Energy Policy Act of 2005 (Ultra-deepwater and Unconventional Resources Program)
Improvements to Deepwater Subsea Measurements
The Letton-Hall Group, LLC, Houston, TX 77057
Oceaneering, International, Inc., Houston, TX 77041
Multiphase Systems Integration, LLC, Tulsa, OK 74135
axept, Inc., Palo Alto, CA 94301
The project consists of six distinct tasks as described below. For each task are shown the name of the task, its objectives, a description of the project, its potential benefits/impact, and the major participants.
Deepwater Subsea Sampling -
The goal of this task is to develop hardware and procedures that allow an ROV-based mechanism to collect a sample at the wellhead, and to document the work so that standards for the pieces can be adopted. Prototypes will be built, then tested at the surface and in simulation (underwater) tanks. Success will greatly aid reservoir understanding, as well as improve well head metering accuracy, resulting in better recovery of oil and gas. Major participants will be the LHG and Oceaneering International (OII)
ROV-Assisted Subsea Measurement -
The goal of this task is to develop and prove methods for conveying a clamp-on meter to the sea floor by ROV, and there taking measurements that indicate flow rate. The pieces will be documented as drafts of future standards. Meters/sensors will be marinized for prototype demonstration in surface flow loops and in simulation tanks. If the measurements prove useful, flow rates from individual wells will be known more accurately, thus reducing risk to both producers and to the US government and improving reservoir recovery. Major participants will be the LHG and Oceaneering International (OII).
HP/HT Qualification -
The goal here is to make available for extreme (high-pressure, high temperature) subsea production the sensors needed, which due to small numbers might not be developed through commercial-only forces. The key element needed is a combination pressure-differential pressure (P-DP) sensor that can be used at pressures and temperatures that are far higher than current standard conditions. The benefit from this work is the ability to measure flow in these hugely important HP/HT fields, thus permitting accurate revenue/royalty allocation and improved recovery. LHG and axept are the participants in the development.
Evaluation of Flow Modeling -
Meters that use collections of pressure and temperature sensor data in lieu of a physical multiphase flow meter are Virtual Flow Meters (VFM). A thorough test of commercial VFMs is the goal of this task, with a report that rigorously evaluates them. The desired outcome is greater use of VFM in situations where they are appropriate, e.g. backup of primary physical meters on wells. The main participant is Multiphase Systems Integration (MSI).
Meter Fouling Effects -
The goal of this task is a greater understanding of the effects on meters of principal kinds of fouling – scale, wax, and erosion. Two kinds of meters will be tested at various stages of fouling in various simulated production (multiphase) conditions. The benefits from this knowledge are models which predict the effects on meter readings of common fouling mechanisms and thereby improve accuracy.
Metering System Uncertainty -
The intent of this task is to develop a “tool” that will give users the ability to calculate the uncertainty in measurement at the subsea meter, at the separator topside, and at other points in between. Merging carefully developed models of multiphase flow with separator and meter models in a unified system will result in a useful tool for the production engineer. The primary participants in the work will be MSI and the LHG.
Five of the six technical tasks are due for completion within 24 months from start. ROV-Assisted Measurement has a 30-month duration, as will a seventh task, Technology Transfer.
Principal Investigator: Winsor Letton, Ph.D.