油层物理学：SECTION 5Cementing Materials and Types of Cementation in Reservoir Rocks

SECTION 5SECTION 5 Cementing Materials and Types of Cementing Materials and Types of Cementation in Reservoir Rocks Cementation in Reservoir Rocks Cementing materialsCementing materials are the chemically precipitated are the chemically precipitated substances that bind particles of clasticsubstances that bind particles of clastic rocks rocks together. together. Clay cement, carbonate cement, sulphate cement and silica cement are usually encountered in reservoir rocks. Clastic-碎屑碎屑岩石胶结物中的敏感性矿物岩石胶结物中的敏感性矿物粘土矿物粘土矿物(clay)(clay)：遇水膨胀，使孔隙度降低。遇水膨胀，使孔隙度降低。石膏石膏(gypsum)(gypsum)：高温脱水，影响岩心分析。高温脱水，影响岩心分析。碳酸盐碳酸盐(carbonate)(carbonate)：遇酸分解遇酸分解主要成分：主要成分：蒙皂石蒙皂石、高岭石高岭石、 伊利石伊利石和和绿泥石。绿泥石。1.1 粘土粘土(clay,mud)：泥质胶结物的主要成分：泥质胶结物的主要成分1 Clay Cement（粘土胶结物）（粘土胶结物）Figure 2 Sandstone contains illite（伊利石）(1)(1)粘土矿物的基本结构单元粘土矿物的基本结构单元在中心，在中心，在周围在周围 4Si2Oa.a.硅氧四面体：硅氧四面体： b.b.铝氧八面体铝氧八面体： Al+3（或Mg+2）在中间中间O O-2-2和和OHOH1 1在在周围周围 1.2ClayMineralStructure(2)(2)粘土矿物的结构及遇粘土矿物的结构及遇水膨胀特性水膨胀特性 a. a.蒙皂石蒙皂石(montmorillonite(montmorillonite) )：三片晶层三片晶层 晶层间作用力晶层间作用力： O-OO-O原子间的引力，原子间的引力，结力较弱。结力较弱。 粘土矿物的粘土矿物的特点特点：晶层间的高价阳离子易：晶层间的高价阳离子易被低价阳离子部分置换。被低价阳离子部分置换。 晶层间作用力弱晶层间作用力弱外来水易进入晶层间外来水易进入晶层间平衡电价的阳离子解离平衡电价的阳离子解离 晶层表面带负电晶层表面带负电 静电斥力引起粘土膨胀。静电斥力引起粘土膨胀。蒙皂石遇水膨胀的原因:外来水外来水矿化度越低矿化度越低，粘土膨胀越严重；粘土膨胀越严重；反之，膨胀性较小。反之，膨胀性较小。b.b.高岭石高岭石(kaolinite(kaolinite) )：两片晶层两片晶层 分子间作用力强分子间作用力强( (分子分子间力及氢键间力及氢键) )，遇水不膨，遇水不膨胀。胀。 c c伊利石伊利石(illite(illite) ) 三三片晶层片晶层 晶层间的六角环内卡有钾晶层间的六角环内卡有钾离子，连接牢固。离子，连接牢固。 遇水膨胀性很小。遇水膨胀性很小。退化的伊利石，膨胀性退化的伊利石，膨胀性。d d绿泥石绿泥石(chlorite)(chlorite)：四片晶层：四片晶层 晶层间结合力强：氢键分子间力。故晶层间结合力强：氢键分子间力。故遇水不膨胀。遇水不膨胀。 膨胀性程度：膨胀性程度： 蒙皂石蒙皂石 伊利石伊利石 绿泥石、高岭石绿泥石、高岭石自生粘土矿物的产状高龄石伊利石2 Carbonate cement2 Carbonate cement（灰质胶结物）灰质胶结物）Carbonatecementsinthereservoirrockare： 、3CaCO23COCaMg遇酸反应原理遇酸反应原理：2223COOHCaClHCl2CaCO222223224COOHMgClCaClHClCOCaMg2223COOHMgClHCl2MgCO压力显示压力显示打印压力传感器放空阀电源调速旋钮反应杯样品伞盐酸投样控制开关投样控制开关offon实验方法：实验方法：134256 称取一定量(如0.2g)纯碳酸钙，与足量盐酸反应，记录产生CO2的压力； 取一定量的岩样粉末，与足量盐酸反应，记录产生CO2的压力。 岩样岩样岩样岩样纯纯纯纯（碳酸盐质量分数）（碳酸盐质量分数）P%XGPG石膏属硫酸盐矿物，石膏属硫酸盐矿物， (n=2)(n=2) 当当t60t60时，便有结晶水时，便有结晶水析出，析出，8080以上结晶水很快以上结晶水很快析出。析出。 在分析岩心的含水饱和度在分析岩心的含水饱和度时，应注意石膏中结晶水的时，应注意石膏中结晶水的影响。影响。 OnHCaSO243 Sulphate cement（硫酸盐胶结物）（硫酸盐胶结物）措施：措施：1.1.用离心机冷洗岩心。用离心机冷洗岩心。2.2.用氯仿、甲醇用氯仿、甲醇配制的共沸液配制的共沸液( (沸点沸点5555，) )对岩心进行蒸洗。对岩心进行蒸洗。 1)Basalcementation基底胶结基底胶结：Therockcontainsalargeamountofcements.Therockparticlesdonotcontactwitheachother. Basalcementationprovidesthehighestcementationstrength.4 Type of Cementation（胶结类型）胶结类型）2)Porecementation孔隙胶结孔隙胶结 The rock contains a relatively less amount of cements, which locate in the intergranular pores The rock particles contact with each other in a bridge manner. The cements are generally secondarily developed, such as calcite, which fills mainly the larger pores of sandstones. 