【作者】 张虎俊；

【导师】 赵金洲；

【作者基本信息】 西南石油大学 ， 油气田开发工程， 2009， 博士

【摘要】 青西油田主力油藏下白垩统下沟组,平均埋深4500m左右;储集层岩性复杂,碳酸盐岩、碎屑岩(石英和长石)以及粘土矿物含量既不同于常规的碳酸盐岩,又有别于常规砂岩,岩石矿物组份复杂,岩心的基质孔隙度和渗透率都很低,无裂缝的岩心很难测到渗透率,属于高温、高压、低孔、低渗复杂岩性裂缝性断块油藏,开发难度很大。由于储层岩性和矿物组份变化很快,平面上井与井对应层不同,同一口井的剖面上岩性互异:存在较强的水敏和应力敏感,而且天然裂缝在钻井和完井过程中易遭受污染,同时天然裂缝内往往还伴生了一定数量的黄铁矿、菱铁矿、方解石等矿物,这些矿物使得裂缝之间的连通程度大大下降,甚至形成了一些孤立缝隙,只有通过酸压等油藏改造措施解除裂缝污染和恢复、提高裂缝系统的导流能力才能使油井获得高产和稳产。然而常规的酸化(压)工艺技术和酸液体系对青西复杂岩性裂缝性油藏不适应,储层改造效果差,因此根据油田上产的要求及勘探的需要,必须研究针对该类储层的增产工艺技术。本文针对青西深层复杂岩性裂缝性油藏储层改造的一些关键酸化压裂技术进行了较系统研究,取得了如下的成果。1、通过对青西油田深层复杂岩性裂缝性油藏的工程地质、录井、测井、测试、x衍射、室内测试结果等各种资料的研究分析,对工程地质特征有了较为全面的认识,提出了储层工程地质特征对酸化压裂工艺技术的技术难点和要求。2、在岩心观察、成像测井资料分析的基础上,从测井响应机理分析入手,分别提取了溶蚀孔洞、水平裂缝、高角度裂缝的测井响应特征,提出了水平张开裂缝与水平潜在裂缝及层理面的识别技术,建立了泥质白云岩裂缝性油藏有效储层的识别方法。依据测井响应机理推导,根据常规测井资料计算裂缝孔隙度和裂缝渗透率的方法,对13口井进行了精细解释。3、针对青西油田具体的岩石类型,分别对白云质泥岩、泥质白云岩和砾岩三类岩石的力学性质进行了测试,获取了相关力学参数,为酸压设计提供了基础数据。4、分别采用粘滞剩磁分析、热弹性应变恢复二种实验室综合测试方法,并结合测井资料中井孔崩落、钻井诱导裂缝等方法,较准确地确定出了青西油田地应力方向;分别利用差应变地应力数值测试及井孔崩落特征、酸压资料统计等方法对地应力数值大小进行了研究;并在测井资料解释获得参数值的基础上,利用实测数据进行修正计算值,获得了综合柱状应力剖面。5、综合考虑压裂液沿缝高方向的压降、流体重力、地应力梯度、地应力差等因素对裂缝延伸的综合影响,建立起了三维裂缝延伸模型来模拟酸压施工中动态裂缝延伸;同时在考虑酸液纵向传递的基础上,建立了三维酸液流动反应数学模型,该模型能模拟酸液浓度在裂缝长度、宽度及高度方向的变化,适应性更好;6、针对青西油田高温高压复杂岩性裂缝性断块油藏,通过大量室内实验和现场总结,研究成功了针对这类岩性复杂、地层温度高、裂缝性油藏酸压的以胶凝酸和乳化酸有机结合的组合酸液体系。7、通过酸岩导流能力实验,系统评价了几种主要的酸液体系和酸压工艺对青西油田储层岩性的适应性,提出了针对这些岩性储层的酸液类型和酸压工艺模式:研究成功了一套适应青西油田深井酸压施工的井下工具和管柱组合等配套工艺措施,较好地满足了深井高温储层深度酸压的工艺需要。8、通过多年的实践,形成了针对不同岩性、不同裂缝发育程度储层的7种典型酸压工艺技术模式,并在现场实践中成功运用,取得了显著的经济和社会效益,为青西油田增储上产做出了贡献。更多还原

