testing

Well Testing-SWT

Tests on oil and gas wells are performed at various stages of well construction, completion and production. The test objectives at each stage range from simple identification of produced fluids and determination of reservoir deliverability to the characterization of complex reservoir features.

Most well tests can be grouped as productivity testing or descriptive testing.

Productivity well tests are conducted to

* identify produced fluids and determine their respective volume ratios

* measure reservoir pressure and temperature

* obtain samples suitable for pressure-volume-temperature (PVT) analysis

* determine well deliverability

* evaluate completion efficiency

* characterize well damage

* evaluate work-over or stimulation treatment

 

Descriptive tests seek to

* evaluate reservoir parameters

* characterize reservoir heterogeneity

* assess reservoir extent and geometry

* determine hydraulic communication between wells.

Whatever the objectives, well test data are essential for the analysis, prediction and improvement of reservoir performance. These in turn are vital to optimize reservoir development and efficient asset management.

Well testing technology is evolving rapidly. Integration with data from other reservoir-related disciplines, constant evolution of interactive software for transient analysis, improvements in downhole sensors and better control of the downhole environment have all significantly increased the importance and capabilities of well testing.

 

Productivity well testing

Productivity well testing, the simplest form of testing, provides identification of productive fluids, collection of representative samples and determination of reservoir deliverability.

Formation fluid samples are used for PVT analysis, which reveals how hydrocarbon phases coexist at different pressures and temperatures. PVT analysis also provides the fluid physical properties required for well test analysis and fluid flow simulation. Reservoir deliverability is a key concern for commercial exploitation.

Estimating a reservoir’s productivity requires relating flow rates to drawdown pressures. This can be achieved by flowing the well at several flow rates using different choke sizes while measuring the stabilized bottom hole pressure and temperature for each corresponding choke.

Type of surface well testing job

  1.  Conventional Test
  2.  Conventional Clean up
  3.  High Rate Test
  4. High Rate Clean up

1. CONVENTIONAL TEST
Usually use during DST job, To Clean up the well, Measure the flow rates with separator on various choke sizes. Collect the PVT samples.

Max Gas Rate:  35 MMSCF

Max liquid Rate:  8000   bbl/d

2. CONVENTIONAL CLEAN UP
To Clean up the well for production.
Max Gas Rate:   35 MMSCF
Max liquid Rate: 8000   bbl/d

3. HIGH RATE TEST
Completion X-Mass tree is installed to Clean up the well, Measure the flow rates with separator on various choke sizes.
Collect the PVT samples.
Max Gas Rate:     100 MMSCF
Max liquid Rate:   16500 bbl/d

4. HIGH RATE CLEAN UP
To Clean up the well for production.
Max Gas Rate:      100 MMSCF
Max liquid Rate:    16500   bbl/d

Well Testing

Drill Stem Test

  • DST is a method of gathering data on the potential productivity of a reservoir before a permanent completion string is installed. (This acronym is also widely used to describe the downhole test string tools used to conduct drill stem testing.)
  • Drill stem testing or DST has been the industry standard for testing new and especially exploration wells for almost a century.  These tests are one of the primary methods used to evaluate a new formation to determine its commercial feasibility.  These tests are typically performed using a special DST tool that has downhole pressure gauges installed.  Pressure is then recorded during a series of flowing and shut-in tests to measure reservoir characteristics via pressure transient analysis.  These tests are done using downhole pressure gauges.

PDK Special Solution

  With complete Halliburton DST strings and internationally experienced and trained personnel, PDK is perfectly capable to commence DST operations with up to 15 Kpsi down hole pressure and temperatures up to 410 degF.