Application Of Gas Logging Method In Huanghe River Sag,offshore Bohai Bay Basin

Mud logging is one logging method that detects content of separated hydrocarbon from drilling fluid by gas detection system.It can detect oil and gas indication,predict well blowout and gas invasion in time,and comprehensively evaluate reservoir.It plays an important role in oil and gas exploration.The mud logging technology has obvious advantages of timeliness and portability in the actual production process,but it is also obvious that the drilling engineering is affected by the drilling engineering and the gas sample is not accurate enough.Gas composition,engineering factors,logging equipment and other factors in the production process will have a certain impact on the gas logging data.It is necessary to correct the logging process and data use,so that the data value of the mud logging data can reflect the fluid situation more accurately.According to the working principle and technical characteristics of mud logging,combined with the characteristics of the new gas logging equipment Flair logging system,it can be seen that the gas logging technology has the development trend of quantitative,rapid,accurate,diversified and modular.The gas logging data interpretation method can be divided into two qualitative and quantitative methods.The qualitative interpretation is mainly based on the gas measurement curve.The method is simple,but the human factors are larger and the accuracy is poor relatively,only as the oil and gas reservoir.The quantitative interpretation is mainly based on the relative content of each component,and the properties of the reservoir fluid are deeply analyzed,but it is difficult to judge the fluid saturation,and the requirement is higher at the same time.The two methods have their own advantages and disadvantages.In the process of production,the two are often used at the same time.According to the actual conditions,the suitable oil and gas interpretation methods are selected to distinguish the oil and gas layers.The Huanghe River sag in Bohai is mainly a fault block type thick layer light oil and gas reservoir.The hydrocarbon fluid in the reservoir is mostly interlaced with gas and liquid in the longitudinal direction.The gas-oil ratio is very high,the volatility is strong,and the single reservoir is often in the state of oil and gas.It is reflected on the logging curve with the characteristics of the oil layer and the abnormal characteristics of the gas reservoir.The evaluation of oil and gas fluid properties and the identification of oil and gas interface are very difficult.It is of great significance and economic value to develop mud logging methods and improve the accuracy of gas logging interpretation in the process of oil and gas exploration in the Huanghe River sag,when the logging interpretation can not fully distinguish the oil and gas reservoir and the cost of the offshore drilling oil and gas sampling is high.According to the characteristics of the gas logging method and the characteristics of the oil and gas reservoir in the Huanghe sag of Bohai,through the collection of the production data,combined with the logging interpretation and the oil test results,it is found that the hydrocarbon ratio chart and the triangle plate method are more suitable for the Huanghe River sag in Bohai,and a regional plate solution is set up standard of interpretation according to the production data.The application of gas logging in the actual production of Bohai Huanghe sag shows that the gas logging technology,especially the new gas logging technology,has a practical and effective role in the exploration of the fault block type oil and gas reservoirs with thick reservoir,good physical property and rich oil and gas in the Huanghe River sag.The accuracy of gas logging in weak oil and gas display and low resistivity reservoir may be more accurate than electrical interpretation.It can direct drilling production,save drilling cost and create economic value in horizontal well direction.At the same time,gas logging method is an important supplement to oil and gas discrimination and water layer discrimination.