Multivariate Optimization of the Development Systems for Low–Permeability Reservoirs of Oil Fields of the Achimov Formation

Abstract

The aim of this work is to develop an approach to multivariate optimization of development systems for tight oil reservoirs of the Achimov formation, where large volume of drilling of RN-Yuganskneftegaz LLC are currently concentrated on. The approach described in the paper is an integral part of the corporate module "Decision Support System for drilling out new sections of tight oil reservoirs", which allows making quick design decisions for new drilling sites of target objects. The main factors that reduce the development efficiency of such objects, in particular with the use of water flooding methods, are the low piezoconductivity and high heterogeneity of a reservoir that leads to relatively high rates of decline in fluid production and, in particular, to long response productivity time for production wells to injection. In this paper, we consider a multi-criteria assessment of the effectiveness of various well placement systems in various conditions that characterize the geological features of tight oil reservoirs and low-connected reservoirs. A specific example is considered - tight oil heterogeneous reservoir of the northern part of Priobskoye field, for which oil production is calculated by numerical hydrodynamic modeling methods. As a result of development and testing of the approach: Main geological and technological parameters are estimated that affect development indicators and empirical dependencies derivation (of the development indicators) on the geological features of the selected clusters of Priobskoye field target objects; A method being proposed for description of a various geological features of the reservoirs of Achimov formation target objects by using synthetic stochastic 3D geological models; A physically-meaningful approach is proposed for adaption of well dynamics that reveal tight oil reservoirs of target objects using synthetic 3D geological and hydrodynamic models. Based on the actual data of development (well operation), formation parameters are determined for each cluster (section) of the target objects of Priobskoye field, which differ in geological features and development indicators; Prediction multivariate numerical calculations were carried out for various well placement systems under various geological conditions (≈ 3 million calculations). A database of calculated development indicators has been formed for each variation of the well placement system; Different options are presented for visualization of calculation results in the form of dimensional templates of optimal development systems for tight oil reservoirs; Various options for sensitivity analysis visualization for the effectiveness assessment are presented of various well placement systems to changes in geological, technological and scenario conditions.