Oilfield Reservoir Testing

One of the most valuable tools for oilfield reservoir engineers is well testing. Without it, a company cannot know whether a pump is working properly or what its optimum output could be. Well tests provide critical data that confirm or adjust reservoir model parameters and help identify underlying problems. They are a crucial part of the process for estimating reserves and planning future operations, but they can also reveal important information at the exploration stage. For example, if a well has low flow rates, a test can determine if these are caused by skin or natural permeability, which allows operators to take corrective action or plan for a treatment that will improve production.

During a test, technicians flow reservoir fluids to the surface through a packer-isolated zone or a drillstem test (DST) string. They then record the light reflected from the sampled fluids using optical spectroscopy to monitor the composition in real time. This allows engineers to make informed decisions on field activities before they are able to analyze samples in the lab, which saves time and money.

The type of test that engineersĀ http://theinscribermag.com/how-tara-oilfield-services-delivers-customized-solutions-in-production-testing conduct depends on their objectives, but some common tests include buildup, drawdown, injection and interference. In buildup tests, engineers open the well for a period of time and observe the increase in bottomhole pressure (BHP). For drawdown tests, they shut in the well for a specified duration and measure the resulting decrease in BHP. During injection and falloff tests, engineers inject or withdraw fluids from the formation while monitoring adjacent observation wells. The time it takes for changes in the test well to affect pressures in observation wells provides engineers with an indication of reservoir size and flow communication.

These tests can also reveal the extent of damage to the formation induced by drilling and other well operations. Engineers use the results of these tests to determine permeability, which can then be used to evaluate the performance of wells and estimate reserves. This information is particularly valuable at the exploration stage when deciding whether to invest in a project that has potential for commercial success, or to abandon it if the permeability cannot support a viable reserve estimate.

As a producer matures, reservoir testing plays an increasingly important role in optimizing production. By identifying a well’s potential and developing effective completion strategies, engineers can ensure optimal productivity and maximize the value of the assets. This requires accurate measurements of the composition and physical properties of the reservoir fluids, which are essential to reservoir modeling. Consequently, a key goal of the production phase is history matching-comparing actual production with predicted production, which is possible only when data from all wells in the field are available. Moreover, well-integrated PVT studies allow engineers to determine the physical and chemical behavior of a reservoir fluid versus its temperature and pressure changes in the wellbore. This information helps them develop and execute field development plans and to make decisions on capital expenditures.