Objectives and problems to be solved:
The hydrocarbon industry recognizes the need for information that will enable real-time reservoir management and optimisation of well productivity. Borehole seismic (e.g. crosswell, 3D-VSP) and Micro earthquake (Micro seismic) monitoring technology can provide continuous time-lapse information on reservoir processes that will improve reservoir knowledge and management. However a major barrier to the permanent deployment of seismic sensors has been the problem of flow induced acoustic noise in well completions. The objective of this research project is the fundamental physical/mechanical understanding of acoustic noise generation and transmission in flowing wells, enabling the development of practical solutions to the problem of permanent seismic sensor deployment in active hydrocarbon wells. The requirement is to separate the seismic signal, either physically or digitally, from the environmental noise while ensuring good coupling to the rock mass. The physical placement of the sensors with respect to the completion is therefore vital, as is the use of materials and structures in the engineering of the sensor mounting and deployment package. This research project will measure, characterize and understand the propagation of noise through the engineering structures present in a completion and then design and test measures to minimize this in the vicinity of the seismic sensors.
Description of work:
The project comprises three main research elements:
- Experimental investigations: A test borehole comprising a representative element of a well completion will be instrumented using seismic sensors coupled to the tubing, casing and surrounding rock. Propagation of acoustic noise through the structure and into the rock will be systematically characterized
.- Numerical modelling: Finite-element numerical modelling of the completion structure and flow conditions will be used to gain further understanding of the noise propagation mechanisms and the coupling between produced fluids and mechanical vibrations.
- Testing of noise amelioration measures: An experimental sensor package and noise amelioration measures will be designed, tested and characterized. This will lead to the definition of an optimal seismic sensor deployment methodology for oilfield operations.
Expected results and exploitation plan:
The overall result of the research will be proven technology/techniques that can be used in the demonstration of a permanently deployed borehole seismic sensor system.
The specific results and milestones are;
- Definition of the key parameters affecting acoustic noise generation/transmission
- Borehole acoustic noise waveform characterisation
- Predictive modelling tools for assessment and amelioration of acoustic noise
- Definition of noise management techniques
- Specifications for seismic sensor deployment methodology and specifications. The results of the project will be exploited by the industrial partners of the Consortium. In addition, the Consortium policy will be to grant licences against such patents insofar as this does not in any way adversely impact the business interests of the Consortium.
The key technical achievements of the project have been:- Construction and instrumentation of an inclined test well experimental system simulating live oil wells- Flow testing and noise characterisation to flowrates of 30,000 bbls/day- Design & testing of a prototype seismic sensor package that has 30-40 dB better noise rejection than current commercial systems - Sound Path Diagram construction and analysis for well completion and sensor assemblies - FE Numerical modelling based on the waveguide approach. The overall results of the research have been proven technology/techniques that are now being used in the permanent deployment of borehole seismic sensor systems.
The specific milestones have been: - Definition of the key parameters affecting acoustic noise generation/transmission - Borehole acoustic noise waveform characterisation - Predictive modelling tools for assessment and amelioration of acoustic noise - Definition of noise management techniques - Specifications for seismic sensor deployment methodology. The results of the project are now enabling the commercial exploitation of seismic monitoring technology in active hydrocarbon and geothermal wells.
Funding SchemeCSC - Cost-sharing contracts
AB25 1XX Aberdeen
2628 CK Delft