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Gas produced water is originated from formation associated water produced during oil and gas production operations, which is characterized by numerous types, high mineralization and complex pollution components. Through sampling, testing and analyzing gas produced water in the Eastern Sichuan area, it is found that the carboniferous formation is rich in mineral resources, such as strontium (up to 814 mg/L), bromine (up to 717 mg/L), which is much higher than the content in the brine of Qaidam Basin salt lakes or seawater. And currently, China's strontium ore and bromine are in a situation of high import demand and supply shortage. By clarifying the strontium and bromine recovery techniques and evaluating the preliminary economic feasibility of potential mining, it is found that there are significant prospects of development and utilization. This study aims to provide scientific basis for the extraction of strontium and bromine resources in gas produced water in the Eastern Sichuan area and to establish the foundation for better sustainable development and resource utilization of oil and gas fields. [ABSTRACT FROM AUTHOR]

Resulting in dense lithology and poor physical properties, dedolomitization has detrimental effects on reservoir characteristics, so there has been little systematic research reported on the dedolomitization in the Carboniferous Huanglong Formation from the Eastern Sichuan basin. Through well drilling, well logging, thin-section authentication, and geochemistry tests, we studied for the first time the growth characteristics, regularities of distribution, genesis, and geological significance of dedolomitization in rock with typical fabric. From this study, we arrived at three conclusions: (1) the microstructure type divisions of dedolomite are as follows: A. a large micrite core and clear calcite rim, B. dolomite crystal, C. gypsum crystal, and D. rhombohedral pores; (2) rocks had low porosity and high density after dedolomitization in Eastern Sichuan, which is detrimental to reservoir development; and (3) micrite-microlite crystal dolomite and micrite-microlite crystal gypsum dolomite are the protoliths before dedolomitization. Sabkha is the primary sedimentary environment, in which the sabkha brine was kept within the layer and would become the main fluid of dolomitization in the high-quality dolomite reservoir from Eastern Sichuan. Analyzing the instances of dedolomitization has important geological significance in some ways, such as recovering the protolith, recovering the ancient environment, and discussing the relationships between diagenetic fluid properties and the reservoir's development. [ABSTRACT FROM AUTHOR]

Abstract: Natural gas in the Ludong-Wucaiwan area is characterized by typical source-controlled reservoirs. Combining outcrop data, well data and seismic data, this article makes a systematic research and evaluation on the abundance, type, and maturity characteristics of the Carboniferous source rocks in the Ludong-Wucaiwan area. The Carboniferous source rocks are dominantly dark grey and grey mudstones, secondarily tuffs, carbonaceous mudstones, silty mudstones and coals. The source rock abundance of the Upper Carboniferous Batamayineishan Formation (C2b) is higher than that of the Lower Carboniferous Dishuiquan Formation (C1d), while the kerogen type of the Lower Carboniferous source rock is better than that of the Upper Carboniferous. The maturity center of the Carboniferous source rocks is located in the west part of Dinan uplift to the Wucaiwan depression area, with maturity decreased towards south and north. The distributions of the Carboniferous source rocks and volcanic rocks are complementary. The source rocks are distributed in zonal shape in east-west direction, and are most developed in the west part of the Dinan uplift and its southern area. [ABSTRACT FROM AUTHOR]