Software for Estimation of Stochastic Model Parameters for a Compacting Reservoir

Abstract

The paper presents a computer program called SubCom v1.0 for determining mathematical model parameters of compaction layers in areas of oil, gas or groundwater extraction. A stochastic model based on the influence function was used to model compaction and subsidence. Estimation of the model parameters was based on solving the inverse problem. Two model parameters were determined: the compaction coefficient Cm of reservoir rocks, and the parameter tgβ, which indirectly describes the mechanical properties of the overburden. The calculations were performed on leveling measurements of land subsidence, as well as on the geometry of the compaction layer and pressure changes in aquifers. The estimation of model parameters allows the prediction of surface deformations due to planned fluid extraction. An algorithm with a graphical user interface was implemented in the Scilab environment. The use of SubCom v1.0 is presented using the case of an underground hard coal mine. Water drainage from rock mass accompanying coal extraction resulted in compaction of the aquifer, which in turn led to additional surface subsidence. As a result, a subsidence trough occurred with a maximum subsidence of 0.56 m.

Estimation of Mining-Induced Horizontal Strain Tensor of Land Surface Applying InSAR

“…The computations assumed a layer thickness of 2.8 m and two model parameters: 0.70 for the influence factor and 1.5 for the layer strength parameter. These parameters, according to a geometric-integral model, allowed to determine the influence radius r. The numerical calculations were carried out on a grid of 50 m × 50 m, with the use of SubCom software (v1.0., manufactured by Wojciech Witkowski and Ryszard Hejmanowski, AGH University of Science and Technology, Cracow, Poland) [86] (Figure 2). Ground movements were analysed in the presented study using data from Sentinel-1 satellites [87].…”

Modeling of Geodynamic Processes at Hydrocarbon Deposit*

“…Various approaches and algorithms are used to create predictive geodynamic models for hydrocarbon fields. In particular, the use of a stochastic model based on the influence function [11], the creation of a coupled hydrodynamic-geomechanical model of an oil field, as well as the use of cellular automata for modeling geodynamic activity. All of these methods have their own advantages and specific features that must be analyzed on the example of a specific field in order to determine the most effective approach.…”

“…-parametric space-time model of trend, taking into account subsidence rate in the center of bowl [11];…”

State of the Art and Recent Advancements in the Modelling of Land Subsidence Induced by Groundwater Withdrawal

“…Frequently, however, the values of these parameters cannot be obtained directly from in situ tests; in other cases, the density of samples is insufficient [173]. In such a situation, the presented model requires the use of dedicated parameterization methods and a unique computational approach [174].…”

“…He used the method presented to assess subsidence produced by groundwater withdrawal in California, USA. Moreover, Witkowski used the Knothe method to simulate groundwater-induced land subsidence in the Bogdanka hard coal mine in Poland [174]. Other examples include the forecast for rock mass deformation caused by pumping fluidized bed deposits, including crude oil and natural gas [176,177].…”