Sublethal Toxic effects of spent Oil Based Drilling Mud and Cuttings to Earthworm Aporrectodea Longa.

Sublethal toxic effects of spent oil based drilling mud collected from an abandoned oil drilling site in Mpanak, Akwa Ibom State, Nigeria were assessed in the earthworm Aporrectodea longa. The test annelid was exposed to sub-lethal Concentration of 0ppm SPP; 62,500ppm SPP; 125, 000ppm SPP; 250,000ppm SPP and 500,000ppm SPP of drilling mud for 28 days. The procedure for the exposure was according to the Organisation for Economic Co-operation and Development (OECD) recommended method for testing chemicals No 207. There were three replicate jars per treatment and 10 earthworms per jar of soil spiked with drilling mud. Control groups were also set up. At the end of the exposure, bioaccumulation of the chemical constituents of the drilling mud (heavy metals and TPH) increased (p<0.01) with increase drilling mud concentration. Mean weights of earthworms increased in the 62,500 and 125,000SPP and decreased in the 250,000 and 500,000SPP. Glucose levels increased with increase in the drilling mud concentration with the exception of 62,500ppm SPP. The elevated glucose levels could be due to hyperglycemia induced by the toxicity of the drilling mud. Protein levels increased with increase in drilling mud concentration except in the 125,000ppm SPP treatment. The increase in protein content could be due to enhancement of microsomal protein synthesis prompted by the toxicity of the drilling mud to test organisms. The results of this study have shown that drilling mud and cuttings could cause serious health risk to Aporrectodea longa. The discharge of drilling mud into the terrestrial ecosystems should be discouraged. © JASE

The integrated method to select drilling muds for abnormally high pressure formations

The article describes the method for choosing a drilling mud for drilling abnormally high pressure formations. A carefully selected drilling mud formulation would not only enhance an array of interrelated fluid properties, but also minimize the impact on the pay zones when the drill bit first penetrates the pay. To ensure a better assessment of drilling mud impact on the pay zone, it is reasonable to carry out the study focused on the analysis of technological parameters, involving filtration, acid and drilling mud tests, as well as formation damage analysis. This would enable evaluating the degree of mudding off, reservoirs acid fracturing effect and the risks of pipe sticking at significant depth. The article presents the results of the above-described study with regard to the currently used drilling mud and new experimental formulations developed at National Research Tomsk Polytechnic University (Drilling Mud and Cement Slurry Laboratory)

The Effect of pH and Salinity on the Rheological Properties of Drilling Mud Formulation from Natural Polymers

Drilling muds are designed to perform certain functions of drilling operation. Some of the functions are to cool and lubricate the drilling bit, transmit hydraulic power to drill bit, provide filter cake and remove drilling cuttings and maintaining wellbore stability. Various additives with specific properties are added in the mud to help prevent the challenges encountered during drilling process. The work studies the effect of pH and salt on the rheological properties of drilling mud formulation from two natural polymers (Terminaliamantaly(TM) exudate and Guar gum) with the use of Model 35 viscometer. Drilling mud formulation with these polymers was investigated at pH of (7.05, 8.15, 10.07, and 11.13) and salt concentrations of (2, 4, 6, 8 and 10g/ml). Results obtained from drilling mud with TM exudate were compared with drilling mud with guar gum. It was found thatthe rheological properties of drilling mud with Terminaliamantaly exudates increased for higher pH as compared to drilling mud with Guar gum. The increase in salinity reduced the effectiveness of the rheological properties of the mud such that as the salinity in drilling mud increased, the rheological properties of drilling mud with Terminaliamantaly and Guar gum decreased. The performance is attributed to flocculation, dispersion and hydration behavior of particles in the mud

The integrated method to select drilling muds for well construction in difficult geological conditions

The article is concerned with the integrated approach to choose drilling mud composition for pay horizons penetration. An optimal choice of drilling mud composition would not only mean ensuring basic fluid properties, but also should minimize the impact on the pay zones when penetrating the pay horizons for the first time. To carry out better assessment of drilling mud impact on pay horizons, it is reasonable to study both technological parameters and filtration analyses, which would allow us to estimate the level of drilling mud impact on the pay horizon

