低孔隙度低渗透率岩心欠饱和对岩电实验参数的影响分析

岩电实验首先要求用地层水完全饱和岩心.但对于低孔隙度低渗透率岩心,由于受实验周期的限制,岩心往往不能达到完全饱和.岩心欠饱和状态下对地层因素F和电阻增大率I的测量只能是在一定条件下的近似,存在一定误差,误差的绝对值虽然较小,但相对误差却往往较大.通过理论推导、实验验证,说明了岩心欠饱和因素对岩电实验结果中胶结指数m和饱和度指数n的影响,并给出了校正方法.在岩心不能达到完全饱和的情况下,按照正常操作程序实验,对饱和度指数n会产生影响,通常使n值降低,必须增加1个校正值;在岩心无法完全饱和的情况下,按照正常操作程序实验,会对胶结指数m产生明显的影响,且使m值增大,这种影响可以通过引入1个校正量加以校正.     

确定储集层孔隙度和渗透率下限的几种方法

确定储集层孔隙度及渗透率下限值,是识别油气层、计算储量必需的参数,介绍了经验统计法、储集层喉道下限法、相渗曲线法和试气法等4 种常用储集层孔渗下限的计算方法,对鄂尔多斯盆地某气田B 井区石盒子组盒8 段孔隙度和渗透率的下限值进行了确定,其储集层孔隙度下限值确定为6.25%,渗透率下限值确定为0.1×10^-3 μm²。     

渤南洼陷低孔隙度低渗透率地层岩石力学参数测井计算方法

针对胜利油田渤南洼陷低孔隙度低渗透率地层开展了岩石强度测井评价方法研究.以岩石物理学、岩石力学为理论基础,在实验室同步测试岩石强度及声波时差、密度等测井参数.经数理统计分析后建立力学参数计算模型,并将其应用到地层坍塌压力、破裂压力等井壁稳定性评价参数的计算中.与实际钻井工程资料对比表明,所构建的岩石力学参数计算模型对研究工区地层具有较好的适应性,能够给工程设计提供可靠的依据,对提高井身质量、有效保护油气层、降低钻探成本有着重要意义.     

石西地区侏罗系八道湾组低孔渗成因

通过对准噶尔盆地石西地区侏罗系八道湾组碎屑岩储集层特征的系统分析,认为该储集层岩石具有成分成熟度低,结构成熟度较高的特点;成岩作用属渐进埋藏作用,表现为压实作用普遍较强,胶结作用程度弱,主要处于晚成岩的A1期;主要储集孔隙类型以残余粒间孔为主,颗粒溶孔次之。指出岩石中富含千枚岩等塑性岩屑及成岩压实作用较强是造成储集层低渗的主要原因。     

东海低孔渗地层的钻井液体系优化与应用

东海西湖凹陷区块存在一批大型低孔渗油气田,这些油气田大多埋藏较深,地层岩性均质性差,砂泥岩互层胶结疏松且夹发育煤层,这些地质特征易导致钻井过程中泥岩水化膨胀、剥落掉块以及煤层垮塌等井下复杂情况.PEM钻井液体系是东海西湖凹陷区块广泛应用的成熟体系,使用效果和经济性良好.为满足东海井深日益增加的高温深井的作业需求,减少钻...     

Analyzing the Well Production Data of Composite Dual Porosity Single Permeability Oil Reservoirs

Abstract

Analyzing well production data is one of the important methods for estimating reservoir parameters such as hydrocarbon in place. Recent techniques rely on the use of material balance time to account for variable operating conditions. Many dual porosity reservoirs can be modeled by a composite reservoir. So production data analysis of composite dual porosity single permeability reservoirs is of great interest. Apparently, modern methods have not been applied to complex reservoir models such as composite dual porosity single permeability reservoirs. So the purpose of this article is to analyze production data of such reservoirs with the use of material balance time function.

