【作者】 贾倩；

【导师】 赵彦超；

【作者基本信息】 中国地质大学 ， 油气田开发工程， 2008， 硕士

【摘要】 伊通地堑是一个受剪切走滑控制的走滑-伸展盆地。盆地经历了早期右旋张剪、晚期左旋压剪的演化过程。沉积体系多且复杂，以扇三角洲、湖泊、重力流沉积体系为主。沉积物具近物源、快速沉积、分选差等特征。由于盆地性质、盆地演化、构造特征、断裂体系、沉积相和砂体展布均复杂，导致成藏过程机理不清，勘探和研究程度不够，已探明储量不足预测地质储量的15％。岔路河断陷是伊通地堑最大的一个断陷。断陷内储层、油气层类型多样，储层物性和孔喉结构变化大，流体及地层水性质复杂，原油密度小；泥浆性能多样，测井系列多，油层污染严重。上述多种原因造成该断陷油气层电性特征不清、油气层识别评价困难。因此深入认识储层及油气层特征，正确建立油气层四性关系，找出影响电性的主要因素，对比不同方法找到适合本区的流体识别方法，总结今油藏类型及分布规律，是本论文的核心所在。通过对岔路河断陷储层及流体基本特征研究知：（1）储层岩性主要为砂砾岩，其次为粉砂岩、泥质粉砂岩，再次为细砂岩、含砾细砂岩，中粗砂岩少量；（2）含油级别以荧光显示为主，其次为油迹，油斑、油浸较少，有油气显示砂岩的岩性普遍较粗；（3）为低孔、低渗到中孔、中渗，少量为高孔、高渗；随岩性变粗，物性变好；随深度增加，成岩作用增强，物性变差，但在次生孔隙带孔隙度略有增加；（4）岩石类型主要为岩屑长石砂岩、长石砂岩、长石岩屑砂岩，长石以钾长石为主，岩屑以岩浆岩为主，成分和结构成熟度低；（5）原油属挥发一轻质中低粘度油；地层水矿化度总体较低，多数小于10000ppm，变化较大，随深度增加有升高趋势。（6）有效储层可分为五类。通过四性关系研究知，岔路河断陷油藏既有正常油层、水层（即油层电阻率高、水层电阻率低），又有相对低阻油层、油水同层、高阻水层。受岩性及较淡地层水影响，砂砾岩高阻水层较发育。研究认为，该区影响储层电性的主要地质因素有：岩性、地层水矿化度、钙质胶结、含油气饱和度等。其中钙质胶结可引起低声波、高电阻率；低地层水矿化度可引起高电阻率；高泥质含量可以引起高声波、低电阻率；粗颗粒可引起高电阻率、低声波，因此电性特征复杂，一些因素严重掩盖了流体的电性响应。根据上述研究知，复杂地质条件下，地质约束是正确进行流体识别的基础。在对储层、流体、电性及影响因素的认识下，根据岩芯分析及岩电实验资料，建立了测井解释模型；并尝试了曲线快速识别(R_xo/R_t-SP重叠、中子密度孔隙度重叠、电阻率径向对比、S_p-R_t交会)、测井曲线图版识别（AC-R_t图版、R_w-R_t图版）、参数图版识别(AC-R_t/R_w图版、S_w-S_wi图版、Φ-Φ×S_w图版)等流体识别方法，取得一定效果。考虑到研究区砂砾岩储层发育、井眼质量差、泥浆性能复杂等因素，根据阵列感应、时间推移测井、横向测井资料，结合电阻率正演结果对泥浆侵入进行了研究。电阻率正演结果反映，淡水泥浆侵入储层时，随含水饱和度的增加，深侧向及深感应均由低侵向高侵变化；盐水泥浆侵入时，不论含水饱和度大小，深侧向及深感应均为低侵，且深感应受影响较大。实际测井资料反映，研究区无论油层或水层，双感应和双侧向多为低侵，一方面反映感应及侧向测井对泥浆侵入特征反映不明显，一方面也说明储层含水饱和度较高。阵列感应及横向测井反映，淡水泥浆侵入时，高含油饱和度储层为高值低侵，低含油饱和度储层电阻率径向特征为先增后减，水层为微低侵或低值高侵；盐水泥浆侵入时，不论油层还是水层均为低侵。根据静态阶跃模型及几何因子，利用VB语言编制电阻率反演程序，并对校正前后的部分模版进行对比，识别精度有所提高。且根据泥浆侵入电阻率径向分布的研究结果，新增了SP曲线形态分析法、电阻率径向对比法两种直观识别法。综合采用以上方法进行了流体识别，并绘制不同二级构造单元多条油藏剖面。通过以上研究，总结出岔路河断陷油藏分布特点为：（1）平面上，靠近凹陷中心，岩性以粉砂岩为主，砂体连续性较好，以岩性油气藏为主；边界处，岩性以砂砾岩、中粗砂岩为主，以断层遮挡油气藏为主；即近物源近断层处以构造油气藏为主，远断层远物源处以构造一岩性油气藏为主；（2）受封闭断层遮挡，断层下盘含油气性较好；即反向断层控制的屋脊式断块圈闭，构成构造油气藏的有效富集；（3）受构造改造的影响，边界及斜坡等张性环境地区，油气保存条件较差；（4）构造、沉积、流体包裹体、温压系统、地层水化学特征及SP反转等资料综合反映，整体上，梁家构造带为顶部油气性好且改造微弱型；万昌构造带为顶部改造强烈型、围斜改造微弱型；孤店斜坡为整体充注差且改造严重型。更多还原

【Abstract】 Yitong basin is a strike slip - extensional basin limitted by sheared sliding movement. Two evolution stages had been undergone for it by earlier right lateral tension - shear and later left lateral compression shear. There are more sedimentary systems in basin, and fan delta、lacustrine deposit, gravity flow deposit are important. The sediment system has characteristics of near to source、rapid deposition and poor sorting ,etc. The basin type、evolution, structural feature、fault system, sedimentary system and sand body distribution are all complex, so as to be unclear in the mechanisms of oil and gas accumulation process and inadequate in the degree of exploration for us. For the reasons, the proved reserves is less than 15% of the predicting geological reserves.Chaluhe fault depression is the largest depression in area in Yitong basin. It is difficult to identify oil-, gas- and water-bearing formation for the reasons which lead to the reservoir logging properties is unclear, as follow: the firstly, there are types of reservoir and oil- and gas-bearing formation in the depression. Heterogeneity in porosity, permeability, pore throat structure of reservoir is greatly. The secondly, properties of crude oil, formation water and drilling mud are complex, such as the lower oil density and salinity of formation water; The thirdly, versatile drilling mud properties lead to reservoir damage acutely. The fourthly, logging system is complex, and so on.For above reasons, the nucleus points of the paper are as follow:①to analyze reservoir features deeply;②to build up relations among lithology、porosity and permeability, degree of hydrocarbon bearing and logging measurement parameters（so called the four-properties’s relation） ;③to find out geological control