U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2017–3082

February 2018

National and Global Petroleum Assessment

Assessment of Undiscovered Continuous Oil and Gas Resources in the 

Bohaiwan Basin Province, China, 2017

Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean undiscovered, technically recoverable continuous resources of 2.0 billion barrels of oil and 20.3 trillion cubic feet of gas in the Bohaiwan Basin Province, China.

Introduction

The U.S. Geological Survey (USGS) completed an assessment of undiscovered, technically recoverable continuous oil 

and gas resources in the Bohaiwan Basin (or Bohai Bay Basin) 

Province (fig. 1), the most prolific petroleum province in China. 

The basin is a composite of grabens, half-grabens, tilted fault 

blocks, and horsts within which sedimentary rocks range in age 

from Cambrian to Neogene (Mao and others, 2017). The complex tectonic history of the Bohaiwan Basin Province affected 

the development of petroleum systems (Allen and others, 1998; 

Ryder and others, 2011; Liang and others, 2016; Mao and others, 

2017). Two major petroleum systems are related to the tectonic 

history. Coals of the late Carboniferous–Permian are known 

sources of gas in the deep subbasins (Huang and others, 2010), 

whereas Paleogene lacustrine shales are known sources of oil and 

gas and are the major petroleum source rocks in the basin (Jiang 

and others, 2016; He and others, 2017).

Total Petroleum Systems and Assessment Units

For the Bohaiwan Basin Province, the USGS defined 

two total petroleum systems (TPSs) and related assessment 

units (AUs): the Carboniferous–Permian Coal TPS with the 

Carboniferous–Permian Tight Gas AU within this TPS and the 

Eocene Lacustrine Shale TPS with the Eocene Shahejie Lacustrine Shale Oil AU and Eocene Shahejie Lacustrine Shale Gas 

AU within this TPS. The geologic model for the Carboniferous–

Permian Tight Gas AU is for gas that was generated from coals to 

have migrated locally into low-permeability rocks at depths generally deeper than 5,000 meters. As many as 25 coals, the thickest 

at 9 meters, have been recorded in the Carboniferous–Permian 

section. The major source of geologic risk in the assessment unit 

is the presence of recoverable gas from low-permeability rock. 

The geologic models for the Eocene Shahejie Lacustrine Shale 

Oil and Shale Gas AUs are for some portion of the oil or gas 

generated within the shales to be retained within the shales following oil or gas migration. Members 1, 3, and 4 of the lacustrine 

Shahejie Formation are potential petroleum source rocks with 

a cumulative source-rock thickness of several hundred meters. 

These lacustrine shales contain Type I and Type II organic matter and have total organic carbon contents as high as 13 weight 

percent, averaging 3 weight percent (Li and others, 2013; Jiang 

and others, 2016; He and others, 2017). The sources of geologic 

risk in the lacustrine AUs are retention of recoverable oil or gas 

in the shales, heterogeneity of lacustrine rift facies (Li and others, 

2013), and extent of source rocks that are thermally mature for 

gas in the subbasins (Jiang and others, 2015).

Assessment input data are summarized in table 1. Well 

drainage areas, success ratios, and estimated ultimate recoveries 

are taken from U.S. tight-gas, shale-oil, and shale-gas analogs. 

Assessment input was modeled using vertical wells.

Undiscovered Resources Summary

The USGS quantitatively assessed undiscovered continuous shale-oil, shalegas, and tight-gas resources in the Bohaiwan Basin Province (table 2). For undiscovered resources, the estimated means are 2,036 million barrels of oil (MMBO), 

or 2.0 billion barrels of oil, with an F95 to F5 range from 423 to 4,774 MMBO; 

20,320 billion cubic feet of gas (BCFG), or 20.3 trillion cubic feet of gas, with 

an F95–F5 range from 4,325 to 46,124 BCFG; and 203 million barrels of natural 

gas liquids (MMBNGL) with an F95–F5 range from 41 to 479 MMBNGL. Of 

the mean total of 20,320 BCFG, 16,814 BCFG, or 83 percent, are estimated to be 

potential tight-gas resources.

Figure 1. Location of the Bohaiwan Basin Province, China, and the three 

assessment units (AUs) defined in this study.

