支撑剂对流模型研究及水平井分级压裂设计模拟软件研制

【作者】 杨立君；

【导师】 郭建春； 赵金洲；

【作者基本信息】 西南石油学院 ， 油气田开发工程， 2005， 硕士

【摘要】 水平井分级压裂技术作为水平井开发的低渗透油气藏主要的增产改造的工艺措施,受到了国内外各油田的高度重视并得到了长足的发展,但相对于水平井压裂单裂缝的延伸模型、温度场模型、施工压力预测模型来说,在水平井单裂缝的支撑剂输送模型的研究方面却进展缓慢。国内外的学者研究表明,支撑剂的对流沉降对于输送的影响远大于单颗粒沉降对其的影响,而传统的单纯考虑沉降作用的支撑剂输送模型已经不能满足压裂模拟技术发展的需要,压裂模拟技术迫切的需要能够更为准确的描述支撑剂在缝中运动状态的模型以指导水平井的压裂设计与施工。 本文针对上述问题,以前人对于对流机理的研究为基础,对支撑剂在缝中的对流运动机理进行了深入的研究,建立了对流引起的支撑剂堆积沉降速度的计算公式,并研究了对流现象发生的条件,讨论了影响对流沉降速度的因素。研究表明,裂缝的宽度、携砂液流态学特征、温度、浓度差、排量等都对支撑剂的对流沉降速度有重要的影响,其中,携砂液的流变学特性和裂缝的宽度对沉降速度的影响最为明显。本文在上述研究的基础上,以二维的液体运动模型为理论依据,建立了支撑剂在缝中水平和垂直方向的运动速度,并以连续性方程和液体运动方程为理论根据,建立了考虑支撑剂对流沉降影响下的输送模型。该模型各参数间相互制约,采用传统的求解方法求解难度较大,为此引入了运动界面追踪的数值模拟方法,对该模型进行了数值求解。在对几口施工过的井进行实例分析后表明,通过该模型,可以较准确的预测支撑剂在输送过程中的运动状态,施工结束后的浓度分布等主要参数。 根据水平井压裂设计的需要,本文以水平井分级压裂施工工艺技术为基础,建立了非对称应力情况下的单裂缝三维延伸模型、裂缝温度场模型。并对水平井压裂施工过程中孔眼摩阻的计算模型进行了改进,建立了水平井压裂施工压力预测模型。 以上述的基础理论研究模型为基础,编制了考虑对流对支撑剂输送过程影响下的水平井分级压裂设计模拟软件。利用该软件可以较准确的掌握水平井分级压裂中裂缝的形态,支撑剂的分布,施工压力预测,裂缝温度分布等情况,对水平井分级压裂设计及现场施工都有重要的理论和现实意义。更多还原

【Abstract】 Horizontal well sectionalized hydraulic fractured technology has been a high speed development as a means of increasing production in low permeability reservoir, but compare to the fracture-extend model, temperature model, surface treatment pressure model, it advanced slowly in the proppant transport model. The propant convection settling has been effect on the transport than the settling after the investigation. And the transport model that it only think over the settling don’t adapt the demand of hydraulic fracture technology. The fracture simulation technology need a good model to describe the propant’s movement in the fracture and to direct the fracture design and treatment in horizontal well hydraulic fracture.Aim at these question, it investigated the convection mechanism when the propant transport in the fracture on the base of scholar’s researched, and establish the calculation of settling because of the proppant convection, then researched the condition of convection arriving. The affect on the convection settling velocity of fracture width, the property of slurry, temperature, concentration and flow rate is discussed. Among the rest, the affect of the property of slurry and the fracture width is very evidence. On the base of research, it set up the movement velocity of uprightness and horizontal direction, then set up the convey model including the proppant convection affect. Because of the parameter affected each other, the traditional solving process can’t solved the question, so we lead in the interface trace means to solve the convection model. After the analysis on location, it indicted that the model can predict the main parameter of movement velocity and concentration distribution.Because the need of horizontal well design, we build the model of fracture extend, temperature model. And improved the model of perforation pressure-drop, then set up theprediction model of treatment pressure.On the base of these theory, we workout the horizontal well sectionalized hydraulic fractured software including the convection affect. Use it, it can know the shape of fracture, concentration of proppant, treatment pressure, temperature of fracture and so on, it has a very important theory and reality value to the treatment.更多还原