碳酸鹽巖縫洞型油藏縫洞單元形成機制及模式研究進展報告

金強 鄒勝章 鐘建華 田飛 康遜

摘 要：該研究以塔河油田4、6和7區縫洞儲層為研究對象，對塔河油田縫洞型儲層的成因結構和充填模式進行地質分析，建立塔河油田縫洞儲層的結構模式和充填模式；研究其縫洞單元內儲集空間的分布規律；通過多種地質因素綜合研究，分析研究區奧陶系縫洞單元內儲集空間的成因和主控因素。研究者建立了塔河油田縫洞儲層的三維立體結構模式，明確了表層帶、滲流帶和徑流帶縫洞結構和充填模式。表層巖溶帶主要由地表河、落水洞、斷層及裂縫、坡積物和奧陶系裸露巖石所組成。根據現代巖溶和古巖溶的考察，以及塔河油田的井下資料解釋，地表河和落水洞為河流沉積物和垮塌角礫巖充填。滲流巖溶帶的縫洞主要由滲流井和駐水洞以及縫洞復合體組成。滲流井是連通表層巖溶帶與徑流巖溶帶的水流通道，一般沿斷層或裂縫發育滲流井廢棄后常常被表層碎屑物或垮塌角礫充填，而駐水洞如果不受垮塌影響，則充填程度一般比較低，是非常好的油氣成藏和產出空間。徑流帶內水流以橫向流動為主，潛水面是徑流帶的底界。地下河溶洞是徑流帶縫洞的主要類型，在塔河油田根據地下河溶洞相互連通關系和規模，可以劃分出干流洞、支流洞和末梢洞。在斷層附近、地表落水洞下方可以形成規模巨大的廳堂洞。徑流帶溶洞大都具有比較強烈充填作用：地下河沉積碎屑充填，垮塌角礫充填和碳酸鈣化學充填。針對表層帶地表河和徑流帶溶洞系統沉積物巖性和沉積水動力條件進行研究，初步闡明了表層帶和徑流帶不同成因結構水動力條件與沉積物物源。以南方和塔北古巖溶縫洞系統發育與充填特征研究，建立了洞穴垮塌機制與控制因素。裸露期巖溶洞穴垮塌和埋藏期巖溶垮塌成因機理差異明顯。研究者基于不同充填物分別進行物性評價的思路，形成了縫洞充填物類型約束下多參數配合的物性評價方法。針對不同類型的縫洞充填物采用多參數組合法分別計算物性，建立不同縫洞充填物的物性評價方程，并與取心井實測孔隙度和滲透率進行對比分析。實踐證明，與巖心實測物性對比符合率高，有效評價了研究區縫洞儲集性能。

關鍵詞：縫洞成因結構 充填模式 沉積機制 垮塌機制 物性評價 儲集空間

Abstract：This topic takes fracture-cavity reservoir as the research object in Tahe Oilfield NO.4， 6， and 7 zone to analyze geological structure and filling pattern， to establish the structure of the fracture-cavity reservoir in Tahe Oilfield mode and filling mode； Study the distribution rule of reservoir space inside fracture-cavity unit； Through a variety of geologic factors comprehensive research and analysis of the Ordovician in the study area. Researchers fracture-cavity reservoir in Tahe oil field is established three-dimensional structure model， has been clear about the surface， seepage flow and runoff with fracture-cavity structure and filling patterns.Runoff water is given priority to with transverse flow， groundwater level is runoff zone at the bottom of the world. Underground river water-eroded cave is the main type， the run-off zone fracture-cavity in Tahe Oilfield according to the underground river water-eroded cave and scale interconnected relations， can be divided into main tributaries hole， hole and peripheral hole. Near the fault， surface sink below can form a huge hall hole. Runoff belt cave has relatively strong filling： mostly underground river sedimentary clastic filling， collapse breccia filling and chemical filling calcium carbonate. On the surface with the surface of the river sediment and runoff belt cave system lithology and sedimentary hydrodynamic conditions， a preliminary illuminates the surface with different genetic structure belt and runoff hydrodynamic conditions and sediment source. System development in the southern and northern ancient karst fracture-cavity and filling characteristics research， cave collapse mechanism and control factors is established. Stage nudity karst cave collapsed and buried karst collapse formation mechanism difference is obvious.Researchers， property evaluation based on different fillings， respectively， to form the stitch holes fillings type constraints under multiple parameter with property evaluation methods. For different types of stitch holes fillings multi parameter set legal properties are calculated respectively， set up different property evaluation equation of stitch holes fillings， and coring Wells with the measured porosity and permeability were analyzed. Practice has proved that compared with core properties measured coincidence rate is high.

Key Words：Fracture-cavity formation structures；Filling pattern；Deposition mechanism；Collapsing mechanism；Property evaluation；Reservoir space

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