【正文】 election, application, repair and maintenance of screw drill according to drilling demand. As a result, our screw drill may bring into play in its reliable technical function, to enhance drilling economic efficiency. Principle Screw drill is a kind of downhole dynamic drilling tool upon the power of drilling mud. Mud stream from the outlet of mud pump flows through a bypass valve into the motor. This stream produces pressure loss at both inlet and outlet of the pump, to push the rotor into rotating, and to transmit the torque and speed onto the bit. The screw drill property mainly depends upon its property parameters Constitution Screw drill is posed of four assemblies of bypass valve, motor, cardan shaft and drive shaft ( Fig. 1) . 上海奧森油田服務有限 公司 Shanghai Ocean Oilfield Service Co. Downhole Motor 2 3． 1 旁通閥 總成 它有旁通和關閉兩個位置（如圖2），在起下鉆作業(yè)過程中處于旁通位置，使鉆柱中泥漿循環(huán)繞過不工作馬達進入環(huán)空，這樣起下鉆時泥漿不溢于井臺上。 本手冊主要介紹螺桿鉆具的 性能和使用要 求以及注意事項，便于用戶更好地了解我公司 的鉆具，結合鉆井的需要，選好、用好、維護好鉆具，發(fā)揮其應有的技術性能，提高鉆井經濟效益。 2．螺桿鉆具工作原理 螺桿鉆具是以泥漿為動力的一種井下動力鉆具。當泥漿流量和壓力達到標準設定值時，閥芯下移，關閉旁通閥孔，此時泥漿流經馬達，把壓力能轉變成機械能。橡膠內孔是具有一定幾何參數的螺旋。 馬達轉子的螺旋線有單頭和多頭之分（定子的螺旋線頭數比轉子多 1）。每級額定工作壓降為 ,最大壓降為額定工作壓力的 倍，如四級馬達，額定壓降應為 ,最大壓降為 。 馬達的輸出扭矩與馬達的壓降成正比，輸出轉速與輸入泥漿量成正比，隨著負載的增加，鉆具的轉速有所降低，因此在地面只要根據壓力表控制壓力，根據流量計控 制泵的流量，就可以控制井下鉆具的扭矩和轉速。因此在選擇轉子噴咀尺寸時，應確保馬達密封腔流量始終保持或高于最小推薦流量值，這樣才能使馬達正常運轉。 流經馬達密封腔的流量為 Qm，通過馬達噴咀的流量 Qz。萬向軸大多采用瓣形，也有采用撓軸形式的。我公司制造的鉆具傳動軸總成有兩種結構： （ 1） 鉆頭水眼壓降為 ，采用硬質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 ，采用硬質合金徑向軸承和金剛石復合片（ PDC）的平面止推軸承，其壽命更長、承載能力更高。 5．使用須知 5． 1 井場鉆井技術人員和司鉆必須了解鉆具的結構原理和使用參數。 5． 3 對鉆井液的要求：螺桿鉆具的馬達為容積式，決定鉆具性能的因素是馬達的輸入流量和作用于兩端的壓力 降，而不是鉆井液的類型。 Bit nozzle pressure loss is Mpa。 5． 4 使用鉆頭的選擇：與螺桿鉆具一起使用的鉆頭在選擇上是十分重要的問題。 A：除了鉆頭水眼造成的壓降外，要使鉆井液流經鉆頭底部時別再形成其他較大的壓力損失，尤其是鉆頭水眼壓降已達到該型號鉆具規(guī)定的壓降值時更應注意。 (2) Formation Edge Structure。 (6) Design of Bit Nozzle Pressure Loss Please refer relevant professional information for detail bit selection on formation structure. Hereby it briefly describes bit selection for performance of drilling operation with screw drill. A: Except bit nozzle pressure loss, in order to avoid producing higher pressure loss while drilling fluid flowing through bit bottom, attention shall be specially paid to this matter when the nozzle pressure loss has reached the specified loss value of this kind drilling tool. This does not affect rock bit, but for the crown passage design of PDC bit. The problem shall be considered that passing fluid area may cause much extra loss, meanwhile to ensure prompt discharge of cuttings and bit cooling. B: Rock Bit : When this kind of bit is used with screw drill it is more appropriate to shorter drilling period, such as directional deflection and reentry etc. 上海奧森油田服務有限 公司 Shanghai Ocean Oilfield Service Co. Downhole Motor 9 C： PDC 鉆頭： PDC 鉆頭不僅適用于定向造斜，更適用于鉆井周期較長的作業(yè)，如打直井等。改善傳動軸的穩(wěn)定性，例如加穩(wěn)定器，對提高鉆具壽命發(fā)揮鉆頭性能是有幫助的。使用油基泥漿液，井底溫度低于 95 C，鉆具工作狀態(tài)最佳。 我公司生產兩種定子。每種鉆具都有一定 C: PDC Bit: It is not only used for directional deflection, and also more appropriate to longer drilling period, such as vertical well drilling. During longer period of drilling operation, the more important factor is to integrate bit and screw drill. It is to avoid unnecessary trip operation due to some problem. It is known that PDC bit can last longer time than rock bit, and it is integral in structure, having more advantages. D: It is also an important factor to prolong running life of bit and tool. It is helpful to extend screw life and to develop bit property by improving stability of drive shaft, . stabilizer. And it shall be considered the close relationship between diamond geometric dimension, allocation , drilling weight load and the required high speed and lower drilling weight of downhole tool. In general, it is hard to obtain satisfactory effect without strictly matching bit and screw drill, it can also cause earlier damage onto the tool. Requirement for Hole Bottom Temperature: It is unfavorable to the motor property, and it may intensify all disadvantageous factors if temperature goes too high. When using oil base mud, the hole bottom temperature shall be lower than 90176。C of maximum temperature。 5． 7 鉆井液壓力與鉆壓的特點：鉆具進行空運轉時，若保持泥漿流量不變，鉆具與鉆頭的壓降為一個常數，該值隨鉆具型式和規(guī)格的不同而有所不同。如果泵壓表突然增加了幾兆帕，繼續(xù)增加鉆壓 ，泵壓不再增加，這說明鉆具發(fā)生了泄漏，此時鉆具定子與轉子間密封破壞，鉆井液通過破壞的馬達密封腔從鉆頭水眼中流出。 5． 8 預先進行必要的水利計算：鉆井作業(yè)時，由泥漿泵泵出的鉆井液依次經立桿、水龍頭、方鉆桿而進入鉆桿、鉆鋌、無磁鉆鋌、鉆具（馬達）、鉆頭水眼及環(huán)空而返回地面。對于現場操作者來說可以采用一種簡便的做法，只要將鉆頭稍稍提離井底，在額定排量下，主管壓力表上的讀數值就是上述總壓力損失值。 6． 1． 3 吊起提升短節(jié)，把鉆具放入轉盤中，把旁通閥置于轉盤中易于觀察的位置。 The energy loss will be shown from the pressure loss. Total pressure loss can be calculated by accumulating pressure loss in each portion. After calculation of total pressure loss according to the determined drilling depth, it can be a parameter to determine the pump pressure. It is plicated to calculate large amount of pressure loss. Therefore, the site operator can adapt a simple method. Only by lifting the bit a little bit from the bottom, the reading on the pressure gauge of main pipe shall be the mentioned total pressure loss at the rated flow rate. 6. Application When selecting the screw drill and its bination, you should work out drilling program, fully consider hole size, hole trace, bit type, specification, formation structure and hydrau