【Abstract】 The average buried depth of Xiagou group in the major reservoir of Qingxi oil field is at about 4500m.The reservoir lithology is complex,carbonatite,clasolite(quartz and feldspar) and clay mineral content are different from conventional carbonatite and sandstone,the mineral composition of rock is complex,the matrix porosity and permeability of the rock core are considerably low,the permeability of the untracked rock core is hard to measure.It is difficult to explore such fault block oil reservoir which have characters of high temperature、high voltage、low porosity and low permeability.Because of the reservoir lithology and mineral composition change too fast the corresponding layers of each well are different,furthermore the lithologies are mutual conductance on the profile of the same well.The water-sensitive and stress sesitivity conditions are strong,the natural fracture is prone to be polluted in the process of drilling and completion.Meanwhile some extent of mineral such as pyrite,siderite and calcite which will decline the connectivity conditions of fractures are existing in the natural fracture.The worse thing is that it will forms some isolation apertures which only could be reformed by fracture acidizing to release the fracture polluting and improve the conductivity of network of fracture. But the conventional acidification and acidizing fluid are not suit to the Qingxi fractured reservoir.According to the requirement of production of exploration,we have to study the enhanced recovery techinique aimed at this kind of reservoir.This paper do some research on the key fracturing technology of Qingxi deep complex lithology fractured reservoir and get the fruits as follows.1.Analyse a lot of data such as indoor test result and,a comprehensive recognition of engineering geology characteristic and present the technology difficulties and requirements of reservoir engineering geology to acid fracturing.2.On the basis of analysis of rock core observation and imaging well-log information, get the log response characteristics of corrosion holes,horizontal fracture and high angle fracture,present the recognition technology of the horizontal open fracture,potential horizontal fracture and bedding plane,establish recognition technology of the effective reservoir of argillaceous dolomite fractured reservoir,calculate fracture porosity and permeability according to conventinal log data and interpret the 13 wells.3.Test the mechanical properties of dolomitic mudstone,argillaceous dolomite and conglomerate aiming at the specific rock type of Qingxi oil field,get the related mechanical parameters which provide data base for fracture acidizing design.4.Finding the stress direction of Qingxi oil field according to the analysis of viscous remanent magnetization,the restoration of thermal elastic strain,borehole avalanche and drilling-induced fracture.Study the value of stress on the basis of test of stress value, characteristics of borehole avalanche,data of fracture acidizing.Obtain integrated styloid profile using the measured data to correct and calculate the value on the basis of get parameter by the interpreting of well-log information.5.By considering the combined influences to crack propagation form the influential factors such as pressure drawdown alone the fracture,fluid gravity,crustal stress gradient, stress contrast and so on,built the triaxial fracture extension model to simulate the dynamical fracture extension during the acid fracturing,at the same time by considering the acid longitudinal mass transfer,built the triaxial acid flowing reaction model which can simulate the alteration of acid concentration by the change of length,width,height and orientation of fracture and has a better performance in accommodation.6.Aiming at HTHP complex lithology fault block oil reservoir of Qingxi oil field, develop combination of acidizing fluid system which is organic synthetised by Gelled acid and emulsified acid,this kind of system is helpful to Qingxi oil field.7.Through acid rock conductivity experiments,has accessed adaptability of several major acid system and the process of acid pressure for the lithology of Qingxi oil field,then the type of acid and acid fracturing process model which aimed at the lithology have been proposed; underground construction tools and string combination Which adapt to acid and facture in deep well of Qingxi oil field has been Studied successfully,the supporting measures better meet the needs of the deep well and high-temperature reservoir acid fracutre.8.Through practice for years,the seven kinds of typical acid pressure technology modes that aimed at the formation of a different lithology and different degree of fracture are built up and have been applied successfully in the field,have achieved remarkable economic and social benefits.The technologies have made good help to add the production of Qingxi oil field.更多还原