CN102996114A - Inclined hole correction method of logging information - Google Patents

Abstract

The invention discloses an inclined hole correction method of logging information. The inclined hole correction method of the logging information comprises the steps of (a) at first, assuming the curvature of each hole section of an inclined hole required to be corrected as a constant; (b) assuming a hole deviation angle at a depth point as alpha and regarding a small-enough section dh of the inclined hole as a linear section; and (c) taking a section from a No. n point to a NO. n+1 point of the drill hole as a length unit and using an average value of the hole deviation angles at the No. n point and the NO. n+1 point as an average hole deviation angle of the hole section to obtain a vertical depth calculation formula, working out each inclined depth point H(n) and each corresponding vertical depth Hz(n) based on the formula, assigning logging data which correspond to H(n) to Hz(n) and simultaneously performing equal interval operations on newly generated data from Hz(n) to Vz log to form the logging data equivalent to the logging data of a straight hole. With the adoption of the inclined hole correction method of the logging information, the inclined hole correction of the logging information can be completed fast; and moreover, the correction result is precise, the correction steps are simple and the correction cost is lowered greatly.

Description

A kind of inclined shaft bearing calibration of well-log information

Technical field

The present invention relates to a kind of inclined shaft bearing calibration of well-log information.

Background technology

The enforcement period of the ninth five-year plan, domestic old well window sidetracking is stood is state key scientific research project, carried out scientific research in Shengli Oil Field, Dagang Oilfield, Liaohe Oil Field, Daqing oil field and Xinjiang Oilfield respectively, be drilled to the old well window sidetracking horizontal well of mean curvature and deep camber, obtained preferably economic benefit.Development through nearly decades, sidetracked hole (sidetrack horizontal well) technology, it at present has been a good technology of the domestic and international old well production of recovery of generally acknowledging, the a lot of aspects of sidetracked hole (sidetrack horizontal well) technology are than straight well, all has sizable advantage, as reducing the oil field development cost, excavate the old filed potentiality of remaining oil, improving recovery ratio etc.Each domestic elephant has generally carried out research and the application of sidetracked hole (sidetrack horizontal well) technology at present, and has obtained in various degree economic benefit.

It is at present domestic that research mainly contains two kinds of methods to rock mechanics: the one, in the laboratory rock core is surveyed; The 2nd, derive the rock mechanics parameter with geophysical log data, and with a small amount of laboratory experiment data correction.Most of core experiment is to test in the situation of dry core sample generally speaking, the well-log information that provides is also many to be obtained before completion, therefore people often regard the rock mechanics that draws thus as invariable, and apply it among the various calculating.Obviously, this limits to very much.Through both at home and abroad the researcher was to the research and analysis of oilfield exploitation procedure all over the world and a large amount of laboratory field data in recent years, people recognize that the oil and gas development process is reservoir pore space pressure, multiphase flow (oil gas water) seepage flow and reservoir rock elastic-plastic deformation Dynamic Coupling process.

The evening that domestic rock mechanics application study is carried out, the rock mechanics theory relevant with oil and gas development be applied in the nearly more than ten years, 1977 just begin to establish later on rock mechanics laboratory, and domesticly only have one in exploitation system of East China Petroleum Institute (predecessor of University of Petroleum) (existing petroleum works institute).Carried out the research of formation fracture pressure forecasting technique during this laboratory " six or five ".The enforcement period of the seventh five-year plan has carried out Casing Failure Mechanism and control and complex salt cream laminar flow and has become a series of researchs such as rule.During " eight or five ", carried out more widely research work, such as researchs such as earth stress determination technology, wellbore stability technology, sanding mechanism, fracturings.At present the mechanism at petroleum industry study of rocks mechanics also is on the increase, and such as the exploration and development academy of CNPC's, Shengli Oil Field drilling well academy etc., has especially obtained faster development since the nineties.On problem is shaked out in the rock mechanics theory application study, in phase early 1990s, some undersized sand prediction tests have been done in domestic minority oil field before the establishment completion program, recognize thus the important function of sand prediction technology, and from then on the sand prediction technology has been carried out comprehensive study.On the basis of foreign sand prediction technology, domestic sand prediction technology makes great progress.

