【作者】 王斌；

【导师】 姚振兴； 王绪本；

【作者基本信息】 成都理工大学 ， 地球探测与信息技术， 2020， 博士

【摘要】 本文为了解决深层砂砾岩勘探中遇到的甜点储层形成机理不明和地震预测技术精度不高等问题,以准噶尔盆地玛湖地区三叠系百口泉组砂砾岩为研究对象,通过基础地质分析、地震岩石物理测试和甜点储层预测方法的综合研究明确了研究区甜点储层形成机理,并开发了高精度的甜点储层预测方法。首先通过基础地质研究明确甜点储层的形成机理,然后结合岩石物理测试总结甜点储层主控因素对岩石弹性性质变化的影响,建立能反映深层砂砾岩沉积与成岩演化过程的地震岩石物理模型,利用该模型指导研究区的甜点储层预测。这项研究既可以为玛湖地区面向深层砂砾岩甜点储层的油气勘探与有利区优选提供技术支撑,与此同时本次研究采用的方法和思路也可以对其他地区深层碎屑岩的油气勘探提供很好的借鉴意义。通过本次研究取得了以下4点成果和认识:(1)在砂砾岩甜点储层形成机理的研究中首次引入致密砂岩中利用储层临界物性判别储层和封堵层的研究思路,建立临界物性下限与深度的关系,按照成岩作用系统论的思路定量分析深层砂砾岩储集能力随每个沉积微相和每种成岩作用在成岩演化过程中的变化规律,建立了玛湖地区沉积和成岩作用双重控制的甜点储层发育模式。综合研究后得到玛湖地区甜点储层受沉积微相和成岩作用双重控制,以远岸或近岸水下分流河道中具有强溶蚀、早期硅质胶结和弱压实成岩相的中细砾岩和粗砂岩为主的认识。(2)在玛湖地区率先开展了深层砂砾岩的高频岩石物理测试,并结合岩石微观结构和动、静态弹性特征测量的结果,对研究区砂砾岩的弹性参数、储层参数以及它们之间的关系进行系统总结,并建立了能反映沉积和成岩作用改造岩石储集能力的岩石物理模型。从研究区样品的测试结果来看,由沉积和成岩作用造成的矿物组分含量的差别、矿物的赋存方式以及孔隙类型和形状的差异对研究区样品的弹性参数及储层参数影响较大。其中比较特殊的现象包括:(1)当岩石中石英含量较多时,大量发育的早期硅质胶结物会有效抑制压实作用对原始孔隙的破坏,从而比早期泥钙质胶结的岩石具有更高的孔隙度和更低的纵横波速度比;(2)在玛湖地区受物源的影响,岩石中普遍发育火山岩岩屑和粘土等塑性矿物,而这类矿物极易受压实作用挤压变形而充填孔隙,减小样品的孔隙度并增大样品的速度。但由于这种情况下纵波速度的增大率要大于横波速度,因此样品的纵横波速度比会随纵波速度的增大而增大。这是研究区塑性碎屑的含量与赋存方式会对砂砾岩样品弹性参数和孔隙度造成很大影响的根本原因。(3)根据准噶尔盆地玛湖地区深层砂砾岩甜点储层的形成机理,提出了“按沉积相分级分类,从砂体到储层由粗到细,逐级控制”的地质物探相结合的甜点储层预测新方法。在考虑沉积和构造演化背景的基础上首次研发了经过倾角校正的古地貌恢复技术,并且采用高精度层序地层解释技术对标志层进行解释从而得到了地层真厚度,提高了有利相带预测的精度。为了有效提取OVT域地震资料中的地质信息,我们初次通过Ruger方程建立具有古地貌和沉积微相等地质背景的优势道集部分叠加模板,并利用该模板在研究区对OVT域资料进行解释性处理,这样就可以为针对深层砂砾岩的相控甜点储层预测提供基础资料;在此基础上预测我们通过岩石物理实验获得的甜点储层敏感参数。利用该方法在玛湖凹陷斜坡区百口泉组共预测甜点储层发育区2100km~2,为有利勘探区的寻找和增储上产提供了有效技术支撑。(4)针对玛湖斜坡区异常高压分布规律不明的问题,创新性的提出了玛湖地区异常高压具有“封闭条件、构造挤压和晚期高熟油气充注”三重因素控制的分布模式。通过设计模拟孔隙超压的高频岩石物理实验,首次总结不同地层压力条件下玛湖地区砂砾岩弹性参数的变化规律,并且利用岩石物理测试结果建立了新的有效应力系数计算方法。将该方法计算的有效应力系数与Biot有效应力系数进行对比后可知,新计算的有效应力系数更适用于玛湖地区砂砾岩。最后利用新的有效应力系数改进双相介质模型后建立了低渗透砂砾岩地层压力预测模型,提高了地层压力预测的精度,并在玛湖地区取得了较好的应用效果。更多还原

