CN106639879A - Method for predicting build-up rate of bottom hole assembly - Google Patents

Abstract

The invention provides a method for predicting the build-up rate of a bottom hole assembly. The method comprises the following steps that firstly, a laboratory test method is adopted for measuring anisotropic indexes of a drill bit and a stratum or real drilling history data are utilized for obtaining the anisotropic indexes of the drill bit and the stratum in an inversion mode; secondly, influence of the various factors of the bottom hole assembly structure, drilling process parameters, the borehole geometrical shape, the anisotropy of the drill bit, the anisotropy of the stratum, the dip angle of the stratum, inclining tendency of the stratum and the like is comprehensively considered, and a relation between the drilling tendency angle Ar and the borehole curvature Kh is established; and thirdly, let the Ar be equal to zero, back calculation is conducted on the borehole curvature Kh, and at the time, the borehole curvature Kh is equal to the build-up rate of the bottom hole assembly. According to the method, the factors are considered comprehensively, the precision for predicting the build-up rate is high, and a novel theoretical basis and analysis means are provided for optimization design for bottom hole assemblies for complex structural wells in future.

Description

A kind of BHA build angle rate Forecasting Methodology

Technical field

The present invention relates to the BHA build angle rate prediction during a kind of complex structural well design and construction Method, belongs to oil and gas well drilling, geological prospecting and mine drilling technique field.

Background technology

Hole trajectory control is always an important process in drilling process, to BHA's structure The selection of reasonable disposition and drilling parameter is the basis that everything goes well with your work is carried out.For a long time, both at home and abroad Relevant expert and scholar make in BHA mechanical analysis, drill bit and stratum interactive analysis and drilling tool The aspects such as the calculating of slope have carried out substantial amounts of research work, achieve many scientific achievements.

With regard to the evaluation and prediction of BHA Drilling Tendency, existing common method mainly has following several：

(1) " three-point circle method "：It is a kind of geometry build angle rate computational methods for stearable assemly.Should Method advantage is to calculate simple, and obtain is bottom drill tool " build angle rate " index, is easy to instruct Field technician uses.But the shortcoming of the method is also very prominent, such as, do not consider drilling tool stress with Impact of the deformation to build angle rate, does not consider impacts of factor such as stratigraphic dip, formation anisotropy, etc..

(2) " bit side force "：It is a kind of to carry out bottom brill using the side force size acted on drill bit The method that tool Drilling Tendency is evaluated.Although the method can qualitative, exactly judge the increasing drop angle of BHA Trend, but the method does not account for the shadow of the factors such as stratigraphic dip, formation anisotropy and bit performance Ring, and because field technician cannot accurately judge BHA according to the size of bit side force Build angle rate size, therefore it is not easy to guide field librarian use.

(3) " balance curvature method "：Think after drilling tool deflecting trend reaches poised state, bottom drill tool group The hole curvature when build angle rate of conjunction should be zero with bit side force value is equal in magnitude.What the method was obtained is " to make Slope " index, is easy to guide field application, but the method is each also without consideration stratigraphic dip, stratum Impact of the factor such as anisotropy and bit performance to build angle rate, thus in most cases with the actual deflecting in scene There is larger error in rate result.

(4) " limit curvature method "：The Computing Principle of limit curvature method substantially homostasis curvature method, leads to first The analysis of drilling tool stress deformation is crossed, hole curvature value when bit side force is zero is tried to achieve, then according to drilling well reality Trample, introduce two empirical coefficients A and B, and then obtain the build angle rate of drilling tool.The shortcoming of the method is drilling tool The computational accuracy of build angle rate is affected larger by the Rational choice of two coefficients of A, B, the drilling experience with user It is closely related.

(5) " Drilling Tendency angle "：It is defined as direction and shaft bottom borehole axis that drill bit will creep into the earth formation Angle between tangential direction." Drilling Tendency angle " is utilized to carry out the evaluation of bottom drill tool Drilling Tendency, its Advantage is that the method Consideration is more comprehensive, and it has considered drilling tool structure, drilling parameter, drill bit The impact of the various factors such as characteristic and formation properties, but its shortcoming is as " bit side force " method, It is not easy to guide field librarian use.

To sum up analyze, if a kind of not only Consideration can be set up comprehensively but also drilling tool " build angle rate " can be obtained The Forecasting Methodology of index, will can provide one kind for the optimization design of complex structural well BHA from now on New theoretical foundation and analysis means.

The content of the invention

Present invention aim at the BHA provided during a kind of complex structural well design and construction is made Slope prediction method, had both considered that the various factors such as bit performance, formation properties affected, and drilling tool can be obtained again " build angle rate " size, is easy to guide field technical staff to use.

