Well test
- Overview. Most well tests consist of changing the rate, and observing the change in pressure caused by this change in rate.
- History
- Purpose. Identifying heterogeneities and boundaries. ...
- Change in rate
- Types. ...
- Functions
- Features
- Other considerations
- References
- Noteworthy papers in OnePetro. ...
What is a “well test?
A “well test” is simply a period of time during which the production of the well is measured, either at the well head with portable well test equipment, or in a production facility. Most well tests consist of changing the rate, and observing the change in pressure caused by this change in rate.
Why is it important to test your well?
Accurate testing and competent reading of the results can help improve efficiency and provide vital information for managing your operation. Each test is used for a specific purpose, so understanding how each works and what exactly is being tested is also important. Before a well can be tested, it needs to be prepared.
What data is collected during a well test?
Data gathered during the test period includes volumetric flow rate and pressure observed in the selected well. Outcomes of a well test, for instance flow rate data and gas oil ratio data, may support the well allocation process for an ongoing production phase, while other data about the reservoir capabilities will support reservoir management.
What is well testing in petroleum industry?
In the petroleum industry, a well test is the execution of a set of planned data acquisition activities. The acquired data is analyzed to broaden the knowledge and increase the understanding of the hydrocarbon properties therein and characteristics of the underground reservoir where the hydrocarbons are trapped.
How is a well test performed?
0:337:39Well Testing - YouTubeYouTubeStart of suggested clipEnd of suggested clipThe first stage of a well test is to run a drill stem text or DST string with tubing conveyedMoreThe first stage of a well test is to run a drill stem text or DST string with tubing conveyed perforating guns. Using high penetration link debris charges gauge carrier with complete memory and
What is a well productivity test?
1. n. [Production Testing] Tests in an oil or gas well to determine its flow capacity at specific conditions of reservoir and flowing pressures. The absolute open flow potential (AOFP) can be obtained from these tests, and then the inflow performance relationship (IPR) can be generated.
What is included in a well test?
These tests could include testing for lead, arsenic, mercury, radium, atrazine, and other pesticides. You should check with your local health or environmental department, or the EPA to find out if any of these contaminants are a problem in your region.
What is Surface well testing?
Surface well testing is the only technique available today that assesses the true reservoir potential at full scale under dynamic conditions. It validates well performance during cleanup and commissioning and provides reservoir monitoring for better field management.
What are the types of well testing?
TypesFlow test. ... RFT. ... Drill-Stem test. ... Drawdown test. ... Multirate tests. ... Production test. ... Buildup test. ... Banker's Test.More items...•
How is well capacity measured?
Turn on the well pump. Measure the flow rate as the time it takes to fill up the 5-gallon bucket. Discharge water at a rate of five gallons per minute for two hours (for a total of 600 gallons) or discharge water at a rate of four gallons per minute for four hours (for a total of 900 gallons).
Why is it important to test water quality?
Regular testing is important to: identify existing problems. ensure water is suitable for the intended use, especially if used for drinking by humans and animals. track changes over time. determine the effectiveness of a treatment system.
How often should a well be serviced?
An annual well maintenance check, including a bacterial test, is recommended. Any source of drinking water should be checked any time there is a change in taste, odor or appearance, or anytime a water supply system is serviced.
What is the best way to test well water?
Often county health departments will help you test for bacteria or nitrates. If not, you can have your water tested by a state certified laboratory. You can find one in your area by calling the Safe Drinking Water Hotline at 800-426-4791 or visiting www.epa.gov/safewater/labs.
What is DST in oil and gas?
A drill stem test (DSTdrill stem test) is a temporary completion of a wellbore that provides information on whether or not to complete the well. The zone in question is sealed off from the rest of the wellbore by packers, and the formations' pressure and fluids are measured.
How do you do a well drawdown test?
