乌里雅斯太凹陷砂砾岩油藏储层改造理论与应用技术研究

【作者】 吕传炳；

【导师】 赵金洲； 赵树栋；

【作者基本信息】 西南石油大学 ， 油气田开发工程， 2006， 博士

【摘要】 二连盆地乌里雅斯太凹陷储集层岩性为砾岩、砂砾岩、中粗砂岩、粉细砂岩等多种类型，但以砾岩、砂砾岩为主，是典型的砂砾岩油藏。其构造类型复杂，具有相变快，岩性、渗透性变化大，孔隙不发育，渗透率低，物性较差，分选和连通性较差，非均质性和各向异性严重，属低孔低渗砂砾岩储层，绝大部分油井没有自然产能需经改造后才能投产。因而油层改造技术对于乌里雅斯太凹陷低孔低渗砾岩、砂砾岩油藏的开发十分重要，但是针对砂砾岩地层增产措施方面的研究却相对较少。因此，开展针对砂砾岩油藏的水力压裂技术研究就很有必要。 本文旨在通过前期压裂评估与分析、整体压裂开发适应性研究、砂砾岩油藏压裂液滤失特性研究、压裂改造工艺技术优化研究等，形成乌里雅斯太凹陷油层增产的综合改造技术，为二连盆地乌里雅斯太凹陷的勘探开发提供有力的技术支撑和技术手段。根据乌里雅斯太凹陷砂砾岩油层改造技术的需要，重点对压裂选井选层、压裂开发方案设计、应力剖面和压裂液体系等进行了较为系统和深入的研究，取得了以下主要成果： (1)建立了乌里雅斯太凹陷油藏压裂改造效果预测的定量分析模型，获得了影响压裂效果的主要因素和影响规律。 (2)建立了油藏整体压裂数值模拟模型，通过对试采井组大量压裂开发方案的数值计算和优化，确定了该井组整体压裂开发的压裂规模和裂缝参数。 (3)实验分析了砂砾岩油藏压裂液动态滤失特性，引入与时间相关的滤失系数来对模型进行改进，充分利用实验数据，建立了基于动滤失实验的考虑多种因素的滤失速度计算新模型。 (4)建立了利用模糊数学和神经网络理论等人工智能方法实现定量选井选层模型，形成了一套运用模糊识别理论来优选压裂井层、优化施工参数和优选施工方案的新方法。 (5)基于室内岩石力学实验，结合动、静态力学参数，确定了储层纵向力学参数剖面，提出了综合运用测井资料和前期压裂施工资料反演压裂井储层的地应力参数。 (6)研制开发了低残渣、低摩阻、低滤失和易返排的低聚合物压裂液体系。 本文针对以上内容进行了较为系统深入的研究，相关内容为乌里雅斯太凹陷砂砾岩油藏提高储层改造效果的关键技术，为砂砾岩油藏储层改造理论与应用技术急需解决的问题。通过论文系统的研究，初步形成了乌里雅斯太凹陷油层改造理论与配套技术，也获得了一些有益的结论： (1)砂砾岩油藏压裂在流体滤失、应力剖面等方面与一般砂岩油藏具有明显区别，砂砾岩油藏压裂设计不能照搬普通砂岩油藏的设计理论。 (2)砂砾岩油藏的纵向和横向非均质强，压裂时在物性条件较好的井层常表现出塑性变形特征，压裂过程中压裂液的滤失较大，压裂后裂缝形态复杂。更多还原

【Abstract】 Consisting of gravell, sand gravell, medium-coarse-grained sandstone and clay etc., Wuliyastai Depression in Erlian basin is a typical grit frame reservoir, where gravell and sand gravell are dominating. Being characteristic of rapid changes of fades, great variability of lithology and permeability, low porosity and permeability, poor separation and connectivity as well as serious heterogeneity and anisotropy, it belongs to low porosity and low permeability sand-gravell reservoir and the majority of the oil wells can be brought into production only after the stimulation. Formation stimulation techniques, therefore, are especially important for the exploitation of Wuliyastai Depression and further study is necessarily to be conducted, as it is relatively fewer.Based on the fracturing pre-assessment and pre-analysis, study on adaptability of systematic fracturing, filtration characteristics research of fracturing fluid and optimization of fracturing etc., an integrated stimulation technology for Wuliyastai Depression is determined in this paper and it provides a technology support as well as a technical means for the exploration of Wuliyastai Depression in Erlian basin. To meet the demand of reservoir stimulation and focused on the systematical and deep researches on the selecting wells and formations for fracturing, fracturing design, stress profiles and fracturing fluid system, the main achievements obtained in this paper are as follows:(1) A quantitative analysis model of post-fracturing response prediction is established and the major influencing factors as well as the effects are discussed.(2) A numerical simulation model of systematic fracturing is present and corresponding reasonable scale of fracturing as well as fracture parameters are determined through abundant numerical calculations and optimizations of different systematic-fracturing project for the pre-production well group.(3) Considering various factors, a dynamic filtration experiments are conducted and the dynamic filtration characteristics of the fluid is experimentally analyzed. Based on the experiment results, a new mode for calculating fluid-loss velocity, with a leakoff coefficient related to the time, is put forward.(4) With fuzzy mathematics and neural network theory, a quantitative model of selecting well and layer is developed as well as a new method to optimize operational wells and layers, parameters and program.(5) Based on the laboratory experiments of rock mechanics and integrated static mechanical parameters with the dynamic, the stress profile is determined a new computing method for in-situ stress by reversion with log information and primary fracturing information.(6) Low polymer fracturing fluid system, with characteristics of little residue, low friction and filtrate loss, being easy to flow back, is developed.The above contents are deeply studied in this paper, where some are the key techniques for improving the fracturing effects and some are the problems for solve urgently during sand-gravell reservoir stimulation. With the researches in this paper, a reasonable stimulation technology for Wuliyastai Depression is primarily formed and following conclusions are obtained:更多还原