横纵波时差比值法用于萨零油层含气识别的可行性探究

常规声波测井技术只能通过测量取得纵波时差,而XMACⅡ不仅能直接测量纵波时差和横波时差,本文首先阐述了利用声波时差和横、纵波时差比值识别气层的方法原理,然后通过对8口XMACⅡ测井给出的横波时差、纵波时差及其比值曲线进行了细致分析。研究表明,由于萨零组油层岩石物性差、变化大,其横波时差、纵波时差测井曲线都无法正常反映砂岩内含气状况,因此单纯应用"XMAC横、纵波时差及其比值法"识别砂岩油藏含气情况是不现实的、不可行的。

英台断陷天然气储集层含水性气测识别方法

松辽盆地英台断陷不饱和气藏投产易出水且出水量大,给后续开发带来很大困难。为解决该断陷天然气储集层含水性识别的难题,首先,分析了该断陷识别储集层含水性的常规气测解释评价图板所存在的不足,即只能识别气水同层及以上价值层,而对于价值层是否含水以及含水量高低无法判断;然后,分别针对气测录井的重烃相对含量、中-重组分比值、全烃异常及其曲线形态、烃湿度比与烃特征比曲线交会特征与储集层含水性的关系进行了深入分析研究,明确指出了各个特征参数及曲线与含水性判断指标,据此通过该断陷多口井有试气结果的多层数据的统计分析,形成了天然气储集层含水性解释标准。在应用过程中,依次利用储集层含水性常规解释评价图板进行识别,对参数与曲线特征进行分析,根据解释标准进行识别,可实现天然气储集层含水性的有效解释评价。经该断陷26口井55层的试气验证,与试气结果相符的为51层,不符的4层,解释符合率为92.72%。

频变AVO属性在塔东碳酸盐岩储层含气检测中的应用

从岩石物理测试和数值模拟出发,塔东碳酸盐岩研究区优质储层和频率息息相关,利用射线域Zoeppritz方程,将频率因素引入AVO分析中,用频变AVO方法分析速度频散异常特征,从而预测优质含气白云岩储层。在塔东地区碳酸盐岩气藏的含气性检测中,取得了良好的应用效果。

致密砂岩气藏含气控制因素研究与评价应用

探究致密砂岩气藏含气控制因素对实现致密气优质高效勘探开发有重要作用。研究认为致密砂岩含气储层主要受构造、岩性、物性和裂缝4种因素控制。构造高部是形成含气储层的首要条件,高含气储层对粗砂岩具有选择性,物性主要提供物质场所,裂缝发育是致密砂岩气层获得高产工业气流的关键因素。在搞清致密砂岩含气储层控制因素基础上建立了致密砂岩流体识别方法和储层分类标准,开展了气层识别与分类评价,实践应用取得了良好效果。

川西坳陷回龙地区沙溪庙组油气富集性预测技术

四川回龙地区川西坳陷沙溪庙组含气丰富,储层多以河道及叠置河道砂体为主。但是由于河道频繁变迁,形成的储集体单层厚度小,纵向上呈砂泥岩互层,横向变化快,非均质性强,所以储层展布及横向连续性难以准确预测。对此,首先通过分析古沉积环境,确定沉积相特征,建立区域储层的地球物理响应模式。然后运用地震属性分析及像素成像体分频,结合钻井资料,对储层进行平面展布、空间展布和非均质性的预测。最后结合含气性检测,预测出储层的含气富集性,为该区寻找砂体气藏提供了依据。

新场气田须四下亚段岩屑砂岩储层评价

须四下亚段岩屑砂岩储层的含气测井响应特征为一高三中一低一负。新场须家河四段下亚段岩屑砂岩储层类型划分为孔隙型和裂缝孔隙型。孔隙发育较好的孔隙型储层具有一定的勘探价值,由于无裂缝沟通,渗透能力较差,一般需要经过有针对性的储层改造,才能获得较好产能。裂缝-孔隙型储层,基质孔隙发育,裂缝发育,可获得较好产能。利用P1/2正态统计法、泊松比与体积压缩系数重叠法和核磁差谱移谱法可以有效地判别储层流体性质。