Just begun the trial that utilizes sidetracking (sidetrack horizontal well) to improve the oil gas field recovery ratio abroad as far back as the twenties in 20th century, the sidetracking seventies (sidetrack horizontal well) technology has had larger breakthrough, particularly developed the steerable drilling technology eighties, caused the technological revolution of current sidetrack horizontal well exploitation, produced a huge petroleum industry technological change, more than 20 oil-producing country formed the larger commercial scale of using horizontal well producing oil field in the world.According to pertinent literature, annual construction sidetracked hole quantity increases year by year in countries such as the U.S., Canada, the Soviet Union, Iran, and the sidetracked hole of the annual construction of country that has is more than up to ten thousand mouthfuls.

Well-log information reflects targetedly to various formation lithologies, physical property.Carry out the Precise logging interpretation of formation lithology, physical property and oiliness, be intended to further to get clear its rock forming mineral composition, accurately calculate the parameters such as degree of porosity, permeability, shale content and oil saturation (remaining oil saturation) on stratum.

Sidetracked hole (sidetrack horizontal well) lithology, physical property research have considerable effect for calculating and the engineering application of rock mechanics parameters, particularly in Well Completion Engineering of Oil Reservoirs.The parameters such as the degree of porosity on stratum, permeability and water saturation are that whether the stratum shakes out direct criterion is provided in sidetracked hole (sidetrack horizontal well) manufacturing process, and accurately calculation side drilling well (sidetrack horizontal well) lithology, physical parameter are significant for the application study of follow-up sidetracked hole (sidetrack horizontal well) formation rock mechanical characteristics.

Summary of the invention

Purpose of the present invention provides a kind of inclined shaft bearing calibration of well-log information in order to overcome the deficiencies in the prior art and defective, and this assay method can be finished fast the inclined shaft of well-log information and proofread and correct, and the correction result is accurate, and aligning step is simple, greatly reduces the correction cost.

Purpose of the present invention is achieved through the following technical solutions: a kind of inclined shaft bearing calibration of well-log information may further comprise the steps:

(a) at first, suppose that the curvature of each well section of inclined shaft that needs are proofreaied and correct is a constant, namely hole angle δ is with the constant that is changed to of degree of depth h;

(b) suppose that a certain depth point hole angle is α, the enough segment dh on inclined shaft can regard straightway as.Namely get an infinitesimal section dS near this well track point, then its latitude is;

dH _z＝cos?adS

Need when (c) vertical depth calculates n to this section of n+1 point well as a length cell, and use n point and the n+1 hole angle average of ordering is as the average hole angle of this well section, then its geometrical relationship can be expressed as follows:

$\left\{\begin{array}{c}\mathrm{dS}=H(n+1)-H\left(n\right)\\ {\mathrm{dH}}_z=H_z(n+1)-H_z\left(n\right)\\ a=\frac{a(n+1)+a\left(n\right)}{2}\\ {\mathrm{dH}}_z=\mathrm{dS}\cos a\end{array}\right.$

Thus, can obtain the vertical depth design formulas:

$H_z(n+1)=H_z\left(n\right)+[H(n+1)-H\left(n\right)]\×\cos \left(\frac{\mathrm{\α}(n+1)+\mathrm{\α}\left(n\right)}{2}\right)$

In the following formula, H _zThe expression vertical depth; H represents tiltedly dark (being the depth-logger value); α represents hole angle,

N is to the average hole angle between the n+1 depth point in expression.When drift azimuth changes greatly, adopt minimum-curvature method to carry out hole-deviation correction without formula (3.3).

Calculate each tiltedly dark some H (n), corresponding vertical depth H by following formula _z(n), and with the log data corresponding with H (n) be assigned to H _z(n), simultaneously to newly-generated H _z(n)～V _{Z log}Data are carried out Equal interval, thereby have formed the log data that is equivalent to straight well.

In sum, the invention has the beneficial effects as follows: the inclined shaft that can finish fast well-log information is proofreaied and correct, and the correction result is accurate, and aligning step is simple, greatly reduces the correction cost.

