SEG Technical Program Expanded Abstracts. [S. l. ]: Society of Exploration Geophysicists, 1982: 502-503. [13] EBERHART-PHILLIPS D, HAN D H, ZOBACK M D. Empirical relationships among seismic velocity, effective pressure, porosity, and clay content in sandstone[J]. Geophysics, 1989, 54(1): 82-89. doi: 10.1190/1.1442580 [14] BOWERS G LB. Pore pressure estimation from velocity data: Accounting for overpressure mechanisms besides undercompaction[J]. SPE Drilling & Completion, 1995, 10(2): 89-95. [15] 林正良, 孙振涛, 胡华锋, 等. 四川盆地WR区块页岩气藏孔隙压力分布特征[J]. 地球物理学进展, 2021, 36(5): 2045-2052. https://www.cnki.com.cn/Article/CJFDTOTAL-DQWJ202105026.htmLIN Z L, SUN Z T, HU H F, et al. Pore pressure distributional characterization of shale gas reservoir in WR Block of Sichuan Basin[J]. Progress in Geophysics, 2021, 36(5): 2045-2052. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-DQWJ202105026.htm [16] 胡华锋, 胡起, 林正良. 页岩气储层地层压力预测方法及其在四川盆地的应用[J]. 石油物探, 2018, 57(3): 362-368. doi: 10.3969/j.issn.1000-1441.2018.03.005HU H F, HU Q, LIN Z L. Pore pressure prediction for shale gas reservoirs and its application in the Sichuan Basin, China[J]. Geophysical Prospecting for Petroleum, 2018, 57(3): 362-368. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-1441.2018.03.005 [17] HAN T, PERVUKHINA M, CLENNELL M B. Overpressure prediction in shales[C]//Anon. Proceedings of the 76th EAGE Conference and Exhibition. Amsterdam: EAGE Publications, 2014: 1-5. [18] 陈超, 印兴耀, 陈祖庆, 等. 基于页岩岩石物理等效模型的地层压力系数预测方法[J]. 石油地球物理勘探, 2022, 57(2): 367-376. https://www.cnki.com.cn/Article/CJFDTOTAL-SYDQ202202013.htmCHEN C, YIN X Y, CHEN Z Q, et al. Prediction for formation pressure coefficients based on an equivalent petrophysical model of shale[J]. Oil Geophysical Prospecting, 2022, 57(2): 367-376. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-SYDQ202202013.htm [19] 井翠, 郝龙, 张婧, 等. 四川盆地五峰组-龙马溪组异常地层压力成因与广义泊松比预测方法: 以长宁地区为例[J]. 地学前缘, 2021, 28(1): 402-410. https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY202101038.htmJING C, HAO L, ZHANG J, et al. Genesis of the abnormal formation pressure in the Wufeng-Longmaxi Formation, Sichuan Basin and a generalized Poisson's ratio prediction method: A case study of the Changning area[J]. Earth Science Frontiers, 2021, 28(1): 402-410. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY202101038.htm [20] SAYERS C, BOER L D. Pore-pressure prediction in the Permian Basin using seismic prestack inversion[C]//Anon. Proceedings of the 7th Unconventional Resources Technology Conference. Denver: American Association of Petroleum Geologists, 2019: 2170-2180. [21] 李玉凤, 孙炜, 何巍巍, 等. 基于叠前反演的泥页岩地层压力预测方法[J]. 岩性油气藏, 2019, 31(1): 113-121. https://www.cnki.com.cn/Article/CJFDTOTAL-YANX201901013.htmLI Y F, SUN W, HE W W, et al. Prediction method of shale formation pressure based on pre-stack inversion[J]. Lithologic Reservoirs, 2019, 31(1): 113-121. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-YANX201901013.htm [22] BIRCHALL T, SENGER K, SWARBRICK R. Naturally occurring underpressure: A global review[J]. Petroleum Geoscience, 2022, 28(2): petgeo2021-051. [23] 李士祥, 施泽进, 刘显阳, 等. 鄂尔多斯盆地中生界异常低压成因定量分析[J]. 石油勘探与开发, 2013, 40(5): 528-533. https://www.cnki.com.cn/Article/CJFDTOTAL-SKYK201305004.htmLI S X, SHI Z J, LIU X Y, et al. Quantitative analysis of the Mesozoic abnormal low pressure in Ordos Basin[J]. Petroleum Exploration and Development, 2013, 40(5): 528-533. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-SKYK201305004.htm [24] 舒志国, 周林, 李雄, 等. 四川盆地东部复兴地区侏罗系自流井组东岳庙段陆相页岩凝析气藏地质特征及勘探开发前景[J]. 