In the first step, a material balance time function is defined in the same way as the single porosity reservoirs and its applicability is confirmed by converting a constant well pressure solution to a constant well rate solution with the use of this time function. It should be noted that the available type curve matching methods cannot be applied to such reservoirs and in this article data analysis is based on the type curveless method. Furthermore, based on the time when each flow regime is observed, a discussion on the analysis of production data with the use of material balance time function for each case is conducted. Finally, applicability and accuracy of the material balance time method for estimation of oil in place of such reservoirs are demonstrated using synthetic reservoir examples.     

变压器油组成对其热膨胀系数的影响

实验室采用ASTM D1903方法考察了烃组成、添加剂及精制深度对变压器油热膨胀系数的影响。研究结果表明变压器油热膨胀系数主要由其基础油烃组成决定,现有生产工艺精制深度、添加剂对其影响不大。不同基属变压器油,热膨胀系数随链烷烃含量增大而增大;同一基属变压器油,热膨胀系数相近,与芳烃含量无关。     

地层压力保持水平对低渗透油藏渗透率的影响

低渗透油藏岩性致密、渗流阻力大、压力传导能力差,地层压力下降会对渗透率造成部分不可逆伤害而影响油井产能。通过室内流动试验模拟地层压力的升降过程,基于原始地层压力下的油藏渗透率,研究了不同地层压力保持水平下渗透率的保留程度;借助压汞、核磁共振、岩石力学等试验手段,对地层压力升降过程中渗透率的变化机理进行了分析。认识到地层压力下降对渗透率的伤害程度取决于岩石的初始渗透率、地层压力初次回升时机和地层压力升降次数等三个主要因素;明确了岩石的弹塑性变形是导致孔喉平均半径减小、渗透率下降的根本原因,其中塑性变形是造成渗透率不能完全恢复的主因;提出了岩石初始渗透率越低,越应及早注水保持地层压力开采的观点。      

The Effects of Multi-component Thermal Fluids on the Viscosity of Offshore Heavy Oil

Multi-component thermal fluids stimulation is a feasible way to recover offshore heavy oil reservoir. As a new technology, its mechanism of enhanced oil recovery should be understood through systematic simulation experiments and quantitative analysis. Laboratory experiments were carried out to investigate the effects of temperature, natural gas, and various gases (N₂, CO₂, or N₂+CO₂) on the viscosity of heavy oil from Nanbao block of Bohai offshore oilfield. The results show that in the range of 56°C (reservoir temperature) to 120°C, natural gas saturated and degassed oils are all very sensitive to temperature, and the viscosity is reduced by more than 90% when heated to 120°C; under lower temperature condition, injection of 5MPa N₂, N₂+CO₂, or CO₂ can significantly reduce the viscosity of natural gas saturated heavy oil, with a viscosity reduction ratio of about 20%, 50%, and 80%, respectively, at 56°C. Therefore, heavy oil production by viscosity reduction can be achieved by raising temperature or through gas injection. Taking into account the equipment, heat loss, and cost of steam injection, the technology of moderate heating, auxiliary gas injection is very promising for the recovery of Nanbao heavy oil.     

Investigation on the Thermal Expansion of Four Polymorphs of Crystalline CL-20

The thermal expansion behaviors of α-CL-20 · 1/2H₂O, anhydrous α-, β-, ε-, and γ-CL-20 crystals have been investigated by means of variable-temperature X-ray powder diffraction (XRD) together with Rietveld refinement. The results show that hexanitrohexaazaisowurtane (CL-20) with four polymorphs exhibits linear thermal expansion. The ε phase performs approximately isotropic expansion in the temperature range of 30 to 130°C, but α, β, and γ phases exhibit anisotropic expansion in the temperature ranges of 30 to 130°C, 30 to 120°C, and 30 to 180°C, respectively. The different expansion behaviors are due to the different structures of the four polymorphs. The different thermal expansion behaviors of α-CL-20 · 1/2H₂O and anhydrous α are revealed in this work. The a-axis expansion of α-CL-20 · 1/2H₂O exhibits a switch from positive thermal expansion (PTE) to negative thermal expansion (NTE) at 90°C, whereas the a-axis of anhydrous α is resilient to PTE. The cause is the loss of the structural water. Moreover, it is easily found that the b-axis of the γ phase shows a constriction that may be attributed to the distortion of the six-membered ring.     

