苗栗地區由東至西三個並列之背斜構造分別為八卦力構造、出磺坑背斜及錦水背斜。其中出磺坑背斜及錦水背斜已生產大量的天然氣以及凝結油，台灣中油公司推測八卦力構造亦有產油潛能。然而，八卦力構造位於內麓山帶，難以進行地物探勘及野外調查工作，在地質資料甚為缺乏的狀況下，無法直接評估其產油氣的潛能。油氣的探勘之故，過去已於出磺坑背斜區域，累積豐富地下地質資料及密集的地質構造剖面，本研究藉此優勢，進行本區之構造分析，以出磺坑背斜為檢核標的，進而針對八卦力地區地質構造的形成機制及裂隙分布的情形進行評估。其中以軟體─Move檢核所繪製剖面之合理性，同時帶入力學分層之觀念修繪此構造剖面，及以數值分析方法─顆粒流程式(Particle Flow Code, PFC)，模擬出磺坑背斜與八卦力構造，進而分析裂隙之分布，並推算目標儲集層之孔隙率。
研究結果顯示，苗栗西部麓山帶之向斜與背斜構造特徵與拱彎作用產生的褶皺特徵相符，可依此機制以數值模擬的方式模擬其形貌。透過彙整五指山層至卓蘭層地層柱，本研究依各地層岩性組成與力學特性將地層重新劃分為由老至年輕A、B、C、D、E、F、G及H層，共8個力學層。根據複層褶皺理論中，褶皺軸部軟硬層形貌特徵對地質構造剖面進行修繪。研究結果顯示，硬層強度分別為軟層強度之25倍與50倍且水平應變量達38%時，可成功模擬出八卦力構造與出磺坑背斜之構造形貌，同時顯示區域內之裂隙生成與水平應變量值呈正相關。根據不同硬軟層強度比進行模擬結果顯示，當硬層強度為軟層強度之25倍時，裂隙集中發育於錦水背斜西翼與八卦力構造西翼，於出磺坑背斜兩翼亦有零星裂隙發育，出磺坑背斜東翼孔隙率高於西翼，東翼木山層孔隙率達4.7~4.9%；八卦力構造區域，八卦力構造西翼孔隙率高於東翼，西翼木山層孔隙率達4.3~9.9%。當硬層強度為軟層強度之50倍時，裂隙發育於八卦力構造之西翼、軸部A層與出磺坑背斜背斜兩翼，且東翼裂隙較為密集，出磺坑背斜東翼孔隙率高於西翼，東翼木山層孔隙率達6.0~7.1%；八卦力構造區域，八卦力構造西翼孔隙率高於東翼，西翼木山層孔隙率達4.8~9.6%。將數值模擬中孔隙率分析結果與岩心孔隙率進行比較顯示二維模擬計算出之孔隙率皆小於岩心試驗與NMR試驗得到之孔隙率。

The main oil and gas production structure is a series of parallel anticlines in NNE-SSW orientation in western foothills. Chinshui and Chuhuangkeng anticlines are the most productive structures among them. The CPC (Chinese Petroleum Corporation) surmises that Pakuali structure, which is east of Chuhuangkeng anticline, could also have the potential to be a production structure. Nevertheless, it is inefficient to carry out geophysical exploration and field investigation in the inner western foothills where Pakuali structure is located. Taking advantage of the abundant surface and subsurface geological data of anticlines west of the Pakuali structure, it is legitimate to reason the tectonic characteristics and structural evolution of Chuhuangkeng-Pakuali area. The aim of this study is to construct a geological cross-section which can be balanced kinematically and simulated mechanically by MOVE commercial software and PFC2D simulation software, respectively. Furthermore, fracture distribution analysis and porosity assessment are performed based on the simulation results.
Based on my cross-section, the structural characteristics of crustal folds in the western foothills in Miaoli are similar to the folds produced by the mechanism of buckling. Accordingly, the numerical simulation of this study are founded on the buckling mechanism. The stratigraphic assemblage of the oldest Wuchishan Formation to Cholan Formation are collated and divided into eight structural lithic units, re-named as layer A to H, based on the difference of lithology and mechanical properties. According to the theory of multi-layer folding, the geological cross-section is modified as lobate and cuspate shapes for the contacts of the soft and hard layers at the fold axis, and the structural section is then used as a reference for the successful simulation of the Chuhuangkeng anticline and the Pakuali structure.