多波地震技术在中国部分气田的应用和进展

多波地震技术可同时采集地下地质体反射的纵、横波信息,通过处理提取反射纵、横波各项物性参数,并利用其在不同地质体中的反射特征差异,进行综合对比和解释,以预测储层的横向变化和含油气性。自2002年以来,中国石油天然气集团公司在鄂尔多斯苏里格气田、四川广安气田、柴达木三湖地区、松辽徐深气田开展了二维、三维多波地震勘探试验,积累了宝贵经验。本文在此基础上结合近年来国外多波地震勘探技术的发展,分析了当前国内多波地震勘探应用中仍然存在的问题,提出了加速推进国内多波地震技术应用的设想。

EEMD和SVM相结合的储层流体识别模型

针对深层储层地震响应微弱、含气性识别困难的问题,提出了一种基于聚合经验模态分解(ensemble empirical mode decomposition,EEMD)和支持向量机(support vector machine,SVM)的地震属性提取及储层含气性识别方法。对地震信号运用EEMD方法进行分解,得到一系列本征模态函数(intrinsic mode function,IMF)。优选具有强相关性的本征模态函数重构特征子信号提取地震属性。通过相关性和R型聚类分析评估地震属性,最终选取4种相对独立的属性作为SVM的输入特征参数,并利用粒子群优化(particle swarm optimization,PSO)算法优化参数后得到的SVM模型实现对储层含气性的识别。实验结果表明,所提方法能够有效地提取储层地震属性及进行含气性识别。

阳泉矿区煤层气气源层分析与PNN测井技术

阳泉矿区多数矿井煤层回采的过程中出现矿井瓦斯涌出量大,远高于15号煤层瓦斯含量。PNN测井是一种利用测量地层中剩余热中子数量随时间变化关系,从中提取地层宏观俘获截面,利用两个中子探测器上得到的中子计数的比值有效的识别气层的方法。利用PNN测井技术对阳泉矿区已施工的煤层气井进行PNN测井,并进行含气层识别,对识别的气层进行射孔并压裂,根据后期排采发现,该技术对识别气源层有重要的意义。

Fluids discrimination by ray-path elastic impedance inversion: A successful case from Sulige tight gas field

Existing seismic prediction methods struggle to effectively discriminate between fluids in tight gas reservoirs,such as those in the Sulige gas field in the Ordos Basin,where porosity and permeability are extremely low and the relationship between gas and water is complicated.In this paper,we have proposed a comprehensive seismic fluid identification method that combines ray-path elastic impedance(REI)inversion with fluid substitution for tight reservoirs.This approach is grounded in geophysical theory,forward modeling,and real data applications.We used geophysics experiments in tight gas reservoirs to determine that Brie's model is better suited to calculate the elastic parameters of mixed fluids than the conventional Wood’s model.This yielded a more reasonable and accurate fluid substitution model for tight gas reservoirs.We developed a forward model and carried out inversion of REI.which reduced the non-uniqueness problem that has plagued elastic impedance inversion in the angle domain.Our well logging forward model in the ray-path domain with different fluid saturations based on a fluid substitution model proved that REI identifies fluids more accurately when the ray parameters are large.The distribution of gas saturation can be distinguished from the crossplot of REI(p=0.10)and porosity.The inverted ray-path elastic impedance profile was further used to predict the porosity and gas saturation profile.Our new method achieved good results in the application of 2D seismic data in the western Sulige gas field.

Application of multi-component joint inversion in oil and gas exploration:A case study of reservoir and gas saturation prediction of the Xujiahe formation in the PLN area of the central Sichuan Basin

Multi-component seismic exploration is an important technique in the utilization of P-waves and converted S-waves for oil and gas exploration.It has unique advantages in the structural imaging of gas zones,reservoir prediction,lithology,and gas-water identifi cation,and the development direction and degree of fractures.Multi-component joint inversion is one of the most important steps in multi-component exploration.In this paper,starting from the basic principle of multi-component joint inversion,the diff erences between the method and single P-wave inversion are introduced.Next,the technique is applied to the PLN area of the Sichuan Basin,and the P-wave impedance,S-wave impedance,and density are obtained based on multi-component joint inversion.Through the velocity and lithology,porosity,and gas saturation fi tting formulas,prediction results are calculated,and the results are analyzed.Finally,multi-component joint inversion and single P-wave inversion are compared in eff ective reservoir prediction.The results show that multi-component joint inversion increases the constraints on the inversion conditions,reduces the multi-solution of a single P-wave inversion,and is more objective and reliable for the identification of reservoirs,effectively improving the accuracy of oil and gas reservoir prediction and development.