RU2032071C1 - Method and apparatus to determine beginning of stratum fluid appearance and absorption of drilling mud - Google Patents

Abstract

FIELD: oil and gas extracting industry. SUBSTANCE: sensors are measuring consumption and concentration of drilling mud рat borehole input and its output. Signals from concentration sensors 1 and 2 and from consumption sensors 3 and 4 are coming to comparison blocks 5 and 6. Values of differential consumption and differential concentration of drilling mud at borehole output and value of pipeline inner diameter in place of measurements drilling mud consumption at borehole input are determined. Amplified by amplifiers 10 and 11 signals after passing through multiplying blocks 12 and 15 are fed to summer 16 and after that are registered by computation block 17, that determines mean value and value of dispersion of dynamic pressure absolute increment distribution, obtained from numeral measurements. Signal from block 17 through key members 19 and 20 comes to memory blocks 22 and 23, to which signal from clock 18 is also fed. Computation block 17 signals, corresponding previous and following distributions of pressure absolute increments values, are compared in comparison block 7. Block 7 output signal is analyzed by threshold block 24. In case input signal exceeds threshold value, then signal from block 24 output goes to registering block 26. EFFECT: method and apparatus increased accuracy to determine beginning of stratum fluid appearance and beginning of absorption of cleansing solution by permeable stratum. 2 cl, 1 dwg

Description

 The invention relates to the oil and gas industry and is intended to determine the onset of the manifestation of the reservoir fluid and the absorption of the flushing agent when drilling wells.

 A known method of determining the onset and release during drilling of wells, which consists in measuring and recording over time the volume of washing liquid in the receiving tanks, calculating the allowable value of the increase in volume of the liquid, determining the initial value of the volume of washing liquid in the receiving tanks and pressure on the riser, measuring during drilling current values of the volume and pressure of the liquid, comparing them with the initial ones and determining the onset of manifestation and discharge by changing the indicated volume and pressure [1].

 The disadvantage of this method is the low accuracy of determining the onset of development and ejection, since the information obtained about the onset of development and ejection during drilling significantly lags behind real processes.

 A known method for determining the onset of manifestation and ejection during drilling of wells, in which the following parameters are simultaneously measured and recorded in time: the mechanical speed of penetration, the volume of solution leaving the wells as a percentage of the injected, the volume of solution in receiving tanks, the specific gravity of the drilling fluid leaving the well [2].

 A device for automatically measuring the differential flow rate of a drilling fluid during drilling, containing a circulating system, flow rate sensors of the flow rate of the drilling fluid at the inlet and outlet of the well, the adder and recorder [1].

 The disadvantages of the device are the low accuracy of determining the differential flow rate and the associated determination of the onset of development and discharge of formation fluid when drilling wells, since the principle of calculating the difference of two signals that differ by a small amount of signals from independent sensors is used.

 A device is known that contains a circulation system, mud flow sensors at the well entrance and exit, an adder, a recorder, a module allocation unit, a memory unit, a delay line, and three keys.

 A disadvantage of the known method and device is the low accuracy of determining the start of the ejection and manifestation due to the low sensitivity in determining the controlled parameters from the beginning of the ejection and manifestation, as well as due to the ambiguity in the interpretation of measurements of the controlled parameters.

 The purpose of the invention is to increase the accuracy of determining the onset of formation fluid and the absorption of drilling fluid permeable formation.

 The goal is achieved by the fact that in the method for determining the onset of formation fluid and the absorption of the drilling fluid, including measuring the flow rate of the drilling fluid at the entrance to and from the well, measuring the density of the drilling fluid at the exit of the well and determining the differential flow rate, additionally measure the density of the drilling fluid at the entrance to the well, determine the value of the differential density of the drilling fluid at the entrance to the well, set the value of the internal diameter of the pipeline at the measurement site mud flow rate at the inlet of the well, from the data determining the absolute value of the increment of the dynamic pressure at the exit of the borehole, the measurement of these parameters and the determination of the absolute dynamic pressure increment is performed repeatedly, and then calculating the mean value and the value of the inhomogeneity of absolute dynamic pressure increment; the current average value of the absolute increment of the dynamic pressure is compared with the average value, and the result of this comparison is with the heterogeneity of the distribution of the absolute increment of the dynamic pressure obtained from the previous measurements, and the results of comparison, taking into account the sign of the differential flow rate, judge the onset of formation fluid or drilling fluid uptake solution.

