半地堑式断陷盆地的油气成藏模式——以松辽盆地梨树断陷为例

半地堑式断陷盆地是松辽盆地深部断陷的主要类型,是今后油气勘探重点。以梨树断陷为例,根据半地堑式断陷盆地的构造和层序地层发育特点,针对此类盆地的生储盖组合规律,总结出该类盆地中主要存在有滚动背斜油气藏、断层油气藏、超覆型上倾尖灭岩性油气藏、相变型上倾尖灭岩性油气藏、透镜型岩性油气藏、潜山油气藏等6种类型;探讨了半地堑式断陷盆地的油气成藏模式。

地堑式断陷盆地油气成藏规律分析--以伊通地堑岔路河断陷南部为例

伊通地堑属佳—伊地堑的南段,是郯庐断裂带的北延部分,其内的岔路河断陷为一典型的地堑式断陷盆地。综合剖析表明,该断陷内的砂体主要为重力流性质的湖底扇沉积。湖底扇内扇中的水下泥石流或垮塌堆积砂砾岩对油气具有封堵性,湖底扇的中扇砂体具有一定的储集性能。内扇发育水下泥石流或垮塌堆积的湖底扇中扇砂体易于构成岩性圈闭。纵向上,此类断陷盆地具有广泛的含油性,易于形成多个含油层位;平面上,其有利勘探区带位于距控盆断裂一定距离的盆地两侧边缘区,特别是盆地盖层断裂有一定程度发育的边缘带,更有利于岩性油气藏的形成。油气勘探的目标主要为湖底扇中扇的舌状岩性油气藏和滚动背斜油气藏。

地堑式断陷盆地储层流体综合识别——以伊通盆地岔路河断陷为例

伊通盆地岔路河断陷古近系为地堑式断陷盆地沉积,其储层主要为重力流成因的湖泊水下扇,具有物源近、堆积速率快、岩性复杂多变的特征,加之后期成岩作用的影响,造成这类砂体物性变异系数大,非均质程度高。储层内部含流体时,流体性质难以识别,易造成测井解释上油气水层的误判。为了能够应用常规测井资料评价此类油气储层,提高测井解释的成功率,通过综合分析本区储层岩性、物性和含油气性特征,结合试油结果建立了本区岩性、物性及含油气性解释模型。岔路河断陷测井解释参数交汇图版可以明显区分出气层、油层、气水同层、油水同层、水层和干层等不同的地层油气产状。图版显示:岔路河断陷产油气储层含油饱和度下限为20%,并且产气层比产油层具有更高的深浅双侧向电阻率差值;纯水层虽然具有较好的物性条件,但含油饱和度均小于20%;干层泥质体积分数均大于22%,总孔隙度小于10.5%,物性变差,一般为无效储层。

吉林省敦化盆地地质特征及地质发展史

敦化盆地是由白垩—古近纪的新开岭盆地、大山嘴子—镜泊湖盆地和新近—第四纪敦化火山盆地的组合总称。它的形成严格受敦密断裂带地堑式两条平行断裂所控制。敦密断裂带在侏罗—白垩纪时期受伊佐奈歧板块的向西俯冲、挤压形成的火山造山带的地堑式断裂带,而新近—第四纪则主要受长白山火山地幔热柱和太平洋板块向西俯冲带而形成的不完整复式裂谷型深大断裂带而形成。经普查,大山嘴子—镜泊湖盆地具有良好的成煤和成油条件,并且已初步探明煤矿地质储量5.82亿吨,远景储量10亿吨;油气总资源量为1.24亿吨。敦化火山盆地的玄武岩喷发期次多,分布也很广,造就了许多风光景点及优质板材、铸石、纤维、硅藻土等资源。

Study on Character of Micro-Canal Deposit and Its Significance in Petroleum Geology——Case study of Tuo-147-well in north zone of Dongying depression

Exploration on reservoir of glutenite segment in steep slope zone of half graben-like basin is one of the hot spot targets at present and in the future for new reservoirs; And the study of sediment character of sandy-conglomerate bodies is the keystone and also the difficult problem. Taking Tuo-147-well area in north zone of Dongying depression as an example, the micro-canal sedimentation was researched. The result shows that many micro-canals exist at the end of slope grain-flow in steep slope zone of half graben-like basin; The micro-canals grow at the end of subaqueous grain-flow deposited bodies of 3rd member of the Shahejie formation. The main condition of micro-canal formation is the slope angle less than 18° and a long suitable sedimentary slope. These micro-canals may communicate the reservoir of glutenite segment in steep slope zone and the hydrocarbon stratum as a bridge role. Therefore, it is significant in theory and practice for discovering a series of micro-canals at the end of slope grain-flow in steep slope zone of half graben-like basin.