CN113216949B - Oil testing and reservoir transformation method for ultra-deep high-pressure exploratory well - Google Patents
Oil testing and reservoir transformation method for ultra-deep high-pressure exploratory well Download PDFInfo
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
Abstract
The application discloses an oil testing and reservoir reconstruction method of an ultra-deep high-pressure exploratory well, which comprises the following steps of: s1, predicting a fracture pressure profile; s2, optimizing the perforation section and the cracking position; s3, optimizing the high-density well killing fluid; s4, checking and optimizing the strength of the perforation-acidification-test tube; s5, modifying the type and the scale of the liquid to be optimized; s6, perforating by adopting a time delay detonation mode; s7, high-density well killing fluid is subjected to trial extrusion; s8, pumping a high-temperature-resistant acid liquor system; s9, performing over-displacement operation. According to the application, by combining geological requirements and engineering capability, the reservoir reconstruction process is optimized, the hydrocarbon reservoir is protected, the engineering complexity is reduced, the well control risk is reduced, the success rate of the ultra-deep high-pressure exploratory well in fracturing the reservoir is improved, and the operation cost is reduced.
Description
Technical Field
The application relates to the technical field of reservoir reconstruction, in particular to an oil testing and reservoir reconstruction method of an ultra-deep high-pressure exploratory well.
Background
Along with the expansion of the exploration field to the ultra-deep reservoir with the side structure, the target layer is deeper, the pressure is higher, the temperature is higher, the well structure is more complex, meanwhile, the geological engineering reference information of the exploratory well is lacking, and the construction risk is unknown. Ultra-deep exploratory wells generally have ultra-deep and ultra-high temperature, and part of ultra-high pressure characteristics, and face the difficult problems of high fracture pressure, short acid solution acting distance and high risk of pipe column corrosion. The ultra-deep high pressure and high temperature storage retrofit method generally comprises the following steps: the method aims at opening the reservoir and improving the transformation range as much as possible under the ultra-deep high-temperature environment without considering the problem of well control risk caused by the fact that the reservoir cannot be opened by the ultra-deep ultra-high-pressure reservoir. Conventional reservoir fracturing measures often adopt a weighted acid fracturing process to reduce reservoir fracturing pressure, and if reservoir acid cannot be fractured, the acid cannot flow back and stay in the stratum to cause corrosion of downhole tubular column tools, so that the downhole is complicated, and the oil testing cost is increased.
Disclosure of Invention
Aiming at the technical problems, the application provides the oil testing and reservoir reconstruction method for the ultra-deep high-pressure exploratory well, which can reduce underground complexity, improve construction success rate and improve reservoir reconstruction effect.
The application is realized by the following technical scheme:
an oil testing and reservoir reconstruction method for an ultra-deep high-pressure exploratory well comprises the following steps:
s1, predicting a fracture pressure profile;
s2, optimizing the perforation section and the cracking position;
s3, optimizing the high-density well killing fluid;
s4, checking and optimizing the strength of the perforation-acidification-test tube;
s5, modifying liquid type and scale optimization
S6, perforating by adopting a time delay detonation mode;
s7, high-density well killing fluid is subjected to trial extrusion;
s8, pumping a high-temperature-resistant acid liquor system;
s9, performing over-displacement operation.
Further preferably, in step S1, the fracture pressure profile prediction method includes: the method comprises the steps of obtaining original logging data, obtaining rock mechanics and ground stress data by taking a core of a test oil layer to conduct experiments, and carrying out iteration calculation on fracture pressure values of stratum with different depths as fracture pressure sections by combining a fracture pressure empirical formula and longitudinal and transverse acoustic time differences and densities of the original logging data.
Specifically, fracture pressure profile prediction may be achieved by: the method comprises the steps of obtaining reservoir original acoustic logging data, taking a core to conduct rock mechanics and ground stress experiments to obtain data such as Young's modulus, poisson's ratio, horizontal minimum principal stress, horizontal maximum principal stress and the like, and carrying out iteration calculation on fracture pressure values of stratum with different depths, namely fracture pressure sections, according to a fracture pressure empirical formula and longitudinal and transverse acoustic time differences and densities of the original logging data.
Further preferably, in step S2, logging data, core and crack development conditions are comprehensively analyzed, and geological dessert development areas are selected as perforation segments; and selecting a lower value of fracture stress as a perforation initiation point in combination with the fracture stress profile.
Preferably, when the perforation section and the cracking position are preferred, the well section with high siliceous and argillaceous content is avoided, the distance from the water layer is more than 30m, and the coupling position is avoided by more than 2 m.
