CN106801602A - Using the method for the pressure wave signal real-time monitoring gas cut of measurement while drilling instrument - Google Patents

Abstract

The invention belongs to the technical field of monitoring methods, and relates to a method for real-time monitoring of gas intrusion using pressure wave signals of a Measurement While Drilling (MWD) tool, which is implemented by using the Measurement While Drilling tool and a wellhead surface monitoring device. The specific steps are as follows: Using the pressure pulse fluctuation signal generated by MWD when transmitting downhole data as the pressure wave source, the pressure wave signal propagates along the two paths of the annular space and the drill pipe to the surface annular pressure sensor and the standpipe pressure sensor respectively, and then passes through the filter The processor filters the pressure wave signals received by the two sensors, amplifies the filtered weak signals through the weak signal amplifier, calculates and records the time difference of the pressure pulse signals returning to the ground from the two lines through the data processing and real-time monitoring system, Finally, the alarm judges whether to carry out early warning and alarm according to the time difference. The process is simple in operation, low in cost, easy to install, scientific and reasonable in principle, high in reliability, and easy to popularize and use.

Description

Real-time Gas Kick Monitoring Method Using Pressure Wave Signal of Measurement While Drilling Tool

technical field

The present invention relates to the technical field of real-time monitoring of borehole annular air intrusion in the process of oil and natural gas drilling, in particular, to a real-time monitoring of annular air intrusion by using the pressure pulse fluctuation signal generated by the measurement-while-drilling tool when transmitting downhole data during the drilling process method. It is used for real-time monitoring and early detection of formation gas intrusion into the wellbore annulus, so as to gain more time for timely well control measures.

Background technique

Gas invasion is a phenomenon in which natural gas in the formation invades the drilling fluid in the annulus of the wellbore when the effective liquid column pressure at the bottom of the well is lower than the formation pressure when drilling into a high-pressure formation during drilling; the gas has strong compressibility, and the gas In the initial stage of invasion into the wellbore, due to the large upper liquid column pressure, the gas is in a compressed state, and the gas volume is very small, so it is difficult to find gas invasion. With the circulation of drilling fluid, the gas rises along the annular space of the wellbore, the pressure of the upper liquid column on the gas gradually decreases, and the volume expands continuously. The closer the gas is to the wellhead, the more it expands, and the faster the pressure of the annular liquid column decreases, the easier it is to cause blowout accidents. Therefore, it is necessary to monitor whether gas kick occurs in real time during drilling operations, and the earlier it is found, the lower the risk of well control.

Existing gas intrusion monitoring methods mainly include mud pool liquid level monitoring technology, wellhead flowmeter method, annular pressure monitoring while drilling method and acoustic wave monitoring method, etc. The first two methods are based on the expansion of gas volume, which are simple and practical, but when drilling in high-temperature and high-pressure deep wells, ultra-deep wells and some complex geological conditions, the time to discover gas invasion has a large lag. Annular pressure monitoring while drilling can detect gas intrusion in a timely and effective manner, but the requirements for supporting facilities are high and the cost is high. Acoustic monitoring gas kick technology is an early gas kick monitoring method proposed by the former Soviet Drilling Research Institute. Subsequently, many experts, scholars and companies at home and abroad have also carried out research in this area, but due to various factors, they have not been able to effectively solve the relevant technical bottlenecks, and have not been popularized and applied so far.

The pressure wave early monitoring gas kick technology mainly utilizes the principle that the propagation speed of pressure wave in pure drilling fluid is much higher than that in gas kick drilling fluid. was monitored. Under the condition that there is no gas invasion in the annulus, the propagation velocity of the pressure wave in the drill string and the annulus are basically the same; after the gas invades the annulus of the wellbore, the propagation velocity of the pressure wave in the annular air-invaded drilling fluid decreases significantly , while the propagation velocity in the uninvaded drilling fluid in the drill string remains unchanged, so there will be a certain difference in the time for the pressure wave to travel from the bottom hole to the wellhead along the two paths of the drill string and the annulus, and the pressure wave can be used in the The time difference between the inside of the drill string and the annulus to the surface is used to monitor whether gas kick occurs in the annulus of the wellbore. The existing practice is to use the pressure wave generated by the drilling fluid pump located on the ground as the pressure wave source, whose fluctuation characteristics are not obvious, and the method of changing the pressure wave characteristics by adjusting the pump speed or displacement is too complicated; and the present invention utilizes the installation The pressure pulse fluctuation signal generated by the Measurement While Drilling (MWD) tool near the drill bit when transmitting downhole data is used as the pressure wave source, and the pressure wave signal generated by it has obvious characteristics, which is convenient for the ground analysis system to effectively distinguish and process. In the current directional drilling operation and some vertical well drilling operations, MWD is installed near the drill bit to measure wellbore trajectory parameters while drilling. Based on the present invention, real-time monitoring of annular air intrusion can be realized only by adding wellhead devices; the process is simple and easy to operate. The utility model has the advantages of low cost, easy installation, scientific and reasonable principle, high reliability and convenient popularization and use.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the prior art, seek to design a method for monitoring air intrusion in the borehole ring of oil and gas drilling, detect air intrusion early, take countermeasures in time, avoid loss of property and personnel, and provide reliable guarantee for safe drilling.