地面渗透率与地下渗透率的关系

岩石的地面渗透率是在常压、常温下测量的。地层中的压力和温度都比地面高,岩石在地层中因为压力升高而压缩,致使渗透率有所降低;因为温度升高而膨胀,致使渗透率增大。通过研究,给出了通过地面渗透率计算地下渗透率的公式。计算公式综合考虑了压力和温度的影响。计算结果表明,地下渗透率与地面条件下的渗透率相差甚微。     

低孔隙度低渗透率泥质砂岩储层中胶结指数m和饱和度指数n的计算和应用

低孔隙度低渗透率储层的孔隙结构复杂,连通性较差,孔隙中流体分布不均匀,Archie公式中系数m、n的确定存在较大误差.由传统统计分析方法求取的m和n参数会随孔隙度和含水饱和度的不同变化,使测井电阻率计算的含油气饱和度精度降低.从数学物理边界条件和低孔隙度低渗透率储层的地质特征出发,分析了低孔隙度低渗透率储层中胶结指数m和饱和度指数n的变化特征.从储层岩石的地质作用和岩石物理变化过程探讨低孔隙度低渗透率储层中地层胶结指数m随孔隙度变化的一般规律,并用渗滤门限理论(PPTT)解释这一变化过程,建立了地层胶结指数m和饱和度指数n的准确计算方法.应用新参数对应的饱和度关系对QL油田不同水淹程度的2口井进行了处理解释,获得了良好的效果.     

双螺杆泵的热网络分析

为防止螺杆转子啮合热态间隙不等于设计间隙,有必要对螺杆泵系统进行温度场和热分析研究,而准确地给出热边界条件是开展这一工作的基础。鉴于此,以同步式双螺杆泵为研究对象,用热网络法建立了该部件的热平衡方程组及热阻、功率损失、对流换热系数计算模型,计算了该部件在原油润滑条件下的边界温度,综合考虑了各工况参数对泵温升的影响。     

准噶尔盆地西北缘风城组烃源岩热演化生物标志化合物变化及意义

以准噶尔盆地西北缘玛湖凹陷二叠系风城组泥质烃源岩为研究对象,通过封闭体系热模拟实验,以热模拟温度为成熟度标尺,对风城组烃源岩的典型生物标志化合物判识参数,如姥植比、Pr/nC₁₇、β-胡萝卜烷绝对含量、C₂₀、C₂₁和C₂₃三环萜烷分布样式以及孕甾烷与规则甾烷比值等,进行不同成熟度阶段的生物标志化合物演化特征及其适用范围的研究,以期通过与盆1井西凹陷的原油进行对比,更加准确地判识盆地西北缘风城组来源的高熟油气。结果表明,除C₂₀、C₂₁与C₂₃三环萜烷的分布样式外,姥植比、Pr/nC₁₇、β-胡萝卜烷绝对含量等参数受成熟度影响较大,不能用作高熟凝析油气的来源判识。通过在油源对比分析过程中加入成熟度因素的考量,结合新建立的风城组烃源岩正构烷烃单体碳同位素图版,对盆1井西凹陷盆5井来源有争议的高熟凝析油进行对比分析,推测其主要来源于风城组烃源岩。     

Prediction of Thermal Conductivity Effects on in-situ Combustion Experiments

Abstract

In this work a mathematical model for a combustion tube was developed. The model takes into account: (a) the heat transfer ahead and behind the combustion front, (b) the combustion zone thickness, (c) the heat generated and lost in the combustion front, and (d) the variation of thermal conductivity with temperature. The predicted combustion front temperature and temperature profiles are in good agreement with experimental data for heavy oils reported in literature. After validation of the mathematical model, further investigations of the effects of thermal conductivity on the temperature profiles ahead and behind the combustion front were studied. Expressions proposed in literature for effective thermal conductivity were used. It was found that: (a) when the functionality of thermal conductivity with temperature is taken into account, the predicted lost heat is different from that using constant thermal conductivity and (b) temperature profiles are affected principally at the beginning and at the end of the tube. The porosity effects on temperature profiles were also studied. In this case, the temperature profiles ahead and behind the combustion front and the combustion front temperature are smaller as the porosity becomes smaller.     

