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Identification method for gas layer and gas-water coexistence layer of a tight sandstone reservoir

A technology of tight sandstone reservoir and identification method is applied in the field of fluid identification for tight sandstone reservoir gas layer and gas-water layer, which can solve the problems of difficult fluid identification, small proportion of fluid information, and large proportion of skeleton information.

Active Publication Date: 2020-09-04
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Under such conditions, skeleton information accounts for a large proportion in the response characteristics of well logging curves, while fluid information accounts for a small proportion, and the signal is weak, which brings difficulties to fluid identification
Second, the pore structure of the reservoir is complex and the irreducible water content is high
However, it is not easy to identify gas layers in tight reservoirs, and it is even more difficult to identify gas-water layers from the fluid properties
Array acoustic logging plays an outstanding role in identifying gas layers and gas-water layers, but the limitation is that not every well has array acoustic logging curves

Method used

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  • Identification method for gas layer and gas-water coexistence layer of a tight sandstone reservoir
  • Identification method for gas layer and gas-water coexistence layer of a tight sandstone reservoir
  • Identification method for gas layer and gas-water coexistence layer of a tight sandstone reservoir

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Effect test

Embodiment 1

[0083] like figure 2 as shown, figure 2 It is a cross-sectional view of the logging curve of the gas layer test section of Well X1 in the embodiment of the present invention.

[0084] figure 2 The daily gas production in the dotted box is 26,152 m3 / day, the unimpeded flow rate is 29,053 m3 / day, and the daily water production is 1.6 m3 / day. The actual test result is the gas layer.

[0085] The dotted line shows the typical logging characteristics of gas reservoirs, as follows: the CNL of the compensated neutron curve decreases significantly, and the excavation effect is remarkable; the HT12 of the deep induction logging curve ILD and the deep lateral logging curve LLD both have an increasing trend; The density value curve DEN is obviously lower; the air test response is obvious.

Embodiment 2

[0087] like image 3 as shown, image 3 It is a cross-sectional view of the logging curve of the gas-water same layer test section of the X2 well in the embodiment of the present invention.

[0088] image 3 The daily gas production in the dotted box is 0.6008 million cubic meters per day, the unobstructed flow rate is 0.617 million cubic meters per day, and the daily water production is 7.1 cubic meters per day. The actual test results show that the gas and water are in the same layer.

[0089] The dotted line box shows the typical logging characteristics of gas and water in the same layer, as follows: the compensated neutron curve CNL has excavation effect due to the decrease of gas content; the deep induction logging curve ILD and the deep lateral logging curve LLD There is a decreasing trend; the density value curve DEN decreases; the gas measurement curve has a response characteristic.

Embodiment 3

[0091] like Figure 4 as shown, Figure 4 It is a cross-sectional view of the logging curve of the test section of the water layer of well X3 in the embodiment of the present invention.

[0092] Figure 4 The daily water production in the dotted box is 12.6 cubic meters per day, and no gas is produced. The actual test result is the gas layer.

[0093] The dotted line box shows the typical water layer logging characteristics, as follows: compensated neutrons have no excavation effect; the deep induction HT12 and deep lateral LLD logging curves have a significant downward trend due to water content; the density logging curve DEN has a slight Decrease; air test response is not obvious.

[0094] like Figure 5 as shown, Figure 5 It is the fluid identification plate obtained by the embodiment of the present invention based on the X-axis and Y-axis formed by the combination of the constructed gas enhancement factor and water enhancement factor.

[0095] Figure 5The Medium F...

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Abstract

The invention relates to an identification method for a gas layer and a gas-water coexistence layer of a tight sandstone reservoir. The identification method comprises the following steps: 1, determining a logging curve set sensitive to different fluid properties in a research area; 2, according to the logging curve set, a gas strengthening factor and a water strengthening factor are constructed;3, according to the step 2, an X-axis calculation formula and a Y-axis calculation formula are determined respectively; 4, drawing a fluid identification plate according to the step 3; and 5, identifying fluid properties according to the fluid identification plate. According to the method, a fluid response sensitive curve is determined, a gas strengthening factor and a water strengthening factor are constructed, and finally two coordinate axis calculation formulas of the fluid identification plate are synthesized, so that the development of the fluid identification plate is completed. According to the method, the logging response characteristics of the gas layer are highlighted, and the logging response characteristics of the gas-water same layer are highlighted, so that the purpose of identifying the gas layer and the gas-water coexistence layer from the gas-containing water layer and the water layer is achieved.

Description

technical field [0001] The invention belongs to the technical field of exploration and development of oil and gas fields, and in particular relates to a fluid identification method for tight sandstone reservoir gas layers and gas-water layers. Background technique [0002] Tight sandstone gas reservoirs are widely distributed in my country, including orogenic foreland basins, faulted basins and relatively stable platforms, and the geological structure is very complex. Domestic tight sandstone gas reservoirs are developed in the western Sichuan Basin, the Ordos Basin, the Eastern Faulted Basin and the southern Junggar Basin. According to statistics, the recoverable resources of tight sandstone gas are very considerable, but the current production capacity is still very small. Logging fluid identification is an important part of the description of tight sandstone gas reservoirs, and improving its accuracy plays a very important role in the exploration and development of tight...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/10G06T11/20E21B47/00
CPCG06F17/10G06T11/206E21B47/00Y02A10/40
Inventor 魏修平李浩张广权陈舒薇贾超王丹丹谷宁
Owner CHINA PETROLEUM & CHEM CORP