Organic rich dark shale of Q Formation can be found in many areas(e.g.,in the North of S Basin).The shale target stratum is easy to hydrate and often undergoes spallation.Therefore,centering the casing in the horizont...Organic rich dark shale of Q Formation can be found in many areas(e.g.,in the North of S Basin).The shale target stratum is easy to hydrate and often undergoes spallation.Therefore,centering the casing in the horizontal section of the irregular borehole is relatively difficult.Similarly,achieving a good cementflushing efficiency under complex borehole conditions is a complex task.Through technologies such as centralizer,efficient preflushing,multi-stageflushing and ductile cement slurry,better performances can be achieved.In this study,it is shown that the cementing rate in the DY2H horizontal section is 97.8%,which is more than 34%higher than that of adjacent wells.This cementing matching technology for sidetracking horizontal wells can be used to improve the cementing quality of continental shale and provides a reference for future applications in thisfield.展开更多
The application of polycarboxylic acid as a fluid loss additive for cement(i.e.,a substance specifically designed to lower the volume of filtrate that passes through the cement)can prolong the thickening time of cemen...The application of polycarboxylic acid as a fluid loss additive for cement(i.e.,a substance specifically designed to lower the volume of filtrate that passes through the cement)can prolong the thickening time of cement slurries.Given the lack of data about the effects of carboxylic acid monomers as possible components for the additives traditionally used for oil-well cement,in this study different cases are experimentally investigated considering different types of these substances,concentrations,temperatures,and magnesium ion contamination.The results demonstrate that itaconic acid has a strong retarding side effect,while maleic and acrylic acids have similar influences on the thickening time of the cement slurry.The rheological properties of the cement slurry tend to deteriorate when the carboxylic acid monomer content in the fluid loss additive is increased to 40%.If the temperature exceeds 80°C,there is a significant decrease in the related impact on the thickening duration.With an increase in the intrusion of magnesium ions to>0.5%,both the rheological properties of the cement slurry and the thickening time are affected in a negative way.展开更多
基金funded by the CNPC Science and Technology Department Project(2021ZZ10-03)。
文摘Organic rich dark shale of Q Formation can be found in many areas(e.g.,in the North of S Basin).The shale target stratum is easy to hydrate and often undergoes spallation.Therefore,centering the casing in the horizontal section of the irregular borehole is relatively difficult.Similarly,achieving a good cementflushing efficiency under complex borehole conditions is a complex task.Through technologies such as centralizer,efficient preflushing,multi-stageflushing and ductile cement slurry,better performances can be achieved.In this study,it is shown that the cementing rate in the DY2H horizontal section is 97.8%,which is more than 34%higher than that of adjacent wells.This cementing matching technology for sidetracking horizontal wells can be used to improve the cementing quality of continental shale and provides a reference for future applications in thisfield.
文摘The application of polycarboxylic acid as a fluid loss additive for cement(i.e.,a substance specifically designed to lower the volume of filtrate that passes through the cement)can prolong the thickening time of cement slurries.Given the lack of data about the effects of carboxylic acid monomers as possible components for the additives traditionally used for oil-well cement,in this study different cases are experimentally investigated considering different types of these substances,concentrations,temperatures,and magnesium ion contamination.The results demonstrate that itaconic acid has a strong retarding side effect,while maleic and acrylic acids have similar influences on the thickening time of the cement slurry.The rheological properties of the cement slurry tend to deteriorate when the carboxylic acid monomer content in the fluid loss additive is increased to 40%.If the temperature exceeds 80°C,there is a significant decrease in the related impact on the thickening duration.With an increase in the intrusion of magnesium ions to>0.5%,both the rheological properties of the cement slurry and the thickening time are affected in a negative way.