Use one of the methods described in Chapter 2 to find the depth to water.Step 1: Find the static level. Manually turn off the pump.Step 2: Find the pumping level. Turn on the pump. ... Step 3: Calculate the drawdown. Calculate the drawdown by subtracting the static level from the pumping level.
What is well test data?
Well test analysis provides information on the reservoir and on the well. Geological, geophysical and petrophysical information is used where possible in conjunction with the well test information to build a reservoir model for prediction of the field behavior and fluid recovery for different operating scenarios.
What is isochronal well test?
The isochronal test is a series of single-point tests developed to estimate stabilized deliverability characteristics without actually flowing the well for the time required to achieve stabilized conditions at each different rate.
What is the purpose of drill stem test?
A drill stem test (DST) is a method of formation evaluation. The test allows fluids in the formation being evaluated to flow into the drill stem and to the surface. Pressure-recording devices in the drill stem test tool measure and record pressure in the well while it is both flowing and not flowing (shut in).
What is the purpose of a well test?
Well tests provide information about reservoir continuity, flow capacity, and pressure distribution. Figure 8.3 is a typical Horner plot for wells in the Valley Fill study. Table CS.8A is a tabulation of shut-in pressure versus time data for the pressure buildup test. The PBU test used a production period of 24 hours at a stabilized flow rate of 100 STB/D in a well with inner radius of 0.25 feet.
What is well testing?
Well testing is one of the most valuable tools used by reservoir engineers. It is routinely used to evaluate well and field performance, diagnose reservoir characteristics, integrate test results with other studies, plan for future development, and perform the overall management of the reservoir.
When offset wells are producing and interfere with the testing well, the PBU derivative curve of the testing well will gradually?
Therefore, when the offset wells are producing and interfere with the testing well, the PBU derivative curve of the testing well will gradually “downwarp” in the middle and late stages , and the “downwarping ” speed depends on the dimensionless rate ∑ j = 2 X q j D of the affecting offset wells and the ratio Δ t D t pD of shut-in time to production time, as shown in Fig. 3.18.
Is multilayer test widely applied?
In well testing, the multilayer test is widely applied. However, will the corresponding pressure buildup data show the multilayer characteristics? On the other hand, if we apply a single layer test, will the pressure buildup data not show the multilayer features? For both questions, empirical data shows that the answer can be negative. The following is true:
What are the problems with well water?
There are known problems with well water in your area. You have experienced problems near your well (i.e., flooding, land disturbances, and nearby waste disposal sites) You replace or repair any part of your well system. You notice a change in water quality (i.e., taste, color, odor)
What to do if your water test says germs?
Please remember that if your test results say that there are germs or chemicals in your water, you should contact your local health or environmental department for guidance in interpreting the test.
What does it mean when you have a positive E. coli test?
Fecal coliforms and E. coli are usually harmless. However, a positive test may mean that feces and harmful germs have found their way into your water system. These harmful germs can cause diarrhea, dysentery, and hepatitis.
What is a nitrate test?
A nitrate test is recommended for all wells. If the nitrate level in your water is higher than the EPA standards, you should look for other sources of water or ways to treat your water. Volatile Organic Compounds (VOCs) VOCs are industrial and fuel-related chemicals that may cause bad health effects at certain levels.
What VOCs to test for?
Some VOCs to ask about testing for are benzene, carbon tetrachloride, toluene, trichloroethelene, and methyl tertiary butyl ether (MTBE).
What are some examples of water quality indicators?
Examples of Water Quality Indicators: Total Coliforms. Coliform bacteria are microbes found in the digestive systems of warm-blooded animals, in soil, on plants, and in surface water. These microbes typically do not make you sick; however, because microbes that do cause disease are hard to test for in the water, “total coliforms” are tested instead.
Does the EPA protect public water?
The U.S. Environmental Protection Agency’s (EPA) rules that protect public drinking water systems do not apply to individual water systems, such as privately owned wells. As an individual water system owner, it is up to you to make sure that your water is safe to drink.
What is a well test?