In order to achieve the above object, the gas invasion monitoring method involved in the present invention is implemented by using a measurement-while-drilling tool and a wellhead surface monitoring device. The wellhead surface device mainly includes an annular pressure sensor, a riser pressure sensor, a filter processor, a weak signal amplifier, a data processing and real-time monitoring system and an alarm. In the present invention, the pressure wave signal emitted by the MWD installed near the drill bit is transmitted to the wellhead through the two paths of the drill string and the annular space, and the riser pressure sensor and the casing pressure sensor installed near the wellhead respectively receive signals from the inside of the drill pipe and the casing pressure sensor. For the pressure wave signal of the annular space, use the filter processor to filter the pressure wave signal received by the annular pressure sensor and the standpipe pressure sensor, use the weak signal amplifier to amplify the filtered weak signal, and finally use the data processing and real-time monitoring system Calculate the time difference of the pressure wave propagating from the two paths to the two sensors at the wellhead. If the real-time monitoring system calculates that there is not enough time difference between the annular pressure sensor and the standpipe pressure sensor receiving the pressure wave signal emitted by the bottomhole MWD, it indicates that the well If there is no gas intrusion in the eye annulus or the gas intrusion is not serious, the alarm will not send out an early warning or alarm signal; If the time difference reaches the pre-set warning value, it indicates that serious gas intrusion has occurred in the annular space of the wellbore. The time difference when the sensor receives the pressure wave signal emitted by the bottomhole MWD is lower than the warning value.

The downhole signal transmitter involved in the present invention is a MWD that transmits signals by means of pressure pulses.

The main structure of the device for real-time monitoring of gas intrusion using the pressure wave signal of the measurement-while-drilling tool according to the present invention includes: pressure wave signal generator MWD, annular pressure sensor, standpipe pressure sensor, filter processor, weak signal amplifier, data processing And real-time monitoring system, alarm, etc.

Compared with the existing gas intrusion monitoring technology and devices, the present invention has the following characteristics:

1. The downhole signal transmitter is a MWD that uses pressure pulses to transmit signals, because all directional wells and some vertical wells will be installed with MWD, so in the present invention, only need to add wellhead devices to realize real-time monitoring of annular air intrusion, and its process operation is simple , low cost, easy to install, scientific and reasonable principle, high reliability, easy to popularize and use.

2. The characteristics of the pressure wave signal generated by MWD are obvious, easy to identify, high monitoring accuracy, strong real-time performance, low professional operation requirements, good stability, and the measurement process is monitored by computer, so the degree of automation is high.

3. Realize that when gas invasion occurs in the wellbore annular space, it can accurately judge whether there is formation gas invasion in the early stage of gas invasion, and give an early warning.

Description of drawings

Fig. 1 is a schematic diagram of the main structure of a device for real-time monitoring of air intrusion using MWD pressure wave signals involved in the present invention.

In the figure, 1-MWD pressure wave generator, 2-annular pressure sensor, 3-standpipe pressure sensor, 4-filter processor, 5-weak signal amplifier, 6-data processing and real-time monitoring system, 7-alarm .

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

The main structure of the real-time monitoring gas intrusion device using MWD pressure wave signal involved in this embodiment includes MWD pressure wave generator 1, annular pressure sensor 2, standpipe pressure sensor 3, filter processor 4, weak signal amplifier 5, data Processing and real-time monitoring system 6, alarm 7.

The MWD pressure wave generator 1 installed near the drill bit is used to generate pressure waves; the pressure wave signal propagates from the bottom of the well to the wellhead through the drill string and the annular space, and the annular pressure sensor 2 and the standpipe installed at the wellhead are used The pressure sensors respectively receive the pressure wave signals from the annular space and the drill string, use the filter processor 4 to filter the pressure wave signals received by the annular space pressure sensor 2 and the standpipe pressure sensor 3, and use the weak signal amplifier 5 to pair the filtered pressure wave signals The weak signal is amplified and processed, and finally the data processing and real-time monitoring system 6 is used to calculate the time difference of the pressure wave propagating from the two paths to the two sensors at the wellhead. The pressure sensor 1 receives the pressure wave signal emitted by the MWD at the bottom of the well without sufficient time difference, indicating that there is no gas intrusion at the bottom of the well, and the alarm 7 does not issue an early warning or alarm signal; if the data processing and real-time monitoring system 6 calculates that the annulus There is a time difference between the pressure sensor 2 and the standpipe pressure sensor 1 receiving the pressure wave signal emitted by the MWD at the bottom of the well and reaches the preset warning value, indicating that gas intrusion has occurred in the annular space of the wellbore, and the alarm 7 will send out an early warning or alarm signal An instruction is issued to allow on-site personnel to take measures until the time difference between the annular pressure sensor 2 and the standpipe pressure sensor 1 receiving the pressure wave signal emitted by the bottomhole MWD is lower than the warning value.

