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Cross discipline use of the Modular Formation Dynamics Tester (MDT) in the North Sea. John Costaschuk, Dann Halverson, Andrew Robertson Res. Eng. Petrophysicist Geologist. Content.
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Cross discipline use of the Modular Formation Dynamics Tester (MDT) in the North Sea John Costaschuk, Dann Halverson, Andrew Robertson Res. Eng. Petrophysicist Geologist
Content • Defining the Value of Information and the Functionality of the Modular Formation Dynamics Tester (MDT) • Examples of value creation within BP’s North Sea operations: • Summary and Conclusions A. Operational Value • B. Subsurface Value • C. Project Value InSitu Fluid Analysis (IFA) IFA & Asphaltene EoS Vertical Interference Test Acquisition of live microbial samples
Defining the Value of Information • Many E&P decisions are difficult to make, involving significant capital expenditure for uncertain gain. • Value enhancement comes from allowing more robust decisions to be made, as a result of more reliable forecasting of the uncertain parameters and outcomes. • Operational • Subsurface • Project • Value of Information (VoI) compares the value associated with a decision, informed with and without extra information. • The reliability of the additional data is crucial to understand.
The Functionalityof the Modular Formation Dynamics Tester (MDT) Reservoir Formation Reservoir Formation • Conventional openhole pressure data is difficult to interpret in some areas of the resource: • Depletion signal impacts interpretation • Low matrix perm in parts of the reservoir • Adding IFA* data increases reliability of the fluid interpretation: • Viscosity • Optical Density • Fluid Density • Resistivity Sample Chambers InSitu Fluid Analyser High Pressure Pump Focused Sampling Probe Large Diameter Probe Guard Fluid Analyser for focused sampling * (IFA) InSitu Fluid Analyser
Operational Value of MDT • Operational Value of IFA: • Rapid determination of fluid contacts • Allows on the fly programme modification • Allows on the fly well test design modification • Resultant time cost saving on data acquisition. • Conversely allows you to optimise a programme when you only have a very limited time window. • Recent appraisal experience: • The top ranked objective of a well was to confirm OIP by establishing FWL within the segment • It was critical to ensure that a reliable free water sample was captured before weather terminated the operation. A. Operational Value • B. Subsurface Value • C. Project Value Insitu Fluid Analysis (IFA) IFA & asphaltene EoS Vertical Interference Test Acquisition of live microbial samples
Operational Value of MDTIFA confirmation that well objective met • What is the critical time estimate for clean-up, before which quality samples can be taken? Is the rock of adequate mobility? • Should the sample point be re-placed along the open-hole environment and clean-up restarted? • Under poor weather conditions, when have the objectives been met, and thus can the run be terminated?
Operational Value of MDTIFA confirmation that well objective met Shut-in Resistivity Shut-in Density
Operational Value of MDTIFA confirmation that well objective met Well Objective (#1) • Confirm OIP by establishing FWL within segment. IFA Observation • FLOWING: Resistivity saturated up to 6900s, but after this resistivity drops in spikes: non-continuous water phase (droplet) becomes more continuous; relatively low viscosity bulk phase • SHUT-IN: After the pumps are stopped at 10600s two immiscible fluids appear to segregate in the flowline, and a water density is measured at the AFA sensor at the bottom of the flowline IFA Interpretation • Mixed flow of two immiscible fluids when sampling • Free water phase • Oil phase or mud filtrate Reliable Information
Subsurface Value of MDTIFA integration with lab and depletion data Reliable Information • Subsurface Value of IFA and asphaltene EoS: • Alternate matches to the petroleum system model • Connectivity and compartmentalisation • B. Subsurface Value A. Operational Value • C. Project Value IFA & asphaltene EoS Vertical Interference Test Insitu Fluid Analysis (IFA) Acquisition of live microbial samples IFA Data Pressure Data
Subsurface Value of MDTVertical Interference Test Data • Subsurface Value of Vertical Interference Test data: • Uncalibrated petrophysical model • DST test / no test decision required • Kh and Kv/Khuncertainty in missing core interval • B. Subsurface Value A. Operational Value • C. Project Value IFA & asphaltene EoS Vertical Interference Test Insitu Fluid Analysis (IFA) Acquisition of live microbial samples
Project Value of MDTAcquisition of live microbial samples • Project Value in acquisition of live microbial samples • Reduce uncertainty on reservoir souring mechanism and evaluate injection water design options • Recent appraisal experience: • A specialised bottle preparation and sample handling protocol has been developed between BP, OilPlus and Schlumberger • Pressurised water samples are not required for molecular work • Pressurised water samples are required for transferring and setting up the culture • After three months incubation of the pressurised culture no significant hydrogen sulphide generation was observed (multiple bottles for each penetration). • B. Subsurface Value A. Operational Value • C. Project Value IFA & asphaltene EoS Vertical Interference Test Insitu Fluid Analysis (IFA) Acquisition of live microbial samples
Summary and Conclusions • Operational Value of InSitu Fluid Analyser (IFA): • When and where to sample relative to well objectives • Subsurface Value of IFA & asphaltene Equation of State: • Alternate matches to the petroleum system model • Connectivity and compartmentalisation • Subsurface Value of Vertical Interference Test data: • DST test / no test decision • Kh and Kv/Kh in missing core interval • Project Value of acquisition of live microbial samples
Questions • Thank you for your attention and interest. Credit: Paul Roylance & Gavin Fleming (Operations Geologists) Ilaria de Santo & Jonathan Haslanger (Schlumberger) Keith Robinson & Richard Jonson (Oil Plus)