碳酸盐岩微观储层三维孔喉结构的定量数值表征研究

发布时间：2018-06-25 22:09

本文选题：碳酸盐岩储层 + 孔喉结构　；参考：《中国地质大学》2016年博士论文

【摘要】：海相碳酸盐岩是十分重要的油气储层。但是,我国碳酸盐岩储层非均质性强烈,特别是作为油气储集空间的孔-洞-逢,更是类型多样,复杂多变。以四川盆地普光气田飞仙关组鲕粒白云岩储层为例,相同岩性的同一层段往往发育有铸模孔、粒内溶孔、粒间溶孔等。又如罗家寨气田部分地区储层一方面孔隙度虽然很高,达20%,渗透率却仅为0.1×10-3μm2,甚至更低,属于低渗-特低渗；另一方面,岩性、孔隙类型、孔隙度相同的情况下,渗透率却相差数十倍,甚至百倍。不同的孔喉系统类型,孔隙的大小、几何形态、喉道的结构、孔喉的连通性和空间的延展性等有很大的差异,其对孔隙度、渗透率的贡献和影响也大不相同。为此,需要新方法、新技术对复杂的碳酸盐岩孔喉系统进行精细的刻画和描述,定量表征其在三维空间上的展布、几何形态、孔喉连通性等。三维高精度微纳米CT及高性能图形图像处理技术的发展,为碳酸盐岩微观储层的三维孔喉结构定量表征提供了实现途径和理论指导。结合CT技术和分形与多重分形理论,对碳酸盐岩微观储层的三维孔喉结构进行了深入的传统几何学参数表征和分形与多重分形分析,研究表明：1.基于高分辨率工业CT的技术方法能对碳酸盐岩微观储层的三维孔喉结构进行有效定量表征和孔喉结构的精细刻画；2.碳酸盐岩储层的孔隙和喉道三维结构具有分形与多重分形特征。进一步,文章以Choquette和Pray (1970)、Lucia (1983)等经典的碳酸盐岩储集空间分类为前提,分别对孔隙型、孔洞型和裂缝型储层进行了分类表征与分析,结果如下：1.孔隙型碳酸盐岩中,粒间孔和晶间孔孔隙形状多为三角形,三维空间上表现为放射状,孔隙相对细长,喉道发育,连通性较好；铸模孔和膏模孔孔隙形状规整,二维平面上表现为圆形,三维空间上近似球体,此类样品往往孔隙度较为发育,但是孔喉系统连通性差,渗透率差；藻格架孔和混合孔(发育多种孔隙)孔隙和喉道非均质性较强,受岩石组构特征影响显著；溶蚀孔隙非均质性强,孔隙的发育程度受后期的成岩作用、溶蚀作用影响,其孔隙形状多为港湾状,喉道与溶蚀强度相关；2.溶蚀孔洞型碳酸盐岩储层分为分散型和连通性,分散型溶蚀孔洞提供了储层的主要储集空间,但是孔洞孤立、形状大小不均；连通性孔洞系统孔洞为主要的储集空间,沟通的喉道主要为“溶缝、裂缝、基质孔”,特别是基质孔不仅可以沟通各自孤立的孔洞,还可以作为主要的储集空间,储集石油和天然气。3.裂缝的储集空间较小,空间延伸较长,与各自平面的夹角各异,如果储层有多条裂缝,则相互交错,切割。4.三维孔隙分维数、双对数下分配函数、质量指数函数等显示碳酸盐岩微观储层三维孔喉结构具有分形与多重分形特征多重分形频谱曲线的左侧能很好地反映较大孔隙的分异程度,而右侧多反映较小孔隙的分异程度；非对称指数R能刻画大、小孔隙相对分异的程度,也是曲线是否对称的定量表征；对于粒间孔样品LJ1-1的孔隙空间多重分形频谱为右偏,非对称指数R小于0,△αL明显小于ΔαR,频谱宽度△α值大,具有极强的多重分形特征,与其较大的孔隙度和特高的渗透率有一定的对应关系。晶间孔样品具有较小的△α值和较小的孔隙度和渗透率值,ΔαL与ΔαR值相差不大,非对称指数R接近0,显示空间上大、小孔隙的分异不明显。4.盒子维数是反映形状规则度的函数,对不同的孔隙类型有明确的响应,如二维系列图片的盒子维数值相对大小为：铸模孔粒间孔晶间孔混合孔。具体表现为：晶间孔ZG9值为1.58～1.67,均值为1.648；粒间孔LJ1-1值为1.66～1.72,均值为1.691；铸模孔的LJ5值为1.73～1.88,均值为1.757～混合孔的LJ2-2值为1.53～1.61,均值为1.563。孔隙形状越规整则盒子维数函数值越大,如二维圆形的盒子维数为2,三维球体的盒子维数为3。均值最大的LJ5样品铸模孔发育,而铸模孔孔隙形状较为规整,近圆形分布；均值最小的LJ2-2为混合孔发育样品,其孔隙类型较多,有粒间孔、粒间溶孔、铸模孔和晶间孔等,因此其对应的盒子维数仅为1.563。在上述三维盒子维数分析中,LJ5样品的盒子维数值也较高,达2.7834,接近球体形态。从盒子维数与孔隙度、渗透率的数据对比可以发现,即孔隙度可能也对盒子维数产生影响。基于CT扫描数据,文章通过颗粒识别法、VTK平台的体绘制法、种子充填法,并结合常规几何学、分形与多重分形等方法理论的系统研究,提炼了孔喉体积、连通体积比、孔隙和喉道半径、最大/小值、形状因子、连通性、裂缝宽度(开度)、延伸长度、裂缝夹角、盒子维数、多重分形的宽度Δα、非对称指数R、质量函数τ(q)、多重分形谱函数f(α)等30余个表征参数。
[Abstract]:Marine carbonate rock is a very important reservoir of oil and gas. However, the heterogeneity of carbonate reservoirs in China is very strong, especially in the hole and hole of oil and gas reservoir space. It is more diverse and complex and changeable. Taking the oolitic dolomite reservoir of the Feixianguan Formation of the Puguang gas field in Sichuan basin as an example, the same layer of the same lithology often develops the mold hole. In some areas of the Luo Jia Zhai gas field, although the porosity of the reservoir is very high, up to 20%, the permeability is only 0.1 x 10-3 Mu m2, or even lower, which belongs to low permeability and ultra-low permeability. On the other hand, the lithology, pore type and porosity are the same, the permeability is a difference of several times and even a hundred times. Different pore throat systems. Type, pore size, geometry, structure of throat, connectivity of pore throat and space extension are very different, and their contribution and influence on porosity and permeability are very different. Therefore, new methods are needed. New techniques are used to describe and describe