The results show that when the hard layer strength is 25 times and 50 times greater than the soft layer strength and the horizontal shortening is 38%, the structural configuration of the Pakuali structure and the Chuhuangkeng anticline can be successfully simulated. For the case of layer strength ratio of 25 times, the cracks are concentrated in the western limb of the Chinshui anticline and the western limb of the Pakuali structure. There are also sporadic cracks in the both limb of the Chuhuangkeng anticline. The porosity of the eastern limb of the Chuhuangkeng anticline is higher than that of the western limb, and the porosity of the B layer in the eastern limb is about 4.7 to 4.9%. The porosity of the west limb of the Pakuali structure is higher than that of the east limb, and the porosity of the B layer in the west limb is about 8.8 to 9.6%. For the case of layer strength ratio of 50 times, cracks develop in the western limb of the Pakuali structure, both limbs of the Chuhuangkeng anticline and the cores of two structures at the A layer. The porosity of B layer at the eastern limb of the Chuhuangkeng anticline is about 6.0 to 7.1% while the porosity of B layer at the western limb of Pakuali structure is about 4.8 to 9.6%. Comparing the values of porosity from the numerical simulation with the values of porosity from the tests, the porosity values derived from the two-dimensional simulation are, in general, few percentages less than the porosity values obtained from the core test and the NMR test.

台灣油礦探勘總處，「出磺坑構造地質剖面勘查指南」，地質，7(2)，83-90頁，1986。
何信昌，五萬分之一台灣地質圖說明書，苗栗圖福，經濟部中央地質調查所，新北市中和區，1994。
何春蓀，「台灣西部麓山帶的地質」，地工技術，20，80-98頁，1987。
何春蓀，台灣地質概論：台灣地質圖說明書，經濟部中央地質調查所，台北縣中和市，1986。
吳柏裕，「出磺坑淺部油氣層天然裂隙方位之初步研究」，石油季刊，22(3)，1986。
吳偉智，范振暉，陳大麟，吳健一，王勝雄，葉榮富，吳柏裕和彭日昇，「出磺坑淺層油氣再開發評估」，探採研究彙報，21，461-476頁，1998。
李錦發，五萬分之一台灣地質圖說明書，東勢圖福，經濟部中央地質調查所，新北市中和區，2000。
周佳儀，「出磺坑背斜構造發育之三角剪切模型」，國立中央大學，碩士論文，2008。
林慶偉和楊耿明，「台灣西北部內麓山帶橫移構造特性分析之砂盒模型研究」，國科會報告，2009。
洪奕星，「台灣西北部麓山帶中新統至下部上新統岩相和生痕化石相分析以及沉積環境」，國立台灣大學，博士論文，1988。
孫其誠和王光謙，顆粒物質力學導論，科學出版社，2009。
張憲卿，五萬分之一台灣地質圖說明書，白沙屯圖福，經濟部中央地質調查所，新北市中和區，1990。
陳文山，台灣地質概論，中華民國地質學會，台北市，2016。
陳采蔚，「苗栗地區錦水背斜下構造演育與裂縫發育」，國立台灣大學，碩士論文，2016。
陳振華，「由晚期新生代沈積物之岩象學與構造地層學研究探討台灣中西部褶皺逆衝帶之演化」，國立台灣大學，博士論文，1993。
游能悌和鄧屬予，「出磺坑剖面中新統的岩相與沈積環境」，地質，15(1)，127-151頁，1995。
黃旭燦和陳耀輝，「台灣的油氣田」，科學發展，534，38-43頁，2017。
黃富文和周青，「台灣西北部打鹿砂岩儲集問題」，探採研究彙報，8，25-40頁，1985。
黃鑑水，五萬分之一台灣地質圖說明書，台北圖福，經濟部中央地質調查所，新北市中和區，2005。
塗明寬和陳文政，五萬分之一台灣地質圖說明書，竹東圖幅，經濟部中央地質調查所，新北市中和區，1991。
楊宜蓉和胡植慶，「顆粒體離散元素法模擬西部麓山帶細道邦構造裂縫儲油潛能之評估」，台灣鑛業，65(3)，13-18頁，2013。
慧美麗，「台灣中部晚期中新世至更新世二氧化碳 儲集層及蓋層之地層暨礦物組成研究」，國立中央大學，碩士論文，2018。
潘國樑，工程地質通論，台灣五南圖書出版股份有限公司，台北市，2007。
鄧屬予，台灣地質系列第9號：台灣的沉積岩，經濟部中央地質調查所，臺北縣中和市，1997。
鍾開增，「苗栗地區麓山帶之地質構造」，國立中央大學，碩士論文，1996。
魏聲焜，「苗栗地區上新世至中新世之構造地層學之研究」，國立成功大學，碩士論文，1994。
羅仕榮，「區域性儲集岩資料分析」，探採研究彙報，25，131-148頁，2003。
嚴珮綺，「利用鑽井資料推估台灣新竹至台中地區的地下」，國立中央大學，碩士論文，2012。
Carena, S., Suppe, J. and Kao, H., "Active detachment of Taiwan illuminated by small earthquakes and its control of first-order topography", Geology, Vol. 30(10), pp. 935-938, 2002.
