扭力冲击器复合钻进工艺在干热岩钻井中的试验应用

Test of compound drilling with the torsional impactor in hot dry rock geothermal wells

摘要:

扭力冲击器在石油、天然气行业钻井中得到广泛应用，具有提速增效的作用。而干热岩钻井工作环境不同于油气钻井，面临着高温、高压、硬岩、强研麿性以及深井、超深井等问题，因此对扭力冲击器进行了针对性设计，并进行试验应用。在扭力冲击器2次入井试验中，对硬-极硬岩地层进行了不同钻具组合下的钻进试验，确定了扭力冲击器对钻进效率的影响机理。结果表明：（1）扭力冲击器能够消除螺杆钻具因离心惯性力造成钻具的横向振动，验证了扭力冲击器与螺杆钻具组合应用的可行性。相比未使用扭力冲击器井段，机械钻速提高29.59%。（2）从碎岩机理和地层适配性上，相比PDC钻头，牙轮钻头在扭力冲击器+螺杆钻具+转盘复合钻进的方式下，有着较高的钻进优势。试验成果可为扭力冲击器与牙轮钻头匹配性研究和扭力冲击器与螺杆钻具的耦合性研究提供较好的技术基础。

Abstract:

The torsional impactor which can increase drilling rate and efficieny has seen wide use in oil and gas drilling industry. But hot dry rock drilling is quite different, where many difficulties such as high temperature, high pressure,hard rock, strong abrasiveness,deep and ultra-deep wells, are encountered. Specific design has been made on the torsional impactor in regard to these issues and trial use was conducted. A series of drilling tests were conducted on the torsional impactor with different drilling tool combinations in hard-extremely hard rock strata during two drilling trips to study its influence on drilling efficiency.The test results show that the torsional impactor can eliminate the lateral vibration of PDM caused by centrifugal inertia force， which verifies the feasibility of the combined application of the torsional impactor and PDM. ROP increased by 29.59% from the well section where the torsional impactor was not used.In addition， the roller cone bit had higher drilling advantages over the PDC bit in the combined drilling mode of the torsional impactor+PDM+the rotary table in terms of the rock fragmentation mechanism and the formation adaptability. The test results can provide theoretical basis for both the study of the matching between the torsional impactor and the cone bit and that for the coupling between the torsional impactor and PDM.