Why do a low pump speed test?
The main purpose of low pump speed test is to provide critical data for well operations, including:
Calculation of well pressure parameters: Key parameters such as initial cycle pressure and final circulation pressure can be obtained.
Initial circulation pressure = shut off vertical pressure + low pump speed test pump pressure (+ additional safety pressure)
Final cycle pressure = low pump speed test pump pressure x well pressure fluid density / original drilling fluid density,
Operating flow for the low pump speed test
1. Preparation work:
Equipment inspection: ensure the normal operation of drilling pump and diesel engine equipment, and check whether the cylinder liner and fan parts of the pump are in good condition.
Parameter confirmation: to confirm the density, viscosity and other performance parameters of the drilling fluid to ensure that it meets the design requirements.
Safety inspection: check the well control equipment, such as BOP, throttle valve, to ensure it is in good condition,
2. Test operation:
Adjust the pump impulse: adjust the pump impulse of the drilling and pump to 1 / 3 to 1 / 2 of the normal drilling pump flush, (the electric pump record the constant pressure of 30 and 40 flushing, that is, the mechanical pump) to use single fan or reduce the diesel oil door speed to about 800 RPM.
Record parameters: under the stable pump impulse, record the pump pressure, displacement, pump impulse and diesel engine revolutions.
3. data wrangling:
Data record: All the parameters recorded during the test are tabulated to ensure that the accuracy and integrity of the data are recorded on the daily report.
== When do you need to do a low pump speed test =
1. Before drilling through the oil and gas layer
Specific requirements: low pump speed test 100-150 m before drilling,
Reason: At this time, the test can obtain the key data required in advance, prepare for the incoming oil and gas layer drilling, and ensure that the pressure can be applied quickly and accurately in complex situations such as overflow.
2. After replacing the new drill bit
Specific requirements: each new well drill requires a low pump speed test before drilling,
Reason: Different drill hole sizes and drilling characteristics may be different, which can affect the circulating pressure of the drilling fluid. Testing can redefine the cyclic pressure parameters at low pump speed to meet the drilling requirements of the new drill bit,
3. When the performance of the drilling fluid changes greatly
Specific requirements: When the density, viscosity and other performance parameters of the drilling fluid change significantly, it needs to conduct the low pump speed test again.
Reason: Changes in drilling fluid performance will directly affect its flow characteristics and pressure loss in the annular air. For example, increased drilling density increases the liquid column pressure, and viscosity changes affect circulation resistance. The test can accurately measure the effect of these changes on the circulating pressure, and provide accurate data for subsequent drilling and pressure.
4. When the drilling depth increases
Specific requirements: a low pump speed test for every 200 meters
Reason: As the drilling parallel depth increases, the drill column length increases, the drilling fluid circulation path becomes longer, and the pressure loss will change accordingly. Regular tests can timely grasp the change of circulating pressure to ensure the safety of drilling process and the accuracy of pressure and operation.
5. After the replacement or adjustment of the pump equipment
Specific requirements: after the replacement or adjustment of the cylinder liner, piston, fan and other key components of the drilling pump, a low pump speed test is required.
Reason: The replacement or adjustment of the pump equipment may change the performance curve and displacement characteristics of the pump, thus affecting the circulating pressure of the drilling mixture. The operating parameters of the pump can be recalibrated to ensure its stability and reliability at low pump speed.
Before each class starts to drill in
Specific requirements: conduct a low pump speed test before each shift starts drilling,
Reason: This is to ensure that all equipment and parameters are in normal state before the new team starts drilling, obtain low pump speed parameters in time, and prepare for unknown and control risks.
PS:
1. It should be noted that the pressure at low pump speed cannot be obtained directly away from the pressure gauge in the driller room, but should be read from the pressure gauge at the throttle control box.
2. In the horizontal well or the high pump pressure and adjust the pressure rush 20 and 30 flush respectively.
This article: Reprinted from drilling career, wechat signal: zuanjingshengya