A “well test” is simply a period of time during which the production of the well is measured, either at the well head with portable well test equipment, or in a production facility.
What is the purpose of the reservoir property test?
This test is designed to give large-scale reservoir property trends which can give improved estimates of directional permeability and reservoir storativity.
What is RFT in wells?
RFT. To check pressure equilibrium and thu s homogeneity wells can be tested using wireline-conveyed tools, either in casing or open-hole. These tools include RFT, MDT, etc. and are typically run to the desired depth before actuating levers or other devices seal them against the side of the wellbore.
What is production test?
A production test is just like a drawdown test, except that it is generally run for a longer period of time.
What is drawdown test?
A drawdown test is one in which the rate is held approximately constant while the well pressure is measured. Shut in the well till pressure reaches static level and then flowing the well at a constant rate ,q & measuring Pwf .
Do you test a well before drilling?
In newly developed reservoirs or high-risk developments it may be worthwhile to test the well before completing it or installing full production facilities. This is usually done with a drilling rig on-site, and the string through which the well is produced is manipulated by the drilling rig.
What is the objective of a well test?
The overall objective is identifying the reservoir's capacity to produce hydrocarbons, such as oil, natural gas and condensate .
What is well test?
In the petroleum industry, a well test is the execution of a set of planned data acquisition activities. The acquired data is analyzed to broaden the knowledge and increase the understanding of the hydrocarbon properties therein and characteristics of the underground reservoir where the hydrocarbons are trapped.
How to determine flow rate of a well?
Regularly, for example once a month per well, the flow from one and only one selected well is led into the test separator for determining well flow rate for the selected well. The separator divides the flow from the well into the streams of individual products which typically are oil, gas and water, but may include natural-gas condensate. Contamination may also be removed and fluid samples collected. This helps to allocate individual flow rate contributions, but the method has uncertainties. Flow rate, water cut, GOR and other parameters for the test system can deviate from production separators. This is generally taken into account by the allocation of products back to individual wells based on the field total, and by using data from the individual well tests.
What are the two main categories of well tests?
There are many flavours of well tests and various ways to categorize test types by its objectives, however two main categories only by objectives, these are productivity tests and descriptive tests. According to The Lease Pumper’s Handbook of Oklahoma Commission on Marginally Producing Oil and Gas Wells, ...
What data is collected during a well test?
Data gathered during the test period includes volumetric flow rate and pressure observed in the selected well. Outcomes of a well test, for instance flow rate data and gas oil ratio data, may support the well allocation process for an ongoing production phase, while other data about the reservoir capabilities will support reservoir management.
Why is it important to know the contributions of individual wells?
It is important to know the individual contributions to account hydrocarbon material balance and for well monitoring and reservoir management.
How do test objectives change?
Test objectives will change throughout the different phases of a reservoir or oil field, from the exploration phase of wildcat and appraisal wells, through the field development phase and finally through the production phase, which may also have variations from the initial period of production to improved recovery by the end of the field lifecycle time.
Why is it important to test a well?
Accurate testing and competent reading of the results can help improve efficiency and provide vital information for managing your operation . Each test is used for a specific purpose, so understanding how each works and what exactly is being tested is also important.
What is the purpose of a well pressure test?
The name pretty much says it all. This test determines the ratio of oil and gas being produced from the well. This can be useful information for a number of reasons, but it’s particularly important as too high a percentage of gas can lead to a drop in reservoir pressure. That can have a wide impact on the production of any wells drawing from the same reservoir.
What does it mean when a well is normalized?
It seems like this should be fairly straightforward; hopefully wells are operating at ‘standard’ production rates most of the time. However, that does mean the well can’t be experiencing any reductions in production from faulty equipment, mis-set valves, and other common problems. If the production measured after normalizing isn’t close to the estimated production, it can mean that there is a problem somewhere.
What does normalizing a well mean?
Normalizing a well merely means that it is operating and producing in a standard way for that well, and has been doing so for at least 24 hours. When tests need this sort of preparation, you’re usually measuring, in some way, how the well is performing on a regular basis.
