CN-121993064-A - Positive-circulation nonlinear displacement control method for strong drilling of sulfur-containing and gas-containing stratum

CN121993064ACN 121993064 ACN121993064 ACN 121993064ACN-121993064-A

Abstract

The invention discloses a positive circulation nonlinear displacement control method for strong drilling of a sulfur-containing and gas-containing stratum, which belongs to the technical field of displacement control methods, and comprises the steps of measuring the static liquid level of a drilling liquid column before drilling and pumping under the condition of leakage return of a drilling well, measuring the dynamic liquid level after drilling and pumping, calculating the liquid column pressure before drilling and pumping, calculating the stratum pressure after pumping and pumping, comparing whether the liquid column pressure before pumping and the stratum pressure after pumping and pumping are balanced or not, adjusting the annular air dynamic liquid level if unbalance exists, always keeping the annular liquid column pressure equal to or greater than the stratum pressure, enabling the annular liquid column pressure to stabilize a leakage layer, and adopting different displacements to meet the condition that the water under different annular gaps of a drill collar section and a drill rod section can carry drilled rock cuttings into the leakage layer after stabilizing the leakage layer. In the process of clean water strong drilling, the annular liquid level height above the leaking layer is controlled through positive circulation, so that the annular liquid column pressure is higher than the stratum pressure, and the pressure stabilizing layer is used for preventing overflow.

Inventors

HUANG BING
HE CHAO
WANG MINGHUA
ZHONG GUANGRONG
LAI XIAN
FU HUACAI
WANG HUAPING
CHEN TAO
ZHUO YUN
WANG YONG

Assignees

中国石油天然气集团有限公司
中国石油集团川庆钻探工程有限公司

Dates

Publication Date: 20260508
Application Date: 20241106

Claims (10)

1. A positive cycle nonlinear displacement control method for strong drilling of a sulfur-containing and gas-containing stratum is characterized by comprising the following specific steps: Step S1, under the condition of lost returns of a drilling well, measuring the static liquid level of a drilling liquid column before a drilling pump is started; step S2, under the condition of lost returns of the drilling well, measuring the height of the working fluid level after the drilling well is started to pump stably; Step 3, calculating the pressure of the liquid column before the pump is started by utilizing the static liquid level of the drilling liquid column measured before the pump is started in the drilling process; step S4, calculating formation pressure after pump start stabilization by using the measured working fluid level height after pump start stabilization of the well drilling; Step 5, comparing whether the liquid column pressure before the pump is started and the formation pressure after the pump is started and stabilized are balanced; step S6, if balance is carried out, the annular liquid column pressure is kept to press the gas-stabilizing layer; if unbalance exists, adjusting the level height of the ring air movement, and always keeping the annular liquid column pressure equal to or greater than the stratum pressure, so that the annular liquid column pressure presses a gas stabilizing layer; and step S7, after the gas stabilizing layer is pressed, adopting different displacement to meet the requirements of clear water strong drilling operation under different annular gaps between the drill collar section and the drill rod section, and taking the drilled rock scraps into the leakage layer.
2. The positive cycle nonlinear displacement control method for the heavy drilling of the sulfur-containing and gas-containing stratum according to claim 1, wherein the lost circulation situation in the step s1 comprises normal displacement heavy drilling and large displacement heavy drilling.
3. The positive circulation nonlinear displacement control method for the strong drilling of the sulfur-containing and gas-containing stratum is characterized in that step s6 is characterized in that the original static liquid level is kept during normal displacement strong drilling, the working liquid level is adjusted, the empty height of a wellhead section is reduced, the length of a drilling fluid column is increased, and the wall of the upper well of a leakage layer is stabilized under the conditions that the pressure of the stratum and the wall protecting capacity of the drilling fluid are balanced by the drilling fluid column pressure.
4. The positive circulation nonlinear displacement control method for the strong drilling of the sulfur-containing and gas-containing stratum according to claim 1-2, wherein in the step s7, after the gas-stabilizing layer is pressed, when the normal displacement strong drilling is kept, the drill collar section gradually enters the position below the leakage layer along with the increase of the drilling depth, the annular flow is increased, and rock fragments are brought into the leakage layer.
5. The positive cycle nonlinear displacement control method for the strong drilling of the sulfur-containing and gas-containing stratum is characterized in that step s6 is performed by keeping the liquid level of the normal displacement strong drilling when the large displacement strong drilling is performed, increasing the liquid level of the working liquid level of the displacement strong drilling again, controlling the normal displacement strong drilling range after the pump is opened by the strong drilling when the large displacement strong drilling is performed, and controlling the displacement above the normal displacement strong drilling after the normal displacement strong drilling is achieved.
6. The positive circulation nonlinear displacement control method for the strong drilling of the sulfur-containing and gas-containing stratum is characterized in that in the step s7, during the strong drilling of the large displacement, the drilling depth is increased, the drill collar section and the drill rod section are all positioned below a leakage layer, the annular gap of the drill collar section and the annular gap of the drill rod section are increased and the annular return speed is reduced at the same time, and at the moment, the displacement is increased again for the strong drilling, so that rock scraps are brought into the leakage layer.
7. A positive-cycle nonlinear displacement control method for heavy drilling of a sulfur-containing and gas-containing stratum according to claim 1-2, wherein the drilling wellhead is controlled by using a rotary blowout preventer in the step s1.
8. The positive circulation nonlinear displacement control method for the strong drilling of the sulfur-containing and gas-containing stratum according to the claim 1-2, wherein in the step s1, a stable way is adopted to clean water and drill the strong well until the well is completed or the well depth is completed, and the method enters the well completion operation.
9. The positive circulation nonlinear displacement control method for the strong drilling of the sulfur-containing and gas-containing stratum is characterized in that the normal displacement strong drilling well hole is 152.4mm, the positive circulation pump is started, the displacement is 13-20L/s, and the annulus return speed is 1.28-1.97m/s.
10. The positive circulation nonlinear displacement control method for the strong drilling of the sulfur-containing and gas-containing stratum is characterized in that the large displacement strong drilling well hole is 152.4mm, the positive circulation pump is started, the displacement is greater than 20L/s, and the annulus return speed is greater than or equal to 1.97m/s.