factors on logging features ;④to explore the best method to identify oil-, gas-and water-bearing formation;⑤to summarize the pool types and distribution.The research about reservoir has been made by using lab data. The conclusion is as follow: （1）The lithology of reservoir is mainly sandy conglomerate, siltstone and muddy siltstone are in second position; thirdly is fine sandstone and pebbled fine sandstone, and the moderate-coarse sandstone is little. （2） The oil-bearing degree is mainly fluorescence level, secondly is oil trace, oil immersion and oil patch are little. The coarser is sandstone, and the better in oil show is it. （3） It is low-moderate porosity and low-medium permeability for reservoirs. There is only a little good quality reservoir in basin. Generally speeking, the coarser is sandstone in grain size, and the better in porosity and permeability is. The deeper in burial depth is, the more intensity is in diagenesis,and more poor in porosity and permeability is, but porosity and permeability of the reservoir increases slightly in the secondary pore zone in deeper burial formation. （4） The main santstone type is lithic arkose、arkose and feldspathic litharenite, K-feldspar is in rich. Magmatic debris is inportant, and the compositional and texture maturity are lower. （5）lt is volatile-light、middle-low viscosity oil for crude oil feature; formation water salinity is lower, most of formation water salinity is less than 10000ppm, changes greatly, and it inclines to increases with depth. （6）The five groups of the reservoir can be divided.From depression margin to center, （1） The line of facies is about alluvial fan, fan delta plain, fan delta front, pro-fan delta and offshore -shallow lacustrine; （2） Lithology change is about grain-supported sandy conglomerate, matrix-supported sandy conglomerate, sandstone, fine sand and siltstone; （3） Grain- size of sandstone decreases, and the porosity and permeability of sandstone decreases with the increase of calcareous cementitious intensity and decrease of the effect of mud pebble in sandstone; （4） The tendency of that formation water salinity increases reflects that the shallow reservoir on basin margin obviously is affected by the leaching of meteoric fresh water due to the tectonic uplift and erosion.The study the four-properties’s relation has shown that the types of oil-, gas- and water-bearing reservoir includes oil and water layer with normal resistivity （oil layer’s resistivity is higher, water layer’s resistivity is lower）, oil layer with relatively lower resistivity, oil layer with water、water layer with high resistivity in Chaluhe fault depression. Because of the effect of lithology and fresh water of lower salinity, sandy conglomerate water layers with high resistivity has been occurrence commonly in the study area.It is showed by study that the key geologic factors affecting reservoir electrical property features are as follow: lithology, formation water salinity, calcareous cementition, hydrocarbon saturation,etc. Calcareous cementition can cause lower interval transit time and high resistivity; lower formation water salinity can cause high resistivity; high shale content can cause high interval transit time and lower resistivity;coarse grain can cause lower interval transit time and high resistivity; so the electrical property features is complex,some factors cover up fluid’ s electrical response.Based on the above study,under the complex geological conditions,geological constraint is the basis of correct fluid identification.On the study of reservoir feature, fluid feature, electrical behavior, the interpretation modelsof reservoir parameters are set up by using core and logging data. Fast identification