二氧化碳地質封存 (Carbon-Dioxide Capture and Storage, CCS) 已被證實：可以針對工業活動排放的二氧化碳進行減量的可行辦法。本研究利用高解析反射震測法，調查合適的二氧化碳封存場址，並探討地下地層構造，作為鑽井及未來監測的參考基準。高解析反射震測法可以提供很好的CCS場址需要的精細地下形貌，在地表下3公里範圍，解析度可達10公尺。 本研究調查台灣中部可能作為二氧化碳封存場址的雲林麥寮六輕工業區，共實施9條反射震測測線，並利用中油的王功一號井、台西一號井、崙豐一號井、褒忠一號井等井資料做為震測資料解釋的依據，推估未來六輕井可能的地下地層細部構造。 根據震測資料與井資料分析，獲得以下結論： (1) 地下地層朝向西北方向上傾約1.5度，若在六輕進行二氧化碳封存，注入之二氧化碳會往外海移棲。(2) 麥寮地區地下的中新世以上的地層平緩，構造完整，無斷層痕跡。(3) 儲集層以北寮層最佳，深度位於1340～1500 公尺，而蓋層的打鹿頁岩深度約在1260～1340 公尺。麥寮六輕地區有合適的蓋層與孔隙率佳、滲透率良好的儲集層。適當的地層深度，再加上地層平緩、無斷層影響，整體而言非常適合做為二氧化碳封存場址。 ;The geological storage of CO2 is recommended by IPCC to be an efficient and feasible way to reduce the CO2 emission concerning the global warming. In this study, we use high-resolution seismic reflection method to investigate a possible CO2 storage site in the middle Taiwan. The method provides high resolution signals to detect fine structures which are needed in the CCS application. The resolution power is expected to be as small as 4m with a depth up to 3km.
The proposed CCS site is along the coast, where Taiwan’s Sixth Naphtha Cracking Plant is located. In its ocean side, a PeiKang basement high exists which makes the structural layers tilt by about 2 degrees toward the sea. Eight 2D seismic lines are acquired, which connect four wells previously drilled by an oil company. The well data provide appropriate stratigraphic information of the region. By aligning these seismic lines, we are able to extrapolate well stratigraphic data to the target area.
The conclusions are: 1) The structural layers are found to dip 1.5 degrees and strike 15 degrees west to the north. This means that the CO2 will migrate toward the sea direction after storage. 2) The seismic lines have good ties, which guarantee excellent data quality of the survey. The layered structures are quite flat without any trace of interruption by the fault. 3) The caprock layer of shale is at the depth 1260~1340m and the reservoir layer of sandstone is at 1340~1540m. This site has good caprock, thick reservoir with high porosity and, most important, at suitable depths. This could be a good CCS site.
