The acquisition methods of shale gas-bearing formation standardization open-flow capacity based on gassiness index
Technical field
Shale gas exploration and development has become as world's focus, and the U.S., Canada are carried out in multiple basins
Shale gas commercial-scale operation.Equally, the shale gas stock number in China's Main Basins and area is the abundantest.Grind
Studying carefully and show, the only shale gas stock number in the Sichuan Basin is equivalent to the 1.5 of China's basin conventional gas stock number
More than Bei.Therefore, China's shale gas stock number is enriched, and fair exploration is wide.
Shale gas exploration and development is world-class technical barrier.At present, domestic in Shale Gas Accumulation mechanism, money
The aspects such as source potentiality, evaluating reservoir achieve huge advance, but in terms of shale gas horizontal productivity analysis
Research is still in the starting stage, and the especially acquisition aspect of shale gas horizontal well open-flow capacity rests on theory more and grinds
Study carefully the stage.And traditional Absolute Open Flow of Gas Wells acquisition methods mainly for lithology be sand shale and carbonate
Rock, the effect that these methods obtain in shale is unsatisfactory.
Background technology
Open-flow capacity prediction be a highly important link in natural gas exploration and development, be to reservoir quality,
The comprehensive evaluation index of reservoir fluid oil-containing character and its oil productive capacity, be also simultaneously most important index it
One.
Shale gas refers to that main body is positioned in dark-coloured mud shale or high-carbon mud shale, based on absorption or free state
Want the gas accumulation of existing way.Shale gas reservoir has the feature of ultralow porosity, permeability;And part
Gas absorption, in reservoir rock particle surface, is present in reservoir with ADSORPTION STATE, and this gives shale gas interpretation and evaluation
Bring difficulty.Shale gas well is required for carrying out massive hydraulic fracturing before going into operation, thus causes shale gas reservoir production capacity with often
The influence factor more having its Special complex compared by rule gas reservoir.
Traditional absolute open flow (AOF) acquisition methods is mainly one point method and pseudopressure method etc., by well testing means
Realizing, these all determine that sets up open-flow capacity equation under original gas reservoir pressure.For shale gas reservoir,
Owing to seepage flow mechanism is complicated, it is difficult to set up the open-flow capacity model being suitable for by these methods.
Summary of the invention
It is an object of the invention to for the above-mentioned state of the art, it is desirable to provide a kind of method is easy, can improve shale
Absolute Open Flow of Gas Wells precision of prediction, and the on-the-spot shale based on gassiness index surveying logging explanation needs can be met
The acquisition methods of gas-bearing formation standardization open-flow capacity.
The implementation of the object of the invention is, obtaining of shale gas-bearing formation standardization open-flow capacity based on gassiness index
Access method, concretely comprises the following steps:
1) obtain work area by survey log data and try shale gas horizontal well horizontal segment shale gas layer parameter, specifically
Parameter is gas pay thickness H, horizontal section length L, pressure coefficient Kf, porosity POR, gas saturation Sg and
Organic carbon content TOC;
2) acquisition has tried shale gas horizontal well horizontal segment shale gas layer fracturing parameter, and design parameter is fracturing liquid
Long-pending Vf, pressure break proppant volume Vs;
3) shale gas horizontal well horizontal segment shale gas-bearing formation open-flow capacity has been tried by the acquisition of tested productivity data
AOFg;
4) use step 1), step 2) and step 3) parameter that obtains calculates successively and tried shale gas horizontal well
Horizontal segment shale gas layer fracturing reform index IFR, standardization open-flow capacity IAOF, gassiness index Ig, specifically public
Formula is as follows:
IFR=(Vf+Vs)/10000,
IAOF=AOFg/L/IFR,
Ig=H × Kf × POR × Sg × TOC;
In formula: fracturing fluid volume Vf dimension is m3,
Pressure break proppant volume Vs dimension is m3,
Fracturing reform index IFR dimension is 104m3Or 10km3,
Horizontal section length L dimension is hm or 100m,
Thickness H dimension is m,
Open-flow capacity AOFg dimension is 104m3/ d,
Standardization open-flow capacity IAOFDimension is 104m3/d/hm/104m3,
Thickness H dimension is m,
Pressure coefficient Kf dimensionless,
Porosity POR, gas saturation Sg dimension are decimal,
Organic carbon content TOC dimension is %;
5) the standardization open-flow capacity I that will calculateAOFThe gassiness index Ig calculated with corresponding well testing passes through
Little square law determines model IAOF=a × eb×IgModel coefficient a, b;
6) by surveying log data acquisition work area horizontal well to be predicted horizontal segment shale gas layer parameter, design parameter
For gas pay thickness H 1, pressure coefficient Kf 1, porosity POR 1, gas saturation Sg 1 and organic carbon content
TOC 1;
7) step 6 is used) parameter that obtains calculates horizontal well horizontal segment shale gas-bearing formation gassiness index Ig to be predicted
1;
8) model I is utilized0OF1=a × eb×Ig1Calculate horizontal well horizontal segment shale gas-bearing formation standardization to be predicted without choked flow
Amount IAOF1;
9) draw the shale gas-bearing formation standardization open-flow capacity vertical cross section of well to be predicted, export level to be predicted
The shale gas-bearing formation open-flow capacity result of calculation of well horizontal segment.