 The goal is also achieved by the fact that a device for determining the onset of formation fluid and drilling fluid absorption, containing a circulation system, mud flow sensors at the inlet and outlet of the well, a module selection unit, a memory unit, three key elements, an adder and a recorder , is additionally equipped with mud density sensors at the entrance and exit of the well, three comparison units, two linear amplifiers, four multiplication units, a threshold unit, a value calculator unit, and the heterogeneity of the absolute increment of the dynamic pressure, a clock, a second recorder, a second module allocation unit and a second memory unit, while the outputs of the mud density sensors are connected to the inputs of the first comparison unit, the outputs of the mud flow sensors are connected to the inputs of the second comparison unit, the output of the first and the first output of the second comparison blocks are connected respectively to the inputs of the first and second blocks of the module selection, the second output of the second comparison block is connected with the first recorder, the second and third outputs of the mud flow sensor at the well entrance through the first and second linear amplifiers are connected to the first inputs of the first and second multiplication units, the outputs of the first and second module isolation units are connected to the second inputs, respectively, the outputs of the first and second multiplication units are connected to the first inputs of the third and fourth multiplication units, respectively, to the second inputs of which the outputs of the density and flow sensors at the entrance to the well, respectively, are connected, the outputs of the third and fourth multiplication blocks are connected to the inputs of the adder, the output of which is connected to the block of the calculator of the average value and the inhomogeneity of the absolute increment of dynamic pressure, the first output of which is connected through the first and second key elements to the inputs of the first memory block, the output of which is connected to one of the inputs the third comparison unit, the second input of which is connected to the output of the second memory unit, the second output of the first key of the element and the first output of the generator, the first, second and third outputs of the clock connected respectively to the second inputs of the first, second and third key elements, the second output of the unit for calculating the average value and the inhomogeneity of the absolute increment of the dynamic pressure through the third key element, and the third output of the clock the output of the third comparison unit is directly connected respectively to the three inputs of the threshold block, the output of which is connected to the input of the second recorder.

P

=ρ

Q

+

, (1) где / ΔР_дин/ - абсолютное приращение динамического давления, н/м²;
ρ - плотность бурового раствора на входе в скважину, кг/м³;
Q - расход бурового раствора на входе в скважину, м³/с;
/Δρ / - абсолютное значение приращения плотности бурового раствора, кг/м³;
/ ΔQ/ - абсолютное значение приращения расхода бурового раствора, м³/с;
d - внутренний диаметр трубопровода, м.The choice of methods of the proposed method is determined by the fact that dynamic pressure is highly sensitive to the processes of formation fluid manifestations and absorption of the drilling fluid in the well, the absolute value of the dynamic pressure increment is functionally related to changes in the parameters of the circulation of the drilling fluid through the well. The absolute increment of the dynamic pressure at the exit from the well has the form:

P

= ρ

Q

+

, (1) where / ΔР _din / is the absolute increment of dynamic pressure, n / m ² ;
ρ is the density of the drilling fluid at the entrance to the well, kg / m ³ ;
Q is the flow rate of the drilling fluid at the entrance to the well, m ³ / s;
/ Δρ / is the absolute value of the increment in the density of the drilling fluid, kg / m ³ ;
/ ΔQ / is the absolute value of the increment of the flow rate of the drilling fluid, m ³ / s;
d is the inner diameter of the pipeline, m

, (2) где t_{α , n} - безразмерный коэффициент Сююдента при заданном уровне значимости α и при числе измерений n;
σ_{/ Δ}

