Characteristics, Accumulation Conditions, and Exploration Prospects of Tight in China* Caineng Zou 1 Search and Discovery Article #80230 (2012)** Posted June 18, 2012 *Adapted from oral presentation given in Singapore at the Geoscience Technology Workshop (GTW) on Unconventional Hydrocarbons, 15-16 March 2012 **AAPG 2012 Serial rights given by author. For all other rights contact author directly. 1 Research Institute of Petroleum Exploration & Development (RIPED), PetroChina Beijing (zcn@petrochina.com.cn) General Comments Characteristics of China s Tight Coexisting source and reservoir, indistinct trap boundaries, extensively distributed in good source rocks. Continuous and non-buoyancy accumulation, typically short-distance migration. Poor properties: matrix permeability 0.1md, porosity 10%. Nano-level pore-throat system developed, diameters typically between 40 and 900 nanometers. Major types: lacustrine carbonates, deep gravity quickstone and submerged delta. Relatively high pressure coefficient, relatively low crude density Rapid production decline, long production cycle, maintaining production by new well drilling Major Differences between China and US Tight North America: Typically marine deposit, widely distributed China: Typically nonmarine deposit, heterogeneity North America: Better porosity and permeability North America: More condensate oil North America: Ro: around 1.3%, lighter than that of China Tight : Major Unconventional /Gas Exploration Targets in China Reference Zou, Caineng, 2011, Unconventional petroleum geology: Beijing, China, 310 p.
PetroChina Characteristics, Accumulation Conditions, & Exploration Prospects of Tight in China ZOU Caineng Research Institute of Petroleum Exploration & Development (RIPED) Singapore, March, 2012
Table of Contents 1. Current Status & Definition of Tight 2. Characteristics of China s Tight 3. Exploration Potentials of Tight in China
1. Current Status & Definition Rapid Development of Tight E&D in USA 1/1/2009 7/15/2011, Gas/, Wells, USA Heath Bakken Mowry Collingwood Green River Wasatch Niobrara Monterey Cane Cherokee Creek Atoka Cleveland Mississippian Granite Wash Barnett Lower Tuscaloosa Bone Spring Woodbine Wolfcamp Utica 成熟致密油区 Mature Tight Source: IHS 数据来源 :IHS Eagle Ford 勘探区 Exploration 天然气液生产区 NGL Production Recoverable Resources: 6,800 MMT 2010 Production: 30 MMT 2020 Production: 150 MMT (Source: IHS, 2011)
Tight : A New Drive for US /Gas Industry 2,500 MBPD Condensate Production Tight Production MBPD 2,500 2,000 2,000 1,500 1,500 1,000 1,000 500 500 0 2008 2010 2012 2014 2016 2018 2020 Eagle Ford Marcellus and Utica Cleveland-Atoka Granite Wash Historical (PFC, 2011) 0 2000 2005 2010 2015 2020 Bakken Eagle Ford Niobrara Permian Utica Monterey Others Historical Production
Definition of Tight Tight : Petroleum Collects in Source Rock or in the closely related Tight Sands or Tight Carbonates Permeability typically 0.1mD Indistinct Trap Boundaries Difference from Shale, Shale, Fractured Shale in Accumulation & Distribution, Production Techniques
Definition of Tight of Tight Migration & Accumulation Mode Shale Tight Limestone Shale Tight Sandstone Depth Shale (KM) Collects in source rock or in closely related tight sands or tight carbonates ZOU Caineng, 2011 Typically short-distance migration & accumulation, no distinct trap boundaries
Table of Contents 1. Current Status & Definition of Tight 2. Characteristics of China s Tight 3. Exploration Potentials of Tight in China
2. Characteristics of China s Tight ❶Coexisting Source and Reservoir, Indistinct Trap Boundaries, Extensively Distributed in Good Source Rocks. ❷Continuous & Non-buoyancy Accumulation, Typically Short-distance Migration. ❸Poor Properties: Matrix Permeability 0.1mD, Porosity 10%. ❹Nano-level Pore-throat System developed, Diameters typically between 40 and 900 Nanometers. ❺3 Major Types: Lacustrine Carbonates, Deep Gravity Quickstone and Submerged Delta. ❻Relatively High Pressure Coefficient, Relatively Low Crude Density ❼Rapid Production Decline, Long Production Cycle, Maintaining Production by New Well Drilling
2. Characteristics of China s Tight ❶ Coexisting Source and Reservoir, Indistinct Trap Boundaries, Extensively Distributed in Good Source Rocks Litho. Strati. Struc. Tight Shale Tight Gas CBM Shale Gas Carbo. Frac.& Cavity Gas Accumulation Mode of Source-Reservoir Coexistence