石油与天然气地质, 2021, 42(1): 212-223. https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT202101019.htmSHU Z G, ZHOU L, LI X, et al. Geological characteristics of gas condensate reservoirs and their exploration and development prospect in the Jurassic continental shale of the Dongyuemiao Member of Ziliujing Formation, Fuxing area, eastern Sichuan Basin[J]. Oil & Gas Geology, 2021, 42(1): 212-223. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT202101019.htm [25] 陈爱琼. 兴隆-泰来地区陆相页岩"甜点"地震评价[C]//佚名. 油气地球物理学术年会论文集. 南京: 中国地球物理学会, 2019: 518-524.CHEN A Q. Seismic evaluation of continental facies shale "sweet" in Xinglong-Tailai area[C]//Anon. Proceedings of the Annual Meeting of Oil & Gas Geophysics. Nanjing: Chinese Geophysical Society, 2019: 518-524. (in Chinese with English abstract) [26] 杜栩, 郑洪印, 焦秀琼. 异常压力与油气分布[J]. 地学前缘, 1995, 2(4): 137-148. https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY504.001.htmDU X, ZHENG H Y, JIAO X Q. Abnormal pressure and hydrocarbon accumulation[J]. Earth Science Frontiers, 1995, 2(4): 137-148. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY504.001.htm [27] 郭旭升, 魏志红, 魏祥峰, 等. 四川盆地侏罗系陆相页岩油气富集条件及勘探方向[J]. 石油学报, 2023, 44(1): 14-27. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB202301002.htmGUO X S, WEI Z H, WEI X F, et al. Enrichment conditions and exploration direction of Jurassic continental shale oil and gas in Sichuan Basin[J]. Acta Petrolei Sinica, 2023, 44(1): 14-27. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB202301002.htm [28] 刘忠宝, 胡宗全, 刘光祥, 等. 高成熟陆相页岩油气源-储特征及富集层段评价方法: 以川东复兴地区侏罗系东岳庙段为例[J]. 天然气工业, 2022, 42(10): 11-24. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG202210002.htmLIU Z B, HU Z Q, LIU G X, et al. Source-reservoir features and favorable enrichment interval evaluation methods of high mature continental shale: A case study of the Jurassic Dongyuemiao Member in the Fuxing area, eastern Sichuan Basin[J]. Natural Gas Industry, 2022, 42(10): 11-24. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG202210002.htm [29] 胡东风, 魏志红, 刘若冰, 等. 四川盆地拔山寺向斜泰页1井页岩油气重大突破及意义[J]. 中国石油勘探, 2021, 26(2): 21-32. https://www.cnki.com.cn/Article/CJFDTOTAL-KTSY202102003.htmHU D F, WEI Z H, LIU R B, et al. Major breakthrough of shale oil and gas in Well Taiye 1 in Bashansi syncline in the Sichuan Basin and its significance[J]. China Petroleum Exploration, 2021, 26(2): 21-32. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-KTSY202102003.htm [30] 彭伟, 舒逸, 陈绵琨, 等. 四川盆地复兴地区侏罗系凉高山组致密砂岩储层特征及其主控因素[J]. 地质科技通报, 2023, 42(3): 102-113. doi: 10.19509/j.cnki.dzkq.tb20220282PENG W, SHU Y, CHEN M K, et al. Tight sandstone reservoir characteristics and main controlling factors of Jurassic Lianggaoshan Formation in Fuxing area, Sichuan Basin[J]. Bulletin of Geological Science and Technology, 2023, 42(3): 102-113. (in Chinese with English abstract) doi: 10.19509/j.cnki.dzkq.tb20220282 [31] 胡东风, 李真祥, 魏志红, 等. 四川盆地北部地区巴中1HF井侏罗系河道砂岩油气勘探突破及意义[J]. 天然气工业, 2023, 43(3): 1-11. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG202303001.htmHU D F, LI Z X, WEI Z H, et al. Breakthrough in oil and gas exploration of Jurassic channel sandstone in Well Bazhong 1HF in northern Sichuan Basin and its significance[J]. Natural Gas Industry, 2023, 43(3): 1-11. (in Chinese with English abstract) https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG202303001.htm [32] MAVKO G, MUKERJI T, DVORKIN J. The rock physics handbook: Tools for seismic analysis of porous media[M]. Cambridge: Cambridge University Press, 2009.