_/ - среднеквадратическое отделение случайной величины / ΔР_дин/, н/м².Thus, from the totality of the results obtained, the absolute increment of the dynamic pressure at the well exit is determined by the formula (1). In the real drilling process, there are relatively small fluctuations in the differential flow rate and density of the drilling fluid, associated with loss of fluid for filtration in the wall of the well and in the formation, as well as in the treatment system, and changes in the density of the drilling fluid due to the input of cuttings, etc. n. The foregoing leads to the fact that during drilling the quantity (ΔР _din ), firstly, is a random variable; secondly, non-zero in each dimension. However, to determine the beginning of the deviation of the drilling fluid circulation process from normal, it is necessary to compare the current average value of </ _{ΔР dyn.tek} /> with the average value </ ΔР _din />, determined from the results of previous multiple measurements. The result of this comparison is compared with the magnitude of the heterogeneity of the value of the absolute increment of the dynamic pressure determined by the results of previous measurements / ΔP _din / i (i = 1, 2, ... n). The measure of heterogeneity of the absolute increment of dynamic pressure is the value
Δ = t _{α, n}

, (2) where t _{α , n} is the dimensionless Student coefficient for a given significance level α and for the number of measurements n;
σ _{/ Δ}

_/ - rms branch of a random variable / ΔР _din /, n / m ² .

<

P

> - <

P

>

>t_α,n

(3) указывает о начале осложнения процесса бурения. Для определения направленности процесса выясняют знак величины дифференциального расхода, и положительный (+) свидетельствует о начале проявления или выброса, отрицательный (-) - о начале поглощения бурового раствора в скважине.Thus, analyzing the dependence </ ΔР _{din, tech} /> - </ Δ Р _din />, judge the process of circulation of the drilling fluid through the well. Exceeding the specified difference in Δ, i.e., the fulfillment of the condition:

<

P

> - <

P

>

> t _{α, n}

(3) indicates the beginning of a complication of the drilling process. To determine the direction of the process, the sign of the differential flow rate value is ascertained, and a positive (+) indicates the onset of development or discharge, a negative (-) indicates the beginning of the absorption of the drilling fluid in the well.

 The drawing shows a block diagram of a device for implementing the method for determining the onset of formation fluid and the absorption of drilling fluid.

 The device contains sensors 1 and 2, respectively, of the density of the drilling fluid at the entrance to and exit from the well, sensors 3 and 4, respectively, of the flow rate of the drilling fluid at the entrance to and from the well, first, second and third comparison blocks 5, 6, 7 respectively; the first and second blocks 8, 9 allocation module, respectively; the first and second linear amplifiers 10, 11, respectively; the first, second, and fourth multiplication blocks 12, 13, 14, 15, respectively; the adder 16, the block 17 of the calculator of the average value and the magnitude of the heterogeneity of the absolute increment of the dynamic pressure 17, the clock 18, the first, second and third key elements 19, 20, 21, respectively; the first and second memory blocks 22, 23, respectively; threshold block 24, the first and second recorders 25, 26, respectively. The transmission of signals is carried out through electrical connections indicated in the diagram by solid lines.

 The method is as follows.