the complex carbonate pore throat system in a quantitative way. The development of three-dimensional high precision micro nano CT and high performance graphic image processing technology provides a way and theoretical guidance for the quantitative characterization of three dimensional pore throat structure of carbonate micro reservoirs. Combined with the theory of CT and fractal and multifractal, the three-dimensional reservoir of carbonate rocks is three-dimensional. The pore throat structure is characterized by deep traditional geometric parameters and fractal and multifractal analysis. The study shows that 1. based on the high resolution industrial CT technology, the three-dimensional pore throat structure of the carbonate micro reservoir can be effectively quantified and the pore throat structure is fine depicted; 2. the pore of the carbonate reservoir and the three-dimensional throat are three-dimensional. The structure is characterized by fractal and multifractal. Further, the classification of pore type, pore type and fractured reservoir is classified and characterized on the premise of Choquette and Pray (1970), Lucia (1983) and other classical carbonate reservoir space. The results are as follows: 1. pore shape carbonate rock, the pore shape of intergranular Kong Hejing pore Most of them are triangle, three-dimensional space is radiated, pore is relatively long, throat development, connectivity is good, mold hole and paste hole pore shape is regular, the two-dimensional plane is round, three-dimensional space is similar to the sphere, such samples tend to be more porosity, but the pore throat system connectivity is poor, the permeability difference; algal frame hole The heterogeneity of pore and larynx of mixed pore (developing multiple pores) is strong, and it is strongly influenced by the characteristics of rock fabric. The heterogeneity of the pore is strong, the development degree of pore is affected by late diagenesis and corrosion, the pore shape is mostly harbor shape, the throat is related to the dissolution strength, and the 2. karst cave type carbonate reservoir is divided into two types. Dispersion type and connectivity, dispersed corrosion hole provides the main storage space of the reservoir, but the hole is isolated and the shape is not uniform, the hole in the connected hole system is the main reservoir space, the communication throat is mainly "dissolve, crack, matrix hole", especially the matrix hole can not only communicate the isolated hole, but also can be used as the reservoir. In the main reservoir space, the reservoir space of the reservoir oil and gas.3. cracks is small, the space extends long and the angle of each plane is different. If there are many cracks in the reservoir, it interlaced each other, cutting.4. three-dimensional pore fractal dimension, double logarithmic distribution function and mass index function, showing the three-dimensional pore throat structure of the carbonate micro reservoir. The left side of the multifractal spectrum curve with fractal and multifractal features can well reflect the degree of differentiation of the larger pores, while the right