DST测试.doc

地层中途测试工艺简介1、MDT（Modular Formation Dynamics Tester）是指模块式地层动态测试器，斯伦贝谢公司第三代电缆地层测试工具通,过压力剖面、光学流体分析、取样技术可以准确识别流体类型，通过测量压力剖面可以确定油水界面、研究油藏类型，利用测压及产量测试取样可以研究油气藏性质。仪器工作时上下封隔器座封后，泵将中间抽空后让地层流体进入，测得地层实际压力，比较准确，但停留时间较长，易卡。图1为MDT结构示意图。其工作原理参考第七部分“重复地层测试RFT基本原理”。图1 MDT结构示意图。2、DST 测试类型（煤层例）2. 1中途裸眼测试这类测试是打开煤层后立即进行测试, 此时地层损害最轻, 并且所有的产层都可进行测试, 便于对地层做出准确的评价。2. 2套管坐封测裸眼这类测试是套管下到煤层顶部后, 打开煤层, 封隔器坐在套管内测试煤层。2. 3完井测试这类测试是完井后下套管、射孔、射开煤层, 在套管内测试。2. 4改造后测试这类测试是在对煤层进行压裂或造洞穴后进行的测试, 与改造前的参数比较, 评价改造的效果和经济效益。3、多流测试器（MFE）一、产品概述（1）MFE地层测试器是一套完整的井下开关工具，整套测试工具均借助于钻杆的上、下运动来操作和控制井下工具的各种阀，具有操作方便、动作灵活可靠，地面显示清晰的特点。测试时在地面可以比较容易地观察和判断井下工具所处的位置，并能获得任意次开井流动和关井测压期,为评价地层提供了更多的资料。MFE系统通常包括多流测试器、封隔器、液压锁紧接头、旁通阀和安全密封等。（2）MFE中所装的双控制阀通常是借助钻杆的上、下运动来打开或关闭的。下井时阀处于关闭状态，到达井底后，通过钻柱施加重力，经过一段延时，测试阀打开。在打开的一瞬间，钻柱突然下坠25.4mm，这种在地面可以直接观察到的显示表明阀已打开。如果要关闭测试阀时，只需将钻柱上提并略超过自由点，然后再下放钻柱加重力即可关井。如此反复上提和下放钻柱，可将测试阀重开或重关，获得多次流动和关井期。在终流动期结束时，MFE的双控制阀可以收集1200或2500ml的地层流体样品。这些保持终流动结束时状态的样品随钻柱起出井眼，供分析用。图2 DST系统二、多流测试器的特点（1）测试阀开启和关闭安全可靠，保证测试成功。（2）在终流动结束时，取得流动状态下的地层流体样品，95mm的MFE可取1200ml，127mm的MFE可取2500ml。（3）仅仅靠管柱的上下运动来控制测试阀开关，操作简便。（4）测试阀打开时，管柱有自由下坠25.4mm的地面显示。（5）MFE心轴两端受压面积不相等，这可使测试阀在下井时保持在关闭状态。（6）取样机构还配备有安全泄压阀，在运输过程中如遇到火灾或高温，样品压力超过80MPa时，安全泄压阀将高压泄入内腔，不致于引起爆裂的危险。三、多流测试器的规格和主要技术参数 MFE地层测试器以外径不同分为127mm、108mm、95mm和79mm等几种型号，通常使用的是127mm和95mm两种，其基本结构和原理大致相同。这种测试器是由换位机构、延时机构和取样机构所组成的。下表列出的是这种测试器的规格和主要技术参数：4、DST测试地面配置实例4. 1地面设备DST 测试地面设备主要有: 井口控制头、活动管汇、钻台管汇、井口显示头、压力表。4. 2下井管柱对裸眼井, 通常采用的测试管柱自下而上为: 保护接头+ 调节钻铤+ 重型筛管+ 裸眼封隔器+ 裸眼封隔器+安全密封+ 安全接头+ 振击器+ 压力计托筒+ 裸眼旁通+ M FE+ 钻铤+ 反循环接头+ 钻杆+ 井口控制头。对套管井通常采用的测试管柱自下而上为: 死堵+机械压力计+ 机械压力计+ 筛管+ P - T 封器+ 电子压力计托筒(电子压力计在内) + 锁紧接头+ M FE+ 油管+反循环接头+ 油管。山西晋城地区(以潘2 井为例)(1) 管柱结构127 mm钻杆+ 158. 75 mm反循环阀+ 158. 75 mm 钻铤+ 变扣接头+ 127 mmMFE + 127 mm裸眼旁通+ 127 mm伸缩接头+ 120. 65 mm 振击器+ 120. 65 mm 安全接头+ 152. 4 mm安全密封+ 168. 275 mm裸眼封隔器+ 168. 275 mm 裸眼封隔器+ 133. 35 mm 外挂式电子压力计托筒+123. 825 mm 机械压力计托筒+ 127 mm重型筛管。5、DST 测试施工步骤5. 1丈量需要使用的管柱及测试工具的长度、电子压力计编程、机械压力计时钟上弦、准备好液垫。5. 2测试工具下井a1 测试管柱要按设计要求的管柱组合连接、涂抹丝扣油, 上紧扣, 不得猛刹猛放。b1 按设计要求加入一定数量的测试液垫。5. 3测试过程a1 下完测试管柱, 装钻台及地面设备。b1 探井底两次, 每次加压不超过5 吨。c1 量好方余、坐封封隔器。d1 观察环空, 一旦环空液面下降很快, 要立即操作,上提管柱关井解封, 及时补充压井液。e1 根据测试设计结合现场实际, 把握井底开关井。f1 测试完毕后解封, 起钻。g1 回放电子压力计数据, 求取各项参数。6、测试方式的选择在塔河油田,测试方式可分为原钻具测试、座套测裸测试和裸眼双封测试三种。2. 1 原钻具测试原钻具测试是在钻遇大的放空井段,泥浆漏失严重,起钻较困难的情况下,为尽快了解地层产液而进行的一种简易测试。该测试方式是将钻头提至套管内,关闭钻井防喷器半封闸板,井口安装控制头,通过在钻杆内正注一个钻杆内容积的轻质油形成一定的生产压差,诱使地层流体产出。该方法优点是简单易行,缺点是无封隔器将油套环空封隔,放喷求产时井控存在一定风险。2. 2 座套测裸测试座套测裸测试是在钻遇好的油气显示层段,且该层段距离7套管鞋较近时而采取的一种测试方式。该测试方式是选用套管封隔器座封在7套管内,对裸眼井段测试,由于碳酸盐岩地层岩性坚固、稳定,井径规则,不易垮塌,因此,该测试方式与套管测试一样,风险最小。2. 3 裸眼双封测试在长裸眼井段中钻遇好的油气显示层段时,为了选择性的搞清该层段的液性和产量,针对目的层段,选择裸眼支撑双封隔器座封在目的层上部井径规则段,对目的层裸眼段进行二流二关测试。与砂泥岩裸眼地层相比,碳酸盐岩地层岩性坚固、稳定,井径规则,不易垮塌,因此,该测试成功率较高,风险较小。7、重复地层测试RFT 1、简介重复地层测试RFT( Repeat Formation Tester)是测量地层压力及流体性质的一种新型的测井工具,是斯伦贝谢公司研制的地层测试器，主要测量地层中的某一深度点地层压力随时间的变化，获取地层的压力能够直接反映地层的地质信息，具有直观、快速、经济等特点。大量生产实践证明，RFT 测井技术在许多方面弥补了常规测井方法不能解决或难以解决的地质问题。尤其在复杂细小断块油藏中，在具有多套油水系统、低孔、低渗及不同压力系统的情况下，已成为地质分析及油气层评价的重要手段。RFT测试仪器分地面仪器和井下仪器两部分，地面一起通过仪器车系统和电缆对井下仪器进行供电、控制和对测量信息的接受和转换。井下仪器主要由液压系统、传感器和压力变送系统组成。2 RFT 仪器测试原理及过程2.1 基本原理当地面仪器向井下仪器发出测量指令时，液压系统的电机带动液压泵旋转驱动推靠器、探测器和封隔器（PACKER）向相反方向运动，使探测器进入井壁并密封。其后，探测器内的活塞收缩，地层中的流体进入取样室，使与取样室相连的压力传感器产生一个直流电压信号。