How long should a well head be shut off?
The standard shut-in time is at least 24 hours before you plan the test. However, that time period can vary, depending on the behavior of the well.
What is the purpose of a productivity test?
This test covers the most area, with the goal of discovering how to produce the most oil while not reducing the well’s producing life. The idea is to operate the well in with few different ‘standard’ setups, and then measure the output of each. For productivity tests, you’ll usually need to normalize the well.
What is a daily well test?
The daily test is fairly straightforward, and is used to determine the normal daily production of a well . The daily test is run on the same day every month, and a record is kept to track this amount over the long term. As you’re trying to determine standard production, the well should be normalized before the test.
What is a well flow test?
A true well flow test or well draw down test will discover the ability of the well to deliver water, without confusion caused by the characteristics of the building's own well pump, pump control, water pressure tank, water piping, or fixtures.
What about testing water flow and pressure from a well by using a flow gauge attached to a faucet?
What about testing water flow and pressure from a well by using a flow gauge attached to a faucet? This is a "for show" measurement, not a real one - it is simply very inaccurate.
What is a Reasonable Water Flow Rate in a Building?
Subjectively, we should be able to go to the highest bathroom or other plumbing facility in the building and run two fixtures simultaneously, seeing a reasonable water flow in which one could shower or wash. If you turn on the top floor shower and then open a sink faucet and you see the shower slow to a trickle, the building water pressure is unacceptable.
How long does it take for a well pump to work?
The inspector can vary the rate at which the pump draws water out of the well in order to determine the rate at which the well can deliver a sustained water flow rate or quantity over a measured time period, usually several hours, typically 3 hours or 4 hours, and in some cases over 24 hours.
What is the water pressure of a well?
The water pressure at a fixture served by a private well, pump, and pressure tank, will normally vary between the pump cut-in pressure (typically 20 psi or 30 psi) and the pump cut out pressure (typically 40 psi to 50 psi or a little higher).
Is it ok to waste well water?
Provided the home, community, and season are not in a time or area of drought and water shortage, it is reasonable to "waste" some well water for the benefit of the chance of discovery of a very important and costly water shortage at the individual well being tested.
Can you check if a well is insufficient?
But there are some steps that an amateur can take first to check on the well water quantity. In fact it's possible use mere visual inspection to form a reasonable suspicion that a building has insufficient well water before testing anything.
What is the purpose of pumping tests?
The goal of a pumping test, as in any aquifer test, is to estimate hydraulic propertiesof an aquifer system. For the pumped aquifer, one seeks to determine transmissivity, hydraulic conductivity(horizontal and vertical) and storativity(storage coefficient). In layered systems, one also uses pumping tests to estimate the properties of aquitards(vertical hydraulic conductivityand specific storage). Pumping tests can identify and locate recharge and no-flow boundariesthat may limit the lateral extent of aquifers as well.
What is pumping test?
A pumping testis a field experiment in which a well is pumped at a controlled rate and water-level response (drawdown) is measured in one or more surrounding observation wells and optionally in the pumped well (control well) itself; response data from pumping tests are used to estimate the hydraulic properties of aquifers, evaluate well performance and identify aquifer boundaries. Aquifer testand aquifer performance test(APT) are alternate designations for a pumping test. In petroleum engineering, a pumping test is referred to as a drawdown test.
What is a constant rate pumping test?
This is the most commonly used pumping test method for obtaining estimates of aquifer properties.
Why terminate pumping test?
The decision to terminate a pumping test is best made on the basis of hydrogeologic conditions at the test site and the objectives of the test. Longer tests may be necessary to estimate specific yield in an unconfined aquifer or to observe boundary effects.
What is the tolerance for pumping rate?
USBR (1995)suggests a tolerance of ±5% for the pumping rate. State and local regulations may offer additional guidance regarding an acceptable tolerance for rate variation during a pumping test.
