Testing for Life

Abstract

Management Well testing provides answers you cannot get any other way. Whether testing is performed during exploration and appraisal, development, or production, it provides the greatest levels of security to support decisions—decisions that can affect the reservoir for its active life. At today's commodity prices, it has become increasingly important to differentiate reservoir description from reservoir characterization. Reservoirs can be described in many excellent and reliable ways: with seismic images, with geologic or petrophysical analyses using well data taken during drilling or logging, or by monitoring production parameters from nearby wells. These methods all tell what the reservoir looks like, but they do not tell how the reservoir will behave over time. Now, much more than simple reservoir description is possible. Today we can see the big picture, looking deep within the reservoir to get insights about the reservoir fluids and their dynamics. Reservoir characterization is about proving a reservoir's potential, confirming its performance, and improving its productivity. Testing accomplishes this by providing a better basis for all sorts of life-of-reservoir decisions, including how much to invest, where to place additional wells and how to complete them, how to enhance and sustain production, and how to minimize risk. Reservoir characterization is achieved by combining the best reservoir description parameters with reservoir behavior analysis derived from testing. Today's critical reservoir decisions demand the very best information available—saying "no" to testing is not an option. Testing transcends static well descriptive data by providing insights on what is going on between wells with analysis of pressure and flow under controlled conditions. Testing reacts to formation and fluid heterogeneities that are invisible to seismic and discontinuous between wells or levels. With modern testing analysis, heterogeneities can be characterized and their long-term effects predicted. Testing is Back, With Added Value The old days of the oilfield, with derricks and pumpjacks sprouting up everywhere, are over. Today, operators strive to drill fewer, but much better, wells. They take great pains to steer wellbores into the highest quality reservoir sections, to understand and exploit each reservoir compartment, and to maximize return on capital. To accomplish this requires accurate and timely information, and testing can provide the critical data to fill the gaps in the dynamic reservoir model. With accurate reservoir characterization, wells can be properly placed, completion intervals and techniques can be optimized, and productivity forecasts and decline curves can be more precise. Surface facilities can be properly scaled and reservoir drainage patterns can be better understood, leading to more effective injection programs.