Further preferably, in step S3, the equivalent well control fluid density is calculated according to the fluid column pressure satisfying the well control safety condition, and the well control fluid type is selected according to different density requirements.
Further preferably, calculating the density of the well killing liquid, wherein the lower limit of the equivalent well killing liquid density corresponding to the difference between the formation pore pressure and the highest well closing pressure of a wellhead is min { the safe bearing } equivalent well killing liquid density of an oil pipe, a casing annulus and a downhole tool method; and (3) selecting the type of the well killing fluid: density of less than 1.5g/cm 3 Selecting solid-free well killing liquid with density higher than 1.5g/cm 3 Selecting superfine powder well killing liquid. The well control liquid needs to develop and reform the compatibility experiment of the acid fracturing system, and ensures compatibility with the acid fracturing system.
The formula of the solid-phase-free well killing fluid is preferably as follows: 60 to 85 percent of clear water, 0.2 to 1.0 percent of deoxidizer, 0.2 to 1.0 percent of corrosion inhibitor and HWJZ weighting agent to the required density.
The formula of the superfine powder well killing liquid is preferably as follows: 2 to 6 percent of raw ore soil slurry, 0.8 percent of caustic soda, 0.5 to 1 percent of PAC-LV, 2 to 5 percent of RSTF, 2 to 5 percent of SMC and superfine barite powder to the required density. The above percentages refer to mass percentages.
Further optimizing the description, in order to avoid the failure risk of the packer and the tool caused by underground heavy mud precipitation, the whole well is replaced by high-density solid-free or superfine micropowder well control working fluid before oil testing, and the well is put into a perforation-acidification-test tubular column after pressure testing is qualified. The lower incident hole section of the construction string is delimited.
And (3) after the tubular column is lowered to a preset position, performing electric measurement and depth correction, namely performing annular pressurization perforation, confirming perforation, putting steel balls into the hole, performing progressive pressurization and setting in the oil pipe, and after the seal is checked to be qualified, setting off the ball seat core.
Further preferably, in step S4, the perforation-acidification-test string structure includes an oil pipe I, an expansion joint, an oil pipe II, a DBE valve, an HP-RDS circulation valve, an RTTS safety joint, an RTTS packer, a tailpipe safety joint, an oil pipe III, and a delayed perforating gun set, which are sequentially connected from top to bottom.
Regarding (4) perforating-acidizing-testing string strength check and preferably further optimization: the design principles of the oil casing combination configuration, the packer and the downhole tool are as follows: (1) the pressure bearing under various working conditions is more than the stratum fracture pressure, and (2) the pipe column has a simple structure so as to reduce the underground complex probability, simplify unnecessary tools such as temperature, pressure gauge and the like, and reduce the underground complex probability.
By carrying out mechanical checking of a pipe column, perforation impact load simulation and testing of hydraulic anchor permission of a packer, top force and initial setting pressure optimization of the packer, the 88.9+73.0mm composite oil pipe oil testing pipe column is adopted, wherein the wall thickness of an 88.9mm oil pipe is more than 7.34mm, the wall thickness of a 73.0mm oil pipe is 5.51, and the oil testing operation safety requirement of an ultra-deep ultra-high pressure high temperature well is met.
Considering that the open flow after the mechanical test oil combined pipe column test requires the coiled tubing to be blown down for liquid nitrogen induced injection, the internal diameter of the oil pipe combination above the pipe column packer is required to meet the requirement of the conventional 2 'or 2-1/2' coiled tubing.
The packer position should consider the distance between the perforation top boundary and the tail pipe bell mouth, if the distance is less than 200m, the packer is set in the oil layer casing above the tail pipe bell mouth, otherwise, the dual sieve tube is arranged on the pipe column below the packer or the packer is set in the tail pipe, so that the failure probability of the packer during perforation and reconstruction is reduced.
In addition, the perforating is further optimized by adopting a delayed detonation mode, the perforation is performed by adopting a pressurizing delayed detonation mode, and after the initiator is started, the pressure of a wellhead is rapidly reduced by delay, so that the base pressure of perforation impact load is reduced, and the perforation condition is monitored. The perforation impact load pressure peaks are designed to be above the fracture pressure of the formation, below the yield limit of the tubing and the pressure limit of the casing. The perforating gun is adopted, the large aperture is adopted, the pore density is 16 holes/m, and the phase is 60 degrees.
