旋冲钻井SPE

Well A
A 83" AT533 bit and 178 mm OD too&was used, WOB 180 KN, revolution rate 55 rpm, pump pressure 16 MPa, displacement 301/s, mud weight 1.02 g/ cm3, worktime 88 h while net drilling time 74.38 h, footage 451.71 m, bit integrality 6O%, ROP by 50% or more compared with offset wells. For recent field tests, if ROP is less than 8 m/s with rotary drilling, ROP increases obviously with impact rotary drilling. In hard formations, low revolution rate, impact frequence, WOB and high impact power are available; and in soft formation, as bit is not the main rockbreaking function by impact, adjustment of the percussion tool, property parameters, higher revolution rate and impact frequence, and low impact power can be suitable to improve rock-broken results between two percussions. Applications of the tool never affect other technologies such as jet drilling. Low impact power and high impact frequence can help break rocks when jet drilling in medium and soft formations. And in hard formations, jet drilling is not so important.
Well C
A series of lab and field tests show higher ROP, better deviation control with impact rotary drilling, especially more remarkable results in hard formations.
APPLICATIONS
protection during conventional drilling. Impact rotary drilling technology can be used for the same purpose. A 84'' 52 bit and 7" OD liquid percussion tool was used. Worktime was 75 h while net drilling time 60.39 h, footage 938 m. Compared with offset wells, WOB decreased by 6O%, ROP increases by 30%, maximum deviation angle 3.5", 2.5" less than that of offset well. Deviation protection was successful.
STRUCTURE DESIGN AND THEORY3
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The tool consists of three parts (Fig. 1): (1) control, (2) power part, (3) power transmission part. The tool is used between bit and drill collars. When running to bottom and starting circulation, the tool impacts the bit. As jet impactor, for example: through the nozzles on jet element 2, drilling fluids become high-pressure flow, enter piston 4 and cylinder 3 through channels C and E, respectively. Since the upper area of piston 4 is larger than the lower,
Abstract. Impact rotary drilling is a kind of new drilling technology, developed on the basis of rotary drilling, the principie of which is that the energy of drilling fluid during circulation and hydraulic impactor connected to the bit applies periodic and high-frequency impact loads on the bit to break rocks while rotary drilling. Practices show that the rock-breaking efficiency by the combination of impact and rotary increases 20-80% compared with traditional rotary drilling, especially in medium or harder formations. Meanwhile, drilling costs can be cut down, bit life prolonged and wellbore quality improved. The poster session analyzes the rock-breaking characteristics by impact-rotary drilling, and presents the working principles, lab tests and applications of the
impact rotary-drilling tools.
INTRODUCTION
Impact rotary drilling' is a unique drilling technology that developed on the basis of rotary drilling, the principle of which is that the energy of drilling fluid during circulation and hydraulic impactor applies periodic and high frequence impact load on bits to break rocks while rotary drilling. Applications of the technology can decrease drill collar numbers, reduce downhole accidents such as rear and fatigue, improve wellbore quality, make broken rocks, cut down consumed power, produce larger cuttings for the geological logging and increase drilling capacity without any more extra equipment. Also, high frequency alternate loads can increase bit life. Use of the hydraulic impact rotary drilling tool2 achieves impact rotary drilling. The energy of the tool is from mud pumps, as there is enough power from pumps during oil well drilling. And the existing sliding bearing rock bits are of impact resistance, which ensures oil impact rotary drilling on the premise of no changes in the equipment.
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Fig. 1. Hydraulic impact rotary drilling tool: (B) drain; (C&D) channels; (D&F) control channels. (I) controls; (II) power part; (III) power transmission part.
IMPACT ROTARY DRILLING TECHNOLOGY
Xinghua Tao, 35 East Dondeng Road, Dezhou City, Petroleum Drilling Research Institute, China; Yijin Zeng, Hongxiang Qin, Guoqiang Xu, Petroleum Drilling Research Institute, China
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ADVANCES IN DRILLING AND WELL COMPLETION TECHNOLOGY
Fra Baidu bibliotek
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the piston moves down to bring the hammer 5 to strike the anvil 7. The piston moves to the lower end of cylinder and stops. Pressure in upper cylinder increases, and pressure signal feeds back into control channel D so that the side flow is made to push the main jet flow to attach one side of channel E. The flow pushes the piston to bring hammer upwards until the piston stops on the upper end of the cylinder. Pressure in lower cylinder increases pressure signal feeds back through control channel F and pushes main jet flow to switch over and attach channel C. The flow pushes the piston and hammer downward. Pressure in upper cylinder of hammer anvil increases, and pressure signal feeds back into control channel D to push the main jet flow to switch over and attach channel E. Such repeated work makes the piston and hammer reciprocate. The return water in the upper and lower cylinders flows into drain B through channels C and E, and from the water channel connected to the drain into empty channel in outer case of hammer, then, through bit to clean bottom, at last, returning to the surface. When the tool off bottom, under bit weight and fluid pressure, anvil slides downward, also, hammer piston moves down to seal the entry of the lower cylinder, the piston cannot reciprocate any more, and the tool does not work. Torque transmits from outer case to octagon socket 8, then, to anvil and bit so that impact rotary drilling begins.