Description

Positive-circulation nonlinear displacement control method for strong drilling of sulfur-containing and gas-containing stratum Technical Field The invention belongs to the technical field of displacement control methods, and particularly relates to a positive circulation nonlinear displacement control method for a strong drilling of a sulfur-containing and gas-containing stratum. Background The eastern yellow grass canyon and bronze gorge structures in Chuan Yu area have complex stratum pressure systems, frequent well leakage in the drilling process, well control dangerous situations of lower leakage and upper blowout occur underground, well instability collapses drilling tools to meet clamping, particularly malignant well leakage often occurs when the Jiang river group drills to meet a fractured stratum, and the plugging mode is difficult to work, so that very high cost is paid in the drilling work of the area every year. The "strong drilling" is a target well depth (horizon) which is forced to drill downwards by a special process without normal drilling (well drilling) conditions. The normal drilling refers to the fact that under normal displacement forced drilling, the flow rates of an inlet and an outlet are balanced (equal), the annular liquid column pressure can balance the stratum pressure, stratum fluid (the fluid comprises gas and liquid) is stabilized, and the stratum fluid is prevented from channeling upwards. The "strong drilling" herein mainly refers to a process of increasing the inlet displacement and raising the annulus liquid column height when the outlet flow rate under the normal displacement strong drilling is zero (with or without inlet and outlet) and the annulus liquid column pressure cannot balance the formation pressure, and calculating the liquid column pressure by measuring the annulus liquid level height, so that the annulus liquid column pressure can basically balance the formation pressure, and forcibly drilling down the target well depth (horizon) The grass reservoir 3 well was drilled to a depth of 1243.61m at 2023, 5 and 30 days 07:46 to find out that the outlet was lost, indicating that the designed fractured formation was drilled. When the hoisting drill reaches 1070.8m, the outlet returns, the overflow is judged, the well is immediately closed, the vertical pressure is 0MPa, the casing pressure is 1.80MPa, and the casing pressure is 1.80 ≡4.41MPa during observation. 4-well Jia section of grass reservoir was tested to contain 0.134g/m3 (89 ppm) of hydrogen sulfide, and the presence of a drilling tool in the well was a possibility of hydrogen embrittlement for long periods of time. The copper storage 4-well five-open 215.9mm well is drilled to the well depth 2797.27m by adopting a potassium polysulfonate drilling fluid with the density of 1.05g/cm < 3 > and the viscosity of 47s in a compound way, and the well is drilled to the well depth 2986.87m by adopting clear water in a strong way (the intermittent torque fluctuation from the drilling to 2940-2986.87m is large, the drilling is difficult, the well collapses, and the intermittent drilling is blocked). The copper storage 6-well five-open 152.4mm well is drilled by adopting potassium polysulfonate drilling fluid with the density of 1.05g/cm < 3 > and the viscosity of 47s until well leakage appears at the well depth 2672.82m, the drilling is observed to be 2688.09m (delay depth 2681.80 m), the well leakage is lost, the pumping pressure is reduced to 0MPa, the static liquid level is at about 1420 m, the potassium polysulfonate drilling fluid is adopted to be strongly drilled to a well depth 2866.37m long-emerging group, the outlet is seen to be liquid return, the liquid level rises to 0.6m < 3 >, the well is closed, the casing pressure is changed from 0 ≡4.1MPa, and the vertical pressure is 0MPa. The copper storage 8-well five-open 152.4mm well bore is drilled to the well depth 2892.35m by adopting potassium polysulfonate drilling fluid with the density of 2.15g/cm3 and the viscosity of 56s, the pumping pressure is 22.1MPa, the displacement is 722L/min, the outlet flow is found to be 9.3% ∈0%, the well leakage returns, and the clear water is strongly drilled to the well depth of the finished well. The following problems exist in the face of the current conditions of the cracking and malignant well leakage of sulfur-containing and gas-containing stratum of the yellow grass canyon and bronze gong canyon construction based on the conventional clean water drilling operation: 1. The crack nature of the sulfur-containing and gas-containing stratum and the well control risk under the malignant well leakage condition can not be controlled. 2. The annular liquid level cannot be controlled, so that the pressure of the liquid column of the drilling fluid and the pressure of the leakage layer are unbalanced, and the well wall and the well track cannot be protected. 3. And a large amount of manpower and material resource cost is consumed