簡介：油藏測井，實現(xiàn)精確地層描述，達到地層產(chǎn)能最大化。來自眾多國家和地區(qū)的代表齊聚馬來西亞，發(fā)表油藏描述高見，并研究提出新的測試技術(shù)。
Recognizing that step changes in oil and gas recovery can only be achieved through analogous step changes in reservoir understanding, a recent SPE Applied Technology Workshop aimed to explore the limits and new promises in reservoir testing.

The May 2009 workshop, titled “Reservoir Testing for Maximizing Understanding and Recovery,” gathered more than 60 participants from 18 countries to Kota Kinabalu, Sabah, Malaysia to review different reservoir-testing and fluid-sampling technologies aimed at providing more detailed subsurface information which will ultimately lead to improved recovery.

The participants represented both service and operating companies and had an average of 15 years experience, a point which Tuan Haji Akbar Tajudin Abdul Wahab, senior general manager, Petroleum Engineering Department, Petronas Carigali, acknowledged in his keynote address. He said that collectively there were nearly 1,000 years of wisdom in the room.

Wahab used his keynote to challenge the use of the term “well testing,” suggesting that it fails to capture the diversity of testing available to the industry today. He proposed that it is time to expand the scope of reservoir testing to cover new technologies, and that new ways of working should be developed to allow an optimal use of new technology with the resources. He also emphasized the need to properly integrate reservoir test results into reservoir models, which can be assisted by proper test planning and design. Not only can the value of the reservoir information be better assessed with proper planning, but it may help avoid unnecessary tests and bring innovation back into reservoir testing.

New Technologies, Improved Reservoir Characterization 

In the session titled “Applications of New Technologies,” discussion leaders (DLs) reviewed new methods to collect data cost-effectively and ways to maximize the utility of the information collected. The DLs discussed alternative ways of analyzing large data sets from permanent sensors and the long-term reliability of hardware, such as logging-while-drilling tools, in providing fluid samples that could accurately characterize formation properties. The last DL examined smart-well technologies, demonstrating how these could be useful additions to not only production and recovery optimization, but also in providing greater flexibility in testing at all stages of a well’s life.

The next session reviewed methods to improve reservoir characterization, and included topics ranging from improving test design to the inclusion of test data into 3D reservoir models and holistic reservoir testing with 4D seismic. A lively discussion on test design asked the question of whether it is the operator or the service company who has rightful ownership of the design step.

A geologist’s viewpoint on the critical importance of communication and consistent terminology among engineers was presented, followed by a review of the value obtained from understanding reservoir connectivity using 4D seismic. The information and insight provided by 4D seismic most likely would not be obtainable from other techniques; in one instance, previous assumptions regarding faults in a reservoir were found to be incorrect once new insight was gained by 4D seismic. This led to a different development option?the use of smart wells to counter the different zones on either side of the fault.

Breakout Session 

Attendees assembled into groups for a breakout session designed to generate discussion on the relative importance and potential of various reservoir-testing technologies.

The first group began by asking “Is there life in reservoir testing?,” and the resounding answer was yes. As the E&P industry moves to higher-cost reserves, the group felt that greater emphasis must be placed on design to ensure that maximum reservoir value can be derived. They also stressed that with CO2 sequestration becoming a higher priority, testing methods will need to evolve to ensure a long-term seal of the cap rock. The group also pointed to near-future developments, such as smart completions for reservoir health checks, advanced deconvolution techniques that allow high-frequency pressure and rate data to be used, and incorporating 4D seismic and other remote-sensing techniques.

Another group compared deconvolution techniques with production-data analysis, with a great deal of discussion focused on what could and could not be achieved with both techniques today. In examining both the historical and current advantages and disadvantages of these approaches, the group expressed confidence that rate deconvolution techniques will become more widely applied in the future, particularly as further advances are made in instrumentation and downhole meters.

A third group postulated on where testing techniques and technologies will be 10 years in the future. The group discussed how issues of constrained supply vs. demand?in both hydrocarbons and oilfield personnel?were driving the development of remote, intelligent tools and systems that make their own decisions downhole. As energy demand grows and forces the world to rely more heavily on difficult-to-extract hydrocarbons and aging reservoirs, downhole tools and testing techniques will need to keep evolving toward more expert systems and tools that can successfully operate in greater pressures and temperatures. Assuring this development will require that all parties successfully address the perennial issue of more open relationships between service companies and operators.

In keeping with the keynote speaker’s idea to coin new terminology for well-known issues, the last group suggested that the term “unconventional” should be expanded to include any hydrocarbon resource that was marginally economic. The issue of a lack of tools available to test low-permeability, deep heavy-oil reservoirs was raised as well, with group members recalling personal instances in which their field engineers were forced to use conventional tools in these reservoirs, resulting in less than satisfactory results. An interesting observation noted that the size of many regional operators undertaking unconventional production projects is relatively small, making them less likely to embark on large, expensive testing programs before implementing phased development strategies.

Analysis Techniques 

A session on analysis techniques began with a lively presentation on the current status and limitations of multiwell deconvolution. The consensus of this discussion was that the uncertainties in all but the most homogeneous of reservoirs will limit the applicability of this analytical solution any time soon. The second presentation examined using similar deconvolution techniques to highlight wells that fall outside certain inter-related operating boundaries. For example, one technique has been used in North America to ease the burden of a surveillance engineer who is charged with monitoring more than 300 wells from his office.

The challenges of monitoring and improving the understanding of a large multilayered gas field were discussed next, including the complexities of commingled production?with different wells commingling in different zones. Adding to the challenge of understanding what any well pressure measurement actually means is the fact that crossflow has been observed in some instances under producing conditions. A thought-provoking discussion followed on the possibility of using in-situ temperature sensors or techniques such as geochemical fingerprinting to constantly assess zonal contributors.

Advancements in wellsite pressure/volume/temperature analysis were also reviewed. Particular attention was paid to its advances in recent years, as the technique now allows almost every test to be conducted, on a reasonable sample size, at the wellsite rather than having to transfer and send samples to the lab onshore. A discussion on the portable laboratory’s limitations concluded that now only advanced studies such as minimum miscibility pressure would require samples to be sent back to more advanced laboratories.

An open-floor session closed out the workshop, with discussion focused on how to justify a test program under current global economic conditions. While this was initially heavily weighted toward the face value of the investment, discussion soon expanded to envisioning how a technology might enhance the probability of success, and how earlier involvement from service companies can help ensure that the right test design is in place at the outset to collect the desired information.