Further preferably, in step S5, the retrofitting of the liquid type and scale optimization method comprises the steps of: performing productivity simulation, optimizing the optimal transformation seam length, simulating the seam length relation of the seam under different construction scale conditions, and calculating the optimal construction scale range; and (3) controlling the acidizing operation time by combining the corrosion resistance time of the downhole tool, and calculating the upper limit of the acid liquor scale consumption according to the relation between the acidizing operation time and the displacement.
In the operation process of pumping the high-temperature-resistant acid liquor system, the acid liquor system with good high-temperature resistance, resistance reduction and filtration loss reduction performance is selected, and the resistance reduction rate is more than 60 percent for ensuring the construction discharge capacity.
And selecting an acid absorption pressure gradient according to the data such as drilling fluid density, stratum pressure coefficient, horizontal minimum main stress gradient and the like, and calculating the optimal construction displacement by combining wellhead pressure limiting.
The optimal construction scale range can be calculated by utilizing commercial software to simulate the optimal half-length of the split under the conditions of optimal half-length of the split and different construction scales. And (3) by combining the corrosion resistance time of the downhole tool, controlling the acidification operation time, and calculating the upper limit of the acid liquor scale consumption according to the relationship between the acidification operation time and the displacement.
After the well killing fluid is successfully squeezed, the acid fluid is squeezed out, the discharge capacity is gradually increased to the wellhead pressure limiting value, and the pressure is increased to 20m before the acid injection is finished 3 Gradually lower displacement pump is started to avoid the occurrence of supplyThe empty pump of fracturing truck that liquid is insufficient causes the construction discharge capacity unstable.
And controlling the construction oil pressure and the casing pressure according to 80% of the minimum bearing values of the oil casing, the packer and the downhole tool under different working conditions. The whole process of acid pressure operation monitors the pressure of each annulus and timely applies the balance sleeve pressure of the annulus.
Further preferably, in the steps S6 and S8, the high-density well killing fluid trial extrusion and high-temperature acid pressure resistant construction method comprises the following steps:
1) An incidence hole-acidizing-testing tubular column under the condition of high-density well killing fluid;
2) Setting a packer, and pressurizing and checking the seal of an annulus;
3) Pressurizing and delaying detonation perforation of the oil pipe;
4) Trial-extruding high-density well killing liquid into stratum;
5) High extrusion high temperature resistant acid liquor.
Regarding the trial extrusion of the high-density well control fluid, further optimization and explanation are as follows: the pressure of a construction hydrostatic column is increased through original high-density well killing liquid in a shaft, the probability of fracturing a reservoir is improved, and meanwhile, the safety risks that acid liquid cannot be injected into the shaft before fracturing the reservoir and is retained for a long time to cause corrosion of a downhole tubular column are avoided.
And calculating the highest annular control casing pressure in the trial extrusion stage and the high extrusion stage by combining the formation fracture pressure, the operating pressure of the downhole tool, the bearing pressure of the oil casing and the upper limit of the bearing pressure of the packer, so as to deduce the highest construction pump pressure, namely, the highest construction pressure is min { the bearing pressure of the packer, the highest bearing pressure of the oil casing annulus + the liquid column pressure of the oil pipe, the maximum bearing pressure of the wellhead }, wherein the highest bearing pressure of the oil casing annulus is min (the maximum bearing pressure of the weak point of the casing and the maximum operating pressure of the downhole tool).
And (3) a trial extrusion step: and (3) testing the pressure of pumping equipment, a construction pipeline, a wellhead and the like before trial extrusion. When in construction, the sleeve gate is closed, the solid-phase-free/superfine micropowder oil testing working fluid is pressurized step by step in test extrusion, the oil sleeve pressure is controlled, and the safety of the oil layer sleeve, the well completion packer, the pipe column, the underground test tool and the like is ensured. And if the construction curve shows that the pressure is rapidly reduced, performing high acid squeezing construction.
Further preferably, in step S9, the over-displacement operation includes: designing 110% -120% of the sum of displacement oil taking pipe volume and perforation section well Jian Rongji; the water-reducing and blocking agent is adopted for displacement, the formula of the water-reducing and blocking agent is 1.0 percent of the water-reducing agent and 1.0 percent of the cleanup additive, and the discharge capacity is 2m 3 /min～3m 3 /min。
And the displacement operation is generally adopted to avoid serious reduction of the diversion capacity caused by fracture wall collapse due to the overreaction of near-wellbore acid rock.