Technical scheme is followed the steps below：

Step 1：Determined using laboratory experiment method or real drilling well history Data Inversion, obtain bit anisotropy and refer to Number I_bWith formation anisotropy index I_rTwo parameters；

Step 2：Consider the influence factors such as bottom drill tool structure, drilling technology parameter, borehole geometry, build Vertical drill head mechanics parameters and hole curvature K_hBetween relation；

Step 3：Based on rock-bit interaction model, consider drill bit mechanical characteristic, drill bit respectively to The factor such as different in nature, formation anisotropy and stratigraphic dip and tendency affects, and obtains Drilling Tendency angle A_rMeter Operator expression formula；

Step 4：Make A_r=0, inverse hole curvature K_hSize, then now hole curvature size K_hIt is equal to bottom The build angle rate of portion's BHA.

The technical characterstic of the present invention is also resided in, and described BHA can be conventional BHA, spiral shell All drilling tool types such as bar BHA, automatic vertical drilling system and rotary steerable drilling system.

In addition, the Drilling Tendency angle A in step 3_rCan be calculated according to equation below：

Wherein：

w₁=k₁₁s₁+k₂₁s₂+k₃₁s₃

w₂=k₁₂s₁+k₂₂s₂+k₃₂s₃

w₃=I_r(k₁₃s₁+k₂₃s₂+k₃₃s₃)

s₁=I_bI_r cosα_f+I_r(1-I_b)cosα_af cosα_a

s₂=I_bI_r cosβ_f+I_r(1-I_b)cosα_af cosβ_a

s₃=I_bI_r cosγ_f+I_r(1-I_b)cosα_af cosγ_a

cosα_a=cos A_αcos A_φ

cosβ_a=sin A_φ

cosγ_a=sin A_αcos A_φ

In formula, α_f、β_f、γ_fThe respectively angle of drill bit resultant force vector and shaft bottom coordinate system three axes；α_a、 β_a、γ_aThe respectively angle of drill bit axial direction direction vector and shaft bottom coordinate system three axes；α_afMake a concerted effort for drill bit The angle of vector and drill bit axial direction direction vector；P_BTo act on the pressure of the drill on drill bit；α, φ represent respectively well The hole angle at bottom, azimuth；β、Respectively stratigraphic dip and dip direction；N_Bα、N_BφRespectively act on Change hole deviation power and variable-azimuth power on drill bit；A_α、A_φRespectively drill bit axial direction direction vector and hole deviation plane, The angle of aximuthpiston.

The invention has the beneficial effects as follows having considered bottom drill tool structure, drilling technology parameter, well geometry The impact of the various factors such as shape, bit anisotropy and formation anisotropy, stratigraphic dip and tendency, And with higher build angle rate precision of prediction, the optimization design for BHA from now on provides one kind New theoretical foundation and analysis means.

Description of the drawings

Fig. 1 is to be made with live real boring using the theoretical build angle rate under the calculated different the pressure of the drill of the inventive method The comparative result figure of slope.

Fig. 2 is a kind of BHA build angle rate Forecasting Methodology block diagram of the invention.

Specific embodiment

With reference to specific embodiment, the invention will be further described.

1 mouthful of certain oil field drilled well well depth 5236m, horizontal segment length 1362m, 88.1 ° of maximum hole deviation, orientation 160°.During horizontal segment creeps into, " double centralizers " routine BHA is used：Ф 152.4mmPDC drill bits Double female joint × 0.38m+ Φ 148mm centralizers × 1.41m+ Ф 120mm the stub borings of × 0.25m+ quickly × 5.88m+ Φ 147mm centralizers × 1.41m+ Ф 120mm non magnetic drill collars × 9.17m+ Ф 120mm drill collars × 9m+ Ф 101.6mm Drilling rod, applies 40～80kN of the pressure of the drill, and the real build angle rate that bores is -2.13～2.37 °/100m, is achieved preferably steady Oblique drilling effect, shown in the solid black lines in Fig. 1.Other relevant parameters are：Drilling fluid density 1.45g/cm³, Well amplification degree 4%, 3 ° of purpose inclination layer, 10 ° of dip direction.

In order to calculate the theoretical build angle rate of well " double centralizers " BHA, using bottom drill tool of the present invention Combination build angle rate Forecasting Methodology, follows the steps below：

First, using the real brill data (the mainly real build angle rate that bores is with the pressure of the drill Changing Pattern) of offset well for being somebody's turn to do Block carried out inverting using the anisotropy on drill bit and stratum, the drill bit of the Jing invertings wells and stratum respectively to Different in nature index is respectively 0.25 and 0.95.

