Abel Chacon - Academia.edu (original) (raw)
Papers by Abel Chacon
Proceedings of SPE Asia Pacific Oil and Gas Conference and Exhibition, 2004
International Petroleum Technology Conference, 2007
... is a unique development which ties-back six small to medium-sized oil and gas ... Experiences... more ... is a unique development which ties-back six small to medium-sized oil and gas ... Experiences in the Use of Intelligent Well Technology to Improve Reservoir Management A. Chacon ... Data for Identifying Moving Interfaces In East Anstey, a single-well lean gas reservoir, downhole ...
Proceedings of Latin American & Caribbean Petroleum Engineering Conference, 2007
This paper analyzes the effect of stress on the rock properties fracture and matrix compressibili... more This paper analyzes the effect of stress on the rock properties fracture and matrix compressibilities, fracture and matrix porosities, and permeability in naturally fractured reservoirs (NFRs). In NFRs, fluids are stored inside the matrix pore space and inside the fractures of the rock. The reservoir characterization parameter indicating the volumetric fraction of fluids deposited inside the fractures is the storage capacity ratio, which is function of the fracture and matrix porosity, and fracture and matrix total compressibilities. Due to the difficulty to obtain these values, in reservoir engineering computations such as pressure transient analysis and reservoir simulation, among others, it is generally assumed that the matrix and the fracture total compressibilities are equal. This induces a big uncertainty in the estimation of the storage capacity ratio and leads to a wrong estimation of the volume of fluids inside the fractured rock. Changes in pore pressure due to production or injection of fluids affect the effective reservoir in-situ stress. The mechanical behavior of the fractured rock and its effects on the rock properties permeability, porosity and compressibility in the matrix and fracture frames are analyzed using the elastic properties bulk modulus and normal compliance of the fracture. These properties can be obtained from petrophysical core analysis or multi-component seismic interpretation, and linked to pressure transient analysis through the storage capacity ratio equation. A step-by-step procedure of the analysis is presented and illustrated with an example for quantifying the effects of changes in effective stress on the fracture and matrix compressibilities.
Proceedings of Latin American & Caribbean Petroleum Engineering Conference, 2007
In naturally fractured reservoirs (NFRs), current analyses for quantifying reserves based on the ... more In naturally fractured reservoirs (NFRs), current analyses for quantifying reserves based on the material balance equation (MBE) assume that fractured reservoirs behave similar to homogeneous reservoirs, which implies that the fracture and matrix pore volume compressibilities are equal. There is considerable evidence that such assumption is not always valid leading to wrong estimation of reserves. In order to overcome this deficiency a complete treatment of the material balance formulation for naturally fractured reservoirs is presented. The proposed general MBE takes into account the fact that fracture and matrix pore volume compressibilities are different. This equation is used to investigate the impact of pressure depletion on the estimation of oil in place and recovery factors. As results of this study, new equations to compute hydrocarbons originally in place in NFRs are developed for undersaturated and saturated reservoirs. New plotting schemes for the MBE involving the storage capacity ratio at initial reservoir conditions of fracture and matrix pore volume compressibilities are proposed. The capacity ratio is computed from pressure transient test performed during the early stages of production. These new plotting schemes requires only one regression parameter, the slope of a straight line passing through the origin on a Cartesian plot, which reduces the uncertainty that traditionally two regression parameters (intercept and slope) introduces; as consequence, better estimation of oil in place with fewer historical production data can be obtained. This new method is illustrated by several field examples. It is concluded that (a) the proposed material balance formulation gives better estimation of oil in place than the traditional MBE computations; (b) the split of hydrocarbons originally in place between fracture and matrix frames depends upon the storage capacity ratio at initial reservoir conditions and; (c) the impact of pressure depletion on the estimation of reserves and recovery factors in naturally fractured reservoirs is significant. Introduction This paper presents methods to quantify hydrocarbons in place and recovery factors taking into account the differences between fracture and matrix pore volume compressibilities, and their changes caused by pressure depletion for undersaturated and saturated naturally fractured reservoirs. Such methods are based upon the integration between pressure transient analysis and the material balance equation. For undersaturated reservoirs, the assumption that matrix and fracture pore volume compressibilities are equal leads to underestimations of the fractional recovery. For saturated reservoirs only negligible differences in estimation of reserves and recovery factors have been observed. The General Material Balance Equation for Naturally Fractured Reservoirs The link between the elastic behavior of the rock and the recovery predictions in the material balance modeling resides in the effective compressibility term and the storage capacity ratio. Therefore, to model the effect of changes in stress due to changes in pore pressure in the fracture system, the general volumetric material balance equation must be modified using the correct effective compressibilities of the fracture rock. The general MBE, initially presented for homogeneous reservoirs by Schilthuis 1, has been improved by Chacon 2 to take into account changes and differences in fracture and matrix pore volume compressibilities in naturally fractured reservoirs.