methods(such as R_xo/R_t-SP overlapping, neutron-density porosity overlapping, Sp—R_t cross plot), crossplot chart methods (AC—R_t cross plot chart, R_w—R_t cross plot chart, AC—R_t/R_w, S_w—S_w（?）,Φ—Φ×S_w) have been used,and proved being effective. Considering the sand-conglomerate reservoirs develop, bad quality of borehole, complex mud property , etc.According to array induction logging, time-lapse logging, laterologging data combined with the result of resistivity forward and inversion modelling, resistivity calibration of reservoir about mud invasion is studied. The results of resistivity forward modelling reflect that deep lateral and deep induction resistivity changes from high-invasion to low-invasion with the water saturation increasing when fresh muds invase reservoirs; deep lateral and deep induction resistivity have shown lower-invasion in spite of high or low water saturation, and deep induction is affected significantly when brine muds invase reservoirs. Dual induction log or dual lateral logging almost are low-invasion no matter what oil layer or water layer is in the study area by the the practical logging data. This reflects the influence of mud invading on the induction logging and lateral logging responses is not obvious, and reservoir water saturation is high. The tested resistivity has high value and low-invasion when oil saturation is high by the response of resistivity radial characteristic of array induction logging and lateral logging when fresh mud invases reservoirs; the resistivity first increases and then decreases when oil saturation is low, the resistivity is low and low-invasion in water layer; the invasion radial profile is low-invasion in spite of water layer or oil layer when brine mud invases reservoirs.According to static step profile model and resistivity geometric factor theory, VB computer language is used to program the resistivity inversion program. The recognition accuracy has been improved after comparing the identification charts before and later of resistivity invasion correction. Two kinds of identification methods（include SP curve shape and resistivity radial-contrast method） are added newly, according to the research results on profiles of formation resistivity when the mud filtrate invades reservoirs.Using a combination of above methods to recognize the fluid, several profiles of pool have been made in different secondary tectonic units. Based on above study, the characteristics of pool distribution in Chaluhe depression is summarized as follow:（1） In plane, close to depression center, reservoir lithology is mainly siltstone, sand body is continuous, lithologic pool type is main; lithology is mainly sandy conglomerate and moderate-coarse sandstone close to the depression boundary; fault pool type is main; structural pool type is main close to source and fault; structural-lithological reservoir type is main away from source and fault;（2） Because of the fault screened, oil-bearing properties in the downthrow block of fault is batter, that is to say, the trap of ridge of antithetic fault controls oil concentration;（3） Affected by tectonic reworking, hydrocarbon preservation condition is poor in tensional area, such as boundary and slope area;（4） Comprehensively, the structure, deposition, fluid inclusion, temperature-pressure system, formation water chemical characteristics, SP reverse ,etc. data reflect the top of Liangjia structural belt is the good petroliferous properties and is faint under later reformation; the top of Wanchang structural belt is strongly later reformation, the area of around structural belt is faint later reformation; Gudian slope is litter hydrocarbon accumulate by strongly later reformation.更多还原