The present invention solves the tradition open-flow capacity acquisition methods shale gas-bearing formation open-flow capacity essence at prediction level well
Exactness is the highest, poor reliability problem, and easier than traditional open-flow capacity acquisition methods, become
This is lower, and scene is more practical.
The present invention has applied 25 mouthfuls of wells in certain shale gas field, and the shale gas-bearing formation standardization that the present invention calculates is without choked flow
Standardization open-flow capacity after amount converts with the open-flow capacity that on-the-spot pressure break gas testing obtains is close, and mean error is not
More than 20%, can reach to predict the needs of on-the-spot standardization open-flow capacity.
Accompanying drawing explanation
Fig. 1 is workflow block diagram of the present invention,
Fig. 2 is 10 mouthfuls of F shale gas field of the present invention well standardization open-flow capacity and gassiness index cross plot,
Fig. 3 is S3HF well shale gas-bearing formation standardization open-flow capacity vertical cross section,
Fig. 4 is S8HF well shale gas-bearing formation standardization open-flow capacity vertical cross section.
Detailed description of the invention
With reference to Fig. 1, the present invention concretely comprises the following steps:
1) the shale gas layer parameter of shale gas horizontal well, design parameter has been tried by surveying log data acquisition work area
For gas pay thickness H, horizontal section length L, pressure coefficient Kf, porosity POR, gas saturation Sg and organic
Carbon content TOC;
2) acquisition has tried the shale gas layer fracturing parameter of shale gas horizontal well horizontal segment, and design parameter is fracturing fluid
Volume Vf, pressure break proppant volume Vs;
3) the open-flow capacity AOFg of shale gas horizontal well horizontal segment has been tried by the acquisition of tested productivity data;
4) step 1 is used) and step 2) parameter that obtains calculates the shale gas horizontal well level tested successively
Shale gas layer fracturing reform index IFR, the standardization open-flow capacity I of sectionAOFWith gassiness index Ig;
5) the shale gas horizontal well horizontal segment shale gas-bearing formation standardization open-flow capacity I of examination that will calculateAOFWith relative
Should well testing calculate gassiness index Ig determine model I by method of least squareAOF=a × eb×IgModel coefficient a,
b;
6) the shale gas-bearing formation obtaining work area shale gas horizontal well horizontal segment to be predicted by surveying log data is joined
Number, design parameter is gas pay thickness H1, pressure coefficient Kf1, porosity POR1, gas saturation Sg1 and have
Machine carbon content TOC 1;
7) step 6 is used) parameter that obtains calculates the shale gas-bearing formation of shale gas horizontal well horizontal segment to be predicted and contains
Gas index Ig1;
8) model I is utilizedAOF1=a × eb×Ig1The shale gas-bearing formation standardization calculating horizontal well horizontal segment to be predicted is without hindrance
Flow IAOF1;
9) draw the shale gas-bearing formation standardization open-flow capacity vertical cross section of well to be predicted, export well to be predicted
Standardization open-flow capacity result of calculation.
With specific embodiment in detail the present invention is described in detail below.
Example one: F shale gas field S3HF well, proving standardization open-flow capacity result of calculation.
