Log-based in situ stress prediction of deep coalbed methane reservoirs in the Daji block
For deep coalbed methane(CBM)exploration and production,accurate in situ stress prediction holds critical significance for safe and efficient drilling and completion of wells.Deep CBM reservoirs,once considered restricted areas for exploration and exploi-tation,have been highly anticipated owing to their high yields in recent years.However,their in situ stress prediction model has not been investigated effectively.Hence,this study systematically analyzed six in situ stress prediction models commonly used for conven-tional oil and gas reservoirs and unconventional gas(like CBM)reservoirs.Based on these prediction models,this study calculated the in situ stress,and found that the combined spring model and the Newberry model yielded relatively high accuracy through comparative analysis of closure pressures.To improve the accuracy of in-situ stress prediction models,the effective stress coefficient of coal rocks was employed to optimize the two models.The optimized in-situ stress models yielded prediction accuracy errors reduced by 4%,roughly meeting the requirements of in-situ stress prediction accuracy for deep CBM exploration and production in the Daji block.
deep coalbedin situ stressapplicability analysiscombined spring modelNewberry model
万方数据
维普
