【正文】 mers. In order to ensure rotor seal in good condition, the matching size between rotor and stator relates closely to depth temperature. Therefore, correct downhole temperature shall be provided to the manufacturer for reliable selection of appropriate motor. The actual mud flow rate is required in the remended range. Otherwise incorrect flow rate may affect the motor efficiency, even cause speeding up motor wear. Motor torque is proportional to its pressure loss, but its outlet speed is inversely proportional to mud flow rate. With load increasing, screw drill speed decreases. Thus, pressure shall be controlled by the pressure gauge and flow rate shall be controlled by the flow rate gauge on surface. This way may control both torque and speed of downhole screw drill. 3． 2． 1 Hollow Rotor Motor To increase hydraulic horsepower and upward speed of mud stream, rotor is manufactured into hollow rotor with nozzles. Thus, motor total flow rate is equal to the sum of the flow rate through seal cavity and rotor. Each type of motor has its own remended maximum and minimum flow rate value. If flow rate is too high, rotor may be running at over speed, earlier damage would occur onto stator and rotor. If it is too low, motor will stop operating. Therefore, the flow rate through seal cavity shall be ensured or even higher than the remended maintenance value ,while selecting nozzle size. Only in this way, can motor be kept in normal operation. 上海奧森油田服務(wù)有限 公司 Shanghai Ocean Oilfield Service Co. Downhole Motor 4 在泥漿密度、 噴咀尺寸和馬達流量為定量時，流經(jīng)轉(zhuǎn)子噴咀的流量和流經(jīng)馬達密封腔的流量總是隨 負載變 化而變化的。鉆頭離開井底，馬達負載近似為零，此時流經(jīng)轉(zhuǎn)子噴咀流量最小，而流經(jīng)馬達密封腔的流量最大。鉆頭鉆進，使馬達壓差不斷增加，使流經(jīng)轉(zhuǎn)子噴咀流量增加，而此時流經(jīng)馬達密封腔流量減少。 流經(jīng)馬達密封腔的流量為 Qm，通過馬達噴咀的流量 Qz。 即：總流量 Q=Qm+Qz 設(shè)定馬達轉(zhuǎn)速 n 值計算 Qm 值 )/(60 sLnqQM ?? ?? 容積效率 ?v 取 ∴ Qz = Q – Qm (L/s) 噴咀直徑 )(898422 mmPpd Q?? Qm馬達密封腔流量 (L/s) Qz轉(zhuǎn)子噴咀的流量 (L/s) Q中空轉(zhuǎn)子馬達的總流量 (L/s) ?v 容積效率 馬達壓降 ?P = ?Pst + ?Pop ?Pst—— 馬達啟動壓降 (Mpa) ?Pop—— 馬達工作壓降 (Mpa) ρ —— 泥漿比重 (kg/L) 計算公式中 q 為中空轉(zhuǎn)子馬達的每轉(zhuǎn)排量 (L/r) 其數(shù)值參見表 1。 When mud density, nozzle size and total flow rate is a constant value, the flow rate through nozzle and seal cavity always changes with the load. On bit leaving hole bottom ,the load is approximately zero . Whereas, the flow rate bees minimum through nozzle on the rotor, but the flow rate bees maximum through the seal cavity. While the bit dropping down, motor pressure loss will continuously increase, and the flow rate through rotor nozzle will bee higher, but the flow rate through the seal cavity will bee lower. Flow rate through seal cavity is Qm, Flow rate through nozzle is Qz. Then ,total flow rate Q = Qm + Qz Suppose motor speed n, calculate Qm Volumetric efficiency ?v is )/(60 sLnqQM ?? ?? So Qz = Q – Qm (L/s) Nozzle diameter )(898422 mmPpd Q?? QmFlow rate of motor seal cavity (L/s) QzFlow rate of rotor nozzle(L/s) QTotal flow rate of motor with hollow rotor (L/s) ?v Volumetric efficiency Motor pressure loss ?P = ?Pst + ?Pop ?Pst—Motor start pressure loss (Mpa) ?Pop—Motor operating pressure loss (Mpa) ρ —Mud density (kg/L) In the equation, q is flow rate of hollow rotor motor (L/r) For the parameters, see table1 上海奧森油田服務(wù)有限 公司 Shanghai Ocean Oilfield Service Co. Downhole Motor 5 表 1 Table 1 BH BH q = BH BH q= BH q = BH q = 按以上推薦計算公式，用戶可以根據(jù)使 用需要隨時更換不同直徑的噴咀，從而達到理想的效果。 Based on the above remended equation, the customers can timely change different diameter nozzles according to the actual demand, so as to reach ideal effect. 上海奧森油田服務(wù)有限 公司 Shanghai Ocean Oilfield Service Co. Downhole Motor 6 3． 3 萬向軸總成 萬向軸的作用是將馬達的行星運動轉(zhuǎn)變?yōu)閭鲃虞S的定軸轉(zhuǎn)動，將馬達產(chǎn)生的扭矩及轉(zhuǎn)速傳遞給傳動軸至鉆頭。萬向軸大多采用瓣形，也有采用撓軸形式的。渤海啟明鉆具的瓣型萬向軸采用線切割技術(shù)制成，切口平行度高，粗糙度可達 且不破壞金屬化學(xué)成分，因此使用壽命高、機械損失?。ㄈ鐖D 4）。 鉆具使用后，應(yīng)立即拆卸，檢查萬向軸，如磨損量超過維修標(biāo)準(zhǔn)，應(yīng)及時更換有關(guān)易損件，否則會因萬向軸的使用過度致使鉆具無法正常工作。 3． 4 傳動軸總成 傳動軸的作用是將馬達的旋轉(zhuǎn)動力傳遞給鉆頭，同時承受鉆壓所產(chǎn)生的軸向和徑向負荷。我公司制造的鉆具傳動軸總成有兩種結(jié)構(gòu)： （ 1） 鉆頭水眼壓降為 ，采用硬質(zhì)合金徑向軸承和中間有一組推力軸承的傳動軸總成（如圖 5）； （ 2） 鉆頭水眼壓降為 ，采用硬質(zhì)合金徑向軸承和金剛石復(fù)合片（ PDC）的平面止推軸承，其壽命更長、承載能力更高。 Cardan Shaft The function of cardan shaft is to convert plaary motion into fixed constant rotation of drive shaft, to transmit torque and speed from motor on the drive shaft ,and to the bit. Cardan shaft mostly use flat shaft ,but some are flexible shafts .Our flat type shaft used on our screw drill is made by linear cutting technology. So the cut has high parallelism ,roughness can reach And it doesn’t damage metal chemical position. Thus, it has longer running life and less mechanical loss (). Screw drill shall be disassemblied as quickly as possible after use to examine cardan shaft. If it is found out that wear degree is over maintenance standard, relevant consumable ponents shall be changed promptly. If it is not, screw drill can not be running normally due to over run time of cardan shaft. Drive Shaft Assembly Drive shaft is to transmit motor rotary dynamic force onto the bit, meanwhile to withstand axia