摘 要
厘清成岩作用导致的致密砂岩储层的非均质性对指导油气的勘探开发有至关重要的作用。鄂尔多斯盆地合水地区延长组长7段作为典型的致密砂岩储层是一个重要的产油层，但由于其经历了多样的成岩作用，储层存在很强的非均质性，通过成岩相划分可以在一定程度上消除储层的非均质性，再结合成岩相的测井识别又可以预测成岩相的空间分布，进一步实现优质储层的预测。本文结合氦气法孔隙度和渗透率、铸体薄片、X衍射、扫描电镜、阴极发光等资料分析得出，长7段其经历了多样化的成岩作用，拥有丰富的成岩产物，因此非常适合开展致密砂岩储层的成岩演化以及由其导致的储层非均质性的研究。长7储层主要岩性为岩屑长石砂岩、岩屑砂岩和长石岩屑砂岩，粒度以细砂岩为主。储层孔隙度分布在0.5%至13.6%之间，平均 6.8%，水平渗透率分布在0.009×10-3μm2到1.818×10-3μm2之间，平均为0.106×10-3μm2。孔隙类型以原生残余粒间孔、次生溶蚀孔隙、微孔为主，局部存在裂缝。储层经历的成岩作用包括机械压实为主化学压实为辅的压实作用、以含铁方解石和含铁白云石为主的碳酸盐胶结、微晶石英和石英次生加大的硅质胶结、以伊利石和伊蒙混层以及绿泥石为主的粘土胶结、长石和岩屑等不稳定矿物的溶蚀。其中平均压实减孔（COPL）为28.6%，平均胶结减孔为（CEPL）10.7%
党的基本路线是本文在现有资料基础上结合前人研究认为，硅质胶结的物质来源主要为长石溶蚀、粘土矿物转化以及火山物质，估算了沉淀5μm～30μm厚度的石英胶结物需要的时间大约为11Ma～67Ma；碳酸盐胶结物主要在相对深埋阶段（大于1500m）形成，其碳物质来源主要为凝灰质、有机质脱羧作用以及微生物的甲烷
生成作用，而钙镁的物质来源主要为斜长石的溶蚀和粘土矿物的转化；分析了伊利石主要为二八面体的蒙脱石伊利石化形成，高岭石和钾长石的伊利石化也有贡献；绿泥石主要为早期沉淀的三八面体蒙脱石颗粒包膜转化形成，火山物质和黑云母等为其转化提供了铁镁物质；高岭石来自长石的溶蚀，后期与钾长石相互作用形成伊利石被消耗殆尽；有机质产生的有机酸、油气与水的水解歧化反应以及粘土矿物转化促进了次生孔隙的生成，而压实释水和大气淡水对次生孔隙的生成贡献较小。在此基础上，分析了成岩作用对储层质量的影响，其中压实作用对储层质量起着主控作用，微晶石英颗粒包膜对保存储层孔隙的作用有限，石英次生加大、碳酸盐胶结以及粘土矿物主要以填充孔隙的形式出现，对储层孔隙的保存
起着破坏作用，绿泥石包膜虽然抑制石英次生加大，但其也占据较多的孔隙空间，降低了孔隙度，由长石等不稳定组分溶蚀产生的次生孔隙可以有效提高孔隙度。另外，本文研究认为油气侵位在长7段可能起到抑制石英和碳酸盐胶结的作用，但地层超压对储层孔隙的保存意义不大。在上述工作的基础上，将长7储层划分为四种成岩相：不稳定组分溶蚀相、粘土矿物充填相、碳酸盐胶结相、压实致密相，以期将非均质储层划分成相对均质的储层。通过分析成岩相与测井响应之间的关系和对测井识别成岩相的进行可行性评价，分别用常规测井交会图和主成分分析交会图建立了成岩相测井响应图版，结果显示，用五维主成分分析法建立的成岩相识别图版比常规测井响应图版具有更准确的识别效果。在此基础上，分成岩相建立的孔隙度渗透率评价模型明显提高了孔隙度和渗透率的计算精度，进一步
验证了储层划分成岩相及测井识别的重要意义。通过构建成岩相约束下储层潜力指数，预测了优质储层分布规律，结果显示与试油生产资料相匹配。
关键词：成岩作用；成岩相；测井；储层质量；致密砂岩
Prediction of Diagenetic Facies Using Well Logs and Its Application — A Ca Study from The Upper Triassic Yanchang
九上历史思维导图Formation, Ordos Basin
ABSTRACT
Understanding diagenetic heterogeneity in tight sandstone rervoirs is vital for hydrocarbon exploration. As a typical tight sandstone rervoir, the Chang 7 Member of the Upper Triassic Yanchang Formation, Heshui Field, Ordos Basin is an important oil-producing interval. However, varied diagenetic alterations result inten heterogeneity, which can be offt by introducing diagenetic facies. Additionally, distribution of diagenetic facies could be predicted using well logs, which will facilitate rervoir quality prediction. Results of helium porosity and permeability and petrographic asssment from thin ctions, X-ray diffraction, scanning electron microscopy and cat
对自己的期望hodoluminescence analysis, show that Chang 7 Member has encountered varied diagenetic alterations and shows occurrence of various diagenetic minerals, and thus it provides a good opportunity to study the diagenetic alterations and diagenetic heterogeneity of tight sandstones. The sandstones of Chang 7 Member are dominated by fine lithic arkos, feldspathic litharenites and litharenites. Porosity ranges from 0.5% to 13.6%, with an average of 6.8%, and horizontal permeability ranges from 0.009×10-3μm2 to 1.818×10-3μm2, averaged 0.106×10-3μm2. Pore types are mainly remnant intergranular pores, condary pores and micro-pores, along with partial fractures. The diagenetic alterations compri dominated mechanical compaction and minor chemical compaction, carbonate cements mainly including ferroan calcite and ferroan dolomite ankerite, quartz cements including quartz overgrowths and microquartz, clay minerals including illite, I/S mixed layers and chlorite, dissolution from unstable minerals such as feldspars and rock fragments. Compactional porosity loss (COPL) shows an average of 28.6%, whereas cementational porosity loss (CEPL)