The downhole pressure wave transmitter 1 involved in this embodiment is a MWD that transmits signals by means of pressure pulses.

Claims (4)

1. the method for utilizing the pressure wave signal real-time monitoring gas cut of measurement while drilling instrument, it is characterised in that：Existed based on pressure wave Spread speed, can be under during gas cut be also in well much larger than the principle of the spread speed in gas cut drilling fluid in pure drilling fluid Portion, gas cut amount are just monitored to when also smaller；Measurement while drilling instrument (MeasurementWhile Drilling, MWD) is being passed Pass the pressure pulse fluctuation signal produced during downhole data and travel to surface annulus pressure respectively along annular space and the paths of drilling rod two Sensor (2) and standpipe pressure sensor (3), well is received according to annular pressure sensor (2) and standpipe pressure sensor (3) The time difference of the pressure pulse fluctuation signal that bottom MWD launches judges whether bore hole annulus occur gas cut, and gas cut occurs The order of severity, and determine whether to send early warning and alarm signal by alarm (7).

2. the method for the pressure wave signal real-time monitoring gas cut of utilization measurement while drilling instrument according to claim 1, it is special Levy and be, the underground signal transmitter is the MWD that signal is transmitted using pressure pulse, MWD is produced when downhole data is transmitted Pressure pulse fluctuate signal along drill string and annular space simultaneously earthward transmit；If by data processing and real-time monitoring system (6) calculate annular pressure sensor (2) and standpipe pressure sensor (3) receives shaft bottom MWD pressure wave generators (1) transmitting The pressure wave signal for going out does not have time enough poor, shows that bore hole annulus do not occur gas cut, then alarm (7) do not send early warning or Alarm signal；If data processing and real-time monitoring system (6) calculate annular pressure sensor (2) and standpipe pressure sensor (3) receive the pressure wave signal existence time difference launched in shaft bottom MWD generators (1) and reach warning value set in advance, Show that bore hole annulus have occurred gas cut, then alarm (7) sends early warning or alarm signal, and points out Field Force to take well control to arrange Apply, until annular pressure sensor (2) and standpipe pressure sensor (3) receive shaft bottom MWD generation pressure wave signal when Between difference be less than warning value.

3. the method for the pressure wave signal real-time monitoring gas cut of the utilization measurement while drilling instrument according to claim 1-2, its It is characterised by, when without there is gas cut, the pressure arteries and veins that the MWD pressure wave generators (1) produce when downhole data is transmitted Spread speed of the fluctuation signal in drill string and in annular space is rushed basically identical, so passing through data processing and real-time monitoring system (6) the time difference Δ t ≈ 0 for calculating；After there is gas cut in bore hole annulus, propagation time of the pressure wave in pure drilling fluid in drill string It is basically unchanged, is set to t₁；And spread speed of the pressure wave in biphase gas and liquid flow in annular space reduces, propagation time increase is set to t₂；So travel to the time difference Δ t=t of Well mouth sensor respectively from two paths₂-t₁>0.By Δ t and police set in advance Ring value Δ T-phase compares, and as Δ t >=Δ T, shows that bore hole annulus have occurred than more serious gas cut, it is necessary to pass through alarm (7) Send alarm signal；As Δ t<During Δ T, show that bore hole annulus do not occur gas cut or gas cut is not serious, wouldn't need to take well Control measure, but data processing and real-time monitoring system need to continue real-time monitoring of the holding to gas cut.

4. the method for the pressure wave signal real-time monitoring gas cut of the utilization measurement while drilling instrument according to claim 1-3, its Being characterised by the agent set of the utilization measurement while drilling instrument real-time monitoring oil/gas drilling annular space gas cut includes pressure wave signal Generator MWD (1), annular pressure sensor (2), standpipe pressure sensor (3), filter processor (4), small signals amplification device (5), data processing and real-time monitoring system (6), alarm (7)；Situ of drilling well operation is subject in pressure wave signal transmittance process Influence, signal attenuation is big, definition is low, it is therefore desirable to which annular pressure sensor (2) and standpipe pressure sensor (3) are received To pressure wave signal be filtered and enhanced processing.The filter processor (4) combines arithmetic mean value filtering and intermediate value is filtered Wave technology, the former can suppress PERIODIC INTERFERENCE and random disturbances, and the latter has preferable filtration to impulse of pressure wave noise, Both are combined and can reach good filter effect；The small signals amplification processor (5) uses differential amplifier circuit and programming The mode that gain is amplified, differential amplifier circuit can avoid pressure wave from receiving sensor and be subject to more serious interference pressure wave signal The interference pressure wave signal of the common mode of striking resemblances can be even avoided, is very suitable for being amplified pressure wave signal at place Reason.Using pressure wave signal gain amplification disposal, programming can realize relatively broad gain linearity regulation.