YST48R MWD Users Manual.docx

1、YST48R MWD Users ManualTABLE OF CONTENTSChapter One Overview of the Equipment and Its Basic Working PrincipleYST-48R is a retrievable positive pulse MWD, which features delicate design, flexible assembly and easy use. This product is an updated version of YST-48X MWD. The updated product is distingu

2、ished with re-designed ground devices, accessorial function of gamma measurement, as well as a variety of improvements based on the feedbacks of users in the past years.This equipment codes the hole parameters the transducers obtain in some way, and produces pulse signals, which control the movement

3、 of servo poppet. The circulating mud is used to make the main signal poppet move synchronously, thus controlling the mud circulation area between the main signal poppet and the main orifice below. When the main signal poppet rises, the mud inside the drilling column can smoothly pass through the ma

4、in orifice. When the main signal poppet holds down, the mud circulation area decreases, thus producing a positive mud pressure pulse inside the drilling column. The pulse signals the directional probe produces control the duration of the state of the main signal poppet, thus controlling the pulse wi

5、dth and interval. The mud circulation area between the main signal poppet and the main orifice decides the intensity of signals. We can control the intensity of signals by selecting the outside diameter of the main signal poppet and the inside diameter of the main orifice, so that it is suitable for

6、 the working environment of different holes, different displacements, and different hole depths. As a matter of fact, the whole process involves how to obtain the parameters in the holes and how to transmit the data to the ground, and these two functions are completed by the probe and the mud pulser

7、 respectively.1.1 Overview of the equipmentYST-48R MWD is composed of ground equipment and downhole equipment. The ground equipment includes pressure transducer, power supply box, remote data processor, computer, and relevant connecting cables. The downhole equipment includes directional probe, gamm

8、a detector probe, mud pulser, battery, centralizer, retrieval neck, etc. Refer to Picture 1 for the overall structure.The downhole equipment can be retrieved. When such failures as drill bit seizing or fish fall take place, retrieval neck can be used to retrieve the equipment in time, so as to minim

9、ize the loss.Picture 1 Overall structure of YST-48R MWD1.2 Basic working principle 1.2.1 Directional probeThis instrument uses the known local gravity field and geomagnetic field as the base direction parameter, and uses the mutual relation between the directional probe coordinate system and the bas

10、e direction parameter to calculate the new direction parameter. Therefore, it is necessary to establish the probe coordinate system as Picture 2 shows. Picture 2 Diagram of the measuring probe coordinate systemThe XOZ plane of the X, Y, Z and O rectangular coordinate system is parallel to the T-shap

11、e slot plane, while axis Z is parallel to the axial direction of the measuring head. The sensitive axes of three accelerometers Gx, Gy and Gz as well as three magnetometers Bx, By and Bz are parallel to OX, OY and OZ respectively. Therefore, the former can sense the components of the acceleration of

12、 gravity in the three directions, while the latter can sense the components of the geomagnetic field in the three directions. When these transducers sense the inputs, they, together with the servo circuit, change the inputs into the corresponding voltage outputs. The temperature probe and its circui

13、t turn temperature signals into voltage output (VT). The 9 voltages, including the 7 voltage outputs, one base voltage (VR) and one power supply voltage (VD), are input into the V/T converter through the multiplexer. After 8 times of sampling and averaging, a group of pulse output strings (P8) form.

14、 P8 and the synchronous pulse (PS) form P0 inside the V/T converter, which is input into the CPU. CPU changes the pulse intervals of these pulse strings into numerical quantities, and works out the values of such parameters as toolface, inclination, and azimuth. CPU will further code these parameter

15、s to form pulse strings, thus driving the follow-up circuits to work.1.2.2 Gamma detector probeGamma detector probe (GDP) is an equipment for comprehensively measuring the natural radiation level of rock strata. The rock strata contain natural radionuclides (mainly U238, TH232 and K40), which emit r

16、ay during natural decay. The GDP is used to measure the rock strata in the hole to get natural gamma recordings of the strata.According to the geochemistry and geophysics, the properties of rock strata (such as types, formation, sedimentation environment, and age) are related to their natural radiat

17、ion level. On this basis and with the results obtained with other measurement methods, the oil strata can be effectively figured out. This is the major purpose of the application of natural gamma measurement.In order to accurately and reliably conduct natural gamma measurement with the MWD, and taki