检测到的直流电压信号经放大后，用来控制一个压控振荡器（VCO），压控振荡器产生的振荡信号经电缆传到地面仪器的控制面板，经过解调制变为直流电压，以模拟形式显示在记录仪上，并送往模数转换器转换后以数字形式显示其压力值（pai）。在探测器内活塞收缩后，取样室内的压力逐渐升高直至与地层的孔隙压力达到平衡，完成这一层的压力测试，不同渗透率的地层所需要的压力恢复时间是不同的。当地面仪器面板发出回缩指令时，井下仪器的液压系统再次启动推靠器、探测器和封隔器回收，地面仪器显示泥浆液柱的压力值，这时可以进行下一个单层测量。2.2 RFT 测井解释精度探讨 预测试的模拟压力曲线显示先后两次记录的井内流体液柱压力,根据井内流体重度计算出测试深度的液柱压力,与测出的静液柱压力值核对,可比较检查仪器的漂移和可靠性。读数差应小于12psi 。原始地层压力一般在1121135 之间,当压力系数大于114 时,此数据则为不可信数据,很可能是仪器漏失或遇卡造成的,造成仪器漏失的原因是多方面的。在测量过程中应考虑多方面的因素,避免数据失真。外部条件是指井眼质量和泥浆性能,内部条件则包括仪器自身的防卡措施及合理的操作规程。根据实践分析,FRT 遇卡几乎都和井眼条件有关,从广义上讲,井眼条件对测试的影响主要来自两个方面:泥浆与井眼几何形状。（1）泥浆的影响泥浆失水量高造成泥饼加厚,当仪器进行定点测量时,易造成电缆吸附卡,吸附卡约占80 %。泥浆保护井壁的性能差,造成测试过程中岩块脱落卡死仪器,这种泥浆悬浮性能差,造成泥浆内的固体颗粒在重力作用下下沉,在井眼较小或靠近井底时易造成沉砂井卡。（2）井眼几何形状的影响理想的井眼几何形状应该是与钻头直径相近的圆柱体且井壁光滑,但实际情况并非总是如此,主要表现为:椭圆井眼、弯曲井眼、螺旋井眼。测试前提前做好准备,全面了解最大井斜及深度、泥浆性能、加重晶石数量、井下落物情况、防卡措施。测试时,要缓慢下放和提升电缆,防止吸附井卡,防止仪器猛烈碰击井壁,防止电缆在井内打结。其他测井过程中,有遇卡现象时,必须通一次井并调整泥浆性能。8、DST部件分类简介8.1 HiPack Packer System ImageThe HiPack High-Performance Testing Packer combines many features of a conventional retrievable packer with those of a hydraulic-set permanent packer, including a built-in floating seal assembly that eliminates the need for drill collars and slip joints. When combined with the IRIS Intelligent Remote Implementation System dual valve, the HiPack system can significantly reduce the number of tools in the DST string.The HiPack packer has three sectionsa setting mechanism, the packer body, and a stinger-packer bypass release configuration. The system is run in the hole with the stinger locked to the packer body and the stinger seal positioned in the sealbore. When the system reaches the required depth, annulus pressure is applied to activate the hydraulic setting mechanism. Hydrostatic pressure sets the bidirectional slips, closes the packer bypass, and energizes the sealing element. A positive ratchet mechanism then locks the packer in the set position and retains the applied setting forces.Once set, the stinger is released from the packer body, and the seals are free to move in the sealboreoperating similarly to a production packer with floating seal assembly. When the DST is completed, the below-packer circulating valve (BPCV) can be opened with annulus pressure, and any migrated gas below the packer element can be reverse-circulated out prior to releasing the sealing element.A straight pull moves the slips to a relaxed position within the packer body and releases the packer. Continued pulling reopens the packer bypass to eliminate swabbing when coming out of the hole.8.2 Hydraulic JarDuring drillstem tests (DSTs), if a packer or tailpipe becomes stuck, the hydraulic jar is used to provide an upward-moving shock that will help pull the string loose.The jar consists of a housing and a mandrel that move relative to each other. An oil chamber, separated by a flow restrictor in series with a check valve, is located between the housing and mandrel.Applying weight to the packer causes the jar to close. If the tools below the jar become stuck, an overpull is applied to the string, which causes the jar to begin metering hydraulic oil. As the oil flows slowly through the restrictor from the upper chamber into the lower chamber, elastic