Determination of sedimentation conditions of sandy rocks when calculating boron content from logging data

Abstract

Relevance. Determination of sedimentation conditions of sandy reservoir rocks is an important part in the search for new deposits and in effective development of hydrocarbon fields. Boron content in sandstones allows establishing the palaeosalinity of the sedimentation environment. There are many different methods for determining boron concentration from cores, but often the quality of the rock material extracted from the well does not allow such studies to be carried out, or the core from the required interval has not been sampled at all. Therefore, there is a need for alternative techniques to study boron content in reservoirs. Aim. Determination of relative boron content in sandstones of the Yaronga Formation of one of the fields of the Yamal Peninsula based on the data of geophysical well surveys and identification of the regularities of its accumulation taking into account the facies settings identified using classical methods. Methods. Determination of geochemical parameters from the data of geophysical well surveys, identification of electrofacial patterns using the methodology of V.S. Muromtsev, classical methods of determining the conditions of sedimentation from the data of core and geophysical well surveys. Results and conclusions. The relative boron content in terrigenous reservoirs has been determined only on the basis of geophysical well studies. The authors have established the facies conditions of sedimentation of rocks in the study area and revealed the relationship between boron concentration in sandstones and conditions of their sedimentation. It was found that the intensity of boron accumulation in terrigenous reservoirs is mainly related to the hydrodynamic activity of the sedimentation environment, taking into account the palaeosalinity of the basin. The relative boron content when superimposed on the facies map allows us to obtain additional information not contradicting that obtained using traditional methods.

Keywords

• boron
• facies analysis
• geophysical studies of wells
• terrigenous reservoir
• hydrodynamic activity of the sedimentation medium
• palaeosalinity