CN-117780290-B - Wellbore operation method for multi-outer-diameter coiled tubing oil-gas well

Abstract

The invention relates to the technical field of downhole operation methods for oil and gas field development, in particular to a wellbore operation method for a multi-outer-diameter continuous oil pipe oil and gas well, which comprises the following steps of (1) selecting a continuous oil pipe combination according to the trafficability characteristic of an operation wellbore; the method for configuring the blowout preventer stack comprises the steps of (2) configuring the blowout preventer stack in a manner related to the specification types of the outer diameter of the coiled tubing, wherein N sections of coiled tubing with different outer diameter specifications are provided with N matched blowout preventer stacks, and (3) determining the coiled tubing combinations and the blowout preventer stacks and then performing a butt joint process of the coiled tubing with different pipe diameters. The invention can realize the efficient operation of the coiled tubing of the ultra-deep and variable-diameter shaft (horizontal well or vertical well), breaks the technical bottlenecks of limited strength, insufficient end effect, poor trafficability and the like faced by the operation of the single-diameter coiled tubing in the complex shaft, realizes the purpose of 'efficient operation of the variable-diameter tubular column in the variable-diameter shaft', and is beneficial to efficient and safe operation.

Inventors

• AIBAIBU ABULIMITI
• SUN CHANGYOU
• LI JIANGNAN
• GAO YANRU
• Sandik Stick
• WANG YIQUAN
• CHEN BO
• GUO XINWEI
• ZHOU HUA
• YANG BOYUAN
• Jiao Wenfu
• ZHANG MANNIAN
• WANG JIANLEI

Assignees

• 中国石油天然气集团有限公司
• 新疆石油管理局有限公司

Dates

Publication Date

20260512

Application Date

20220922

Claims (3)

1. 1. A wellbore operation method for a multi-outer diameter coiled tubing oil and gas well is characterized by comprising three parts of (1) a coiled tubing selection criterion, (2) a blowout preventer stack configuration method and (3) a butt joint process of coiled tubing with different pipe diameters; (1) The continuous oil pipe selection criterion comprises the steps of selecting a continuous oil pipe combination according to the trafficability characteristic of an operation shaft, namely determining basic parameters of the specification and the length of the continuous oil pipe according to the minimum inner diameter and the operation depth of a shaft reducing point, performing performance evaluation on the continuous oil pipe with the basic parameters determined, including pipe column running performance analysis, pipe column strength check and hydrodynamic parameter check, determining final parameters of the specification and the length of the continuous oil pipe according to operation requirements, and guaranteeing operation safety; (2) The blowout preventer stack configuration mode is related to the specification type of the outer diameter of the continuous oil pipe, and N sections of continuous oil pipes with different outer diameter specifications are combined to be provided with N matched blowout preventer stacks; (3) After the coiled tubing combination and the blowout preventer stack are determined, carrying out a butt joint process of the coiled tubing with different pipe diameters, and after the butt joint of the coiled tubing with different pipe diameters is completed, putting the butt joint of the coiled tubing into a specified operation depth to carry out wellbore operation; The basic parameter selection principle of the specification and the length of the continuous oil pipe is as follows: The parameter range of the outer diameter specification and the length of the 1 st section of continuous oil pipe is determined according to the minimum inner diameter D 1min , the depth L B1 and the working depth L W of the variable diameter point 1 of the working shaft, and the basic parameters of the outer diameter specification and the length of the N section of continuous oil pipe are determined from the depth of the variable diameter point N, the minimum inner diameter and the depth of the variable diameter point N-1 from the 2 nd section of continuous oil pipe to the N section of continuous oil pipe, wherein the basic parameters are represented by the following formula: Wherein D LN represents the diameter of the Nth section of continuous oil pipe; l LN represents a basic length parameter of the Nth section of continuous oil pipe; D Nmin denotes the minimum diameter of the nth reducing point; L BN represents the depth of the Nth reducing point; L W denotes a job depth.
2. 2. The method for operating the oil-gas well by using the multi-outer diameter continuous oil pipe is characterized by comprising the following steps of: The method comprises the steps of installing N blowout preventers assembled according to N sections of coiled tubing with different outer diameter specifications at a wellhead, sequentially reducing the outer diameter specifications of the corresponding coiled tubing from top to bottom, fixedly installing an injection head and a lubricator on the uppermost blowout preventer from top to bottom, building a bracket which is convenient for an operator to operate at the lubricator, wherein the descending operation mode of the 1 st section of coiled tubing is the same as that of a conventional coiled tubing, namely, the 1 st section of coiled tubing is lowered into a well through the injection head by a coiled tubing operation machine, when the 1 st section of coiled tubing is lowered to the last half circle left, the last tube head of the 1 st section of coiled tubing is pulled to the upper plane of the uppermost blowout preventer by utilizing a crane in a matching way, then, the 2 nd section of coiled tubing is lowered into the cylinder of the coiled tubing operation machine, after the initial tube head of the 2 nd section of coiled tubing is lowered into the injection head, opening the lubricator by an operator standing on the bracket, completing the butt joint of the end tube head of the 1 st section of coiled tubing and the initial tube head of the 2 nd section of coiled tubing by using a different diameter coiled tubing butt joint device, completing the butt joint operation of the coiled tubing with the N sections of different pipe diameters, and completing the butt joint operation of the coiled tubing at the specified depth.
3. 3. The method for working a wellbore of a multi-outer diameter coiled tubing oil-gas well according to claim 1 or 2, wherein when the blowout preventer stack is configured, the blowout preventer installed at the uppermost part of the wellhead adopts a four-ram blowout preventer, the inner diameter dimension of which corresponds to the outer diameter of the nth section of coiled tubing, the remaining blowout preventer stack configuration is at least provided with a double-ram blowout preventer according to the coiled tubing corresponding to the outer diameter dimension, and the respective blowout preventer dimensions of the blowout preventer stack are sequentially reduced from top to bottom.

