| Horizontal well geo-steering drilling technology is an efficient technology for developing reservoir. In the process of drilling horizontal well geo-steering, by using the real-time LWD data to know the actual locations of reservoir and borehole, horizontal wells can land precisely and the drilling rate can be improved, thus increasing economic returns. The research of horizontal well geo-steering drilling technology starts early abroad and now it has been a mature technology. However the related researches at home lag behind; domestic instrument development and technology research is still in the exploratory stage. Because in the process of drilling horizontal wells, the kick-off section of stratigraphic structure is uncertain, simulation reservoirs may not be the actual reservoirs. The actual reservoirs may appear earlier and later. In the process of horizontal section drilling, there probably exists drilling fault, sandwich and so forth. The lack of the control efficiency of wellbore trajectory causes to low drilling in the target layer. This paper forms an analytical method of horizontal well geo-steering interpretation while drilling from the two perspectives of the horizontal well section and horizontal section landing to provide a foundation for controlling the accurate landing of well trajectory and for ensuring the drilling in the optimal position, thus increasing the rate of drilling in the reservoir.As for the problems of the uncertain landing period of reservoir and whether horizontal section drill bit drill in the reservoir drilling, the Simulation-Contrast-Model update method is used to achieve geo-steering process in combination of with site geo-steering LWD data to carry out horizontal well geo-steering interpretation while drilling method study. The following researches have been done. An analysis that LWD gamma ray, neutron, resistivity logging curves is not affected by the formation factors in the logging environment is made; corresponding environmental effect correction and deviated well depth correction of a variety of LWD curves are done. In the process of kick-off section drilling, a comparison is made using the method of median filtering real-time stratigraphic classification and orderly elements best real-time stratigraphic correlation matching method; an analysis method of safe drilling of kick-off section is put forward to interpret the real situation of drilling downhole formation according to the real situation of formation, the wellbore tracks are controlled to ensure accurate kick-off section landing. According to the requirement that the bit must drill in the reservoir during the drilling process of the horizontal section, an analytical method is proposed to interpret horizontal section geo-steering drilling. The method can interpret the direction and inclination of formation in real time when drilling into the target zone and judge whether the bit is out of the top or bottom of the reservoir. It can provide a useful basis for controlling wellbore trajectory to drill in the best location of reservoir, increasing the drilling rate of reservoir and reaching the desired effect of drilling. Based on the above researches, a set of interpretation software of horizontal well geo-steering drilling are developed. In the process of horizontal well drilling, those software divide and compare formation in real time interpret the real situation of the formation while drilling, providing decision-making basis for guiding well hole trajectory.Horizontal well geo-steering interpretation while drilling can be vised to explain the software system; well testing and analysis have done on the well-ZJ2_H. The test results show that the system software runs stable and can accurately determine whether the actual reservoir appear earlier or later and determine the distance. The analysis results are accurate and reasonable, which can carry on the division and correlation of real formation and meet the requirements of drilling engineering field application. |
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