【作者】 马建民；

【导师】 刘永红；

【作者基本信息】 中国石油大学 ， 机械电子工程， 2011， 博士

【摘要】 油气井出砂已成为疏松砂岩油藏开采中遇到的普遍问题,严重影响着油气藏的正常开发。如何开发新型的防砂装备,改进现有防砂工艺,有效防止与控制油气井出砂,降低作业成本,已成为相关科研机构竞相研究的重要课题。在分析油层出砂影响因素和出砂机理基础上,进行了出砂模拟实验。研究表明:驱替压力的变化对出砂的影响不大;出砂量随含水量增加的幅度不大,出砂主要发生在见水初期;当临界环压为2MPa和临界流速为7ml/min时,出砂均出现明显增加;产砂量和油井产能随流速的增大而增加。提出了膨固结合、刚柔相济的防砂筛管设计新理念,完成可自适应膨胀防砂筛管这一新型防砂设备的结构设计,该设备由防护外壳、可膨胀防砂筛网、砾石充填膨胀层和内支撑复合割缝筛管四部分构成。基于开发的SFEM分析软件,对内支撑管的壁厚、缝长、缝宽、布缝形式、割缝密度等参数进行了优化,分析了这些要素对应力的影响规律。对筛管防砂筛网的层间组合结构形式进行了分析,给出了合理的筛网网孔设计尺寸。用高压液携带砾石充填挤压扩张实现砾石层的软膨胀,使膨胀与砾石充填一次完成,实现膨胀段的“零环空”和膨胀压力均一。研究了筛管充填膨胀机理,利用锥形流模型导出了新压降计算公式,并对膨胀层压降进行了分析计算。通过实验,优选可自适应膨胀防砂筛管充填工艺参数,研究表明,当膨胀层充填压力在15~20MPa、充填厚度为25~30mm、砾砂中值比在7左右时,可达到最佳充填效果。采用可膨胀防砂筛网、砾石充填层和内支撑割缝筛管构成复合防砂体系,防砂效果明显。利用自主研制的多功能防砂检测实验装置和实验流程,进行渗流实验、参数优选实验、防砂效果实验等相关模拟实验与分析,研究防砂规律。建立了用于防砂方法优选的BP神经网络模型,并通过具体算例进行防砂方法优选计算,从防砂作用、增产作用、有效期、井底流动条件改善、防砂效益五个方面对防砂效果进行了综合评价分析。利用自制的实验装置和流程,对割缝管进行冲蚀和腐蚀实验,分析冲蚀和腐蚀机理。研究表明:当含砂流体流速和冲蚀角增大时,冲蚀磨损增大;砂粒粒径和浓度增大时,冲蚀量先增加后减小;温度在30℃～80℃之间升高时,腐蚀加快,在80℃时达到最高点回落;随着氯离子浓度增加,腐蚀呈下降趋势,割缝在含氯离子溶液中易发生点蚀;钙离子对割缝腐蚀起抑制作用;pH值在3～6范围内增加时,腐蚀速率呈下降趋势。更多还原

【Abstract】 Sand production becomes a generally problem encountered in oil and gas wells. It has affected the normal development of oil and gas reservoirs. How to develop the new equipment to prevent sand production, how to prevent and control sand production effectively, and how to lower operating costs, have become a race-related issue for scientific research institutions.The sand-production simulation experiments are finished based on the analysis of sand production mechanism and influencing factors. The result shows that the drive pressure variety gave little affection to sand production. The capacity of sand production have little increase with the addition of water content, and sand production is occurred at the beginning of water appeared. When the critical pressure is 2MPa and critical fluid velocity is 7ml/min, sand production is increased largely. The yield of wells and sand production are all increased with the accretion of fluid velocity.The structure of self-adapted expanding screen is designed based on the concept of particle expansion and the combination of hardness and softness. The new type of screen is made up of protective outer shell, expandable mesh, gravel pack layer and the slotted screen as the base pipe. The parameters of the base pipe like tube wall thickness, slot length, slot width, slot distribution form, slots distribution density and other parameters are considered for the design of the base pipe based on the self-developed software (SFEM). Also, the relationship of the above parameters and the stress of the base pipe is analyzed and summarized. Meanwhile, mesh combination structure between the layers were analyzed, a reasonable design of screen mesh size is proposed.The high pressure liquid carrying gravel fills the space between base pipe and expandable mesh and the soft expansion is completed. The "zero annulus" for irregular borehole section of the well and uniform expansion pressure is achieved by one expansion process. The screen expansion mechanism is researched and the new pressure drop formulation is deduced and used to calculate the pressure drop of the expansion layer base on the conical flow model. The filling pressure, fill thickness and filling gravel size are optimally chosen base on the calculation results. The research show when the gravel packing pressure is about 15-20MPa, the thickness of gravel packing zone is about 25-30mm, the gravel-to-sand median diameter ratio is about 7,the screen can attain the best pccking effect.The compound sand control system is new type of screen is made up of expandable mesh, gravel pack layer and the slotted screen, and it made a good sand control effect. The flow experiments, optimal parameters chosen experiments and sand prevention effects experiment are carried out using the self-developed sand control simulation equipment. The BP neural network model for the sand control method chosen is established and the specific examples are used to carry out calculation for the optimally chosen. The sand control effect is comprehensive evaluated from five aspects of sand control function, yield increase, availability time, flow condition improve of well bottom, benefit of sand control.The erosion mechanism and corrosion mechanism of base slotted pipe are analyzed on the erosion experiment and corrosion experiment using the self-developed test simulation equipment. The research shows that the erosion is serious with the increase of fluid velocity and impact angle. When the sand particle size and sand concentration are increased, the erosion quantum is increase at the beginning, and then decreased. The surface corrosion rate is expedited with the temperature increase during 30 oC～80 oC, it reach the highest spot at 80 oC and then declined. The screen surface occur dot-corrosion easily in solution which contain chlorine ion, corrosion rate decline with the concentration increase of chlorine ion. The calcium ion can restrain the screen surface corrosion rate. Corrosion rate is decline with the pH value increase during the pH value of 3～6.更多还原