Formation characteristic while-drilling interpretation method suitable for under-balanced drilling

A technology of formation and characteristics, applied in the fields of earthwork drilling, wellbore/well components, measurement, etc., can solve the problems of long calculation result accuracy, difficult to guarantee, time-consuming calculation, etc., and achieve real-time accurate formation pressure and permeability, The effect of improving safety and timeliness

Active Publication Date: 2020-11-06
YANGTZE UNIVERSITY
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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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  • Formation characteristic while-drilling interpretation method suitable for under-balanced drilling
  • Formation characteristic while-drilling interpretation method suitable for under-balanced drilling
  • Formation characteristic while-drilling interpretation method suitable for under-balanced 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 formation characteristic while-drilling interpretation method suitable for under-balanced drilling. Formation characteristic while-drilling interpretation is carried out with bottom hole pressure and liquid phase outlet flow as measurement parameters. The determination process of interpretation parameters comprises the following steps that basic parameters of a simulation well are obtained, and an oil-gas-water three-phase variable mass flow model is established; a state equation and a measurement equation of a wellbore hydraulic system are established, wherein the state equation is established according to the interpretation parameters, and the measurement equation is established according to the oil-gas-water three-phase variable mass flow model; and accordingto the state equation and the measurement equation, prediction, updating and correction of the interpretation parameters are carried out on the basis of an interpretation algorithm of traceless Kalmanfiltering to obtain values of the interpretation parameters. In the drilling process, the formation pressure and permeability are predicted accurately in real time, and the method is of important theoretical and practical significance to improving the safety and timeliness of under-balanced drilling and later well completion practices.

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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IPC IPC(8): E21B47/12E21B47/06
CPCE21B47/12E21B47/06
Inventor 何淼许明标宋建建
Owner YANGTZE UNIVERSITY
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