Secondly, the drill bit that inverting is obtained and formation anisotropy index and drilling fluid density, well expand The relevant parameters such as rate substitute into the build angle rate computational methods that the present invention is provided, and can obtain should be " double under different the pressure of the drill The theoretical build angle rate result of centralizer " BHA, as shown in the red straight line in Fig. 1.

By the theoretical build angle rate and real brill build angle rate of " double centralizers " BHA under the different the pressure of the drill of contrast As a result, it can be seen that theoretical build angle rate and real build angle rate error of boring are less than 1 °/100m, show offer of the present invention A kind of BHA build angle rate Forecasting Methodology have higher precision of prediction, be fully able to meet scene Using needs.

Claims (3)

1. a kind of BHA build angle rate Forecasting Methodology, it is characterised in that comprise the following steps：

Step 1：Using determination of experimental method or real drilling well history Data Inversion, bit anisotropy index I is obtained_b With formation anisotropy index I_rTwo parameters；

Step 2：Consider the influence factors such as bottom drill tool structure, drilling technology parameter, borehole geometry, build Vertical drill head mechanics parameters and hole curvature K_hBetween relation；

Step 3：Based on rock-bit interaction model, consider drill bit mechanical characteristic, drill bit respectively to The factor such as different in nature, formation anisotropy and stratigraphic dip and tendency affects, and obtains Drilling Tendency angle A_rMeter Operator expression formula；

Step 4：Make A_r=0, inverse hole curvature K_hSize, then now hole curvature size K_hIt is equal to bottom The build angle rate of portion's BHA.

2. a kind of BHA build angle rate Forecasting Methodology according to claim 1, it is characterised in that Described BHA can be conventional BHA, helicoid hydraulic motor combination, automatic vertical drilling system And all BHA types such as rotary steerable drilling system.

3. a kind of BHA build angle rate Forecasting Methodology according to claim 1, it is characterised in that In the step 3, Drilling Tendency angle A_rComputing formula it is as follows：

$A_r=arccos\left(\frac{k_{11}{w}_1+k_{12}{w}_2+k_{13}{w}_3}{\sqrt{w_1^2+w_2^2+w_3^2}}\right)$

Wherein：

w₁=k₁₁s₁+k₂₁s₂+k₃₁s₃

w₂=k₁₂s₁+k₂₂s₂+k₃₂s₃

w₃=I_r(k₁₃s₁+k₂₃s₂+k₃₃s₃)

s₁=I_bI_rcosα_f+I_r(1-I_b)cosα_afcosα_a

s₂=I_bI_rcosβ_f+I_r(1-I_b)cosα_afcosβ_a

s₃=I_bI_rcosγ_f+I_r(1-I_b)cosα_afcosγ_a

${\mathrm{cos\α}}_f=\frac{P_B}{\sqrt{P_B^2+N_{B\mathrm{\α}}^2+N_{B\mathrm{\φ}}^2}}$

${\mathrm{cos\β}}_f=-\frac{N_{B\mathrm{\φ}}}{\sqrt{P_B^2+N_{B\mathrm{\α}}^2+N_{B\mathrm{\φ}}^2}}$

${\mathrm{cos\γ}}_f=\frac{N_{B\mathrm{\α}}}{\sqrt{P_B^2+N_{B\mathrm{\α}}^2+N_{B\mathrm{\φ}}^2}}$

cosα_a=cos A_αcos A_φ

cosβ_a=sin A_φ

cosγ_a=sin A_αcosA_φ

${\mathrm{cos\α}}_{af}=\frac{P_B\cos A_{\mathrm{\α}}\cos A_{\mathrm{\φ}}-N_{B\mathrm{\φ}}\sin A_{\mathrm{\φ}}+N_{B\mathrm{\α}}\sin A_{\mathrm{\α}}\cos A_{\mathrm{\φ}}}{\sqrt{P_B^2+N_{B\mathrm{\α}}^2+N_{B\mathrm{\φ}}^2}}$

In formula, α_f、β_f、γ_fThe respectively angle of drill bit resultant force vector and shaft bottom coordinate system three axes；α_a、 β_a、γ_aThe respectively angle of drill bit axial direction direction vector and shaft bottom coordinate system three axes；α_afMake a concerted effort for drill bit The angle of vector and drill bit axial direction direction vector；P_BTo act on the pressure of the drill on drill bit；α, φ represent respectively well The hole angle at bottom, azimuth；β、Respectively stratigraphic dip and dip direction；N_Bα、N_BφRespectively act on Change hole deviation power and variable-azimuth power on drill bit；A_α、A_φRespectively drill bit axial direction direction vector and hole deviation plane, The angle of aximuthpiston.