气体钻井钻速方程的建立与验证

Establishment and verification of the gas drilling ROP equation

实践业已证明,优化钻井技术在钻井液钻井过程中能够提高机械钻速、降低钻井成本,但目前缺乏其对气体钻井过程中应用情况的研究。为此,以气体钻井过程中的优化钻井技术为研究对象,应用多元回归的方法,初步建立了气体钻井的机械钻速预测方程。所建立的方程考虑了钻压、转速、岩石强度等对机械钻速的影响,并将测井参数计算的岩石强度引入该方程,提高了预测的精度。为了验证所建立方程的正确性和实用性,对四川盆地元坝地区侏罗系已完成气体钻井的3口井进行了机械钻速分段预测,预测结果与实际钻井速度基本相符,平均相对误差小于15%,说明该预测方程能够满足工程需要。该方程的建立,为气体钻井过程中优化钻井技术的应用提供了理论基础。

Field practices have proven that drilling optimization can help increase ROP and reduce costs during mud drilling.But no domestic study has ever been done on the application of drilling optimization in gas drilling.Herein the gas drilling optimization was taken as subject in this study,a gas drilling ROP equation was established by use of the multiple regression method,with the effects of the rotary speed and rock strength on ROP being considered.Introducing the rock strength calculated from the log data into this equation improved the prediction accuracy.To verify this equation,3 completed gas drilling wells in Yuanba Jurassic gas reservoirs of the Sichuan Basin were taken as examples to make the ROP prediction.The prediction results were basically similar to the actual ROP with an average error of less than 15%,which showed that this equation can satisfy the engineering needs.The establishment of this ROP equation provides a theoretical basis for gas drilling optimization technology.