water soluble amphoteric graft copolymers of polysaccharide were synthesized via grafting of cationic monomer onto the sodium carboxymethylcellulose ()cmc)( and then used as a shale stabilizer in the water-based drilling fluids. accordingly, five types of cmc-graft copolymers with different ratios of acrylamide am)( and diallyldimethylammonium chloride dadmac)( were synthesized. grafting of mon...

fluid properties with constant improvement in efficiency have been noticeable as important criteria in drilling operation. the main drilling fluid properties highly depend on utilization of new polymers with high efficiency in drilling fluid composition. in this paper, the performance of a new polymer, called partially hydrolyzed polyacrylamide polymer (phpa), is studied which has recently ente...

The poly(styrene-methyl methacrylate) latex particles as potential physical shale stabilizer were successfully synthesized with potassium persulfate as an initiator in isopropanol-water medium. The synthesized latex particles were characterized by Fourier transform infrared spectroscopy (FT-IR), particle size distribution measurement (PSD), transmission electron microscopy (TEM), and thermal gr...

Starch is one of the most widely used biopolymers in water based drilling fluids to control fluid loss. The thermal stability of starch in common drilling fluids is low (93 °C). In this study, the thermal stability of starch has been evaluated in sodium/potassium formate and potassium chloride fluids. Samples of mud were prepared by formate salts (sodium and potassium) and potassium chloride wi...

This paper presents main results of a shale stability study, related to the understanding of shale/ fluid interaction mechanisms, and discusses shale strength correlation. The major shale/ fluid interaction mechanisms: Capillary, osmosis, hydraulic, swelling and pressure diffusion, and recent experimental results are discussed. Factors affecting the shale strength are discussed, and a sonic com...

Physical and geochemical characteristics of shale play conclusive role in confirming operation measures during drilling and stimulation. The properties of shale samples from Jiyang depression were investigated through X-ray diffraction, scanning electron microscope, adsorption isothermal, high pressure mercury intrusion, methylene blue trihydrate, pressure pulse decay, tests of specific water w...

Fluid invasion from water-based drilling mud (WBDM) into the shale formations causes swelling, high pressure zone near the wellbore wall, and eventually wellbore instability problems during drilling operations. For the stability of the wellbore, physical plugging of nanoscale pore throats could be considered as a logical approach toward avoiding the fluid invasion into the shale formation. This...

The rheological regulation of the “three high” (high temperature, high density and high salinity) water-based drilling fluid is a worldwide problem due to the combined influence of temperature, solid content and salinity. This paper investigates the factors and regulation methods about rheological property of “three high” water based drilling fluid, and the effects of clay, salinity and weighti...

SUMMARY The hydro-mechanical behaviour of shales is becoming one of the most important issues in modern geomechanics, largely driven by petroleum industries (i.e., the extraction of shale gas), the sequestration of CO2 and the nuclear waste geological storage. In any such application, a deep understanding of the hydro-mechanical behaviour of the involved materials is of primary significance. Th...

The past decade has seen increased focus on nanoparticle (NP) based drilling fluid to promote wellbore stability in shales. With the plugging of NP into shale pores, the fluid pressure transmission can be retarded and wellbore stability can be improved. For better understanding of the interaction between shale and NP based drilling fluid based on previous pressure transmission tests (PTTs) on A...