116° 118° 120° 122° 124° 126°

43°

41°

39°

37°

35°

BEIJING

Qingdao

CHINA

BOHAI

BAY

YELLOW

SEA

Yello w River

Base map from U.S. Department of the Interior National Park Service

Bohaiwan Basin Province boundary

Eocene Shahejie Lacustrine Shale Oil AU

EXPLANATION

Eocene Shahejie Lacustrine Shale Gas AU

Carboniferous–Permian Tight Gas AU 0 50 100 MILES

0 50 100 KILOMETERS

CHN

MNG RUS

JPN

PRK

KOR

 SEA

 OF

JAPAN 

PACIFIC

OCEAN

Map area
ISSN 2327-6916 (print) ISSN 2327-6932 (online) https://doi.org/10.3133/fs20173082

Bohaiwan Basin Province Assessment Team

Christopher J. Schenk, Marilyn E. Tennyson, Tracey J. Mercier, Cheryl A. Woodall, Thomas M. Finn, Michael E. Brownfield, Phuong A. Le, 

Timothy R. Klett, Stephanie B. Gaswirth, Kristen R. Marra, Heidi M. Leathers-Miller, and Christopher J. Potter

For More Information

Assessment results are also available at the USGS Energy Resources Program website at https://energy.usgs.gov.

Assessment input data—Continuous AUs

Eocene Shahejie Lacustrine Shale Oil AU Eocene Shahejie Lacustrine Shale Gas AU

Minimum Mode Maximum Calculated

mean Minimum Mode Maximum Calculatedmean

Potential production area of AU (acres) 800 5,156,000 10,313,000 5,156,767 800 2,011,250 4,023,000 2,011,683

Average drainage area of wells (acres) 40 120 200 120 80 120 160 120

Success ratios (%) 10 50 90 50 10 50 90 50

Average EUR (MMBO, oil; BCFG, gas) 0.04 0.08 0.3 0.092 0.1 0.25 0.7 0.273

AU probability 1.0 1.0

Assessment input data—Continuous AU

Carboniferous–Permian Tight Gas AU

Minimum Mode Maximum Calculated

mean

Potential production area of AU (acres) 800 8,784,000 17,568,000 8,784,267

Average drainage area of wells (acres) 40 120 200 120

Success ratios (%) 10 50 90 50

Average EUR (BCFG) 0.2 0.4 1.2 0.444

AU probability 1.0

Table 1. Key assessment input data for three continuous assessment units in the Bohaiwan Basin Province, China.

[AU, assessment unit; %, percent; EUR, estimated ultimate recovery per well; MMBO, million barrels of oil; BCFG, billion cubic feet of gas. Well drainage areas, EUR, and success 

ratios are from U.S. shale-gas, shale-oil, and tight-gas analogs. The average EUR input is the minimum, median, maximum, and calculated mean. Shading indicates not applicable]

Total petroleum systems 

and assessment units (AUs)

AU probabilityAccumulation type

Total undiscovered resources

Oil (MMBO) Gas (BCFG) NGL (MMBNGL)

F95 F50 F5 Mean F95 F50 F5 Mean F95 F50 F5 Mean

Eocene Lacustrine Shale Total Petroleum System

Eocene Shahejie Lacustrine Shale Oil AU 1.0 Oil 423 1,710 4,774 2,036 240 998 2,964 1,224 2 10 30 12

Eocene Shahejie Lacustrine Shale Gas AU 1.0 Gas 499 1,975 5,084 2,282 5 19 53 23

Carboniferous–Permian Coal Total Petroleum System

Carboniferous–Permian Tight Gas AU 1.0 Gas 3,586 14,415 38,076 16,814 34 141 396 168

Total undiscovered continuous resources 423 1,710 4,774 2,036 4,325 17,388 46,124 20,320 41 170 479 203

Table 2. Assessment results for three continuous assessment units in the Bohaiwan Basin Province, China.

[MMBO, million barrels of oil; BCFG, billion cubic feet of gas; NGL, natural gas liquids; MMBNGL, million barrels of natural gas liquids. Results shown are fully 

risked estimates. For gas accumulations, all liquids are included in the NGL category. F95 represents a 95-percent chance of at least the amount tabulated; other fractiles 

are defined similarly. Fractiles are additive under the assumption of perfect positive correlation. Shading indicates not applicable]

References Cited

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Brouet-Menzies, Christine, 1998, Transtensional deformation in the 

evolution of the Bohai Basin, northern China, in Holdsworth, R.E., 

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