提高大直径井眼机械钻速的几项措施

随着我国西部地区石油勘探开发的进展，5000－7000m的深探井所钻数量不断增多，套管程序增加，特别是大尺寸井眼所钻深度明显加大。由于国产大尺寸钻头结构单一、型号少，破岩机械能量和水力能量不足，在易斜井段目前尚无可靠的防斜保直措施，以及钻井液性能不适宜等原因，大尺寸井眼的钻这远远低于215．9mm井眼的钻速。据此，提出了几项可以提高大尺寸井眼钻速的措施：增加大尺寸钻头的种类，采用阶梯式扩眼钻头，强化钻井参数和水力参数，选用中速动力钻具，改善钻井液性能以及采用冲击旋转钻具等。

Several effective measures for raising penetration rate in large size hole

Number of 5000~7000m prospecting wells in the westcrn part of China is adding and the depth of large size holesis increasing. foe penetration rate in large holes is far less than that in 215.9mm holes owing to unitary structure andscaree type of homemade large size bit with insufficient penetrating mechanical energy and hydraulic energy, and lack of good deviation control measures. Thereby several effective measures for raising the penctration rate in large size holes are put forward, including developing new types of large size bit, adopting stepped reamer, changing drilling parameters and hydraulic parameters, selecting middle speed downhole motor, improving drilling fluid properties and applying impact ro-tary drilling tools.