【作者】 张文忠；

【导师】 汤达祯；

【作者基本信息】 中国地质大学（北京） ， 矿产普查与勘探， 2009， 博士

【摘要】 苏里格气田是我国迄今为止发现的最大的天然气田,属于大型砂岩岩性气藏。该气田地质储量可观,但其地质条件复杂,储层非均质性严重,呈现出典型的“低孔、低渗、低压、低产、低丰度和难动用”的特征,气井生产一直不理想。深入研究苏里格气田构造演化史、烃源岩热演化史、古流体演化特征、古地温及古压力恢复、剥蚀厚度恢复、油气运聚规律、地层水与成藏关系以及成藏组合等关键问题,对于明确该地区异常低压的成因及促进该地区天然气的有效勘探开发有着重要的意义。本论文针对目前亟待解决的苏里格气田异常低压成因机制问题,通过对该地区构造演化、沉积与成岩作用、油气生成、运移和聚集成藏、构造抬升-地层剥蚀反弹、成岩过程中的水化学作用、流体包裹体热力学和激光拉曼等的分析,研究了孔隙反弹、地层温度变化、轻烃扩散和成岩过程中的水化学作用等对苏里格气田异常低压形成的影响程度,阐明了苏里格地区上古生界气田异常低压形成的主要原因和地层压力的演变过程。通过研究得出:苏里格地区上古生界气田地层压力总体以异常低压和超低压为主;上古生界储层封闭条件较好,有利于压力封存箱的形成和天然气的聚集成藏;低压流体封存箱主要分布在长期、中期基准面上升半旋回的中晚期,所在地层的沉积微相多为水上分流河道、天然堤、河口坝和水下分流河道;研究区上古生界地层压力经历了“正常压力→常压或异常低压→异常高压或超高压→异常低压或超低压”的演变过程;构造抬升地层剥蚀引起的地层温度降低和轻烃扩散是研究区上古生界储层异常低压形成的主要原因,因地层温度下降造成地层压力下降约为23%,因轻烃散失造成地层压力下降约15%~25%,此外孔隙反弹、下生上储的成藏组合方式、成岩过程中的水化学作用和流体的供排不平衡、气柱高度和气水密度差等因素也对研究区异常低压的形成起到了一定的作用。本论文有助于丰富低压油气藏成因理论研究,对苏里格气田及同类型气田的勘探开发具有重要的参考价值和指导意义。更多还原

【Abstract】 So far, Sulige gas field has the most abundant reserves of natural gas in China and it belongs to lithologic gas reservoir. There is ample geological reserves of Sulige, but because of complex geologic setting and reservoir heterogeneity, the characteristics of Sulige gas field show low porosity, low permeability, low gas abundance, subnormal formation pressure, minor production and difficult to develop. To study the history of structural evolution, the history of source rock thermal evolution, the character of paleofluid evolution, recovery of formation temperature and formation pressure, recovery of denudation thickness, the character of gas migrating and accumulating, the relation between formation water and gas conserving and the structure of gas play will be important to realize the causation of subnormal formation pressure and exploration & development of Sulige gas field.This dissertation focuses on the main controlling factors of the causation of subnormal formation pressure in Sulige gas field. Through the analysis on structural evolution, sedimentation and lithogenesis, gas generating, migrating and accumulating, tectonic denudation, thermodynamics and laser Raman spectroscopy of fluid inclusion, the main controlling factors of the causation of subnormal formation pressure and the formation pressure evolutionary process of Sulige gas field are illustrated.Based on the above study, the following conclusions were drawn: firstly, most of the formation pressure of the upper Paleozoic is subnormal formation pressure; secondly, the closing conditions of Shihezi formation is preferable and it is advantageous to the development of subnormally pressured fluid compartment and the accumulation of natural gas; thirdly, the subnormally pressured fluid compartment is mainly in the middle-late period of uplifting half cycle in long-term and mid-term datum level, the main microfacies of which are distributary channel deposit, natural barrier deposit and mouth bar deposir etc; fourthly, the formation pressure of the upper Paleozoic in Sulige gas field underwent the following evolutionary process since mesozoic: from normal pressure(T) to normal pressure or subnormal pressure(J1) to abnormal high pressure or extra high pressure(J2~K1) to subnormal pressure or extra low pressure(K2~present); fifthly, tectonic uplifting, formation denudation and gas diffusionshy are the main controlling factors of the causation of subnormal formation pressure in Sulige gas field, the reduction of formation temperature resulted in about 23% decrease of formation pressure and gas diffusionshy resulted in about 15~25% decrease of formation pressure, at the same time, the structure of gas play, drochemistry activity of lithogenesis, the disequilibrium of gas loss and supply, gas column height and the difference between the density of gas and water did some work to the formation pressure.This thesis will be helpful to the study on subnormal formation pressure and it will be of great importance to the exploration and development of Sulige gas field and the similar gas fields.更多还原