What is recovery test?
Although often interpreted separately, a recovery test is an integral part of any pumping test.
When to use barometric sensor?
For any pumping test, an on-site barometric sensoris recommended in the event that water levels require correction for barometric efficiency .
Overview
- Most well tests consist of changing the rate, and observing the change in pressure caused by this change in rate. To perform a well test successfully one must be able to measure the time, the rate, the pressure, and control the rate. Well tests, if properly designed, can be used to estimate the following parameters: 1. Flow conductance 2. Skin fact...
Purpose
- Exploration wells
1. Fluid sampling (Primary reason) 2. Measuring the initial pressure 3. Estimating a minimum reservoir volume 4. Evaluating the well permeability and skin effect 5. Identifying heterogeneities and boundaries. - Producing wells
1. Verifying permeability and skin effect 2. Identifying fluid behavior 3. Estimating the average reservoir pressure 4. Confirming heterogeneities and boundaries 5. Assessing hydraulic connectivity.
Types
- Flow test
A Flow test is an operation on a well designed to demonstrate the existence of moveable petroleum in a reservoir by establishing flow to the surface and/or to provide an indication of the potential productivity of that reservoir. Some flow tests, such as drill stem tests (DSTs), are perf… - RFT
To check pressure equilibrium and thus homogeneity wells can be tested using wireline-conveyed tools, either in casing or open-hole. These tools include RFT, MDT, etc. and are typically run to the desired depth before actuating levers or other devices seal them against the side of the wellbore.
Noteworthy Papers in OnePetro
- Al Rbeawi, S.J.H., and Tiab, D. 2012. Locating Closed Perforations and Damaged Sections Using Well Test Analysis. Presented at the SPE Eastern Regional Meeting, Lexington, Kentucky, USA, 3-5 October. SPE-161000-MS. http://dx.doi.org/10.2118/161000-MS. Bourgeois, M., and Couillens, P. 1994. Use of Well Test Analytical Solutions for Production Prediction. Presented at the Europea…
Noteworthy Books
- Buchwald, R.W. and Thompson, J.H. . 1973. Gas field developmental strategy from exploration well test data. Dallas: Society of Petroleum Engineers of AIME. WorldCat Earlougher, R.C. 1977. Supplement to Advances in well test analysis. New York City: Henry L. Doherty Memorial Fund of AIME. WorldCat Earlougher, R.C. 1977. Advances in well test analysis. Richardson, Texas: Henry …
Overview
In the petroleum industry, a well test is the execution of a set of planned data acquisition activities. The acquired data is analyzed to broaden the knowledge and increase the understanding of the hydrocarbon properties therein and characteristics of the underground reservoir where the hydrocarbons are trapped.
The test will also provide information about the state of the particular well use…
Scope and definitions
There are many flavours of well tests and various ways to categorize test types by its objectives, however two main categories only by objectives, these are productivity tests and descriptive tests. According to The Lease Pumper’s Handbook of Oklahoma Commission on Marginally Producing Oil and Gas Wells, there are four basic well test types: potential tests, daily tests, productivity tests, and gas oil ratio tests, the latter three in the broader productivity test category.
Exploration phase
Professionals working with reservoir modelling may get information about the rock permeability from core samples. Other sources of information to the model are well log data and seismic data, but such data are complementary only, and for example, seismic data is insufficient to interpret whether a structural trap has been sealed. Information from well tests will supplement the amount of information with flow rate data, pressure data, and other, which is needed to build a rich reser…
Field development phase
The reservoir model is further developed to support the field development planning and to advise for the optimal location for extra production wells to be drilled. Descriptive well tests are designed and performed in the new wells.
Field production phase
This test has also been called daily test and may have various other namings. Often, and especially at offshore fields, a number of wells produce to a common separator, and flows from several separators or facilities may be headed into a commingled flow in pipeline that transports oil or gas for sale (export).
The total flow rate of all wells in total are measured, but the contributions of th…