Известия Томского политехнического университета: Инжиниринг георесурсов (May 2018)
Geological model of the vikulovskaya suit deposits, including analysis of a manifold connectivity and the data on horizontal wells
Abstract
Relevance. Deposits of the Vikulovskaya suite of Krasnoleninsky uplift have high productivity and complex geological structure. In addition, a large number of deposits are drilled with a rare and often irregular well network. In consequence of that there is significant deficit of empirical data for adequate 3D geological and simulation modeling. The aim of the research is to develop a methodology for 3D geological modeling, which considers irregularity of measurements, connectivity of reservoir and horizontal wells' data. This methodology helps greatly increase accuracy of geological model and decrease amount of iterations of simulation model. Methods: analysis of rocks lithological composition, division of accumulation cycles into cyclites by lithological characteristics, adaptation of results of semivariogram analysis into undrilled areas by the data of the drilled ones, geosteering by horizontal wells, criterions of reservoir connectivity and 3D geological and simulation modeling. Results. Three cyclites in VK1 and VK2 reservoirs were determined by the results of core analysis. This allows making detail correlation with determinations of three layers in each several reservoirs. Parameters of semivariogram which were obtained in the areas with high density of measurements and seismic data, as well as the data on horizontal wells give the reason to update structural framework, lithology, reservoir properties and saturation in 3D geological model. The above listed models gave high correlation with the original data. The increased accuracy of geological models allowed decreasing computation complexity of simulation modeling. Results. We defined the main complicating factors which influence the efficiency of rod pump operation. The analysis of the rod screw pumps repair causes shown that low quality of polished rods produced by the manufacturer, rod deviation from geometric parameters of different structures, hardness, chemical composition of rods (factory defect) are often the causes of breaks. Open threaded rod or polished rod was primarily due to insufficient torque screwing the threaded connection or a bend in the rod head. The breackage of polished rods mainly occur in the oil seal and due to fatigue voltage. The fatigue fracture occurs as a result of permanent deformation forces and temperature action. One of the main causes of the elastomer swelling is the maintenance with pressure at the reception of rod screw pumps below the saturation pressure. It leads to saturation of elastomer material with gases and rotor jamming in the stator which can turn into breakages of the rod string and polished rod.