❷Continuous & Non-buoyancy Accumulation, Typically Short-distance Migration. Formation Temperature of Hydrocarbon Fluid Inclusion: 55~125 : CONTINUOUS OIL ACCUMULATION Feldspar Grains Quartz Grains Frequency Calcite Cement Temperature ( ) Temperature Distribution of Fluid Inclusion, Ordos Mesozoic Continuous Tight Play
❸Poor Properties: Matrix Permeability 0.1mD, Porosity 10%. Porosity & Permeability of Major Tight Formations, Lower-Middle Jurassic, Sichuan Basin Frequency (%) Da anzhai Shell Limestone Non-fracture Blocks: 11 Wells: 38 Samples: 2297 Ave.: 0.97% Frequency (%) Blocks: 11 Wells: 38 Samples: 2167 Ave.: 0.07mD Da anzhai Shell Limestone Shell Limestone, Da anzhai Φ<1% K<0.1mD Porosity (%) Permeability (md) Frequency (%) Frequency (%) Lianggaoshan Sandstone Non- Fracture Sha-1 Sandstone Non-Fracture Porosity (%) Blocks: 6 Wells: 13 Samples: 550 Ave.: 1.47% Blocks: 3 Wells: 16 Samples: 555 Ave.: 3.4% Frequency (%) Frequency (%) Blocks: 6 Wells: 13 Samples: 511 Ave.: 0.09mD Permeability (md) Blocks: 3 Sha-1 Sandstone Wells: 16 Non-fracture Samples: 508 Ave.: 0.23mD Lianggaoshan Sandstone Non-fracture Lacustrine Sandstone, Lianggaoshan Φ<2% K<0.1mD Lacustrine Sandstone, Lower Sha-1 Φ<5% K<1mD Porosity (%) Permeability (md)
❹Nano-level Pore-throat System Developed, Diameters typically between 40-900 NM Ordos Basin Sichuan Basin 400nm 50nm 100nm 50nm 100nm Quartz Intragranular Pores, Gao 46 Well, Chang 6, 1742.5m Calcite Intragranular Dissolved Pores, Pingchang 1, Da anzhai, 3186.8m 10μm Illite Interlayer Pores Xi 233 Well, Chang 72, 1968.15m 10μm Intercrystalline Micropores, Ren 1 Well, Da anzhai, Grainstone
❺3 Major Types in Lacustrine Carbonates, Deep Gravity Quickstone and Submerged Delta. Sea Level CBM Struc. reservoirs Biogas Litho Reservoirs Struc. Reservoirs Hydrate Volca. Reservoirs Strati. Reservoirs Tight Shale Carbo. Gas Shale Gas Tight Gas Metamo.& Frac. Gas ZOU Caineng, 2011 Sand Shale Carbo. Metamo. Coal Volca. Gas /Gas Water Distribution of Conventional & Unconventional Accumulation Types
❻High Pressure Coefficient and Low Crude Density Basins Formation Ro(%) Pressure Coefficient Crude Density (g/cm 3 ) Notes Williston Upper Devonian 0.6~1.0 1.35~1.58 0.81~0.83 Bakken S. Texas Cretaceous 0.5~2.0 1.35~1.80 0.82~0.87 Eagle Ford Bohai Bay Shahejie 0. 5~2.0 1.30~1.80 0.67~0.85 Liaohe Sag Bohai Bay Shahejie 0. 5~2.0 1.53~1.80 0.68~0.78 Jiyang Sag Sichuan Da anzhai 0.5~1.6 1.23~1.72 0.76~0.87 Chuanzhong Songliao Qingshankou 0.5~2.0 1.20~1.58 0.78~0.87 Gulong Sag Ordos Yanchang 0.7~1.2 0.75~0.85 0.70~0.76 Yixia Slope Qaidam E System 0.5~0.8 1.47 0.72 Mangya Sag Pressure Coefficient: 1.2-1.8, Density: 0.7-0.9g/cm 3
❼Rapid Production Decline, Long Production Cycle, Maintaining Production by New Well Drilling Fractures: Key to High Production Pores: Main Plays Fracture Pores 年产油 (t) 6000 5000 4000 3000 2000 Luo 罗 30 30 井 Well, Chuanzhong Early Stage (1960-1962): Mainly via Fractures Accum. Production: 7,687 tons Later Stage (1963-present): Mainly via Pores Accum. Production: 6,735 tons, 46.7% of total cumulative 1000 0 1958 年 1964 年 1970 年 1976 年 1982 年 1988 年 1994 年 (Source:Southwest /gasfield, PetroChina) Early Stage: Mainly via Fractures, Later Stage: Mainly via Pores
Table of Contents 1. Current Status & Definition of Tight 2. Characteristics of China s Tight 3. Exploration Potentials of Tight in China
Case 1: Yanchang Formation, Ordos Basin Strata Sequence Columnar Section, Yanchang Formation, Yanhe Section Ordos Mesozoic Source Rocks Developed in C-7 and C-9 Intervals Tight May Be In the Lake Center Sandstone Mudstone Lake Reservoirs Name Ablation Delta Line Bank
3. Exploration Potentials of Tight in China Major Differences between China & US Tight ❶ North America: Typically Marine Deposit, Widely Distributed China: Typically Nonmarine Deposit, heterogeneity ❷ Better Properties in North America Porosity and Permeability higher than that of China ❸ More Condensate in North America Ro: around 1.3%, Lighter than that of China Tight : Major Unconventional /Gas Exploration Targets in China
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