Fluid Characterization and Sampling
Operators need to obtain quality reservoir data across a multitude of conditions yet stay within budgetary constraints. Choosing the right wireline formation tester from the available options can help to meet operators’ specific needs, minimize risk and costs, and get the desired reservoir information.
Understanding pressure and fluid properties is a key factor for effectively producing a reservoir. Wireline formation testers can measure pressure and fluid mobility at different points in the reservoir to help operators understand production behavior. These testers can also flow reservoir fluid to measure fluid properties and capture samples for laboratory analysis.
Acquiring Formation Pressure Measurements in Challenging Borehole Conditions
Michael Piber, RAG RohC6l-Aufsuchungs Aktiengesellschaft; Sam Ash, Jeff Hemsing, and Robert Kuchinski, Weatherford
Horizontal and multilateral wells are being drilled as a cost-effective approach to increasing production and adding reservoir value. The data acquisition strategy makes extensive use of formation pressure measurements that are critical to the understanding of the economic potential of a reservoir. Conventional formation testing techniques have proven inadequate for determining producibility and formation pressures in horizontal and highly deviated wells due to high costs and extreme operational risks. In this paper, a low-risk solution is described for obtaining early-history formation pressures in these challenging borehole conditions using a very small sized formation tester combined with robust new operational planning, practices, and techniques. The Compact Repeat Formation Tester (MFT), of diameter approximately 2.4 inches, was deployed in memory mode and conveyed to test depth. Extensive operational planning and pre-job modelling were completed to allow for optimum data acquisition while minimizing total operation time. Well conditions prohibited the formation tester from providing real-time surface communication. The formation tester was programmed to accommodate as wide a range of test scenarios as possible. All tool data were stored in onboard memory for retrieval after the formation tester returned to surface. Twenty-two pressure stations were attempted in two wells to a depth of 2,250 m under borehole conditions where information is usually not attainable. The data obtained from the stations was of good quality, and the pressure results were subsequently confirmed by production. Several examples are presented to demonstrate that this new technique was successful in obtaining pressure data of highest quality and confidence, allowing reservoir insights that would otherwise have been unavailable. The ability to take pressures at multiple stations throughout the reservoirs has produced a detailed understanding of critical economic information. Further developments allow very near-time transmission of drawdown pressures back to surface to allow for instant analysis.
Leveraging Slim Hole Logging Tools in the Economic Development of the Ghawar Fields
I. Ariwodo, A.R. Al-Belowi, and R.H. Bin Nasser, Saudi Aramco; R.S. Kuchinski and I. Zainaddin, Weatherford
Traditionally, brown field developments have often required the plugback and sidetrack of existing drain holes to target any nearby opportunities. With advances in drilling technology, there is a general preference to drill small-diameter wells because of the comparative cost advantage. In the recent times, this preference has led some wireline service companies to start to offer openhole formation evaluation services with slim tools with diameters in the 2-in. to 2½-in. range. At present, most traditional petrophysical measurements can be acquired using slim tools. In addition, several "specialized” measurements, such as cross dipole sonic, formation pressure testing, and resistivity imaging, can also be acquired. The use of battery and memory technologies has allowed deployment of these tools using a broader range of conveyance techniques for reduced risk in the entry of slim wells. The provision of slimhole logging services has created an opportunity to leverage these tools for the economic development of brown fields. Therefore, short horizontal sidetracks and well re-entries to test deeper horizons can be drilled and logged successfully. Saudi Aramco has leveraged these tools in its continued development of the giant Ghawar field. Some of the development projects are listed below: Some horizontal sidetracks with 3-in. hole sizes have been drilled under higher doglegs than was previously possible and logged successfully. It is now possible to run well completions in newly drilled wells that have a well control problem. A provision is made to subsequently log these wells with slim wireline logging tools. It is now possible to run a complete suite of wireline logs across some old wells that were previously completed without a full formation evaluation logging suite. Slimhole formation resistivity imaging services are now being provided to aid in identification of borehole breakout and fracture features that might affect the well productivity. Slimhole formation pressure testing has been acquired in slim wells to generate a pressure gradient, determine oil mobility, and define oil-water contacts.
We offer several suites of wireline formation testers to meet your specific application needs.
Exploration or difficult technical conditions may call for the full-suite reservoir evaluation system (RES). For basic pressure and sampling on projects with tight economics, we recommend the flow rate tester (FRT) and Compact™ formation tester (MFT). For very small boreholes, poor hole conditions, or high fishing risks, our MFT has options that are not available with traditional formation testers. From our many options, you can choose the system best suited for obtaining the formation pressures and samples you need to better understand the dynamics of the reservoir.
Our Compact formation pressure tester (MFT) is the shortest, lightest, and slimmest sampling tool in the industry.
Unlike conventional sampling tools, the MFT can collect pressure, volume, and temperature (PVT) samples in slim holes. The slim design of the MFT enables the tool to pass through restrictions smaller than 3 in., yet it operates reliably in boreholes up to 14 in. in diameter.