Basil seed,containing anionic heteropolysaccharides in its outer pericarp,swells as gelatinous hydrocolloid when soaked in water.In this study,basil seed powder(BSP)was used as a multifunctional additive for water-bas...Basil seed,containing anionic heteropolysaccharides in its outer pericarp,swells as gelatinous hydrocolloid when soaked in water.In this study,basil seed powder(BSP)was used as a multifunctional additive for water-based drilling fluids.The chemical composition,water absorbency,rheological properties of aqueous suspension of BSP were tested.The effect of BSP on the rheological and filtration of bentonitebased drilling fluid before and after thermal aging was investigated.The inhibition characteristics were evaluated by linear swelling,shale cuttings dispersion and shale immersion test.Lubricity improvement by BSP was measured with extreme pressure lubricity test.The results revealed that incorporation of BSP into bentonite suspension improved rheological and filtration properties effectively after thermal aging of 120℃.BSP exhibited superior inhibitive capacity to xanthan and synergistic effect with KCl.BSP could reduce friction by forming hydration layer.The nanoscale three-dimensional network structures enable BSP to maintain high water retention and absorb strongly on bentonite and metal surface,contributing to enhanced rheology,filtration,inhibition and lubrication properties.The versatile characteristic of BSP,as well as biodegradation makes it a promising additive using in high performance water-based drilling fluid and a potential alternative to conventional synthetic polymers.展开更多
In order to reveal the development mechanism of high-quality clastic rock reservoir, the basic characteristics of Sha-3 Member of the Shahejie Formation in the Raoyang sag, Bohai Bay Basin, are analyzed based on cores...In order to reveal the development mechanism of high-quality clastic rock reservoir, the basic characteristics of Sha-3 Member of the Shahejie Formation in the Raoyang sag, Bohai Bay Basin, are analyzed based on cores observation, thin-sections and SEM images, and petrophysical properties measurements as well. It is found that high-mature composition and texture, early oil charging, and dissolution are the main factors controlling the formation and preservation of pores in deep reservoirs. Compaction is the major factor destructing pores, whereas formation overpressure is conducive to the preservation of original pores, high compositional and medium textural maturity can enhance the resistance capacity to compaction and protect primary pores. Early oil charging could lead to temporary cessation of diagenesis and thus inhibit the cementation. When organic acids entered reservoir formations, considerable amounts of secondary pores were formed, leading to the local improvement of petrophysical properties. When predicting good quality belt in exploration of deep basin, it is recommended that the superimposing effects of the multiple factors(overpressure, early oil charging, compositional and textural maturity, diagenesis) be taken into consideration.展开更多
Based on paleogeomorphology, drilling and seismic data, this paper systematically studies the structural and sedimentary evolution, source rock characteristics, reservoir characteristics and formation mechanism, hydro...Based on paleogeomorphology, drilling and seismic data, this paper systematically studies the structural and sedimentary evolution, source rock characteristics, reservoir characteristics and formation mechanism, hydrocarbon accumulation model and enrichment law in the Linhe Depression of the Hetao Basin, NW China. The Hetao Basin mainly experienced three stages of evolution, namely, weak extensional fault depression, strong extensional fault depression and strike-slip transformation, giving rise to four positive structural belts(Jilantai, Shabu, Nalinhu and Xinglong), which are favorable areas for oil and gas accumulation. The two main saline lacustrine source rocks, Lower Cretaceous Guyang Formation and Oligocene Linhe Formation, are characterized by high sulfur content, rich algae, early maturity, early expulsion, and wide oil generation window. The large structural transition belt in the intermountain area around the Hetao Basin controls the formation of large-scale braided river delta deposits, which are characterized by high quartz content(50%-76%), long-term shallow burial and weak compaction, low cement content, and good reservoir properties in delta front sandbody. The burial depth of the effective Paleogene reservoirs is predicted to reach 8000 m. Three hydrocarbon accumulation models, nose-uplift near sag, buried hill surrounding sag, fault nose near source rock, are constructed. The law of hydrocarbon accumulation in the Linhe Depression is finally clarified as follows: near-source around the depression is the foundation, high-quality thick reservoir is the premise, good tectonic setting and trap conditions are the key.展开更多
