Features of geological structure heavy oil field complicated palaeovalley (P-N)

Abstract

The geological study of reservoirs of heavy oil confined to the deposits of the Sheshma horizon, for further involvement of deposits in pilot production, is an expensive project in itself due to the high viscosity of oil from 200 to 200,000 MPa∙s and changes in the depth of the productive formation from 100 up to 500 m. It’s advisable to exclude all kinds of factors, including geological ones, leading to additional costs in the development of heavy oil deposits in an unstable economic situation. The purpose is determining of impact palaeovalley on the efficiency of wells using the example of heavy oil deposits. For the analysis authors have applied, materials the estimation of reserves, laboratory researches and macro descriptions of the core, the results of structural and geomorphological studies, and development parameters. It is viewed heavy oil deposits of the Sheshma horizon, complicated by palevalley, and geological structure. The porosity-permeability properties and characteristics of the bedding are given. The authors’re determined areas of palaeovalley the drilled wells, a macro description of the core and cuttings in the palaeovalley part are given. Zones of deconsolidation of the Upper Permian terrigenous deposits are identified by results of structural and geomorphological studies. A comparison of the map of predictive fracturing with the map of Pliocene formations characterizing the genesis of the palevalley is made. The authors’re comparisoned the operational capabilities of wells with the location of the wellhead in the palaeovalley zone and outside the palaeovalley. Recommendations for the design of horizontal wells complicated by palaeovalleys are determined.