18、ng the working environment and special requirements of the clinometer into considerations, YST-48R adopts scintillating crystal and photomultiplier tube featuring high resistance to vibration and impact and high reliability, and reasonable system design is made, so as to make sure the equipment work

19、s properly in the relevant working environment. Wireless gamma measurement, comparing with cable gamma measurement, can achieve natural gamma measurement more efficiently, and maintains a variety of other remarkable advantages. Wireless gamma measurement recordings are more reliable, because the mea

20、surement is conducted shortly after the strata are opened. The strata are exposed for a short period of time, and are washed less by the mud, so the recordings are more accurate and reliable. Second, the measurement data can guide drilling work better. The drilling parameters can be selected to impr

21、ove the drilling performance and reduce drilling cost. Third, the relevant risks can be avoided, and the incidence of drilling accidents can be reduced. Further, in horizontal drilling operation, the measurement data can be used to effectively adjust the drilling orientation, so that the hole passes

22、 through the reserve strata, thus improving the mine recovery rate and economic effects. In addition, first-hand measurement data can be obtained once the drilling accident happens, thus protecting precious data from losing.1.2.3 PulserAs said above, YST-48R MWD controls the circulation area between

23、 the main signal poppet and the main orifice through the electromagnetic mechanism, and causes change of pressure of the mud flowing in the drilling column, thus achieving the purpose of transmitting signals. Quite big power is needed for the electromagnetic mechanism to drive the main signal poppet

24、, and it is not practical to achieve this in the hole. In the design, the servo poppet drives the main signal poppet through the flowing mud. As Picture 3 shows, when there is no signal, the servo poppet holds down, and the quickly flowing mud in the non-magnetic drill collar produces reverse pressu

25、re at the main orifice. As a result, the main signal poppet rises; the main spring is compressed; the circulation area between the main signal poppet and the main orifice becomes bigger; the mud passes quickly; the pressure of the mud inside the Kelly declines. When there is signal, the servo poppet

26、, as Picture 4 shows, rises; the mud passes through the servo poppet; the pressure inside and outside the equipment becomes balanced; the compressed main spring is released; the circulation area between the main signal poppet and the main orifice declines; the pressure of the mud inside the Kelly ri

27、ses; the signals are transmitted.Picture 4 Main signal poppet holds downMain orificeDrill collarMain springServo poppetMain poppetMudPicture 3 Main signal poppet rises1.3 Performance indices 1.3.1 Direction probeInclination: 0.2Azimuth: 1.5Toolface: 1.5Max data storage capacity: 45000 groups1.3.2 Ga

28、mma detector probeMeasurement range: 0500APIMeasurement accuracy: 3API (0150API) 10API (150500API) Max data storage capacity: 110000 groupsSensitivity: higher than 1.6 CPS/API Vertical resolution: higher than 130mmRecommended velocity: 30 m/hRecommended sampling period: 812sImpact resistance: 800g,

29、1/2sin three axlesVibration resistance: 20g/10200Hz rms three axles1.3.3 Other performance indicesMax operating temperature: 150Max pressure: 100MPaOutside diameter of the pressure barrel: 48mmTotal length of the downhole equipment: 6.9m (without gamma) 8.8m (with gamma)Working time of battery (stan

30、dard mode): 220h (without gamma) 180h (with gamma)Flow range: 1055L/s (depend on size of drill collar)Pressure drop: 50200PSI (depend on size of drill collar and mud discharge)Mud signal intensity: 20100PSIMud viscosity: 140s (funnel viscosity)Sand content in mud: 1%Mud concentration: 1.7g/m3Chapter

31、 Two Tests of the Equipment2.1 Tests of the centralizer2.1.1 Insulation test of the centralizer1.Plug the two connectors of BJ test unit into both ends of the centralizer, and set the switches in the “OFF” position;2.Set the universal multi-meter at the shift of resistance, and insert the black mete

32、r pen into “Up 1” and the red meter pen into “Up 2”, to measure the resistance; the reading shall be 20M; 3.Keep the black meter pen in the same place, and insert the red meter pen into “Up 3”, “Up 4”, . “Up 10” and the external column respectively; the readings shall also be 20M; 4.Move the black meter pen from 1 to 2, and insert the red meter pen into “Up 3”, “Up 4”, . “Up 10” and the external column respectively; continue to measure this way, and all readings shall also be 20M;5.If any reading doesnt meet the