, задается сигналом, поступающим через ключ (элемент 21) с второго выхода блока 17 на второй вход порогового блока 24, при этом включение ключа (элемента 21) происходит через третий выход тактового генератора 18 в каждом четном или нечетном такте. При превышении указанного порогового значения сигнал с выхода блока 24 поступает на регистратор 26. При открывании ключевых элементов 19-21 одновременно передним фронтом сигналов тактового генератора 18 за время, существенно меньшее (в 10³ раз) инерционности блока 7 сравнения, происходит сброс на "0" выходного сигнала блоков 22, 23 памяти и порогового блока 24, соответствующих предыдущему измерению. Поэтому блок 7 сравнения не фиксирует мгновенную разницу сигналов блоков памяти на время сброса, которое составляет приблизительно 1 мкс, тогда как постепенное время блока 7 сравнения равно примерно 1 с.The signals from the sensors 1 and 2 density and sensors 3 and 4 of the flow rate of the drilling fluid are fed to the inputs of blocks 5 and 6 of the comparison. The outputs of the comparison blocks generate signals proportional to the increment of the density and flow rate of the drilling fluid at the exit from the well, and the signal from the first output of the comparison unit 6 is fed to the input of the module allocation unit 9, and from the second output to the recorder 25. The signal from the output of the comparison unit 5 arrives at the input of module allocation unit 8. At the outputs of blocks 8 and 9, signals are generated that are equal to the absolute increment in the density and flow rate of the drilling fluid, which are fed to the second inputs of the multiplication blocks 12, 13, the first inputs of which receive signals from flow sensors amplified in linear amplifiers 10 and 11, respectively. The gain in the linear amplifier 10 is equal to 16 (π ² d ⁴ ), and in the linear amplifier 11-8 (π ² d ⁴ ). From the outputs of the multiplication blocks 12 and 13, the signal is supplied to the first inputs of the multiplication blocks 14 and 15, the second inputs of which receive a signal from the sensors 1 and 3, respectively, of the density and flow rate of the drilling fluid, respectively, and from the outputs of the multiplication blocks 14 and 15, the signal goes to the first and the second inputs of the adder 16, respectively. The output signal of the adder 16 is recorded by the block 17 for calculating the average value and the inhomogeneity value of the absolute increment of the dynamic pressure, which is a mini-computer, for example, "Armicont-110" with an interface made of functional blocks of the KAMAK standard system. The algorithm by which the signal is processed in the computing unit consists in determining the average value and the variance of the distribution of the absolute increment of the dynamic pressure obtained as a result of repeated measurements of the specified parameter. From the first output of the calculator unit 17 of the average value and the heterogeneity of the absolute increment of the dynamic pressure, a signal equal to the average value of the distribution of the values of the absolute increment of the dynamic pressure obtained as a result of repeated measurements of this parameter is supplied through the key elements 19 and 20 to the first inputs of the blocks 22 and 23 of the memory , the second inputs of which receives a signal from the second and third outputs of the clock generator 18, respectively, while the signal from the second and third outputs of the clock th oscillator is supplied to the second inputs of the key elements 19, 20 respectively. The clock generator 18 generates signals switching in antiphase key elements 19, 20, and the clock cycle is equal to the processing period of the obtained distribution of the absolute increment of dynamic pressure in block 17. When you open the key 19, the key 20 closes (and vice versa). At the same time, in blocks 22 and 23 of the memory, the signals of the block 17 of the calculator of the average value and the heterogeneity of the absolute increment of the dynamic pressure are recorded, and in block 22 of the memory, the signals are fixed after the first and subsequent odd influences, and in block 23 after the second and subsequent even effects. In block 7, the signals of block 17 corresponding to the previous and subsequent distribution of the values of the absolute increment of the dynamic pressure are compared. The output signal of block 7 is analyzed by threshold block 24, and the threshold value determined by the value Δ = t _{α , n} σ _{/ Δ}

is set by a signal coming through the key (element 21) from the second output of block 17 to the second input of the threshold block 24, and the key (element 21) is turned on through the third output of the clock generator 18 in each even or odd cycle. If the specified threshold value is exceeded, the signal from the output of block 24 is sent to the recorder 26. When the key elements 19-21 are opened simultaneously by the leading edge of the signals of the clock generator 18 for a time significantly less (10 ³ times) the inertia of the comparison unit 7, a reset to "0 "the output of the memory blocks 22, 23 and the threshold block 24 corresponding to the previous measurement. Therefore, the comparison unit 7 does not record the instantaneous difference of the signals of the memory units for the reset time, which is approximately 1 μs, while the gradual time of the comparison unit 7 is approximately 1 s.

 An experimental verification of the proposed method was carried out on a bench well. During the test, the flow rate of the drilling fluid was measured at the well entrance and exit, the differential flow rate at the well exit was determined by algebraically adding the values of the indicated expenses. The density of the drilling fluid was measured at the entrance to the well and at the exit of the well, the differential density of the drilling fluid at the exit of the well was determined. In the place of measuring the flow rate of the drilling fluid, the value of the internal diameter of the pipeline was determined and, based on the totality of the data obtained, the absolute increment of the dynamic pressure at the exit from the well was calculated according to formula (1). The measurement of the above parameters and the determination of the absolute increment of the dynamic pressure were performed many times, the average values and the values of the heterogeneity of the absolute increment of the dynamic pressure were calculated.

 The measurements showed that for small values of the increment of the dynamic pressure, the average value and the variance of the distribution of the increment of the dynamic pressure are almost equal, and the distribution of the increment of the dynamic pressure is approximated by the Poisson distribution.