The application has the following advantages and beneficial effects:
according to the application, by combining geological requirements and engineering capability, the reservoir reconstruction process is optimized, the hydrocarbon reservoir is protected, the engineering complexity is reduced, the well control risk is reduced, the ultra-deep high-pressure exploratory well reservoir reconstruction success rate is improved, and the operation cost is reduced.
The application provides an oil testing and reservoir transformation method for an ultra-deep ultra-high pressure high-temperature exploratory well. According to the application, a perforation section is optimized by calculating a fracture pressure section, a high-density environment-friendly working hydraulic well is adopted, a perforation-acidification-test combined tubular column is arranged, perforation is carried out by adopting a time-delay detonation mode, the original high-density well-killing liquid is utilized for trial extrusion, and after the trial extrusion is successful, a high-temperature acid liquid system is pumped to replace the water-dropping operation. The underground complexity can be reduced, the construction success rate is improved, and the reservoir reconstruction effect is improved.
The application has the following advantages:
1. because the formation pressure is high, high-density well killing liquid is needed to test oil, and a solid-free/superfine micropowder oil testing working hydraulic well is adopted, the underground complexity such as packer deblocking caused by mud precipitation is reduced;
2. the solid-phase-free/superfine micro powder oil testing working solution is adopted for test extrusion, so that the risk of corrosion of the underground tubular column caused by incapability of flowback of acid liquor when a reservoir cannot be opened is reduced;
3. unnecessary downhole tools are reduced, the tubular column structure is simplified, and the abnormal risk of the downhole tools in a high-pressure high-temperature environment is reduced;
4. and the construction scale is optimized by using the corrosion-resistant time of the downhole tool, so that the corrosion of the downhole tubular column or the tool caused by long-time operation is avoided.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:
FIG. 1 is a flow chart of a reservoir retrofit method of the present application.
FIG. 2 is a schematic diagram of a perforating acidizing test combined string structure according to the present application.
FIG. 3 is a graph of the JT1, well integrated logging effort for example 2;
FIG. 4 is a cross-sectional view of the fracture pressure of JT1 well according to example 2;
FIG. 5 is a simulation of the relationship between the scale of acid fracturing and the half length of a fracture using FracPro PT software in example 2.
In the drawings, the reference numerals and corresponding part names: 1-oil pipe I, 2-expansion joint, 3-oil pipe II,4-DBE valve, 5-HP-RDS circulation valve, 6-RTTS safety joint, 7-RTTS packer, 8-tail pipe safety joint, 9-oil pipe III, 10-time delay perforating gun group.
Detailed Description
For the purpose of making apparent the objects, technical solutions and advantages of the present application, the present application will be further described in detail with reference to the following examples and the accompanying drawings, wherein the exemplary embodiments of the present application and the descriptions thereof are for illustrating the present application only and are not to be construed as limiting the present application.
Example 1
The embodiment provides an oil testing and reservoir reconstruction method for an ultra-deep high-pressure exploratory well, which is specifically as follows:
step 1: fracture pressure profile prediction
The method comprises the steps of obtaining reservoir original acoustic logging data, taking a core to conduct rock mechanics and ground stress experiments to obtain Young modulus, poisson's ratio, horizontal minimum principal stress, horizontal maximum principal stress and other data, and iteratively calculating fracture pressure values of stratum with different depths, namely fracture pressure sections, according to a fracture pressure empirical formula and longitudinal and transverse acoustic time differences and densities of the original logging data, so that basis is provided for perforation position optimization and compressibility evaluation.
Step 2: preferably the perforation section and the initiation site
Comprehensively analyzing logging data, rock core and crack development conditions, preferably selecting a geological dessert development area as a perforation section, and selecting a lower value of fracture stress as a perforation starting point by combining a fracture stress section. Avoid the development well section with high siliceous and argillaceous content, and avoid the coupling position by more than 2m from the water layer by more than 30 m.
Step 3: high density well control fluid is preferred
In order to avoid the failure of a packer and a tool caused by underground heavy mud precipitation, the whole well is replaced by high-density solid-free or superfine micropowder well control working fluid before acidification and transformation, and the well is put into a perforation-acidification-test tubular column after pressure test is qualified. And constructing the top boundary of the lower incident hole section of the tubular column.
And calculating the density of the well killing liquid, wherein the lower limit of the equivalent well killing liquid density corresponding to the difference between the formation pore pressure and the highest well closing pressure of the wellhead is min { the safe bearing } equivalent well killing liquid density of an oil pipe, a casing annulus and a downhole tool.