【Abstract】 In order to solve the problems of unknown formation mechanism and low accuracy of seismic prediction technology encountered in deep glutenite exploration,we developed a high-precision sweet spot reservoir prediction technology based on the glutenite of Baikouquan formation in Mahu area,Junggar basin.This technology is based on the comprehensive study of basic geological analysis,seismic petrophysical test and sweet spot reservoir prediction method.It greatly improves the accuracy of seismic reservoir prediction by constraining the formation mechanism of sweet reservoirs.Firstly,the formation mechanism of sweet spot reservoir is clarified through basic geological research,and then,combined with petrophysical test,the influence of main control factors on rock elastic properties is summarized,and a seismic petrophysical model reflecting the sedimentation and diagenetic evolution process of deep glutenite is established,which can be used to guide the sweet spot reservoir prediction in the study area.This study can not only provide technical support for oil and gas exploration and favorable area optimization of deep glutenite sweet spot reservoir in Mahu area,but also provide a good reference for oil and gas exploration of deep clastic rock in other areas.Through this research,we have obtained the following4 achievements and understandings:(1)Through a large number of basic geological studies,we systematically summarized the influence of different sedimentary microfacies and diagenesis on deep glutenite reservoir capacity in Mahu area,and clarified the formation mechanism of sweet spot reservoir in the study area.The relationship between the lower limit of critical physical properties and the depth is established for the first time in the formation process of glutenite sweet spot reservoir by introducing the analysis idea of reservoir critical property.According to the idea of diagenesis system theory,the influence of organic acid dissolution pore increase and compaction pore reduction on rock physical properties is refined.Comprehensive analysis shows that the reservoir with the best physical properties in Mahu area is medium fine glutenite and coarse sandstone with quartz support and organic acid dissolution transformation in offshore or nearshore underwater distributary channel microfacies.Comprehensive analysis shows that the reservoir with the best physical properties in Mahu area is medium fine glutenite and coarse sandstone with high content of rigid particles and quartz support in the off shore or nearshore underwater distributary channel,which has been transformed by organic acid dissolution.(2)In the study area,we conducted the first high-frequency petrophysical test of deep glutenite in the Mahu area.Combined with the measurement results of rock microstructure and dynamic and static elastic characteristics,the elastic parameters and reservoir parameters of the glutenite in the study area and the relationship between them are systematically summarized.From the test results of the samples in the study area,the differences of mineral composition content,mineral occurrence mode and pore type and shape caused by sedimentation and diagenesis have great influence on the elastic parameters and physical properties of the samples in the study area.Some special phenomena include:(1)When the content of quartz is high,the porosity of rock is higher,and the velocity ratio of P-wave and S-wave is lower.This is mainly due to the fact that the early siliceous cement is more resistant to compaction than the calcareous cement,which can effectively inhibit the destruction of the original pores by compaction;(2)The content and mode of occurrence of plastic debris have a great influence on the variation of elastic parameters and porosity of samples in the study area,because plastic particles such as volcanic rock cuttings and clay are easy to be transformed and deformed by compaction to fill the pores,which will reduce the porosity of the samples and increase the velocity.However,the influence of this influence on the P-wave velocity is greater than that of S-wave velocity,so the velocity ratio of P-wave and S-wave increases with the increase of P-wave velocity.(3)According to the sweet spot reservoir formation mechanism of deep glutenite in Mahu area of Junggar basin,this paper puts forward a new idea of"classification,from coarse to fine,step by step control"combined with geological and geophysical exploration.This new idea would be used to predict the sweet spot in the study area.On the basis of considering the sedimentary and tectonic evolution background,the Paleogeomorphology restoration technology with dip correction is developed for the first time,and the high-precision sequence stratigraphic interpretation technology is used to interpret the marker bed,so as to obtain the true thickness of the stratum and improve the prediction accuracy of the favorable facies zone.Before pre stack reservoir prediction,in order to effectively extract geological information from seismic data in OVT domain,we proposed for the first time that paleogeomorphology and sedimentary microfacies are used to constrain the selection of dominant gathers,which provides the basic data of facies control for sweet spot reservoir prediction of deep glutenite.When the dominant gathers are partially stacked,the method of using the Ruger equation to build the partial stack template is tried for the first time.Finally,using this set of basic data,the sensitive parameters of sweet spot reservoir obtained by our petrophysical experiments are accurately predicted.In slope area of Mahu sag,we would use this method to predict the sweet spot reservoir and find 2100 km~2 reservoir development area in Baikouquan formation,which provides effective technical support for searching favorable exploration area and increasing reserves and production.(4)Based on the analysis of the causes of abnormal high pressure in Mahu area,the distribution law of abnormal high pressure is preliminarily defined.Then,we design a high-frequency petrophysical experiment to simulate pore overpressure.The variation law of elastic parameters of glutenite in Mahu area under different formation pressures is summarized for the first time,and a new effective stress coefficient calculation method is established based on the rock physical test results.After comparing the effective stress coefficient calculated by this method with that of Biot,it can be seen that the new effective stress coefficient is more suitable for the glutenite in Mahu area.Finally,the new effective stress coefficient is used to improve the dual-phase medium model to establish a low-permeability glutenite formation pressure prediction model,which improves the accuracy of formation pressure prediction,and has achieved good application effect in Mahu area.更多还原