side reflects the degree of the smaller pores. The asymmetric index R can describe the degree of large, small pore relative differentiation, and is also a definite characterization of the symmetry of the curve; for the sample of intergranular pore LJ1-1, Kong Xikong The multifractal spectrum is right deviation, the asymmetric index R is less than 0, the delta alpha L is obviously smaller than the delta alpha R, the spectrum width delta alpha value is large and has a very strong multifractal feature. It has a certain corresponding relationship with the larger porosity and high permeability. The intergranular pore samples have smaller delta alpha value and smaller porosity and permeability values, Delta L and delta R values. The difference is small, the asymmetric index R is close to 0, which shows that the space is large and the fractal dimension of the small pores is not obvious. The.4. box dimension is a function of reflecting the shape rule degree, and it has a clear response to the different pore types. For example, the relative size of the box dimension value of the two-dimensional series of pictures is: the intergranular pore mixed hole in the intergranular pore of the mold. The specific expression is the intergranular pore ZG9 The value is 1.58 to 1.67, the mean value is 1.648, the LJ1-1 value of the intergranular pore is 1.66 ~ 1.72, the mean value is 1.691, the LJ5 value of the mold hole is 1.73 to 1.88, the value of the mean value is 1.757 to the mixed hole is 1.53 ~ 1.61. The more regular the mean of the pore shape is 1.563., the larger the box dimension function is, such as the dimension of the two-dimensional circular box is 2, and the box dimension of the three-dimensional sphere The mold hole of the LJ5 sample with the largest 3. mean value is developed, and the pore shape of the mold hole is relatively regular and near circular, and the LJ2-2 of the minimum mean value is the mixed hole development sample. The pore type is more, there are intergranular pore, intergranular hole, and the mould Kong Hejing hole and so on, so the corresponding box dimension is only 1.563. in the above three dimensional box dimension analysis, LJ The box dimension of 5 samples is also higher, reaching 2.7834, approaching the shape of the sphere. From the comparison of the box dimension and porosity and permeability data, it is found that the porosity may also affect the box dimension. Based on the CT scanning data, the article through the particle recognition, the body drawing method of the VTK platform, the seed filling method, and the fractal geometry, fractal Systematic research on the theory of multifractal and other methods, the volume of pore throat volume, connected volume ratio, pore and throat radius, maximum / small value, shape factor, connectedness, crack width (opening), extension length, crack angle, box dimension, multifractal width Delta, asymmetric index R, mass function tau (Q), multifractal spectrum function f (alpha), etc. are more than 30 Characterization parameters.
【学位授予单位】：中国地质大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P618.13

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