 The experimental application of the proposed method and device design made it possible to identify their high efficiency associated with increased sensitivity to changes in dynamic pressure increments and, accordingly, accuracy in determining the onset of manifestation and absorption of the drilling fluid while drilling a well, while the device allows to increase the productivity of a set of technological operations by introducing additional to a prototype device of blocks and connections.

 The positive effect of the invention is to increase the accuracy of determining the onset of manifestation and release during drilling and the achieved productivity increase of approximately 10 times compared with the prototype.

Claims (3)

 METHOD FOR DETERMINING THE BEGINNING OF THE MANIFESTATION OF THE FORMED FLUID AND THE ABSORPTION OF THE DRILLING MILL AND THE DEVICE FOR ITS IMPLEMENTATION.  1. The method of determining the onset of formation fluid and the absorption of drilling fluid, including measuring the flow rate of the drilling fluid at the inlet and outlet, measuring the density of the drilling fluid at the outlet and determining the differential flow rate, characterized in that, in order to improve accuracy determine the onset of formation fluid manifestation and the absorption of the drilling fluid by the permeable formation, additionally measure the density of the drilling fluid at the entrance to the well, determine the differential flow rate of the drilling fluid at the exit from the well, the value of the internal diameter of the pipeline in the place of measuring the flow rate of the drilling fluid at the entrance to the well is established, the value of the absolute increment of the dynamic pressure at the exit from the well is determined from the data obtained, while the measurement of these parameters and the determination of the absolute increment of the dynamic pressure repeatedly, then calculate the average value and the magnitude of the heterogeneity and the absolute increment of dynamic pressure, compare current e is the average value of the absolute increment of the dynamic pressure with the average value, and the result of this comparison is with the heterogeneity of the distribution of the absolute increment of the dynamic pressure obtained from the results of previous measurements, and according to the results of the comparison, taking into account the sign of the differential flow rate, judge the onset of formation fluid or mud absorption .  2. A device for determining the onset of formation fluid formation and mud absorption, comprising a circulating system, mud flow sensors at the well entrance and exit, a module allocation unit, a memory unit, three key elements, an adder and a recorder, characterized in that, in order to improve the accuracy of determining the onset of formation fluid and the absorption of drilling fluid by a permeable formation, it is additionally equipped with three sensors of the density of the drilling fluid at the entrance and exit of the well, three comparison blocks, two linear amplifiers, four multiplication blocks, a threshold block, a block for calculating the average value and the heterogeneity of the absolute increment of the dynamic pressure, a clock, a second recorder, a second module allocation unit and a second memory block, while the outputs of the mud density sensors are connected to the inputs of the first comparison unit, the outputs of the mud flow sensors are connected to the inputs of the second comparison unit, the output of the first and first output of the second block is the inputs are connected respectively to the inputs of the first and second separation units of the module, the second output of the second comparison unit is connected to the first recorder, the second and third outputs of the mud flow sensor at the entrance to the well through the first and second linear amplifiers are connected to the first inputs of the first and second multiplication units, to the second inputs of which the outputs of the first and second blocks of allocation of the module are connected, respectively, the outputs of the first and second blocks of multiplication are connected to the first inputs of the third and fourth blocks of the mind knives respectively, to the second inputs of which the outputs of the density and flow sensors are connected at the well entrance, the outputs of the third and fourth multiplication blocks are connected to the inputs of the adder, the output of which is connected to the calculator unit of the average value and the heterogeneity of the absolute increment of dynamic pressure, the first output of which is connected through the first and second key elements to the inputs of the first memory block, the output of which is connected to one of the inputs of the third comparison block, the second input of which it is single with the output of the second memory block, the second output of the first key element and the first output of the clock generator are connected to the inputs of the second memory block, the first, second and third outputs of the clock generator are connected respectively to the second inputs of the first, second and third key elements, the second output of the calculation unit the average value and the magnitude of the heterogeneity of the absolute increment of the dynamic pressure through the third key element, and the third output of the clock generator and the output of the third direct comparison unit are connected respectively to the three inputs of the threshold block, the output of which is connected to the input of the second recorder.