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A Formation Properties Interpretation While Drilling Method Applicable to Underbalanced Drilling

A stratum and characteristic technology, applied in earthwork drilling, wellbore/well components, measurement, etc., can solve problems such as difficult guarantee, time-consuming calculation, long calculation result accuracy, etc.

Active Publication Date: 2022-05-17
YANGTZE UNIVERSITY
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  • Claims
  • Application Information

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Problems solved by technology

[0004] Aiming at the technical problems existing in the prior art, the present invention provides a method for interpretation of formation characteristics while drilling suitable for underbalanced drilling, and solves the problems in the prior art that the calculation time is long and the accuracy of the calculation results is difficult to guarantee

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  • A Formation Properties Interpretation While Drilling Method Applicable to Underbalanced Drilling
  • A Formation Properties Interpretation While Drilling Method Applicable to Underbalanced Drilling
  • A Formation Properties Interpretation While Drilling Method Applicable to Underbalanced Drilling

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Embodiment 1

[0077] Embodiment 1 provided by the present invention is an embodiment of a method for interpreting formation characteristics while drilling suitable for underbalanced drilling provided by the present invention. Properties are interpreted while drilling, and the interpretation parameters x include formation pressure and formation permeability.

[0078] Specifically, the measurement parameter z and the interpretation parameter x can be expressed as a vector:

[0079] z=[P 0 (t k ),q out,1 (t k )] T , x=[K(t k ),p r (t k )] T .

[0080] Among them, K represents formation permeability, p r Indicates formation pressure, P 0 Indicates the bottom hole pressure, q out,1 Indicates the outlet flow rate of the liquid phase, t k Indicates the k time points corresponding to the measurement data.

[0081] The determination process to explain the parameter x involves:

[0082] Step 1. Obtain the basic parameters of the simulated well, and construct the oil-gas-water three-pha...

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Abstract

The invention relates to a method for interpreting formation properties while drilling suitable for underbalanced drilling. Bottomhole pressure and liquid phase outlet flow are used as measurement parameters to perform interpretation while drilling formation properties. The process of determining the interpretation parameters includes: obtaining basic parameters of simulated wells , construct the mass flow model of oil-gas-water three-phase change; construct the state equation and measurement equation of the wellbore hydraulic system, the state equation is established according to the interpretation parameters, and the measurement equation is established according to the oil-gas-water three-phase change mass flow model; according to the state equation and measurement equation, The interpretation algorithm based on the unscented Kalman filter is used to predict, update and correct the interpretation parameters to obtain the value of the interpretation parameters; real-time and accurate prediction of formation pressure and permeability during the drilling process is helpful for improving underbalanced drilling and post-completion operations Security and timeliness have important theoretical and practical significance.

Description

technical field [0001] The invention relates to the technical field of underbalanced drilling, in particular to a formation property interpretation method suitable for underbalanced drilling while drilling. Background technique [0002] Underbalanced drilling refers to the drilling process in which low-density fluids such as gas, foam, and aerated drilling fluid are used as circulating media, and the bottom of the well is under negative pressure difference. Due to the negative pressure difference at the bottom of the well, underbalanced drilling is beneficial to increase the rate of penetration, discover reservoirs and reduce reservoir damage, so it has been widely used. When the underbalanced method is used to open the reservoir, formation fluid will enter the wellbore under the action of negative pressure difference, which will lead to changes in flow parameters such as wellbore pressure and flow rate. Due to the coupling effect between the wellbore fluid and the formatio...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B47/12E21B47/06
CPCE21B47/12E21B47/06
Inventor 何淼许明标宋建建
Owner YANGTZE UNIVERSITY