energy is stored in the string. The mandrel housing moves until a seal ring is uncovered, at which time the housing rapidly accelerates to produce an upward impact on the stuck tools.After the jar has tripped, the string weight is set back down on the packer to reset the tool. Oil flows rapidly through the check valve and back into the upper chamber, allowing jarring to be repeated as necessary.8.3 IRISDownhole tool operation and controlIRIS Intelligent Remote Implementation System is operated by coded low-pressure pulses sent down the annulus and detected by the intelligent controller in the tool.Compact fullbore testing toolIRIS has multicycle test and circulating valves. You have considerable flexibility, enabling quick response to evolving job conditions.The test and circulating valves operate independently on commands sent from the surface in the form of pressure pulses in the annulus. These pulses are detected by a pressure sensor and decoded by a downhole microprocessor, which implements the commands by electronics and hydraulics. No other pressure events during the job affect the tool.Automate complex and time-consuming jobsSoftware controls valve operations. The tool responds only to specific pulses, or commands, recognized by its downhole computer. These commands are implemented using hydrostatic pressure downhole to operate the valves. The computer is insensitive to other pressure events.Rugged technologyIRIS has been proven in more than 1000 jobs. The tool has been successful when subjected to considerable mechanical shocks during numerous tubing-conveyed perforating and jarring operations.8.4 Multicycle Circulating Valve with Lock ModuleThe multicycle circulating valve with lock (MCVL) module is a reclosable circulating and reversing valve.Applying a predetermined number of pressure cycles to the tubing opens the valve. The MCVL cycles by the differential pressure between the tubing and annulus, and it is not dependent on pump rate.The valve can be locked in the open or closed position by using the lock module. When the lock is engaged, the tool is insensitive to pressure surges in the tubing and annulus. Applying pressure to the annulus ruptures a disc and disengages the lock module.8.5 PCT Pressure Controlled Tester ValveThe PCT Pressure Controlled Tester valve, operated by annulus pressure, is the downhole valve used to control formation flows and shut-ins for applications that do not use the IRIS Intelligent Remote Implementation System. The PCT valve must be run in conjunction with either the hydrostatic reference tool or the PORT Pressure Operated Reference Tool, either of which traps a reference pressure inside the PCT valve.The two distinct sections of the PCT valve are the ball valve seal section and the hydromechanical operator section.The versatility of the PCT valve can be enhanced by installing a hold-open (HOOP) module that holds the ball open when the annulus pressure is bled off. The HOOP module allows wireline to be run through the ball or circulation through the ball valve when the packer is not set.Operating pressures for the PCT valve vary with depth but are usually between 6.9