基金financially supported by CNPC Innovation Foundation(2020D-5007-0310)National Natural Science Foundation of China(No.51974354)National Key Research and Development Project(2019YFA0708303)。
文摘Basil seed,containing anionic heteropolysaccharides in its outer pericarp,swells as gelatinous hydrocolloid when soaked in water.In this study,basil seed powder(BSP)was used as a multifunctional additive for water-based drilling fluids.The chemical composition,water absorbency,rheological properties of aqueous suspension of BSP were tested.The effect of BSP on the rheological and filtration of bentonitebased drilling fluid before and after thermal aging was investigated.The inhibition characteristics were evaluated by linear swelling,shale cuttings dispersion and shale immersion test.Lubricity improvement by BSP was measured with extreme pressure lubricity test.The results revealed that incorporation of BSP into bentonite suspension improved rheological and filtration properties effectively after thermal aging of 120℃.BSP exhibited superior inhibitive capacity to xanthan and synergistic effect with KCl.BSP could reduce friction by forming hydration layer.The nanoscale three-dimensional network structures enable BSP to maintain high water retention and absorb strongly on bentonite and metal surface,contributing to enhanced rheology,filtration,inhibition and lubrication properties.The versatile characteristic of BSP,as well as biodegradation makes it a promising additive using in high performance water-based drilling fluid and a potential alternative to conventional synthetic polymers.
基金Supported by the China National Science and Technology Major Project(2011ZX05006-005)
文摘In order to reveal the development mechanism of high-quality clastic rock reservoir, the basic characteristics of Sha-3 Member of the Shahejie Formation in the Raoyang sag, Bohai Bay Basin, are analyzed based on cores observation, thin-sections and SEM images, and petrophysical properties measurements as well. It is found that high-mature composition and texture, early oil charging, and dissolution are the main factors controlling the formation and preservation of pores in deep reservoirs. Compaction is the major factor destructing pores, whereas formation overpressure is conducive to the preservation of original pores, high compositional and medium textural maturity can enhance the resistance capacity to compaction and protect primary pores. Early oil charging could lead to temporary cessation of diagenesis and thus inhibit the cementation. When organic acids entered reservoir formations, considerable amounts of secondary pores were formed, leading to the local improvement of petrophysical properties. When predicting good quality belt in exploration of deep basin, it is recommended that the superimposing effects of the multiple factors(overpressure, early oil charging, compositional and textural maturity, diagenesis) be taken into consideration.
基金Supported by the PetroChina Key Science and Technology (2021DJ0703)。
文摘Based on paleogeomorphology, drilling and seismic data, this paper systematically studies the structural and sedimentary evolution, source rock characteristics, reservoir characteristics and formation mechanism, hydrocarbon accumulation model and enrichment law in the Linhe Depression of the Hetao Basin, NW China. The Hetao Basin mainly experienced three stages of evolution, namely, weak extensional fault depression, strong extensional fault depression and strike-slip transformation, giving rise to four positive structural belts(Jilantai, Shabu, Nalinhu and Xinglong), which are favorable areas for oil and gas accumulation. The two main saline lacustrine source rocks, Lower Cretaceous Guyang Formation and Oligocene Linhe Formation, are characterized by high sulfur content, rich algae, early maturity, early expulsion, and wide oil generation window. The large structural transition belt in the intermountain area around the Hetao Basin controls the formation of large-scale braided river delta deposits, which are characterized by high quartz content(50%-76%), long-term shallow burial and weak compaction, low cement content, and good reservoir properties in delta front sandbody. The burial depth of the effective Paleogene reservoirs is predicted to reach 8000 m. Three hydrocarbon accumulation models, nose-uplift near sag, buried hill surrounding sag, fault nose near source rock, are constructed. The law of hydrocarbon accumulation in the Linhe Depression is finally clarified as follows: near-source around the depression is the foundation, high-quality thick reservoir is the premise, good tectonic setting and trap conditions are the key.