The type of the well control liquid is selected, and the density is lower than 1.5g/cm 3 Selecting solid-free well killing liquid with density higher than 1.5g/cm 3 Selecting superfine powder. The well control liquid needs to develop and reform the compatibility experiment of the acid fracturing system, and ensures compatibility with the acid fracturing system.
And (3) after the tubular column is lowered to a preset position, performing electric measurement and depth correction, namely performing annular pressurization perforation, confirming perforation, putting steel balls into the hole, performing progressive pressurization and setting in the oil pipe, and after the seal is checked to be qualified, setting off the ball seat core.
Step 4: perforation-acidizing-testing string strength check and preference
The design principles of the oil casing combination configuration, the packer and the downhole tool are as follows: (1) the pressure bearing under various working conditions is more than the stratum fracture pressure, and (2) the tubular column has a simple structure so as to reduce the underground complex probability.
The oil pipe, the expansion joint, the circulating valve, the safety joint, the testing packer, the well completion packer, the oil pipe, the delay initiator and the perforating gun are adopted, so that unnecessary tools such as a temperature gauge, a pressure gauge and the like are simplified, and underground complex probability is reduced.
By carrying out mechanical checking of a pipe column, perforation impact load simulation and testing of hydraulic anchor permission of a packer, top force and initial setting pressure optimization of the packer, the 88.9+73.0mm composite oil pipe oil testing pipe column is adopted, wherein the wall thickness of an 88.9mm oil pipe is more than 7.34mm, the wall thickness of a 73.0mm oil pipe is 5.51, and the oil testing operation safety requirement of an ultra-deep ultra-high pressure high temperature well is met.
Considering that the open flow after the mechanical test oil combined pipe column test requires the coiled tubing to be blown down for liquid nitrogen induced injection, the internal diameter of the oil pipe combination above the pipe column packer is required to meet the requirement of the conventional 2 'or 2-1/2' coiled tubing.
The packer position should consider the distance between the perforation top boundary and the tail pipe bell mouth, if the distance is less than 200m, the packer is set in the oil layer casing above the tail pipe bell mouth, otherwise, the dual sieve tube is arranged on the pipe column below the packer or the packer is set in the tail pipe, so that the failure probability of the packer during perforation and reconstruction is reduced.
Step 5: retrofitting liquid types and scale preferences
The acid liquor system is a gelled acid liquor system with high temperature resistance, resistance reduction and high fluid loss performance, and the resistance reduction rate is more than 60 percent for ensuring the construction discharge capacity.
And selecting an acid absorption pressure gradient according to the data such as drilling fluid density, stratum pressure coefficient, horizontal minimum main stress gradient and the like, and calculating the optimal construction displacement by combining wellhead pressure limiting.
And simulating the optimal half-length of the crack under the conditions of optimal construction scale by utilizing commercial software to simulate the optimal half-length of the crack under the conditions of different construction scales. And (3) by combining the corrosion resistance time of the downhole tool, controlling the acidification operation time, and calculating the upper limit of the acid liquor scale consumption according to the relationship between the acidification operation time and the displacement.
Step 6: perforation by adopting time delay detonation mode
And (3) perforating by adopting a pressurizing and time-delay detonation mode, and rapidly reducing the pressure of a wellhead through time delay after starting the initiator, so that the base pressure of perforation impact load is reduced, and the perforation condition is monitored.
The perforation impact load pressure peaks are designed to be above the fracture pressure of the formation, below the yield limit of the formation and the pressure limit of the casing.
The perforating gun is adopted, the large aperture is adopted, the pore density is 16 holes/m, and the phase is 60 degrees.
Step 7: high-density well killing fluid trial extrusion
The pressure of a construction hydrostatic column is increased through original high-density solid-free/well killing liquid in a shaft, the probability of fracturing a reservoir is improved, and meanwhile, the safety risks that acid liquid cannot be injected into the shaft before fracturing the reservoir and is retained for a long time to cause corrosion of a downhole tubular column are avoided.
And calculating the highest annular control casing pressure of the trial extrusion stage and the high extrusion stage by combining the formation fracture pressure, the operating pressure of the downhole tool and the upper limit of the bearing strength of the oil pipe and the casing, so as to deduce the highest construction pump pressure.
And (3) a trial extrusion step: and (3) testing the pressure of pumping equipment, a construction pipeline, a wellhead and the like before trial extrusion. When in construction, the sleeve gate is closed, the solid-phase-free/superfine micropowder oil testing working fluid is pressurized step by step in test extrusion, the oil sleeve pressure is controlled, and the safety of the oil layer sleeve, the well completion packer, the pipe column, the underground test tool and the like is ensured. And if the construction curve shows that the pressure is rapidly reduced, performing high acid squeezing construction.
