Research On Forward And Inversion Of Array Induction Logging MIT In Horizontal Well

In recent years, due to the needs in exploration and developing, the amount of horizontal wells and highly deviated wells increased enormously. Consequently the cost of horizontal well drilling dropped substantially, even close to the cost of vertical wells, yet its productivity is three to eight times that of the latter. Compared with the vertical wells, the horizontal wells increase the surface of reservoir stratum to strengthen the lateral connectivity of dispersed reservoir stratum; well trajectory can pass through more vertical cracks and gives full play to the potential of reservoir stratum, makes up for the weakness of vertical wells, improves the oil recovery efficiency. The horizontal well gains a higher productivity than vertical wells. The purpose of well logging is to lead well trajectory to drill along the reservoir stratum direction set by the geology mode and to make assessment on reservoir stratum oil and gas. For the horizontal and vertical wells, there is prominent electrical anisotropy of formation and the log response of its array induction is an issue of three-dimension numerical calculating, the method of log response calculating and reading numbers according to well logging no longer applies.Take the MIT array induction tool as the research object, the thesis first completes inversion study, secondly analyses the MIT field application. The results are as follows.Through the study of MIT forward of horizontal array induction logging response characteristics depend on the layer thickness, electrical conductivity contrast, sub array spacing, instrument layer interface distance and other factors. By analyzing the eddy current and magnetic field distribution features of the imaginary part space reveals the array induction response mechanism in deviated well and horizontal well.In the research on inversion of horizontal well, choose the geological model of the model parameters of instrument measurement, by using the finite element calculation of dual laterolog, dual induction response value, establish logging response information database, to rapidly predict model parameters of inversion and dual induction logging response.At the scene of the actual application of MIT array induction than conventional resistivity instrument more accurate, more intuitive interpretation results, have stronger divided thin layer and the ability to reflect the intraformational heterogeneity, intuitively describe reasonably formation characteristics and true formation resistivity invasion.