Development of Approach to Modelling Complex Structure Carbonate Reservoirs using Example of the Central Khoreyver Uplift Fields

Abstract

When planning development of fractured oil-wet reservoirs one may encounter a number of difficulties associated with the complexity and heterogeneity of their structure, uncertainty in main factors effecting the development: integral wettability of the rock, structure of the void space, presence and location of faults etc. The only instrument allowing taking into account entirely all factors relevant to the reservoir engineer dealing with such objects is a full-scale simultaion model. This paper reviews new approaches to improving quality of simulation models using the example of fields of the Central Khoreyver Uplift (CKU) belonging to the Timano-Pechora petroleum province. When characterizing the carbonate reservoir of the fields the authors have accepted a concept in whichheterogeneities of formation's properties at various levels were considered: micro-level, meso-level and macro-level. -Thin sections studies, results of routine and special core analysis were used to describe the heterogeneity at the micro-level. The results of PLT studies, selective formation flowtests, statistical processing and calculation of NTG ratio from core crossections were used to perform the heterogeneity analysis at the meso-level (well scale). Genetic algorithms of seismic attributes processing and lithofacies analysis were applied for description of macro-heterogeneities. An approach proposed in this paper is based on the concept of binding heterogeneities of reservoir's structure at various levels in the framework of a single model. It has been applied for modelling several small carbonate fields at Timano-Pechora petroleum province. At the opinion of authors the final forecast accuracy for the considered models is a unique achievement for oil-wet fractured vuggy porous reservoirs. Well locations were optimized, a program of well interventions was proposed, oil production plans were adjusted on the basis of the constructed models. The accuracy of made decisions is proven by actual results of wells drilling and operation.