Step 8: high-temperature-resistant gelled acid for pumping
After the well killing fluid is successfully squeezed, the acid fluid is squeezed out, the discharge capacity is gradually increased to the wellhead pressure limiting value, and the pressure is increased to 20m before the acid injection is finished 3 And the lower displacement pump is started to be gradually filled, so that the phenomenon of empty pumping of the fracturing truck caused by insufficient liquid supply is avoided.
And controlling the oil pressure and the casing pressure according to 80% of the minimum bearing values of the oil casing, the packer and the downhole tool under different working conditions. The whole process of acid pressure operation monitors the pressure of each annulus and timely applies the balance sleeve pressure of the annulus.
Step 9: displacement water-stopping operation
And the displacement operation is generally adopted to avoid serious reduction of the diversion capacity caused by fracture wall collapse due to the overreaction of near-wellbore acid rock. The general displacement takes oil pipe volume plus perforation section well Jian Rongji sum of 110-120%, adopts the water-reducing agent to displace, the water-reducing agent formula is 1.0% of the resistance-reducing agent plus 1.0% of the cleanup additive, and the displacement takes 2m 3 /min～3m 3 /min。
By means of the technical scheme, the application has the advantages that: (1) because the formation pressure is high, high-density well killing liquid is needed to test oil, a solid-free/superfine powder oil testing working liquid is needed to test oil, underground complex such as packer deblocking caused by slurry precipitation is reduced, (2) solid-free/superfine powder oil testing working liquid is adopted to test extrusion, underground pipe column corrosion risk caused by incapability of flowback of acid liquor when a reservoir cannot be opened is reduced, (3) unnecessary underground tools are reduced, pipe column structures are simplified, abnormal risk of the underground tools in a high-pressure high-temperature environment is reduced, and (4) the construction scale is optimized by utilizing corrosion-resistant time of the underground tools, so that underground pipe column or tool corrosion caused by long-time operation is avoided.
Example 2
The oil testing and reservoir reconstruction method of the ultra-deep and ultra-high pressure exploratory well provided by the embodiment 1 is taken as an example to specifically illustrate the oil testing and reservoir reconstruction method of the ultra-deep and ultra-high pressure exploratory well. The reservoir depth of the JT1 well is 6972 m-7026 m, the predicted formation pressure coefficient is 2.20, and the formation temperature is 154.2 ℃. The concrete transformation method is as follows:
based on the logging data, a section with dolomite development, pore penetration development, low natural gamma value and high gas content is selected as a geological dessert section, as shown in figure 3.
Rock mechanics and ground stress experiments are carried out on the core to obtain data such as Young modulus, poisson ratio, horizontal minimum main stress, horizontal maximum main stress and the like, and fracture pressure values of stratum with different depths, namely fracture pressure sections, are calculated by combining a fracture pressure empirical formula and longitudinal and transverse acoustic time differences and densities of original logging data, and are shown in fig. 4.
The geological dessert development section and the section with lower fracture pressure are selected as perforation sections, namely 6972 m-6982 m, 6984 m-6993 m and 7006 m-7026 m.
The preferable oil test pipe column structure according to the load of the packer under different working conditions is as follows: oil pipe I1, expansion joint 2, oil pipe II3, DBE valve 4, HP-RDS circulation valve 5, RTTS safety joint 6, RTTS packer 7, tail pipe safety joint 8, oil pipe III9, time delay perforating gun group 10.
The lowest triaxial safety coefficient of the pipe column is 1.68. The downhole tool used a 75/8 "completion packer (105 MPa operating pressure differential) and a 5" APR test tool.
Geological prediction stratum pressure coefficient is 2.20, stratum pressure is predicted to be 151.0MPa, highest well closing pressure of a wellhead is predicted to be 126.86MPa, the highest well closing pressure of a pure gas wellhead is allowed to be only 113MPa, the pure gas well closing requirement is not met, and a well completion packer pipe column is arranged in high-density well killing liquid to ensure the safety of oil testing of the stratum.
The upper limit of the pressure bearing of the circulating valve at the weak point of the tubular column is 60MPa, and the upper limit of the density of the well control fluid is calculated to be 1.4g/cm 3 . Calculation of 1.4g/cm 3 The weighting density is 112MPa of the bottom hole liquid column pressure, the highest bottom hole treatment pressure under the highest oil pressure is expected to be 220MPa, and the bottom hole treatment pressure cannot be improved by further improving the weighting density.
