Abstract

Future energy for Russia will come from additional investment justified by an increased valuation of reserves. Western Siberia is well known for its abundance of laminated, siliciclastic reservoirs. Due to technical limitations of the past, the value of the oil or gas reserves within such reservoirs has been difficult to quantify and typically undervalued. Laminated, hydrocarbon-bearing reservoirs are electrically anisotropic; evaluating them with conventional resistivity tools and computational methods commonly provide pessimistic results. A new generation of wireline tools and analytical methods were purposely developed to provide accurate valuation of reserves within such reservoirs. Triaxial induction measurements of horizontal and vertical resistivity, as well as formation dip and azimuth, are used to determine the true resistivity of the oil-bearing sand laminations. Integrated, high-resolution bulk density and neutron porosity measurements quantify total formation porosity as well as the porosity of the important sand laminations. Magnetic resonance measurements provide essential information on the fluid properties and rock quality. The comprehensive volumetric analysis for the laminated formation provides an accurate reservoir summation for reserves valuation. As our field examples demonstrate, the oil company and Russia have added significant value to their oil reserves that may otherwise have been underestimated, undervalued, or bypassed.

Introduction

Western Siberia represents the heart of the oil industry of Russia. Approximately two-thirds of Russia's oil production comes from fields in Western Siberia. While this region is mature, West Siberian production potential is still significant, but will depend on improving the economics of production at fields which are more complex than once thought. Complexity stems, in part, from laminated formations which are ubiquitous in the region.

Some of the well-known, laminated formations there include the Vikulovskaya, Achimovskaya, Tyumenskaya, and other Cretaceous and Jurassic intervals. We shall illustrate the application of new technology that addresses - and likely improves - the issue of reserves valuation within laminated formations in Western Siberia. We believe that the volume of oil and gas in these formations has been generally underestimated. This results in the underestimation of the asset value of the oil company; and this affects every economic decision within the company from the top down.

The new technology is composed of two parts. The first part is hardware: a triaxial induction logging tool. The second part includes a fresh, new analytical approach to thinking about laminated formations coupled with a modern log analysis computational workflow. All of this new technology, hardware and software, has been applied in Western Siberia with good results for the Russian oil companies.

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