稠油热采闭式热流体循环井筒温度场分析

针对"两高"油田原油流动性差的特点以及闭式热流体循环降粘工艺的复杂性,建立了3种闭式热流体循环井筒传热模型及其边界条件,并采用Matlab编写了相应的模型求解程序。通过对现场具体井眼进行模拟计算,对比分析了3种闭式热流体循环效果,给出了最优热流体循环方案。计算了循环流量、循环介质和管柱材料物性参数等对井筒加热效果的影响。计算结果表明,两侧加热方案最好,随着循环流量的增加井筒温度不断升高,导热油作为循环热载体较好,导热性能差的管柱材料能够提高循环加热段产液流动的平均温度。     

基于岩电参数和颗粒直径的渗透率模型在低孔隙度低渗透率储层中的应用

基于RGPZ渗透率模型分析了岩石中电流导通性能、孔隙结构连通性和渗透率之间的相互关系,并用低孔隙度低渗透率储层的实际测井数据估算的颗粒直径和岩心岩电分析数据预测渗透率。在RGPZ渗透率计算模型中,考虑了反映岩石电流导通特性的地层因素F和表征孔隙结构弯曲度的胶结指数m,以及岩石颗粒直径,三者均可由电测井数据和/或实验分析得到。利用前人发表的多类实验数据和鄂尔多斯某探区的3口井实际测井资料验证了RGPZ渗透率计算模型有效性和对低孔隙度低渗透率储层的适应性,验证结果表明RGPZ渗透率计算模型预测的渗透率在没有微裂缝井段与实测渗透率吻合较好,但在微裂缝发育层段,需要考虑微裂缝对岩电参数的影响。     

岩石热开裂影响因素分析

室内大量岩心的实验结果表明，岩心经过高温热处理后，其渗透率、孔隙度等参数会发生较大的变化且这些变化存在一定的温度界限，不同类型的岩心具有不同的温度界限。从这些实验结果出发，对影响岩石热开裂的因素进行了初步的探讨和分析。     

基于变岩电Pickett图版低孔隙度低渗透率储层流体评价

从低孔隙度低渗透率储层的岩电、压汞实验出发,提出以孔隙结构控制储层导电性为基础,利用储层品质因子计算变岩电参数的高精度模型,结合储层品质特征,改进并建立变岩电参数的Pickett图版,在数值模拟的基础上,给出了变岩电Pickett图版建立的物理意义,并对比分析了固定岩电参数与变岩电参数Pickett图版、不同储层类型的Pickett图版异同点,明确了低孔隙度低渗透率储层饱和度计算误差主控成因及渤海湾盆地中深层出现的高电阻率水层的导电机理,在实际测井资料定性及半定量解释中显示了较好的效果,为油田的低孔隙度低渗透率储层勘探开发提供可靠的参数及流体性质评价方法。     

一种稠油热/化学驱用表面活性剂性能研究

对一种热采用表面活性剂LC进行了性能评价,LC与孤岛三区原油动态界面张力在10^-1mN／m数量级,与NaOH复配时则可达到超低界面张力。70℃下,LC在石英砂上的静态吸附量为3．6185mg／g。LC在150℃下具有很好的耐温性能,200℃下半衰期也在15天以上。LC溶液与原油质量比3：7和2：8混合,降粘率都在85％以上。150℃下动态驱替试验表明,采收率随着加入表面活性剂浓度的增大而增大,但是,活性剂浓度不宜太高;LC与0．5％的NaOH复配能显著提高采收率,当LC商品浓度为0．5％时,热水／碱／表面活性剂驱采收率比热水／碱驱提高10．85％,说明碱与表面活性剂具有很好的协同效应。试验表明LC可以作为稠油热采添加剂。