The Deep Gas Layer Identification Method Research Of Underbalanced Rilling In Xujiaweizi Region

This article puts forward solutions on the identification problem of several sets of gas underbalanced conditions in Xujiaweizi's deep gas layer from the detection of gas information carried by the drilling fluid and the use of comprehensive mud logging parameters.Through the analysis of cuttings gas, and comparison between cuttings gas detection curve and gas logging curve, the measured value of cuttings gas remain changing and appears unusual at the interval where difficult to separate abnormal.The introduction and application of GW-contact hydrocarbon gas detecting technique, especially aim at gas drilling, underbalanced drilling and the inherent shortage of traditional sampling of gas logging. GW-contact hydrocarbon gas detecting technique can be the partial alternative technique. Meanwhile, the sampling points of GW-contact hydrocarbon gas detecting technique are closer to the wellhead than normal gas logging; the detected parameters directly reflect the gas content of drilling fluid, which reflects the oil and gas bearing conditions of formation more realistically.With the analysis and research of the data acquired by comprehensive mud logging unit, we summarized the change characteristics of drilling fluid flow out parameters and gas logging data in gas layer, and combine the gas logging data and wireline logging data to establish the gas identification plot chart.Overall, the research results form the supporting technology for gas layer identification in deep formation which is suitable for underbalanced drilling; realize the deep gas layer identification of underbalanced drilling in Xujiaweizi, and has achieved good effect in production.