Research On 3D Horizontal Well Drilling Technology Of G0-7 Well Group In Changqing Oilfield

Ordos Basin Oil and Gas Reservoir in Changqing Oilfield is classified as 3-low (low pressure, low permeability and low abundance) reservoir, moreover, a large part of it is tight reservoir that means it is difficult to explore in technical and in cost, and make the task of output increase much more hard. Therefore, Changqing Oilfield Company conducted a series of test in cluster well operation by factory drilling method for the following volume fracturing. Thus, it is great significance in control cost and shorten the development period of Ordos Ba-sin Oil and Gas Reservoir to study the key techniques of 3D horizontal well.In the first part, this thesis has focused on deduce the design model of 3D horizontal well trajectory, and calculated the well profile parameters of the well G60-22H2 in the well group GO-7. Based on the design trajectory parameters before, this thesis has deduced the prediction and analysis model of friction-torque of drill stem, calculated the friction and torque of second section drill stem and third section drill stem as well as checked their strength basing on the design trajectory, structure of drilling stem, and drilling parameters and of the well G60-22H2, and proposed a series of measures for friction decrease. This thesis also has studied the stress and strain features of shell-bent screw drill in curve hole, and derived the mechanical model of vertical and horizontal bending beams. And based on this model, this thesis has predicted the factor of shell-bent screw drill’s deflecting ability including tools structure, drilling pa-rameters and geometric of hole, and analyzed the factor of shell-bent screw drill deflecting ability as well as verified its precision by comparing with measured deflection data.On the basis of study above, the following results can be drawn:for the GO-7 well group, the kick-off point is 500m depth, the build-up rates are in the arrange from 0 to 6°/30m, horizontal section length is about 1000m, the change of azimuth is 254°, that can mainly fit for the development of Ordos Basin "3-low" Oil and Gas Reservoir; in the drilling process of GO-7 well group, some part of drill stem prone to bucking because of the sharp increase of friction; bending angle of deflection tool, deviation angle of well, and the WOB have positive effects on the shell-bent screw drill deflection ability while hole diameter has the negative ef-fect.In this thesis, a series of techniques for 3D horizontal well in GO-7 well group have been studied, the each technique has already been checked by comparing the calculation results or design results with actual drilling analysis data and proving that these key techniques can make guidance for 3D horizontal well drilling in this field.