The specific embodiment

Below in conjunction with embodiment, to the detailed description further of the present invention's do, but embodiments of the present invention are not limited to this.

Embodiment:

The present invention relates to a kind of inclined shaft bearing calibration of well-log information, may further comprise the steps:

(a) at first, suppose that the curvature of each well section of inclined shaft that needs are proofreaied and correct is a constant, namely hole angle δ is with the constant that is changed to of degree of depth h;

(b) suppose that a certain depth point hole angle is α, the enough segment dh on inclined shaft can regard straightway as.Namely get an infinitesimal section dS near this well track point, then its latitude is;

dH _z＝cos?adS

Need when (c) vertical depth calculates n to this section of n+1 point well as a length cell, and use n point and the n+1 hole angle average of ordering is as the average hole angle of this well section, then its geometrical relationship can be expressed as follows:

$\left\{\begin{array}{c}\mathrm{dS}=H(n+1)-H\left(n\right)\\ {\mathrm{dH}}_z=H_z(n+1)-H_z\left(n\right)\\ a=\frac{a(n+1)+a\left(n\right)}{2}\\ {\mathrm{dH}}_z=\mathrm{dS}\cos a\end{array}\right.$

Thus, can obtain the vertical depth design formulas:

$H_z(n+1)=H_z\left(n\right)+[H(n+1)-H\left(n\right)]\×\cos \left(\frac{\mathrm{\α}(n+1)+\mathrm{\α}\left(n\right)}{2}\right)$

In the following formula, H _zThe expression vertical depth; H represents tiltedly dark (being the depth-logger value); α represents hole angle,

N is to the average hole angle between the n+1 depth point in expression.When drift azimuth changes greatly, adopt minimum-curvature method to carry out hole-deviation correction without formula (3.3).

Calculate each tiltedly dark some H (n), corresponding vertical depth H by following formula _z(n), and with the log data corresponding with H (n) be assigned to H _z(n), simultaneously to newly-generated H _z(n)～V _{Z log}Data are carried out Equal interval, thereby have formed the log data that is equivalent to straight well.

The above only is preferred embodiment of the present invention, is not the present invention is done any pro forma restriction, and any simple modification, the equivalent variations on every foundation technical spirit of the present invention above embodiment done all fall within protection scope of the present invention.

Claims (1)

1. the inclined shaft bearing calibration of a well-log information is characterized in that, may further comprise the steps:

(a) at first, suppose that the curvature of each well section of inclined shaft that needs are proofreaied and correct is a constant, namely hole angle δ is with the constant that is changed to of degree of depth h;

(b) suppose that a certain depth point hole angle is α, the enough segment dh on inclined shaft can regard straightway as.Namely get an infinitesimal section dS near this well track point, then its latitude is;

dH _z＝cos?adS

Need when (c) vertical depth calculates n to this section of n+1 point well as a length cell, and use n point and the n+1 hole angle average of ordering is as the average hole angle of this well section, then its geometrical relationship can be expressed as follows:

$\left\{\begin{array}{c}\mathrm{dS}=H(n+1)-H\left(n\right)\\ {\mathrm{dH}}_z=H_z(n+1)-H_z\left(n\right)\\ a=\frac{a(n+1)+a\left(n\right)}{2}\\ {\mathrm{dH}}_z=\mathrm{dS}\cos a\end{array}\right.$

Thus, can obtain the vertical depth design formulas:

$H_z(n+1)=H_z\left(n\right)+[H(n+1)-H\left(n\right)]\×\cos \left(\frac{\mathrm{\α}(n+1)+\mathrm{\α}\left(n\right)}{2}\right)$

In the following formula, H _zThe expression vertical depth; H represents tiltedly dark (being the depth-logger value); α represents hole angle,

N is to the average hole angle between the n+1 depth point in expression.When drift azimuth changes greatly, adopt minimum-curvature method to carry out hole-deviation correction without formula (3.3).

Calculate each tiltedly dark some H (n), corresponding vertical depth H by following formula _z(n), and with the log data corresponding with H (n) be assigned to H _z(n), simultaneously to newly-generated H _z(n)～V _{Z log}Data are carried out Equal interval, thereby have formed the log data that is equivalent to straight well.