In this paper, the use of various measurements for performance evaluation of horizontal wells is presented. First, determining formation pressure and permeability distributiosn along the wellbore by using the Multiprobe Formation Tester Packer-Probe Module pressure transient interval tests are investigated. It is shown that reservoir pressure measurements along the wellbore give local as well as reservoir scale information about how the reservoir is being depleted and how cleaup takes place. A few interval pressure transient test examples are presented for both formation pressure and permeability distributions. Second, a horizontal well test interpretation is presented utilizing two buildup tests from the same well conducted at different times. It is shown that uniquely determining the reservoir parameters from short buildup tests is impossible. It is also shown that minimizing the wellbore storage effect is crucial for system identification as well as for parameter estimation. Third, the produtivity of horizontal wells is explored because it has been difficult to determine the horizontal well productivity due to their long length in the formation compared with vertical wells and inadequacy of measurements during drilling and production. Using field examples, we show that the new integrated production logging measurements can be used to assess horizontal well productivity by identifying productive zones, fluid entries, and determining the fluid distribution (oil, gas, and water) in the wellbore. We also show how reservoir heterogeneity affects the reservoir pressure distribution. The field examples indicate that hirizontal wells have permanent water sumps, regardless of whether they produce water. In these wells, we show that when a large percentage of the wellbore cross section is filled with water, reduced oil entry occurs. Performance simulations for these horizontal well indicate 30 to 50 percent productivity reduction when they are compared with their full potential.
展开▼