3)Contactcementation 接触胶结接触胶结The rock contains a little amount of cements, which locate at the points where the rock particles contact each other. The clastic particles are in point contact or in line contact. The contact cementation is the loosest cementation type. 5、储层岩石的、储层岩石的五敏五敏特性特性1 1）速敏）速敏：流体流动速度大于一定值后岩石渗透率流体流动速度大于一定值后岩石渗透率明显降低的现象。明显降低的现象。 流 体 2 2）水敏：）水敏：油气层遇淡水后渗透率降低的现象，称为油气层遇淡水后渗透率降低的现象，称为水敏水敏。 3 3）盐敏：）盐敏：注入流体矿化度高于地层水、低于地层注入流体矿化度高于地层水、低于地层水都会引起渗透率的伤害。水都会引起渗透率的伤害。用地层水、次地层水、蒸馏水测用地层水、次地层水、蒸馏水测K.K.实验流程：实验流程： 4 4）碱敏：）碱敏：高高pHpH的流体进入油层后会造成粘土矿物的流体进入油层后会造成粘土矿物和硅质胶结物的破坏，造成渗透率降低。和硅质胶结物的破坏，造成渗透率降低。5 5）酸敏：）酸敏：油气层与酸作用后引起渗透率降低的油气层与酸作用后引起渗透率降低的现象。现象。总之，五敏实验是评价和诊断油气层损害的重要手段之一，一般来说，每一个区块都应做五敏实验。Section 6 Capillary Tube Model and its application The pores of reservoir rock can be considered as a bundle of capillary tubes. Use Capillary Tube Model, the relations of K to other parameters can be derived.Hagen and Poiseuille presented the equation for fluid flow in a circular conduit. 1. Derivation of Poiseuilles Equation- (“伯稷叶伯稷叶”定律定律)： Such a fluid flow can be regarded as a set of concentric fluid cylinders with the length of L, moving with different rates. L8pprrdr2rrL4ppvdAdqQ2140r022021r0q000“poiseuilles2212rppdrdvrLr=r0,V=0;1. Derivation of Poiseuilles Equation- (“伯稷叶伯稷叶”定律定律)：The viscous force between two cylinders can be described with the internal friction law. The viscous force exerted on the fluid cylinder=the driving force: Lrrppv4220212.Capillary-TubeModel The number of capillary tubes in the rock is N, the real rock and hypothetical rock have the same properties such as permeability, porosity and specific area etc.Poiseuilles law and Darcys law gives: LPkALPrnA8484rnkSuppose: n=N/A, n is the number of capillary tubes per unit area.(1)Correlations between permeability and average radius22rnALLrnAVVfP88222rrrnk3 Correlations between Porosity, Permeability and Specific Surface Area84rnk(2) Correlations between permeability and specific surfacerrrnrnALrLnASv22222vSr2vvSSrk23222288SSSbv 1fPvVASfPbVAS1fPVASSuppose：Svspecific surface based on bulk volume(以外表体积为基础以外表体积为基础) ;Sbspecific surface based on framework volume(以骨架体积为基础以骨架体积为基础);Sspecific surface based on pore volume (以孔隙体积为基础以孔隙体积为基础);Apthe surface area of rock；Vfthe bulk volume of the rock.2223232122SSSkbvvSr228rk For actual rock, the pore is not straight and round, so the coefficient constant 2 is replaced by K. 2223231KSSKKSkbvKozenys equation-高高才尼方程才尼方程 KkSb231LLeLLeexercise：if the rock is composed of crooked(or bent) capillary tubes with same radius, derive the relationships of kr and kSv?-tortuosity (迂曲度)（2.6.18）Determine the specific surface area experimentallykKSb231sPasmPapoise.10100)泊(11114980152323QHLALQAHSb3225cmcmScmkKbHcmP110PALQk(cm2)AH980LQ100H8 . 910AL10Q31