CAJ | 학술논문

根据对国内外致密油气聚集成藏特征的分析，提出致密大油气田存在3种成藏模式，即连续型（深盆气型）、准连续型和不连续型（常规圈闭型）。与连续型油气藏相似，准连续型油气聚集也表现为：油气分布面积较大，无明确边界，也无边底水；源、储邻近，广覆式分布；油气运移主要为非浮力驱动，运移动力主要为异常压力、扩散作用力和毛细管压力，浮力作用受限；运移的方式主要为非达西流，以涌流和扩散流为主。所不同的是：准连续型油气聚集由多个彼此相邻的中小型油气藏组成，油气呈准连续分布；油、气、水分布比较复杂，无显著油、气、水倒置；油气充注以大面积弥漫式垂向排驱为主，初次运移直接成藏或短距离二次运移成藏；储层先致密后成藏或边致密边成藏，且非均质性较强；圈闭对油气聚集成藏具有一定控制作用。研究认为，以深盆气或盆地中心气为代表的连续型油气藏与典型的不连续型常规圈闭油气藏，分别代表了复杂地质环境中致密油气藏形成序列中的两种端元类型，二者之间应存在不同的过渡类型。准连续型油气藏就是这样一种过渡类型的致密油气聚集，并且可能是致密储层中大油气田形成的主要方式。事实上，典型的连续型油气聚集应是那些形成于烃源岩内的油气聚集（如页岩气和煤层气），典型的不连续型油气聚集则是那些形成于烃源岩外近源-远源的常规储层中、受常规圈闭严格控制并且具有边底水的油气聚集；而形成于烃源岩外并且近源的致密油气藏则主要为准连续型油气聚集，其次为非典型的不连续型（常规圈闭型）油气聚集，而像盆地中心气或深盆气那样的连续型聚集则较为少见。
근거대국내외치밀유기취집성장특정적분석，제출치밀대유기전존재3충성장모식，즉련속형（심분기형）、준련속형화불련속형（상규권폐형）。여련속형유기장상사，준련속형유기취집야표현위：유기분포면적교대，무명학변계，야무변저수；원、저린근，엄복식분포；유기운이주요위비부력구동，운이동력주요위이상압력、확산작용력화모세관압력，부력작용수한；운이적방식주요위비체서류，이용류화확산류위주。소불동적시：준련속형유기취집유다개피차상린적중소형유기장조성，유기정준련속분포；유、기、수분포비교복잡，무현저유、기、수도치；유기충주이대면적미만식수향배구위주，초차운이직접성장혹단거리이차운이성장；저층선치밀후성장혹변치밀변성장，차비균질성교강；권폐대유기취집성장구유일정공제작용。연구인위，이심분기혹분지중심기위대표적련속형유기장여전형적불련속형상규권폐유기장，분별대표료복잡지질배경중치밀유기장형성서렬중적량충단원류형，이자지간응존재불동적과도류형。준련속형유기장취시저양일충과도류형적치밀유기취집，병차가능시치밀저층중대유기전형성적주요방식。사실상，전형적련속형유기취집응시나사형성우경원암내적유기취집（여혈암기화매층기），전형적불련속형유기취집칙시나사형성우경원암외근원-원원적상규저층중、수상규권폐엄격공제병차구유변저수적유기취집；이형성우경원암외병차근원적치밀유기장칙주요위준련속형유기취집，기차위비전형적불련속형（상규권폐형）유기취집，이상분지중심기혹심분기나양적련속형취집칙교위소견。
Three patterns of hydrocarbon accumulation in large tight oil /gas fields are proposed ,namely ,continuous accu-mulation (or basin-centered gas type or deep-basin gas type),quasi-continuous accumulation,and discontinuous (con-ventional trap type ) accumulation .Like the continuous accumulation ,the quasi-continuous accumulation also features in large area,without clear boundaries and water lags ,reservoir being adjacent to source rocks and pervasive distribution .In addition,non-buoyancy-driven hydrocarbon migration is dominant .The major driving forcers of migration are overpres-sure,diffusion and capillary pressure ,while buoyancy is limited .The migration is largely in the form of non-Darcy surge flow and diffusion flow .However , the quasi-continuous accumulation is different from the continuous accumulation in many aspects.The quasi-continuous accumulation commonly consists of many adjacent medium to small oil /gas reservoirs and the hydrocarbons are in quasi-continuous distribution .Oil/gas and water contact is complex and no regional updip water present .Hydrocarbon charging is mainly vertical and pervasive expulsion .Hydrocarbon accumulation is characte-rized by direct accumulation via primary migration or short-distance secondary migration .The reservoirs get tight prior to or contemporaneous with the hydrocarbon charging and are highly heterogeneous .The traps have certain controlling effect on hydrocarbon accumulation .The continuous unconventional accumulation represented by the basin-centred gas or deep-basin gas and the typical discontinuous conventional accumulation are representative of two end -member types of tight hy-drocarbon accumulations in complicated geological settings .Hence some transitional varieties must exist between them and the quasi-continuous accumulation is just such a transitional type that might be a universal and predominated pattern for large oil/gas accumulation to occur in tight formations .In reality,a typical continuous accumulation ought to be that occurs within a source rock interval like shale gas or coalbed methane ,while a typical discontinuous accumulation is that occurs within the conventional reservoirs outside or even far away from source rocks ,and it is not only strictly confined by conventional traps but also possesses bottom or edge water .The hydrocarbon accumulations in tight reservoirs out of but close to source rocks are predominantly quasi-continuous accumulation ,followed by atypical discontinuous accumulations . In contrast,continuous accumulations such as basin-centered gas or deep-basin gas are,if any,uncommon.