The configuration from the drill pipe safety valve up through the test head, through the steel flow lines to the floor manifold up to the rigs flare line, is the standard layout for the surface equipment. The zone in question is sealed off from the rest of the wellbore by packers, and the formations pressure and fluids are measured. Drill stem test interpretation drill stem tests were interpreted for. Data obtained from a dst drill stem test include the following. This data is also used to calculate bottomhole pressures 3. From a drill stem test, the average effective permeability can be calculated to reservoir conditions using a set mathematical formula. Drillstem tests provide the petroleum industry information on three critical properties of subsurface formations pressure head, permeability, and water chemistry that the groundwater hydrologist also seeks in making pumping tests of water wells. This seminar paper will present methods for the quantitative analysis of drill stem test. Drill stem test dst drill stem testingdst drill stem. Commonly, dst recoveries from damaged productive zones consist of a combination of gas at low producing rates, oil or gas cut drilling mud, or mud filtrate water. Reservoir analysis during the well test, different drawdowns could be imposed via an mvd to create the required.
Practical considerations of drillstem test interpretation of. A drill stem test dst is a procedure for isolating and testing the pressure, permeability and productive capacity of a geological formation during the drilling of a well. The objective determines which type of test will be run, and frequently more than one objective must be achieved. Data attainable from a drill stem test dst duration. Expro is committed to advancing technology in the field of drill stem testing dst and our investment is driven by the requirements of existing and emerging growth markets. Drill stem testing follows the basic principles of mechanics, hydromechanics, common sense and practicability. Analysis of drill stem testing technology of the malm carbonate rocks of the carpathian foothills, in the aspect of geological research and exploration decisions january 20 doi. In making any interpretation, our employees will give customer the benefit of their best judgment as to the correct interpretation. One or more pressure gauges are customarily mounted into the dst tool and are read and.
This is a unique, drill pipe tubing deployed, wireline controlled, straddle inflate system. Drill stem tests dsts often provide unexpected or incongruous results when compared with data obtained from electric well logs, samples, andor cores. Recommended practice for drill stem design and operating limits. Drill stem testing consists of running a suite of tools on drill pipe and then isolating a section of the open hole for the purpose of evaluating the well. The most popular abbreviation for drill stem test is. When the final flow period is concluded the tool is again closed for a second shutin period which stops the flow of fluid and gas into the drill string. Pdf analysis of drill stem test john ansa academia.
Well tests conducted with the drillstring still in the hole. Practical considerations of drillstem test interpretation of damaged formations. A dst is a systematic procedure for evaluating the hydrocarbon potential of a reservoir. The test is an important measurement of pressure behaviour at the drill stem and is a valuable way of obtaining information on the formation fluid and establishing whether a. This limited information must then be processed by highly skilled analysts to be of any technical use. Principal drill stem test database ubdst and documentation. Very, very common test so learn about them used to determine formation permeability boundary conditions. With close links to our long established subsea product line development group, a dedicated dst engineering team guided by seasoned professionals, work together inhouse to develop and. This test is a valuable and costeffective test that is mainly employed in exploratory wells. This an illustration of the surface control equipment layout. A drillstem test, or dst drill stem test, is the most common method to measure reservoir pressure.
Release of well data and information this notice to lessees and operators ntl supersedes ntl 2008g22, effective november 19. Drill stem testing shot detection expros shot detection system enables the tcp specialist to monitor downhole acoustics by attaching to the tubulars at surface. New technology drill stem testing technology expro. Pdf analysis of drill stem test dst results at osobnica oil field. Drill stem test dst interpretation of a well in kurdistan. Dsts are the most reliable reservoir pressure measurement method if sufficient time elapses during the test for the higher formation pressure to equilibrate with the lower borehole pressure. Aug 22, 2016 animation of drill pipe buckle duration.
There are three generic types of test, the second of which will be examined in detail as it is a wireline. Lynes united services limited drill stem testing 63 pages. Often referred to as dst, these tests are usually conducted with a downhole shutin tool that allows the well to be opened and closed at the bottom of the hole with a surfaceactuated valve. By examining the sample collected from the test, it is possible to calculate the concentration of natural gas or oil that can reasonably be extracted. Analysis of 78 drillstem tests dst from oil and gas wells in the uinta basin. As originally conceived, a drillstem test provided primarily an indication of formation content. A drill stem test dst is a procedure for testing the wellbore pressure. The basic drill stem test operation is divided for discussion into three phases. Drill stem test pressure chart is a chart created while performing drill stem test dst. Whether your goal is to determine reservoir pressure, permeability, skin, or productivity, our down hole technology delivers the right answers. You know us as datamaxx, for dst and plug logging services. Overview drill stem testing dst is a procedure to determine the potential productivity, pressure, permeability or extent of an oil or gas reservoir before the permanent. A drill stem test dst is a systematic procedure for evaluating the hydrocarbon potential of a reservoir. A controlled production of a small amount of fluid from an isolated section of the pay zone into the chamber formed by the drill pipe and a downhole valve.
There are essentially no standard ascii dst data files formats existing that will allow the user to read and process dst data. A drill stem test dst is a procedure for isolating and testing the pressure, permeability and productive capacity of a geological formation during the drilling of a. Drill stem test dst is the conventional method of formation testing and reservoir evaluation which obtains reservoir data under dynamic rather than static conditions. A dst is essentially a temporary completion, a method of evaluating reservoir formations without costly and timeconsuming completion procedures. A drill stem test, or dst drill stem test, is the most common method to measure reservoir pressure. After the operator determines that a formation test is to be conducted, the test tool is assembled and lowered into the wellbore. Jan 12, 2018 drill stem test dst is the conventional method of formation testing and reservoir evaluation which obtains reservoir data under dynamic rather than static conditions. If gas flows to surface a stabilized measured rate is desirable for proper reservoir evaluation. Dsts are the most reliable reservoir pressure measurement method if sufficient time elapses during the test for the higher formation pressure to.
