为了厘清四川盆地自贡地区中二叠统茅口组储层的差异发育机制与分布规律,基于丰富的测井、录井、取心和测试资料,对储层类型及主控因素进行了综合分析.研究结果表明:区内主要存在石灰岩类、白云岩类两种储集岩类.白云岩类储层主要发育于茅二段和茅四段,一般单层厚十几至几十厘米,多发育于向上变浅序列顶部,平面上茅二段白云岩储层主要分布于威远—自贡—富顺一线,而茅四段白云岩储层则主要分布于观音场—青杠坪一带;石灰岩类储层厚度变化大、非均质性强,纵向上可发育于茅二段—茅四段,平面上主要分布于沉积期地貌或风化壳岩溶地貌的高地或斜坡.进一步分析表明,白云岩储层形成与高频海平面下降驱动的蒸发浓缩—回流渗透白云石化和短期暴露岩溶相关,其中沉积期地貌相对坡折和滩体叠置迁移加剧了研究区局限蒸发的海水环境:石灰岩储层主要有滩控早成岩期岩溶、风化壳岩溶和断溶优化3种成因类型,分别受沉积期地貌坡折、岩溶地貌高地和斜坡以及断裂控制.综合分析认为,区内茅口组强非均质性、多成因类型储层具有受沉积期古地貌、古环境、风化壳岩溶古地貌、古断裂等"四古"复合控储特征.有利储层具有"沿高环坡"的分布规律,下一步勘探方向应重视东北部自贡一富顺区带的多层系、多成因类型储层的立体勘探和西南部观音场—青杠坪一带规模性白云岩储层的勘探.

松辽盆地中央古隆起带南部具备良好的油气藏形成条件,是吉林油田油气风险勘探的重要领域之一.笔者综合岩芯、薄片观察,测录井资料分析,孔渗分析和三维地震解释,在大量统计分析和地质研究基础上,探讨了中央古隆起带南部基岩储层特征和油气成藏模式,提出3点认识:①基底岩性主要为花岗岩、花岗闪长岩、闪长岩、片岩、糜棱岩、变质砂岩、安山岩、凝灰岩和灰岩9种,其中花岗岩、花岗闪长岩、安山岩和片岩为成储优势岩性;②基岩主要储集空间为裂缝和溶蚀孔,储层主要发育在基岩顶面风化壳风化淋滤层和裂缝层中;③基岩油气藏可划分为近源缓坡超覆、近源陡坡对接(顺向对接和反向对接)和源内披覆(断阶披覆和背斜披覆)3类成藏模式.该研究明确了中央古隆起带南部基岩油气藏勘探方向,为有利目标区预测提供理论支撑.

目前实施的有机质丰度评价行业标准并不适用于中-高演化阶段烃源岩.为了实现此类烃源岩品质的精细分类评价,该文基于烃源岩原始生烃潜量与残余有机碳含量以及残余生烃潜量关系,建立了不同演化阶段烃源岩有机质丰度评价标准,探讨了烃源岩岩性、干酪根类型以及热演化程度对评价指标界限划分的影响.研究表明,中-高演化阶段烃源岩丰度指标划分界限明显低于行业标准,总体上表现为随热演化程度的增加评价指标界限逐渐降低,且随着有机质类型变差、评价指标界限逐渐升高的趋势.虽然碳质泥岩有机碳含量和生烃潜量要高于泥岩,属于品质较好的气源岩,但并不一定是较好的生油岩.不同含油气盆地由于烃源岩岩性、有机质类型和热演化程度存在差异,其评价指标界限难以统一,但可借鉴该文方法分别建立,为烃源岩的精细分类评价和有利区带优选提供依据.

松辽盆地南部德惠断陷东部、洼槽带营城组致密气勘探获得发现,两口井试气获高产工业气流.本文通过对营城组致密气藏成藏富集因素研究,明确了气藏富集的主控因素,对松南深层乃至其他盆地致密气勘探有一定的参考及借鉴意义.

It has long been considered that thicker volcanostratigraphic sequences should, in theory, contain more favourable reservoir conditions than in thinner sequences, particularly within large-scale stratovolcanoes found in sedimentary basins. However, drilling results from the Wangfu Rift Depression (WRD) in the Songliao Basin, China, show that the thick intermediate volcanostratigraphic sequence contains only one or two layers of favourable reservoir characteristics over approximately 1000 m of volcanic successions. The volcanostratigraphic sequence that is common in the graben basin has a particular distribution pattern as a result of reservoir and origin processes. The Eruptive Interval Unconformity Boundary (EIUB) is introduced and the burial history is investigated in order to determine the reservoir characteristics and origin. We also identify what controls the gas pool accumulation in the thick intermediate volcanostratigraphy. According to the reworked volcanic rocks and weathered crust patterns, the volcanostratigraphy of the basin has 13 wells containing one EIUB, and 2 wells with two EIUBs. The exposed and burial histories of the volcanostratigraphic sequence have produced a variety of pore space including primary pores, secondary pores and secondary fractures. The secondary pores are the most dominant, followed by primary pores and finally fractures. These pore spaces form a reservoir with moderate to low porosity and permeability and the most productive reservoirs are located 40-80 m below the EIUB. The secondary pores are primarily controlled by weathering and leaching as well as deep-burial alteration. Due to the migration of fluids from the overlying strata into the volcanic rocks of the Huoshiling Formation below, the top most layer dissolves first, which significantly enhances the secondary porosity of this layer found 40-80 m below the EIUB. Thus, the number of EIUBs should control the number of favourable reservoir layers. Based on analysis of the reservoir, source and cap rocks in the study area, we conclude that the best exploration targets in these thick volcanostratigraphic sequences, specifically in half-graben basins, are the volcanic inherited-uplift slope areas, followed by the inherited-uplift of the sag area and the uplifted zones. The findings presented in this work provide an insight of the evolution of porosity in other volcanic systems elsewhere and contribute to the likelihood of locating the favourable exploration targets for thick volcanostratigraphic sequences in half-graben basins.

利用ECS (Elemental Capture Spectroscopy)测井资料中Gd和Ti交汇图进行火山地层对比.结果表明王府断陷流纹质火山地层可划分为5个地层单元;存在明显间断期的CS13和CS14井均揭示Ti元素变化特征是上覆层段(晚喷发期)含量高,并推测火山喷发顺序为期次1-期次2-期次3.火山活动从南到北叠置迁移变化,经历了弱(期次1)-强(期次2)-弱(期次3)的喷发序列.对比实测孔隙度、渗透率与喷发期次的关系,可知期次2储层物性最优,期次1次之,期次3储层物性较差,有利储层分布在期次2范围内.

The Fuyu Oilfield, the first oilfield discovered in Fuxin Uplift, has been developed for 50 years, and the exploration degree is relatively higher. In recent years, more and more exploration results are obtained, with the analysis of reservoir-forming conditions of lithologic reservoirs and the application of reservoir lithology identification and modification technologies in the region. Paleouplifts developed in the Fuxin uplift zone, and "crescent-shaped" fluvial sand bodies are overlaid by a large scale, and "oil- rich sags" are distributed in the surrounding areas of the paleouplifts. So the Fuxin uplift zone has favorable conditions for the formation of super large lithology reservoirs. New oil reservoirs are discovered increasingly in the surrounding areas of the old oilfields of Fuyu and Xinli, based on the full application of the 3-D seismic reservoir prediction technology and the sedimentary microfacies technology as well as the large-scale fracturing and horizontal well technology. New layers including the Yangdachengzi layer are revealed gradually below the Fuyu Oilfield, with reserves exceeding 100 million tons.