Chapple, W. M., "Mechanics of thin-skinned fold-and-thrust belts", Geological Society of America Bulletin, Vol. 89(8), pp. 1189-1198, 1978.
Chou, J. T. and Yeh, M. K., "Comparison of the suggested" Szuling sandstone" in the Tiechienshan TCS-34 well, Miaoli and the Paileng formation, Kuohsing, Nantou", Petroleum Geology of Taiwan, Vol. 23, pp. 41-53, 1987.
Cundall, P. A. and Strack, O. D. L., "A discrete numerical model for granular assemblies", Géotechnique, Vol. 29(1), pp. 47-65, 1979.
Currie, J. B., Patnode, H. W. and Trump, R. P., "Development of folds in sedimentary strata", Geological Society of America Bulletin, Vol. 73(6), pp. 655-673, 1962.
Davis, D., Suppe, J. and Dahlen, F. A., "Mechanics of fold‐and‐thrust belts and accretionary wedges", Journal of Geophysical Research: Solid Earth, Vol. 88(B2), pp. 1153-1172, 1983.
Hoek, E., Practical rock engineering, Geosysta Ltd, 2006.
Hung, J. H. and Wiltschko, D. V., "Structure and kinematics of arcuate thrust faults in the Miaoli-Cholan area of western Taiwan", Petroleum Geology of Taiwan, Vol. 28, pp. 59-96, 1993.
Hung, J. H. and Yang, C. N., "Mesoscale deformation mechanisms in the Chuhuangkeng anticline, Miaoli, Taiwan", Proceedings of the Geological Society of China, Vol. 34(1), pp. 17-42, 1991.
Itasca, Particle Flow Code in 2 Dimensions Version 3.0 Online Manual, Itasca Consulting Group Inc., 2002.
Ku, C. C., "Disharmonic folding in the Wenshuichi valley, Miaoli", Proceedings of the Geological Society of China, Vol. 5, pp. 135-139, 1962.
Lin, C. H., Yeh, Y. H. and Roecker, S. W., "Seismic velocity structures beneath the Sanyi-Fengyuan area, central Taiwan and their tectonic implications", Proceedings of the Geological Society of China Vol. 32 (1), pp. 101-120, 1989.
Lin, C. W., Wey, S. K. and Lin, C. J., "Structural lithic units in the western foothills, Taiwan a case study in the Miaoli Wenshui and the Chiayi Alishan areas", Journal of the Geological Society of China, Vol. 39(2), pp. 167-188, 1996.
Marshak, S. and Mitra, G., Basic method of structural geology, Prentice Hall Englewood cliffs, New Jersey, 1988.
Mitra, S. and Namson, J., "Equal-area balancing", American Journal of Science, Vol. 289(5), pp. 563-599, 1989.
Mouthereau, F., Deffontaines, B., Lacombe, O., Angelier, J., Byrne, T. B. and Liu, C. S., "Variations along the strike of the Taiwan thrust belt: Basement control on structural style, wedge geometry, and kinematics", Special Papers-Geological Society of America, pp. 31-54, 2002.
Namson, J., "Structural of the western foothills belt, Miaoli-Hsinchu area,Taiwan: (I) Southern part", Petroleum Geology of Taiwan, Vol. 18, pp. 31-51, 1981.
Namson, J., "Structural of the western foothills belt, Miaoli-Hsinchu area,Taiwan: (II) Central part", Petroleum Geology of Taiwan, Vol. 19, pp. 51-76, 1983.
Ramsay, J. G. and Huber, M. I., The techniques of modern structure geology Vol 2: Folds and Fracture, Vol. 2, Academic Press, 1987.
Rowland, S. M., Duebendorfer, E. M. and Schiefelbein, I. M., Structural analysis and synthesis Blackwell Publishing Ltd, 1986.
Suppe, J., "Geometry and kinematics of fault-bend folding", American Journal of Science, Vol. 283, pp. 684-721, 1983.
Suppe, J., "Mechanics Of Mountain-Building And Metamorphism In Taiwan", Memoir of the Geological Society of China, Vol. 4, pp. 67-89, 1981.
Tai, P. C. and Teng, L. S., "Sequence stratigraphy analysis of the Oligocene strata, northern Taiwan", Journal of the Geological Society of China, Vol. 37(4), pp. 607-640, 1994.
Woodward, N. B., Boyer, S. E. and Suppe, J., Balanced geological cross-sections: An essential technique in geological research and exploration, American Geophysical Union, Washington, D.C., 1989.