Practical considerations of drillstem test interpretation of damaged. Intent to drill well received by kgs jul 07, 2011 well completion report received by kgs mar, 2012 well completion report received by kgs apr 10, 2014 drill stem test received by kgs mar 01, 2012 cement tickets received by kgs mar 01, 2012 cement tickets received by kgs. Productivity tests obtain and analyze representative samples of produced fluids measure reservoir pressure and temperature determine inflow performance relationship and deliverability evaluate completion. A drill stem test dst offers the fastest and safest method of evaluating the potential of a newlydiscovered hydrocarbonbearing formation. Drill stemtest interpretation drillstem tests were interpreted for. Proper interpretation of this data is highly important to the proper use of drill stem testing.
Interpretation of gasproducing dsts requires some additional calculations which were not addressed for simplicity, however, the calculations for gas dsts are shown with the database. A drill stem test dst is some form of temporary completion of a well that is designed to determine the productivity and fluid properties prior to completion of the well. This program was written to assist the user in entering dst data, perform quantitative analysis on the shut in pressure data and then to save the information into a log ascii standard las version 3. Several data were obtained before starting the interpretation methods. It should be understood that careful consideration must be given to all factors involved in the planning of the test in order to obtain the desired results. Drill stem testing horizontal well testing ltd calgary. The use of small bottom choices and large top choices is suggested in order to permit quantitative interpretation for gasoil ratio, productivity, and permeability. What is a drill stem test dst and what data is attainable. After the well has been drilled and cased, the first stage of a well test is to run a dst string in conjunction with a downhole data system with the option to include tubing conveyed sampling. Protest has a high rate of successful tests, a key measure of performance and the major factor in reducing the cost of testing services. Formation fluid pressure from drill stem tests aapg wiki.
Drillstem testing dst is one of the most important completion. The dst data includes permeability, quality codes, drill. In a practical sense, one of the required formula parameters, such as viscosity of the fluid, may not always be readily available. For information on software to view and use the files we. Ppt drillstem testing powerpoint presentation free to. The unit uses state of the art technology to process and record the. Computer generated interpretation operator on log meridian. The basic drillstem test operation is divided for discussion into three phases. The operator monitors remotely and as such the equipment is ex zone 1 rated. Using the latest communication tools, all the team members can communicate, share ideas, and provide recommendations to support field operations in real time. Practical considerations of drillstem test interpretation. The main objective of the test is to study the reservoir characteristics as well as evaluate the commercial aspects of the reservoir. With close links to our long established subsea product line development group, a dedicated dst engineering team guided by seasoned professionals, work together inhouse to develop and introduce innovative dst tools.
Drill stem tests dsts often provide unexpected or incongruous results when compared with data obtained from electric well logs, samples. The data derived from the drill stem test dst give a computation of the formations permeability, damage ratio, productivity index, transmissibility and radius of investigation. Pdf in the paper results of dst tests obtained in two wells at osobnica oil field are presented. It is commonly used to test a newly drilled well, since it can only be carried out while a rig is over the hole.
Pdf analysis of drill stem testing technology of the malm. Aifes drill stem test dst database contains over 170,000 analyzed tests for the united states covering the period 1948 to present. Aug 26, 2017 in order to evaluate a wells productivity there are number of direct and indirect tests but dst or drill stem test is the most authentic test of them all. A drill stem test dst drill stem test is a temporary completion of a wellbore that provides information on whether or not to complete the well. Procedure during normal well drilling, drilling mud is pumped through the drill stem and out of the drill bit. The dst or drill stem test used in both oil and gas wells, in cased or uncased wells. A basic drill stem test bha consist of a packer or packers, which act as an expanding plug to be used to isolate sections of the well for the testing process, valves that may be opened or closed from the surface during the test, and recorders. Geological survey open file report 79365, 2 sheets. Various types of surface pressure tests usually for gas wells. Recommended practice for drill stem design and operating. Drillstem test data analysis considering inertial and.
Each analysis is derived from the original drill stem test report,not transcribed from scout or field data. Drill stem testing companies which run the tests provide a brief description of what the test yielded and how it was run. The test is a valuable and cost effective test that is mainly employed in exploratory wells. In order to evaluate a wells productivity there are number of direct and indirect tests but dst or drill stem test is the most authentic test of them all. Drillstem tests measure pressures, some elements of depletion, and gather samples of the produced fluids. Although a dst can be performed in uncased hole open hole or in cased hole perforation tests, the open hole test is more common. A drill stem test is a test which uses a special tools mounted on the end of the drill string. Times of for each test are dependent on conditions at the well site drill stem tests may. Pc ascii data files load previous dst session log ascii standard las file, versions 2. Drill stem testing, dst drill stem testing provides a method of temporarily completing a well to determine the productive characteristics of a specific zone. Petropedia what is drill stem test pressure chart dst. Drill stem testing protest personnel have extensive experience with open hole drill stem testing services across both conventional oil and gas well and coal bed methane wells. The air blow at surface will indicate whether formation fluid or gas is entering the drill string.
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