Solution of the Gravity Exploration Direct Problem by the Simulated Annealing Method for Data Interpretation of Gravity Monitoring of the Subsoil Conditions

Abstract

The long-term development of hydrocarbon reservoirs (HCR) in the geological environment, complex deformation processes occur. Gravity monitoring is carried out to evaluate the possible geodynamic risk and negative consequences from HCR. As a result, the interrelationships of the continuously changing field-geological situation (changes in production volumes, changes in reservoir pressure, processes of fluid injection into productive formations) are investigated. The main tool for solving the gravity inversion when determining areas of increased industrial hazard is the solution of the gravity direct problem. In these studies, proceeding from a given initial approximation of the environment, the problem is realized through successive approximations. To assess such distributions, the authors of the article recommend using the simulated annealing technique within the framework of stochastic optimization. It is aimed at fitting the optimal parameters of the medium provided that a minimal residual of the gravity field values occurs. The approach is implemented using three simple mathematical models of the geological medium such as horizontal prism, homogeneous sphere, and vertical ledge. This technique allows fitting the media values simultaneously by a pair of its parameters. The operation of the algorithm is described and the simulation results are provided. The results showed acceptable accuracy of the algorithm for solving the direct gravity problem by the proposed method. The simulated annealing technique made it possible to increase the reliability of the HCR model while reduce the time for the analysis of the gravity field.

Optimization of an information system module for solving a direct gravimetry problem using a genetic algorithm

“…This article proposes a solution to the direct gravitmetry problem using the GA for the three simplest models of the geological environment -a homogeneous sphere, a horizontal prism and a vertical step. As part of these studies, a special GeoM IS was created for storage and processing of gravimetric monitoring data [6,16,17]. Free software was used to create the IS: PostgreSQL DBMS, PostGIS, GeoServer, Java.…”

“…The IS allows to import source files of records from gravimeters, convert them, filter data, make necessary corrections, extract statistical information, make samples and summary matrices, average data and perform other linear transformations over them. The article [6] describes the functional modeling of the main business processes for carrying out gravimetric monitoring at this field, describes the implementation of the main subsystems of the IS.…”

“…Within the framework of stochastic optimization to estimate the distribution of gravity anomalies, the authors of the article previously considered the application of the simulated annealing method [6], which is also implemented in the GeoM IS. The method was also implemented using the example of simple mathematical models of the geological environment: horizontal prism, homogeneous sphere, vertical step.…”

“…Interpretation problems are directly related to the solution of the direct gravimetry problem. In the previous paper [6] solved the optimizing problem of the direct gravimetry problem using the simulated annealing method.…”

“…As mentioned earlier, the direct gravimetry problem has already been solved by the authors by another optimization method by the simulated annealing method (SA) [6]. The problem was solved under similar conditions.…”