1) obtain 10 mouthfuls of F shale gas field by survey log data and try horizontal well (S1H well, S1-2H well, S1-
3HF well, S6-2HF well, S7-2HF well, S8-2HF well, S9-2HF well, S10-2HF well, S11-2HF well,
S12-3HF well) the gas pay thickness H of horizontal segment shale gas-bearing formation, horizontal section length L, pressure coefficient Kf, hole
Degree POR, gas saturation Sg and organic carbon content TOC;
2) obtain 10 mouthfuls tried shale gas horizontal well horizontal segment shale gas lamination split fracturing fluid volume Vf used,
Pressure break proppant volume Vs;
3) 10 mouthfuls of without hindrance streams of shale gas-bearing formation having tried shale gas horizontal well horizontal segment are obtained by tested productivity data
Amount AOFg;
4) according to step 1), step 2) and step 3) parameter that obtains calculates 10 mouthfuls of well testing gas-bearing formation pressures successively
Split transformation index IFR, standardization open-flow capacity IAOFWith gassiness index Ig;
5) by step 4) the middle standardization open-flow capacity I calculatedAOFWith the gassiness index Ig calculated by a young waiter in a wineshop or an inn
Multiplication determines model IAOF=a × eb×IgModel coefficient a=0.348, b=0.2496 (see Fig. 2);
6) by surveying log data acquisition horizontal well S3HF well horizontal segment shale gas layer parameter, S3HF gas well gas thickness
Degree H1 average out to 40m, pressure coefficient Kf1 average out to 1.45, porosity POR1 average out to 0.055, gassiness are saturated
Degree Sg1 average out to 0.552, organic carbon content TOC1 average out to 2.36%;
7) by step 6) parameter that obtains calculates well S3HF well horizontal segment gas-bearing formation gassiness index Ig1 to be predicted and is
4.16;
8) model I is utilizedAOF1=a × eb×Ig1Calculate the shale gas-bearing formation standardization open-flow capacity of S3HF well horizontal segment;
9) output result of calculation, draws S3HF well shale gas-bearing formation standardization open-flow capacity vertical cross section (see figure
3) the standardization open-flow capacity I that, S3HF well calculatesAOF1 average out to 0.982 × 104m3/d/hm/104m3.S3HF well
It is 40.01 × 10 that completion pressure break gas testing obtains shale gas-bearing formation open-flow capacity4m3/ d, extended horizontal depth 13.98hm
(1398m), fracturing fluid used and proppant cumulative volume are 2.96 × 104m3, it is converted into shale gas-bearing formation standardization
Open-flow capacity is 0.967 × 104m3/d/hm/104m3, error is 1.6%, less than 20%, meets on-the-spot survey well logging
Explain that the shale gas-bearing formation open-flow capacity prediction of work needs.
Example two: F shale gas field S8HF well, checking utilizes shale gas-bearing formation standardization open-flow capacity to predict shale gas
Horizontal well open-flow capacity calculates error.
1) S8HF well is a bite shale gas prospect pit of F shale gas field, can continue to use model I in example oneAOF=a × eb× ICoefficient a=0.348, b=0.2496;
2) by surveying log data acquisition S8HF well shale gas layer parameter, S8HF well well section 2781-2825m shale
Gas pay thickness H is 44m, pressure coefficient Kf is 1.45, passes through porosity POR with 0.125m for depth interval, contain
Gas saturation Sg, organic carbon content TOC calculate gassiness index Ig, then calculate shale gas-bearing formation by gassiness index Ig
Standardization open-flow capacity IAOF, draw continuous print shale gas-bearing formation standardization open-flow capacity vertical cross section (see figure
4);
3) calculate S8HF well 2781-2825m well section shale gas-bearing formation standardization open-flow capacity average out to 0.71 ×
104m3/d/hm/104m3。
4) output result of calculation, S8HF well 2781-2825m gas-bearing formation standardization open-flow capacity average out to 0.71 ×
104m3/d/hm/104m3, the sidetrack horizontal well a length of 15.07hm of horizontal segment shale gas-bearing formation (1507m), pressure break is made
Industry uses fracturing fluid and proppant cumulative volume to be 4.0 × 104m3, utilize shale gas-bearing formation standardization open-flow capacity parameter
Predict that this sidetrack horizontal well horizontal segment shale gas-bearing formation open-flow capacity is 0.71 × 15.07 × 4.0=42.8
(104m3/ d), this gas well gas layer sidetrack horizontal well horizontal segment production test obtains 48.5 × 104m3/ d open-flow capacity, in advance
Surveying error is 11.8%, and less than 20.0%, the shale gas-bearing formation open-flow capacity meeting on-the-spot survey logging explanation work is pre-
Survey and need.