商场打折shows an average of 10.7%.
丽江古城介绍
开放式构图On the basis of current data and previous study, the following conclusions have been achieved. Quartz cements are sourced by dissolution of feldspars, clay minerals transformation, volcanic miner
als. Precipitation of 5 μm～30 μm quartz cement needs about 11 Ma～67 Ma. Carbonate cements mainly formed during deep burial (below 1200 m). The carbon source were mostly tuff, organic matter decarboxylation, and bacterial fermentation, whereas calcium and magnesium were mainly derived from plagiocla dissolution and clay minerals transformation. Illite were mainly derived from dioctahedral smectite, and partially illitization of kaolinite and feldspar. Chlorite was formed from trioctahedral smectite grain coats, and volcanic minerals and biotite provided iron and magnesium for this conversion. Kaolinite was derived from feldspar dissolution and subquent reaction with feldspar depleted kaolinite. Organic acid from organic matters and hydrolytic disproportionation reactions of hydrocarbon and water contribute to formation of condary pores, whereas compactional pore water and meteoric water made much less contribution to condary pores. Bad on the above, the effects of diagenesis on rervoir quality are analyzed. Mechanical compaction plays a dominated role in destroying the rervoir quality. Grain-coating microquartz coating has limited influence on rervoir quality, whereas quartz overgrowths, carbonate cements and pore filling clay minerals destroy rervoir pores. Secondary pores from dissolution of unstable minerals such as feldspar can effectively enhance porosity. In addition, the following ideas are held in this thesis: hydrocarbon emplacement may inhibit cementation of quartz and carbonate, but overpressure shows no influence on porosity prervation. According to the above study, four diagen黑树莓
etic facies are identified, i.e. sandstones with dissolved unstable components facies, sandstones with clay minerals cements facies, sandstones with carbonate cements facies and tightly compacted sandstones/siltstones facies, to divide the heterogeneous rervoir into relatively homogeneous rervoir. By correlating diagenetic facies and well logs, feasibility of diagenetic facies prediction using well logs are performed. Then Crossplots of well logs and principal components are ud to construct the prediction models. The model using five-dimensional principal components show much higher accuracy than well logs. Calculation models of porosity and permeability built十大英文励志电影
according diagenetic facies show high precision, which emphasize the crucial role of diagenetic facies in rervoir evaluation. The rervoirs potential index, which is built on the constraint of diagenetic facies, are ud to predict distribution of rervoirs with high quality. And the result is consistent with testing and production data.
Key Words：Diagenesis；Diagenetic Facies；Well Logs；Rervoir Quality；Tight Sandstone
