The Problem:

Produced water contributes to high operating expenses for oil producers. Excessive water production also results in many wells and fields being suspended and abandoned, despite the fact that significant volumes of oil are still being produced. The Canadian oil industry produces, on average, almost six cubic meters of water for every cubic meter of oil. Although some wells can be produced economically with water to oil ratios of over 100 with conventional production methods, most wells currently become uneconomic at ratios as low as 10:1 or 20:1 due to the lifting and water handling costs. 
 

C-FER's Solution

C-FER's patented Downhole Oil/Water Separation (DHOWS) technology refers a process that uses liquid/liquid hydrocyclones and conventional artificial lift methods to achieve downhole oil/water separation to produce the oil (with a fraction of produced water) while re-injecting over 90% of the produced water within the same wellbore.  Systems have been developed utilizing ESP, PCP and Rod Pump and Gas Lift systems as shown below.

C-FER developed of the DHOWS technology through a Joint Industry Project (JIP) with over 39 operating and vendor companies.  The culmination of this was the commercial realization of the ESP variant within the relatively short period of time of just over three years.  The technology related to the combination of hydrocyclones with any pumping system driven by an electrical submersible motor (i.e., ESP and ES-PCP) is licensed to Schlumberger/REDA and Baker Hughes Inc./Centrilift.

The economic justification for the system implementation can come from any one of the following conditions:

Physical Setup

• Increased Oil Production: high water cut wells can be drawn down further without taxing surface facilities, shut-in wells can be reactivated and, for production and injection zones in pressure communication, same well re-injection may alter near wellbore flow profiles, providing oil production from previously unswept areas of the reservoir;
• Optimization of Surface Facilities: installing the DHOWS system in the highest water cut wells can free up surface facility capacity (power and water treatment) to allow for increased production from other wells;
• Water Handling Savings: reduction in water associated treatment costs (corrosion, scale, etc.), reduction in capital expenditures associated with the construction of expanded surface facilities to handle increase water, and reduction in the environmental liability associated with handling large volumes of contaminated fluids at surface;
• Increased Economic Recoverable Reserves: Wells which are uneconomical at a relatively low producing WOR (e.g., WOR of 20) may now be economically produced to a WOR of 100 or more; and
• Increased Economic Recoverable Reserves: Power Savings: a reduction in the power needed to produce higher fluid rates in watered out wells and in the power consumed by water disposal pumps.

The development of the DHOWS technology evolved from a three phase JIP organized by C-FER:

Phase I: Concept Generation and Feasibility Study

This phase involved a feasibility study initiated in 1991 to investigate non-conventional means to reduce oil well lifting and water handling costs by reducing the volume of water produced to surface. The methods assessed included membranes, selective filtration, gravitational and kinetic separation techniques (hydrocyclones, centrifuges). Of these, static liquid/liquid hydrocyclones were determined to have the best potential from a practical - hardware and economic - view point;

Phase II: Prototype Equipment and Further Concept Development

In this phase, methods were developed for combining hydrocyclone separators with three different pumping systems [electric submersible pump (ESP), progressing cavity pump (PCP), and beam pump] and prototype designs were completed by selected innovative, well established component manufacturers; and

Phase III: Prototype Separator System Field Trials

This phase consisted of full scale laboratory testing and field trials of the three prototype DHOWS systems (ESP, PCP, and Beam) designed and fabricated in cooperation with and through the in-kind support of the component manufacturers.

In addition to the potential major impact the technology has on conventional production, the JIP approach to the study has resulted in many benefits for the Participants, including:

• Evolution of prototype separation systems from a conceptual stage to commercial application within a three year period;
• Technology management, development and reviews conducted by C-FER, an independent third party, with input from the Participants as well as pump and hydrocyclone vendors;
• Vendor subsidized design and fabrication of three system prototypes;
• Shared risk for Participants’ investments through jointly funded development and prototype field trials (installation, data acquisition, analysis and reporting);
• Participant preferred customer status with the licensed vendors;
• C-FER support for technology implementation into Participant field applications;
• Opportunity to influence the direction of future technology development;
• Ongoing monitoring of field installations and technology developments by C-FER, the results from which are shared among the Participants.

By the completion of the project in 1997, an estimated total of C$9,500,000 had been expended through project-related work including the tasks completed by C-FER, the in-kind support received from pump and hydrocyclone vendors for prototype development, and the expenditures made by project participants in conducting 17 commercial field trials of the various systems over three years of the JIP.

C-FER has continued to further develop the technology with improvement for handling Sand and DHOWS systems for application to Gas-Lift wells.

For more information on the project and implementation support, contact:

Contact: Kelly Piers, Manager, Production Operations

Tel: 780.450.8989 x246