阅读说明：本技术 一种推靠式旋转导向系统地层适应评价方法 (Stratum adaptation evaluation method of push-type rotary steering system ) 是由 贾利春 白璟 陆灯云 张继川 李雷 刘伟 黄崇君 邓虎 陈东 于 2020-05-29 设计创作，主要内容包括：本发明公开了一种推靠式旋转导向系统地层适应评价方法,涉及石油钻井技术领域。本发明首先对所钻进井段地层进行抗压强度压缩试验得到地层抗压强度,然后确定推靠式旋转导向系统翼肋作用在井壁上的压强,通过对比所钻井段的实际造斜率与设计造斜率建立地层适应性评价数据库,判定推靠式旋转导向系统对相同地层的适应性,以评价该推靠式旋转导向系统是否适应该井段地层。本发明的评价方法操作简单,能够很好的为推靠式旋转导向系统的地层适应性作出评价,以避免井下出现复杂情况时对翼肋造成破坏,影响正常的钻井施工。(The invention discloses a stratum adaptation evaluation method of a push-pull type rotary steering system, and relates to the technical field of petroleum drilling. The method comprises the steps of firstly carrying out a compressive strength compression test on a stratum of a drilled well section to obtain the compressive strength of the stratum, then determining the pressure of a wing rib of the push-type rotary steering system acting on a well wall, establishing a stratum adaptability evaluation database by comparing the actual build rate and the designed build rate of the drilled well section, and judging the adaptability of the push-type rotary steering system to the same stratum so as to evaluate whether the push-type rotary steering system is adaptive to the stratum of the drilled well section. The evaluation method is simple to operate, and can well evaluate the stratum adaptability of the push-pull type rotary steering system so as to avoid damage to the wing ribs when complex conditions occur underground and influence on normal drilling construction.)

1. A method for evaluating stratum adaptation of a push-type rotary steering system is characterized by comprising the following steps: the method comprises the following steps:

A. the method comprises the following steps of (1) obtaining the compressive strength of the stratum: collecting underground rock core of stratum of drilled well section, and carrying out compression strength compression test on the collected underground rock core to obtain compression strength sigma of stratum_c；

B. The pressure intensity of the wing ribs acting on the well wall contact surface is obtained: obtaining the pressure P of the wing rib acting on the contact surface of the well wall according to the maximum pushing force P of the wing rib of the pushing type rotary guide system and the contact area A of the wing rib and the well wall_c；

C. And (3) adaptability evaluation step: comparing the actual build rate K of the drilled interval₁Build-up ratio K with design₀When K is₁≥K₀The time-of-flight indication push-type rotary steering system is suitable for the stratum of the drilled section, and the pressure p of the wing rib acting on the contact surface of the well wall at the time is recorded_cCompressive strength sigma to the formation_cRatio n = p_c/σ_cAnd taking the value n as a standard reference value of the push-pull type rotary steering system to adapt to the stratum of the well section, and sequentially obtaining n values of different stratums to establish a stratum adaptability evaluation database.

2. The method for evaluating stratigraphic adaptation of a push-against rotary steerable system according to claim 1, wherein: in the step A, collecting the underground core of the stratum of the drilled well section, and processing the underground core into the diameter 2Grinding the two ends of a cylindrical test sample with the length of 50mm and the length of 5mm, wherein the required number of the test samples is not less than 3, and taking the average value of the compressive strength of all the test samples as the compressive strength sigma of the stratum_c。

3. The method for evaluating stratigraphic adaptation of a push-against rotary steerable system according to claim 1, wherein: in the step B, determining the maximum pushing force P of the wing rib and the contact area A of the wing rib and the well wall according to the design parameters of the pushing rotary guide system, and according to the formula P_cAnd (4) calculating to obtain the pressure of the rib acting on the contact surface of the well wall.

4. The method for evaluating stratigraphic adaptation of a push-against rotary steerable system according to claim 1, wherein: in step C, according to p for any interval of the well_c/σ_cJudging the adaptability of the push type rotary steering system to the same stratum according to the relation with the n value, and repeating the step A, B to obtain the ratio p_c/σ_cComparison of p_c/σ_cIn relation to the value of n, when p_c/σ_cLess than the value of n, the system is not suitable for the formation; otherwise, it is adapted.

Technical Field

The invention relates to the technical field of petroleum drilling, in particular to a stratum adaptation evaluation method of a push-type rotary steering system.

Background

With the progress of well drilling technology, the development of lower drilling tool combinations aiming at controlling experience tracks is rapid, and on the basis of the original common inclination increasing, inclination reducing and inclination stabilizing drilling tools, various types of guide drilling tools are developed and popularized, such as an inclination preventing drilling tool with an eccentric elbow joint, an inclination preventing drilling tool with a flexible joint, an inclination increasing drilling tool with variable rigidity between two stabilizers and other novel lower drilling tool combinations.

A rotary steering drilling system is developed at the end of the 20 th century, the system completely abandons the traditional sliding steering mode, and automatically and flexibly adjusts the well inclination and the direction in a rotary steering drilling mode, so that the drilling speed and the drilling safety are greatly improved, the track control precision is very high, the system is completely suitable for the steering drilling requirement of special process wells such as ultra-deep wells, extended reach wells, smart wells and the like for developing special oil and gas reservoirs, and is a steering mode for meeting the development requirement of closed-loop automatic drilling.

At present, various rotary steering drilling tools have been developed internationally, and the push type rotary steering drilling tool is based on a common rotary drilling tool, and a drill string is stabilized at a required position of a borehole section in a rotating process through a rotary near-bit stabilizer so as to control a borehole track.

