Sensitivity of gravity data to level of ground waters and atmospheric conditions: case study for the Dashava gas storage

Purpose: estimation and evaluation of influence level of outer physical factors to observed gravity during gravitational monitoring execution at underground gas storages. Using of obtained results for quality increasing of final gravity data of gravitational monitoring for condition and exploitation of Dashava underground gas storage. Methodology: calculation of gravitational effects occurred by changes of survey conditions on the basis of experimental data about ground water level changing and atmospheric condition changing with using of known physical dependences. Results: changing of ground water level should be determined as most significant outer non-geological factors that affected on observed gravity field. Atmospheric conditions change have the less significant but also appreciable influence on observed gravity field. Gravitational effects from survey physical conditions changing are calculated and their influence to observed gravity is evaluated. Significance degree of outer non-geological physical factors during execution of high precise gravimetrical monitoring observations is analyzed. Results of experimental investigations are shown. These investigations were provided during execution of gravimetrical monitoring for condition and exploitation of Dashava underground gas storage. Based on obtained results, the assessment and influence of outer non-geological factors to observed gravity field were executed. Originality: influence model is considered. Influence value of outer conditions changes to time-lapse gravimetric observations compared to gravity changes occurred by cyclic exploitation of underground gas storage is evaluated. Procedure and methodology of consideration of outer physical conditions influence to observed gravity field is described. Practical significance: results of investigations were used at gravity data processing stage during execution of gravitational monitoring for conditions and exploitation of Dashava UGS. Calculation and usage of corrections to observed gravity field for outer non-geological survey conditions change is required during high precise gravity survey execution.