Proceedings of SPE Asia Pacific Oil and Gas Conference and Exhibition, 2004
International Petroleum Technology Conference, 2007
... is a unique development which ties-back six small to medium-sized oil and gas ... Experiences... more ... is a unique development which ties-back six small to medium-sized oil and gas ... Experiences in the Use of Intelligent Well Technology to Improve Reservoir Management A. Chacon ... Data for Identifying Moving Interfaces In East Anstey, a single-well lean gas reservoir, downhole ...
Proceedings of Latin American & Caribbean Petroleum Engineering Conference, 2007
This paper analyzes the effect of stress on the rock properties fracture and matrix compressibili... more This paper analyzes the effect of stress on the rock properties fracture and matrix compressibilities, fracture and matrix porosities, and permeability in naturally fractured reservoirs (NFRs). In NFRs, fluids are stored inside the matrix pore space and inside the fractures of the rock. The reservoir characterization parameter indicating the volumetric fraction of fluids deposited inside the fractures is the storage capacity ratio, which is function of the fracture and matrix porosity, and fracture and matrix total compressibilities. Due to the difficulty to obtain these values, in reservoir engineering computations such as pressure transient analysis and reservoir simulation, among others, it is generally assumed that the matrix and the fracture total compressibilities are equal. This induces a big uncertainty in the estimation of the storage capacity ratio and leads to a wrong estimation of the volume of fluids inside the fractured rock. Changes in pore pressure due to production or injection of fluids affect the effective reservoir in-situ stress. The mechanical behavior of the fractured rock and its effects on the rock properties permeability, porosity and compressibility in the matrix and fracture frames are analyzed using the elastic properties bulk modulus and normal compliance of the fracture. These properties can be obtained from petrophysical core analysis or multi-component seismic interpretation, and linked to pressure transient analysis through the storage capacity ratio equation. A step-by-step procedure of the analysis is presented and illustrated with an example for quantifying the effects of changes in effective stress on the fracture and matrix compressibilities.
Proceedings of Latin American & Caribbean Petroleum Engineering Conference, 2007
In naturally fractured reservoirs (NFRs), current analyses for quantifying reserves based on the ... more In naturally fractured reservoirs (NFRs), current analyses for quantifying reserves based on the material balance equation (MBE) assume that fractured reservoirs behave similar to homogeneous reservoirs, which implies that the fracture and matrix pore volume compressibilities are equal. There is considerable evidence that such assumption is not always valid leading to wrong estimation of reserves. In order to overcome this deficiency a complete treatment of the material balance formulation for naturally fractured reservoirs is presented. The proposed general MBE takes into account the fact that fracture and matrix pore volume compressibilities are different. This equation is used to investigate the impact of pressure depletion on the estimation of oil in place and recovery factors. As results of this study, new equations to compute hydrocarbons originally in place in NFRs are developed for undersaturated and saturated reservoirs. New plotting schemes for the MBE involving the storage capacity ratio at initial reservoir conditions of fracture and matrix pore volume compressibilities are proposed. The capacity ratio is computed from pressure transient test performed during the early stages of production. These new plotting schemes requires only one regression parameter, the slope of a straight line passing through the origin on a Cartesian plot, which reduces the uncertainty that traditionally two regression parameters (intercept and slope) introduces; as consequence, better estimation of oil in place with fewer historical production data can be obtained. This new method is illustrated by several field examples. It is concluded that (a) the proposed material balance formulation gives better estimation of oil in place than the traditional MBE computations; (b) the split of hydrocarbons originally in place between fracture and matrix frames depends upon the storage capacity ratio at initial reservoir conditions and; (c) the impact of pressure depletion on the estimation of reserves and recovery factors in naturally fractured reservoirs is significant. Introduction This paper presents methods to quantify hydrocarbons in place and recovery factors taking into account the differences between fracture and matrix pore volume compressibilities, and their changes caused by pressure depletion for undersaturated and saturated naturally fractured reservoirs. Such methods are based upon the integration between pressure transient analysis and the material balance equation. For undersaturated reservoirs, the assumption that matrix and fracture pore volume compressibilities are equal leads to underestimations of the fractional recovery. For saturated reservoirs only negligible differences in estimation of reserves and recovery factors have been observed. The General Material Balance Equation for Naturally Fractured Reservoirs The link between the elastic behavior of the rock and the recovery predictions in the material balance modeling resides in the effective compressibility term and the storage capacity ratio. Therefore, to model the effect of changes in stress due to changes in pore pressure in the fracture system, the general volumetric material balance equation must be modified using the correct effective compressibilities of the fracture rock. The general MBE, initially presented for homogeneous reservoirs by Schilthuis 1, has been improved by Chacon 2 to take into account changes and differences in fracture and matrix pore volume compressibilities in naturally fractured reservoirs.