The pushing type rotary steering system extends out of the wing rib under the hydraulic action in the system, so that the wing rib is pushed to contact with the position required by the cross section of the well hole, the required lateral cutting force is provided for the drill bit, and the regulation and control of the track of the well hole are realized. However, after the wing ribs are pushed against the well wall, enough counterforce is required to be provided by well wall rock to maintain the distance between the rotary steering system body and the well wall, if the strength of stratum rock is not enough to overcome the pushing force of the wing ribs pushing against the well wall, the well wall rock will deform to cause the wing ribs to sink into the well wall, at the moment, the distance between the rotary steering system body and the well wall is reduced to cause the insufficient lateral cutting force required by the drill bit, and further, the regulation and control of the well track are failed or cannot be expected, but at present, a similar stratum adaptation evaluation method does not exist for a push-against type rotary steering system.

Disclosure of Invention

In order to overcome the problems and defects in the prior art, the invention provides a stratum adaptation evaluation method of a push-type rotary steering system. The invention aims to solve the problem that the stratum adaptability of a push-type rotary steering system cannot be evaluated in the prior art. The method comprises the steps of firstly carrying out rock mechanical parameter tests on a stratum of a drilled well section to obtain stratum compressive strength, then determining the pressure of a wing rib of the push-type rotary guide system acting on a well wall, and comparing the pressure of the wing rib acting on a contact surface of the well wall with the stratum compressive strength to evaluate whether the push-type rotary guide system is suitable for the stratum of the well section. The evaluation method is simple to operate, and can well evaluate the stratum adaptability of the push-pull type rotary steering system so as to avoid damage to the wing ribs when complex conditions occur underground and influence on normal drilling construction. Through evaluating the stratum adaptability of the push-pull type rotary steering system, the stratum suitable for being drilled by the push-pull type rotary steering system is selected, on one hand, the regulation and control of the well track are realized, on the other hand, the push-pull type rotary steering system is prevented from being used for blind entering the well, and the service efficiency of the system is improved.

In order to solve the problems in the prior art, the invention is realized by the following technical scheme:

a method for evaluating stratum adaptation of a push-type rotary steering system is characterized by comprising the following steps: the method comprises the following steps:

A. the method comprises the following steps of (1) obtaining the compressive strength of the stratum: collecting underground rock core of stratum of drilled well section, and carrying out compression strength compression test on the collected underground rock core to obtain compression strength sigma of stratum_c；

B. The pressure intensity of the wing ribs acting on the well wall contact surface is obtained: obtaining the pressure P of the wing rib acting on the contact surface of the well wall according to the maximum pushing force P of the wing rib of the pushing type rotary guide system and the contact area A of the wing rib and the well wall_c；

C. And (3) adaptability evaluation step: comparing the actual build rate K of the drilled interval₁Build-up ratio K with design₀When K is₁≥K₀The time-of-flight indication push-type rotary steering system is suitable for the stratum of the drilled section, and the pressure p of the wing rib acting on the contact surface of the well wall at the time is recorded_cCompressive strength sigma to the formation_cRatio n = p_c/σ_cAnd taking the value n as a standard reference value of the push-pull type rotary steering system to adapt to the stratum of the well section, and sequentially obtaining n values of different stratums to establish a stratum adaptability evaluation database.

Further, in the step A, collecting an underground core of a stratum of a drilled well section, processing the underground core into a cylindrical test sample with the diameter of 25mm and the length of 50mm, grinding the two ends of the test sample to be flat, wherein the required test sample number is not less than 3, and taking the average value of the compressive strengths of all the test samples as the compressive strength sigma of the stratum_c。

Further, determining the maximum thrust force P of the wing rib and the contact area A of the wing rib and the well wall according to design parameters of the thrust type rotary steering system, and determining the maximum thrust force P of the wing rib and the contact area A of the wing rib and the well wall according to a formula P_cAnd (4) calculating to obtain the pressure of the rib acting on the contact surface of the well wall.

Further, according to p for any interval formation_c/σ_cJudging the adaptability of the push type rotary steering system to the same stratum according to the relation with the n value, and repeating the step A, B to obtain the ratio p_c/σ_cComparison of p_c/σ_cIn relation to the value of n, when p_c/σ_cLess than the value of n, the system is not suitable for the formation; otherwise, it is adapted.

Compared with the prior art, the beneficial technical effects brought by the invention are as follows:

1. the evaluation method can well evaluate the adaptability between the push-pull type rotary steering system and the stratum, can effectively avoid the failure or unexpected control of the well track, and on the other hand, avoids the influence on normal drilling construction caused by the blind entry of the push-pull type rotary steering system.

2. According to the evaluation method, the accurate compressive strength of the stratum of the drilling well section can be obtained by manufacturing the cylindrical test sample through the underground core, so that high-precision data support is provided for adaptability evaluation, and the effectiveness and precision of the evaluation are improved.

3. According to the evaluation method, the maximum thrust force P of the wing rib and the contact area A of the wing rib and the well wall are determined according to the design parameters of the thrust rotary guide system, the calculated pressure intensity of the wing rib acting on the contact surface of the well wall is the most accurate, high-precision data support is provided for adaptability evaluation, and the effectiveness and the precision of the evaluation are improved.

4. The evaluation method of the invention compares the actual build-up rate K of the drilled well section₁Build-up ratio K with design₀When K is₁≥K₀Recording of the ratio n = p at this time_c/σ_cAnd taking the value n as a reference value of the push-pull type rotary steering system to adapt to the stratum of the well section, sequentially obtaining n values of different stratums, establishing a stratum adaptability evaluation database, and judging the adaptability of the push-pull type rotary steering system to the same stratum.

Drawings

FIG. 1 is a schematic flow chart of the evaluation method of the present invention.

Detailed Description

The technical scheme of the invention is further elaborated in the following by combining the drawings in the specification.