Therefore, 1.4g/cm was selected 3 The solid-free well killing liquid is used as an oil testing working liquid and a pre-weighting liquid system to carry out acid fracturing pre-test extrusion. The formula is as follows: clear water (875L) +HWJZ (525 kg) +0.5% oxygen scavenger+0.5% corrosion inhibitor.
TABLE 1 calculation of downhole operation pressure at different weight densities
Impact load checking analysis is carried out by pulsfrac software, preferably the oil pipe combination is 88.9mm oil pipe (wall thickness 9.53 mm) +88.9mm oil pipe (wall thickness 7.34 mm) +HP-RDS circulating valve+RTTS safety joint+completion packer+88.9 mm oil pipe (wall thickness 7.34 mm) +shock absorber+delay initiator+perforating gun group, and the tensile/compression safety coefficient of the oil pipe below the packer and the buckling joint under perforation impact load is more than 1.5.
Table 2 tensile/compressive safety factor of tubing below packer and stab connector under perforation impact load
127-type perforating gun, 1m bullet, 16 holes/m hole density, 60 degrees phase and detonation mode: and hydraulic delay detonating. The perforation position avoids the tubing coupling by more than 2 m.
Calculation of 1.40g/cm 3 The maximum perforation impact load under the solid-phase-free working fluid is about 230kN, and the phi 88.9mm delta 7.34mm oil pipe below the packer does not bend, deform and fracture.
The total well replacement before oil test is 1.4g/cm 3 And (3) no solid phase test working fluid, perforating-acidizing-testing tubular columns, electrically measuring and correcting depth, throwing a setting ball, and pressurizing and setting the packer. And (5) pressurizing and sealing the annular space, and stopping the ball seat after the sealing is qualified.
The adopted acid liquor system is high-temperature-resistant gelled acid, the temperature resistance can reach 180 ℃, the apparent viscosity is 25mPa & s, the retarding effect is good, the gelled acid rock reaction rate is 31.1% of that of conventional acid under the condition of 160 ℃ in an indoor experiment test, the indoor resistance reduction rate reaches 70%, and the on-site resistance reduction rate reaches more than 65%.
TABLE 3 friction conditions of 160 ℃ resistance gelled acid liquid system field test
According to the density of drilling mud of 2.29g/cm 3 The pressure coefficient of the combined stratum is 2.2, the minimum main stress gradient of the level obtained by experiments is 0.233 MPa/m-0.235 MPa/m, and the pressure gradient value of the acid absorption is selected to be 0.022 MPa/m-0.024 MPa/m. Adopting a 140MPa wellhead, and selecting 3.0m of construction displacement 3 /min～4.0m 3 /min。
TABLE 4 construction displacement prediction of gelled acid
According to the acidizing corrosion resistance of the test tool, in order to ensure the safety of the pipe column, the acid consumption time is recommended to be controlled within 4 hours, and the construction discharge capacity is predicted to be 3.0m 3 /min～4.0m 3 Per min, acid scale < 480m 3 . The PT software is adopted to simulate acid pressure, and the length of an acid etching seam is 300-400 m 3 And thereafter substantially stops growing. Comprehensive analysis, the acid liquor dosage is selected to be 400m 3 。
The construction adopts a 140MPa wellhead, and the oil pressure is controlled according to 125 MPa; the packer is a well completion packer with a sealing pressure difference of 105 MPa: 1.4g/cm 3 The annular control pressure of the solid-phase-free well control fluid is 68MPa, the low value of the operating pressure of the RDS valve at the upper part of the packer is 70MPa, and the balance pressure is controlled according to 55MPa in order to avoid opening the RDS valve in the construction process.
The construction steps are as follows: (1) 1.4g/cm was used 3 Performing trial extrusion on solid-phase-free well killing fluid, controlling pumping pressure to be less than or equal to 84.0MPa and balanced casing pressure to be less than or equal to 55.0MPa, (2) performing high extrusion gelled acid operation if the trial extrusion is successful, wherein the acid liquid scale is 400m 3 The construction discharge capacity is more than or equal to 3.0m 3 Controlling pumping pressure to be less than or equal to 125.0MPa, and balancing jacket pressure to be less than or equal to 55.0MPa; (3) high squeeze water-reducing, scale design is over-displaced, 1.1 times the sum of the oil pipe volume and the perforation section casing volume, namely 27.5m 3 Construction discharge capacity is 2.0-2.5 m 3 A/min; (4) stopping pumping, recording pressure drop for 5-10 min, and then opening the well to drain. The concrete construction pump sequences are shown in table 5.