Plant growth in soil amended with drilling mud

Extraction of natural gas generates drilling fluid and drilling mud that contain high concentrations of salts. Land application of the fluid and mud can have negative impacts on plant growth and soil properties. The objective of this study was to determine the effects of drilling mud on plant growth, plant chemical concentrations, and soil chemical properties. Sudangrass (Sorghum sudanense [Piper] Stapf [Piper]) and bermudagrass (Cynodon dactylon L.) were grown in a Roxana loam soil amended with 0%, 5%, or 10% (w/w) drilling mud in a 6-wk greenhouse study. Plant biomass production and concentrations of elements in biomass were determined. Electrical conductivity, pH, and concentrations of extractable and total elements in soil were analyzed. The addition of drilling mud significantly reduced shoot and total biomass production of both plant species and root biomass of bermudagrass. When drilling mud was added to the soil, plant Ca and Mg levels increased. Soil levels of Na, Cl, and the electrical conductivity significantly increased with increased levels of drilling mud application which indicated that salinity was most likely limiting plant growth. Excessive rates of drilling mud application can adversely impact soil properties and reduce plant growth

Characterization based machine learning modeling for the prediction of the rheological properties of water‑based drilling mud

The successful drilling operation depends upon the achievement of target drilling attributes within the environmental and economic constraints but this is not possible only on the basis of laboratory testing due to the limitation of time and resources. The chemistry of the mud decides its rheological potential and selection of the techniques required for recycling operations. Conductivity, pH, and photometer testing were performed for the physio-chemical characterization of the grass to be used as an environmental friendly drilling mud additive. In this study, different particle sizes (75, 150, and 300 µm) of grass powder were mixed in mud density of 8.5, 8.6, and 8.7 ppg in the measurement of gel strength and viscosity of drilling mud. The grass additive was added in different weight conditions considering no additive, 0.25, 0.5, and 1 g to assess the contribution of grass on the gel strength and viscosity of the drilling mud. The machine learning techniques (Multivariate Linear Regression Analysis, Artificial Neural Network, Support Vector Machine Regression, k-Nearest Neighbor, Decision Stump, Random Forest, and Random Tree approaches) were applied to the generated rheological data. The results of the study show that grass can be used for the improvement of the gel strength and viscosity of the drilling mud. The highest improvement of the viscosity was seen when grass powder of 150 µm was added in the 8.7 ppg drilling mud in 0.25, 0.5, and 1 g weights. The gel strength of the drilling mud was improved when the grass additive was added to the drilling mud 8.7 ppg. Random forest and Artificial Neural Network had the same results of 0.72 regression coefficient (R2) for the estimation of viscosity of the drilling mud. The random tree was found as the most effective technique for the modeling of gel strength at 10 min (GS_10min) of the drilling mud. The predictions of Artificial Neural Network had 0.92 R2 against the measured gel strength at 10 s (GS_10sec) of the drilling mud. On average, Artificial Neural Network predicted the rheological properties of the mud with the highest accuracy as compared to other machine learning approaches. The work may serve as a key source to estimate the net effect of grass additives for the improvement of the gel strength and viscosity of the drilling mud without the performance of any large number of laboratory tests.publishedVersio

Fluid Loss and Filtration Properties of a Citrus Sinensis Pectin Extract-based Drilling Mud

The production of drilling mud using pectin extracted from Citrus Sinensis peels was carried out. The extraction was carried out using water-hot acid technique which is a conventional method, and the extracted pectin was pre-gelatinized using calcium water. The pre-gelatinized pectin biopolymer was used to prepare drilling mud. Filter loss method was used to determine the filtration properties of the mud at 25°C and 200°C and 0.1g/mol concentration of pectin polymer was compared to the filtration behavior of hydroxyl propyl starch modified drilling mud. Our results showed that the pectin biopolymer mud (PPM) has better filtration control behavior than the hydroxyl propyl starch modified drilling mud (CMM). The study also showed that highest sorptivity value of 21.25 was obtained with PPM at 200°C, while the highest diffusivity value of 0.424 was obtained with CMM at 200°C. Keywords: Pectin, Citrus, Biopolymer, Sorptivity, Diffusivity, Drilling mud, Filtration DOI: 10.7176/CMR/12-3-03 Publication date:March 31st 202

Toxicity of oil-based drilling mud (OBM) on the survival of the fingerlings of Niger Delta mudskipper, Periophthalmus papilio (Boch and Schneider, 1801)