Description

Wellbore operation method for multi-outer-diameter coiled tubing oil-gas well Technical Field The invention relates to the technical field of underground operation methods for oil and gas field development, in particular to a wellbore operation method for a multi-outer-diameter coiled tubing oil and gas well. Background Along with the continuous promotion of the development process of oil and gas resources in China, unconventional oil reservoirs and deep oil and gas reservoirs have become main exploration and development objects. In the field of unconventional oil and gas exploration and development, shale oil and tight oil exploration and development technology is a major breakthrough, volume fracturing becomes an essential technical tool for developing unconventional oil and gas reservoirs, the most effective development mode for shale oil and tight oil at present is horizontal well staged fracturing, wherein the staged fracturing technology of 'open hole packer + sliding sleeve' is applied to various large oil fields, but the bore diameter is gradually reduced after the technology is implemented, and a certain difficulty is brought to subsequent bore operation. Meanwhile, in the field of deep hydrocarbon reservoir development, a high-pressure oil-gas well is generally put into production by adopting a permanent packer completion pipe column, a series of functional accessories such as a downhole safety valve, a packer and a plug exist in the production pipe column, even a combination type production pipe column with a large upper part and a small lower part is adopted in the oil-gas well, so that the structural characteristics of multiple diameters of the production pipe column are caused, and the subsequent oil pipe passing operation is challenged. The coiled tubing operation technology has been rapidly developed in recent years, and has been developed from simple dredging operation to complex special operations such as underground cutting, salvaging, drilling and grinding, and the like, thereby making an important contribution to the production and storage of unconventional oil and gas. However, aiming at the problems of multiple diameters and even gradual diameter reduction of the typical coiled tubing operation channel, the adoption of the single-pipe-diameter coiled tubing operation faces a series of problems of limited strength, insufficient end effect, poor trafficability and the like, and the normal production of an oil-gas well is greatly influenced. Disclosure of Invention The invention provides a wellbore operation method for a multi-outer diameter coiled tubing oil-gas well, which overcomes the defects of the prior art, and can effectively solve the problems of limited strength, insufficient end effect and poor trafficability of a single-diameter coiled tubing in a variable-diameter wellbore. The technical scheme of the invention is realized by the following measures that the wellbore operation method of the multi-outer diameter continuous oil pipe oil and gas well comprises three parts of (1) continuous oil pipe optimization criteria, (2) blowout preventer stack configuration method, (3) butt joint process of continuous oil pipes with different pipe diameters; (1) The coiled tubing optimization criterion comprises the steps of selecting a coiled tubing combination according to the trafficability characteristic of an operation shaft, namely determining basic parameters of the specification and the length of the coiled tubing according to the minimum inner diameter and the operation depth of a shaft reducing point, performing performance evaluation on the coiled tubing with the basic parameters determined, including string running-in performance analysis, string strength check and hydrodynamic parameter check, determining final parameters of the specification and the length of the coiled tubing according to operation requirements, and guaranteeing operation safety; (2) The blowout preventer stack configuration mode is related to the specification type of the outer diameter of the continuous oil pipe, and N sections of continuous oil pipes with different outer diameter specifications are combined to be provided with N matched blowout preventer stacks; (3) After the coiled tubing combination and the blowout preventer stack are determined, a butt joint process of the coiled tubing with different pipe diameters is carried out, and after the butt joint of the coiled tubing with different pipe diameters is completed, the butt joint of the coiled tubing is carried out, and the well bore operation is carried out by putting the butt joint of the coiled tubing into a designated operation depth. The following are further optimizations and/or improvements to the above-described inventive solution: The butt joint process of the continuous oil pipes with different pipe diameters comprises the following specific steps: The method comprises the steps of installing N blowout preventers assembled according to N