Table 5JT1 well acid fracturing construction pumping program
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the application, and is not meant to limit the scope of the application, but to limit the application to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the application are intended to be included within the scope of the application.
Claims (7)
1. The method for testing oil and reforming the reservoir of the ultra-deep high-pressure exploratory well is characterized by comprising the following steps of:
s1 fracture pressure profile prediction
Acquiring original logging data, taking a core of a test oil layer to perform experiments to acquire rock mechanics and ground stress data, and carrying out iteration calculation on fracture pressure values of stratum with different depths by combining a fracture pressure empirical formula and longitudinal and transverse acoustic time difference and density of the original logging data to serve as fracture pressure sections;
s2, optimizing perforation section and cracking position
Comprehensively analyzing logging data, rock core and crack development conditions, and selecting geological dessert development areas as perforation sections; and selecting a lower value of fracture stress as a perforation starting point by combining the fracture stress profile;
s3, optimizing the high-density well killing fluid;
s4, checking and optimizing the strength of the perforation-acidification-test tube;
s5, modifying the type and the scale of the liquid to be optimized;
s6, perforating by adopting a time delay detonation mode;
s7, high-density well killing fluid is subjected to trial extrusion;
s8, pumping a high-temperature-resistant acid liquor system;
s9, over-displacement operation
Designing 110% -120% of the sum of displacement oil taking pipe volume and perforation section well Jian Rongji; the water is replaced by adopting a water-reducing and blocking agent formula of 1.0 percent of the water-reducing agent and 1.0 percent of the cleanup additive, and the discharge capacity is 2m 3 /min~3m 3 /min。
2. The method for testing oil and reforming a reservoir of an ultra-deep high-pressure exploratory well according to claim 1, wherein in step S3, the equivalent well control fluid density is calculated according to the fluid column pressure under the condition of meeting the well control safety, and the well control fluid type is selected according to different density requirements.
3. The method for testing oil and improving a reservoir of an ultra-deep high-pressure exploratory well according to claim 2, wherein the method is characterized in that the calculation of the density of the well control fluid is carried out, the equivalent well control fluid density corresponding to the difference between the pore pressure of a stratum and the highest shut-in pressure of a wellhead is taken as the lower limit, and the upper limit is the minimum equivalent well control fluid density in the safe bearing of an oil pipe, the safe bearing of a casing annulus and the safe bearing of a downhole tool method.
4. The method for testing oil and reforming a reservoir of an ultra-deep high pressure exploratory well of claim 3, wherein the type of well killing fluid is selected from the group consisting of: density of less than 1.5g/cm 3 Selecting solid-free well killing liquid with density higher than 1.5g/cm 3 Selecting superfine powder.
5. The method for testing oil and reforming a reservoir of an ultra-deep high-pressure exploratory well according to claim 1, wherein in the step S4, the column structure of the perforation-acidification-testing tube comprises an oil pipe I, an expansion joint, an oil pipe II, a DBE valve, an HP-RDS circulating valve, an RTTS safety joint, an RTTS packer, a tail pipe safety joint, an oil pipe III and a delayed perforating gun set which are sequentially connected from top to bottom.
6. The method for testing oil and reforming a reservoir of an ultra-deep high-pressure exploratory well according to claim 1, wherein the method for testing oil and reforming the reservoir of the ultra-deep high-pressure exploratory well is characterized in that a delayed detonation method is adopted in step S6 for perforation, a high-density well killing liquid is used for testing extrusion in step S7, and a high-temperature acid liquid pumping system in step S8 comprises the following steps:
1) An incidence hole-acidizing-testing tubular column under the condition of high-density well killing fluid;
2) Setting a packer, and pressurizing and checking the seal of an annulus;
3) Pressurizing and delaying detonation perforation of the oil pipe;
4) Trial-extruding high-density well killing liquid into stratum;
5) High extrusion high temperature resistant acid liquor.
7. The method for testing oil and reforming a reservoir of an ultra-deep high pressure exploratory well according to claim 1, wherein in step S5, the method for optimizing the type and scale of the reformed liquid comprises the steps of: performing productivity simulation, optimizing the optimal transformation seam length, simulating the relation of the seam lengths under different construction scale conditions, and calculating the optimal construction scale range; and (3) controlling the acidizing operation time by combining the corrosion resistance time of the downhole tool, and calculating the upper limit of the acid liquor scale consumption according to the relation between the acidizing operation time and the displacement.
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