The toxicity of oil - based drilling mud on the survival of the fingerlings of Niger Delta mudskipper, Periophthalmus papilio were studied using static plastic tanks. The exposure period lasted for 96 hours. Lethal concentration (LC50) and lethal time (LT50) were determined. The control tanks contained no oil- based drilling mud. Results revealed increased in mortality values of the fish to all lethal concentrations. There was no mortality observed in the control tank. The oil- based drilling mud were toxic on Periopthalmus papilio

Potential of Jesse clay as drilling mud

The high bottom hole pressure normally encountered during drilling, poses serious challenges during drilling operations of oil and gas wells. The unavoidable quest for crude oil source of energy by man, required for running its home and industries, makes the high risk pose by the underground hole pressure a risk-worth taking for new discovery of oil and gas reserve. The fear of encountered formation pressure is conquered by the use of drilling fluid (drilling mud). The drilling mud is a mixture of clay, water and chemicals. The drilling clay possesses certain properties that distinguished, and earmarked it as a drilling fluid, highest economy clay that is highly sorted/hunted for, either as purely for export for economic purpose by countries where it is found but have no oil or for oil and gas exploration activities in countries where hydrocarbon exploration takes pace. Nigeria as a country is a practical scenario of the above case the drill-mud–clay is being imported for the exploration of its large oil and gas reserve. Therefore, this paper seeks address the lingering unresolved challenges of the inability to establish Nigeria’s local drilling mud-clay with properties comparable with the existing imported drilling mud-clay through laboratory analysis of Nigeria clay. In searching for suitable Nigerian clay for to be used as drilling mud, two properties (mud density and sand content) of local clay extracted from Jesse, in Ethiope-West local government area of Delta State was analyzed and the results were recorded and compared with those of imported foreign clay. For their densities, the result was recorded as 8.41kg/m3, 8.50kg/m3, 8.50kg/m3 and 8.67 kg/m3 for local clay, and 8.60 kg/m3, 8.66 kg/m3, 8.67 kg/m3 and 8.83 kg/m3 for foreign /imported Bentonite. The percentage of sand content in both the local and imported foreign drilling mud after analysis, were recorded as 0.1%, 0.1%, 0.2%, 0.2% and1%, 1.5 %, 1.5 % and 2% respectively. The little differences noticed between the sand value of in the drilling mud prepared with local clay and imported clay, indicates that the local drilling mud can be at its best as drilling mud like the conventional drilling mud, which is in accordance with the API recommended value range of between 0.25% -1.2% if the experimented properties are further enhanced

Effect of Drilling Mud Contamination on the Properties of Waxy Crude Oil

The operation of well drilling requires the use of drilling fluid which, in this case is drilling mud. Drilling mud is very crucial in the drilling process. Without it, it is nearly impossible to drill wells with the rotary method. The use of drilling mud during drilling process in the exploration of newly found reservoir may affect the crude oil. Problem occurs when the drilling mud mixed with the crude oil at the reservoir being drilled at earlier stage. This occurrence leads to contamination of waxy crude oil with the drilling mud. Due to that, the properties of crude oil such as pour point temperature, wax appearance temperature (WAT) and wax disappearance temperature (WDT) and yield stress may change. These real properties are very crucial to for an engineer to design any facilities related in handling such hydrocarbons. The hydrocarbon sample is usually taken at the bottom of the well at the early stage of the production. The contamination of drilling mud into waxy crude oil may lead to inaccurate properties when the sample is examined. This may further lead to wrong data used in designing certain facilities, especially for upstream facilities. Therefore, it is important to study the effects of the presence of drilling mud on the property of the crude oil (which in this case is waxy crude oil) extracted. Several related test methods are used in order to study the behavior and characteristics of the contaminated crude oil. These test methods include bottle test, pour point test, rheology test and microscopic observation. Bottle test results showed that the mixture requires sometimes to stabilize and separate into its individual component. Nevertheless, complete separation was never achieved during the observation period and created intermediate layer (densed mixture between waxy crude oil and the drilling mud). The work found that the presence of drilling mud did not significantly affected that pour point and freezing point of waxy crude oil, however, it change the WAT and yield stress considerably. Based on the work, it is suggested that that the fresh sample taken from the newly found reservoir was subjected to a bottle test for three days to settle down the drilling mud and get waxy crude oil layer. After that, waxy crude oil from the upper layer can be collected and tested to reveal the real properties